1988 A20A3 Rebuild/Preformance

[hammer3rd]

I am looking for ideas on building/rebuilding my engine and have a few ideas but I cant seem to find a real indepth performance build thread to compare to. I am looking for a good performance engine but I also want no problems for daily street driving.

Here is a little of what I am thinking of doing.

83 mm b series pistons in a 10 1/2 CPR.
Colt stage 1 triflow cam/Bisimoto stage 2 cam??? Dont quite know which one yet. Any personel experience would help.
Mild P&P head with 1 mm bigger valves,bisimoto springs and bronze guides.
B16/18 intake and throttle body.
OBD1 conversion.
Some kind of header(choices are slim)and exhaust.
And a good quality bottom end rebuild.

Any threads,help or personal experience would(mabey even a HP guess) would be very helpfull.

[88lxi-shortram]

youll need a cam gear to go with that cam and i dont think they produce gears for us... but maybe you can get something like a golden eagle cam gear and make it fit

[hammer3rd]

Cam gear? Do you mean adjustable. And which cam. The colt or bisimoto cam.

[rjudgey]

Just lookup some threads created by myself or replied by myself her and at www.preludepower.com

If you gonna change valves don't waste time just going 1mm bigger 2mm bigger all round is better and there are valves available from supertech which you can convert which have a narrower stem and use Civic valve train this is more extreme mod but worthwhile look up threads from Smeado on this, or you can get SI valves to make them for you like i did the stems will be thicker but will be more reliable and you can use all your stock retainers and springs etc reducing cost.

Spend the money on the head this is where the performance gains are to be, wouldn't waste money on B series pistons, just get A20A3/4 oversize pistons at 83mm these are pretty tough items and not too heavy, if you wanted to save weight on rotational mass then get some titanium wrist pins made up but this would be costly! looking around for some patent part wrist pins is cheaper and they tend to be lighter than honda I've never had one fail! I've used Sealed power ones i think. As for the rods the stock ones are lighter just have them stress relieved/polished and shot peened the stock rod bolts are also very good items and can be re-used just torque them up a bit tighter than stock and maybe use a lock thread glue on them as they tend to vibrate off after 20k miles or so of hard use! Just make sure everything gets balanced correctly including the rods, pistons and pins, crank is normally spot on from factory unless you have it reground or modified leave well alone if in good condition, the flywheel and clutch plate will need balancing as well. To increase the CPR just skim .25-.5mm off the block and then take off 1mm on the head you can go further if you want to but will reduce service life of the head and block, you will need to alter the cam timing this can be done with stock cam by modifying the key position or by getting a cam gear i believe some golden eagle ones are around on ebay or Bisi has some. Cam choice go with something around 270-280 degrees anymore and you will need to spend big on custom exhaust header and the system will have to be around 2.5" mandrel bent same as the collector size on the header or it will restrict powerband and power. With a milder cam like a 260-270 you can use a OBX or Pacesetter with a 2.25" mandrel bent system without too much of a bottle neck. Biggest issue will be induction bike carbs or webers are cheapest route but will need someone with good tuning knowledge to set them up, or you can go throttle bodies and find a computer ECU tuner who has good experience with custom setups. Typical power from A20 from mild to wild would be around 150bhp upto 230bhp possibly more but no one apart from me has even attempted to get above 200bhp Natrually aspirated. I had a ET1 that put down 200bhp and i have a A20 and A18 hybrid in the making which will have a higher CR ratio around 11.5:1 with 33mm inlet valves and 37.5mm exhaust valves, thinking about titanium wrist pins possibly as well. This will be running a custom exhaust header and system as the camshaft is 285 degrees all round.

[hammer3rd]

Thanks for the time to wright so much. Will be put to good use. I hear what you are saying but will all this be cool on a daily driven motor. I will have all the old man stuff. You know air,power steering and cruise controll. I also dont want a real choppy idle. I would love to have 200 pluse hp at the ground but 140 or so at the ground would make me very happy. I am also going 5 speed swap with a stage 2 clutch and light weight flywheel. You didnt comment on the b16/18 intake. By my calculations it would be more than enough air flow to make the kind of hp I am after. But I have never built a 4cylinder before. And please if you can think of anything I didnt cover send it to me.

[cygnus x-1]

Thanks for the time to wright so much. Will be put to good use. I hear what you are saying but will all this be cool on a daily driven motor. I will have all the old man stuff. You know air,power steering and cruise controll. I also dont want a real choppy idle. I would love to have 200 pluse hp at the ground but 140 or so at the ground would make me very happy. I am also going 5 speed swap with a stage 2 clutch and light weight flywheel. You didnt comment on the b16/18 intake. By my calculations it would be more than enough air flow to make the kind of hp I am after. But I have never built a 4cylinder before. And please if you can think of anything I didnt cover send it to me.


The B18 manifold is a decent upgrade. If you're going to do this use either a B18B or a B16 manifold. The B18B doesn't have so many extra ports on it like the B18A does. The B16 is good too but the runners are a little short, which is better for mid-range and higher RPM power.

Don't bother with the stage 1 Colt, it's kinda lame. I have one. It's an upgrade from stock but not much. A Bisi or Webcams stage 1 would be better. Any of the stage 2s will affect the idle a little and are tuned more for mid range, so low RPM torque may suffer a little.

Other than that, listen to THE man Rjudgey.


C|

[2drSE-i]

Hey rjudgey, what do you think about playing with rod lengths? We can score some eagle h beams in 140.5mm, raising the rod/stroke ratio a tad, which should lower the reliance on the head a bit. Seeing as how our heads don't flow very well, I would think the longer the rod the better, no?


Clearance becomes an issue at a certain point. What is the a20s piston to valve clearance like?

[snoopyloopy]

Thanks for the time to wright so much. Will be put to good use. I hear what you are saying but will all this be cool on a daily driven motor. I will have all the old man stuff. You know air,power steering and cruise controll. I also dont want a real choppy idle. I would love to have 200 pluse hp at the ground but 140 or so at the ground would make me very happy. I am also going 5 speed swap with a stage 2 clutch and light weight flywheel. You didnt comment on the b16/18 intake. By my calculations it would be more than enough air flow to make the kind of hp I am after. But I have never built a 4cylinder before. And please if you can think of anything I didnt cover send it to me.

he did comment on the intake. itb or individual carbs.

[hammer3rd]

The B18 manifold is a decent upgrade. If you're going to do this use either a B18B or a B16 manifold. The B18B doesn't have so many extra ports on it like the B18A does. The B16 is good too but the runners are a little short, which is better for mid-range and higher RPM power.

Don't bother with the stage 1 Colt, it's kinda lame. I have one. It's an upgrade from stock but not much. A Bisi or Webcams stage 1 would be better. Any of the stage 2s will affect the idle a little and are tuned more for mid range, so low RPM torque may suffer a little.

Other than that, listen to THE man Rjudgey.


C|

Thanks cygnus and I will listen to rjudgey on the A20. But my goal is not an all out performance build. I want a balance between driveability and performance. So if the colt cam didnt make you happy mabey it would be all I would need to make the power I am looking for. I also want to keep the legendary honda reliability. So you are telling me that the colt wouldnt make 140 whp but the other cams loose bottom end torque. So if you guys will tell me about your cams and what they feel like and how they idle. This is why I started this thread. So I could leaern from all you who have built a good A20. I dont want to have to build it twice. Like I said I have never built a 4 cylinder so torque is very important if you dont want rev 10,000 rpms. Thanks again for all you guys help I am takeing notes so I can build this motor and completely rebuild and paint my poor little 89 sedan lol.

[88lxi-shortram]

idk if youve already looked into your cams but bisimoto gives you a great description of how each of their cams affect idle, performance and what mods are compatible or neccesary.

http://www.bisimoto.com/sport-compact/engine/camshafts/a-series-camshafts/a-series-camshafts

[2drSE-i]

The A20 is a torque monster comparatively speaking, so losing some bottom end torque isn't going to be a huge deal, considering the top end power you may gain.

[hammer3rd]

The A20 is a torque monster comparatively speaking, so losing some bottom end torque isn't going to be a huge deal, considering the top end power you may gain.

Thanks for the info. I really dont care if it revs any higher than stock. But with all the factory ac.cruise and power steering still on the car I think bottom end torque would be great.

[hammer3rd]

idk if youve already looked into your cams but bisimoto gives you a great description of how each of their cams affect idle, performance and what mods are compatible or neccesary.

http://www.bisimoto.com/sport-compact/engine/camshafts/a-series-camshafts/a-series-camshafts

Yeah I read all the info but I have also installed cams based if the card and it not be quite what it says in a V8. So I thought I would ask. I like what is says but if no one likes it or has tried it I will go a different route.

[hammer3rd]

A little love guys?????

[rjudgey]

I wouldn't go any higher than 270 degrees then web cams stage 2 would probably be best for you. Has more lift but keeps duration sensible, you would need to change your guides to bronze ones from SI as any uprated camshaft will put more wear on your guides and as they are cast iron tend to wear out quickly. Having port work done and nice valve seats cut with valves heads matched to them makes big differences. Exhaust header stick with a classic 4-2-1 design pacesetter will do unless you got some dollars for someone to make one from scratch. 2" or 2.25" exhaust will be plenty big enough. B18 manifold should be fine just finding a way of controlling the fuel is next issue megasquirt is effective and cheap but you have to be a bit of a electronics wiz and knowing how to tune EFI helps! If not then I'd maybe stick with something simpler like fitting the bike carbs although they will need tuning still. A weber 38/38 is worth considering or even having custom manifold made and running a large single weber dcoe 48 or 50.
I would start with the simple things first, 1 make sure block is healthy so compression test, if not then rebuild it with new pistons, rings and bearings etc. The rebuild the head and have it worked on, header, exhaust, mild cam some larger injectors, adjustable pressure gauge, and see how you get on. should be easy enough to get 140-150bhp from that setup i think a member on preludepower is running a low comp A20 with bolt ons and he's getting really good numbers on dyno.

[hammer3rd]

Thanks a bunch for your time. I will put it all to use. As for the fuel how about the b18 intake and throttle body and a obd1 conversion. Do you think this would be enough???

[MessyHonda]

in my opinion the a20 is not a good NA engine. only if you turbo it will it make some serious power. i bought this car and i been putting it back to the specs if not better now. http://www.3geez.com/forum/showthread.php?t=57136 right now im happy...3 clutches later and 2 transmission later...it makes too much power in first gear and i get alot of torque steer because it has no lsd and the the axles are not the same lengths

[2drSE-i]

B16 lsd fits...

[hammer3rd]

Thanks messy. Sounds like wha I would like to build. But I won't give in. So i will build a very mild daily driver. Around 140 whp will be a big improvement over stock. After all these posts I belive I am going to go with my original set up with the colt cam and follow rjudgeys idea on the head. If it doesn't get me 140 whp it will be very close. And messy if you are haveing thoes problems with torque steer and breaking stuff try going back to a factory transmission. The gears are higher and transfer less torque to the ground through your clutch and axel shafts.

[MessyHonda]

B16 lsd fits...

i know but for him it might be worth it to pick up a GSR engine and drop it in with a type R trans that comes with LSD. now that we have mounts.


Thanks messy. Sounds like wha I would like to build. But I won't give in. So i will build a very mild daily driver. Around 140 whp will be a big improvement over stock. After all these posts I belive I am going to go with my original set up with the colt cam and follow rjudgeys idea on the head. If it doesn't get me 140 whp it will be very close. And messy if you are haveing thoes problems with torque steer and breaking stuff try going back to a factory transmission. The gears are higher and transfer less torque to the ground through your clutch and axel shafts.

i have the integra gears in my trans...witch are short...i like driving it but i just have to practice my launching because the engine revs so fast

[rjudgey]

I haven't any issues breaking transmissions or axles and the torque steer isn't too bad although a LSD would be a great improvement. The only thing i tended to wear out was the syncros but no I've been using Honda MTF that seems to be a thing of the past! Only issue was clutches i used to break them all the time till i found Clutchnet and then praised them so much that everyone else here now uses them!! I've been modding these engines for like 15 years now so there's very little i don't know about, and i know everything they like and everything they don't like!

B18 manifold is fine but to be honest I've allways found these engines respond much better to ITB's or Race carbs, but for the cost it's worth putting one on but definately get the biggest throttle body you can find on it! As for OBD1 i wouldn't bother more hardwork than it is worth, just go down the megasquirt route and DIY the ECU yourself and the additional wiring and crank trigger fitment onto the crank pulley, cygnus-x1 can sort that part out for you and some other bits for a small fee for his time. The engine can definately make the power, and are in fact a superb N/A engine offering incredible torque and some seriously high RPM's!! My engines have no issue revving to 8k rpm on the right cams!!

[2drSE-i]

rjudgey, have you ever experimented with rod lengths in these engines? From what I understand, the longer the rod, the lower the dependence on the head to flow well. Just curious what you think.

[hammer3rd]

I haven't any issues breaking transmissions or axles and the torque steer isn't too bad although a LSD would be a great improvement. The only thing i tended to wear out was the syncros but no I've been using Honda MTF that seems to be a thing of the past! Only issue was clutches i used to break them all the time till i found Clutchnet and then praised them so much that everyone else here now uses them!! I've been modding these engines for like 15 years now so there's very little i don't know about, and i know everything they like and everything they don't like!

B18 manifold is fine but to be honest I've allways found these engines respond much better to ITB's or Race carbs, but for the cost it's worth putting one on but definately get the biggest throttle body you can find on it! As for OBD1 i wouldn't bother more hardwork than it is worth, just go down the megasquirt route and DIY the ECU yourself and the additional wiring and crank trigger fitment onto the crank pulley, cygnus-x1 can sort that part out for you and some other bits for a small fee for his time. The engine can definately make the power, and are in fact a superb N/A engine offering incredible torque and some seriously high RPM's!! My engines have no issue revving to 8k rpm on the right cams!!

Thanks. Just looking at the B18/16 intake for cost and dependability. I have had full house built cars in the past and were fun but they needed regular tuning. And why is it easier to megasquirt than obd1.

[Sickest3G]

Im trying to follow this conversation and im understanding everything but this ITB thing....what is an ITB? And to make sure of it...the b16 LSD will fit into the 3g tranny?

[hammer3rd]

Im trying to follow this conversation and im understanding everything but this ITB thing....what is an ITB? And to make sure of it...the b16 LSD will fit into the 3g tranny?

Individual Throttle Bodies. ITB. Thanks for your info on the lsd.

[88lxi-shortram]

can we use b16 ITBs?... it may be the same as the manifold right?

[stat1K]

^ this would be correct, however, most itbs kits are either too expensive or just plain junk in the lower end. you'd be better off getting a manifold and cutting it up to adapt a set of itbs to.

definitely would be cheaper.

although, recently on carolinahondas.com i saw a set from a modified b16 manifold for 250-300.

[Sickest3G]

I don't know if the B16 LSD will fit. I was asking if it really did fit into the A20 tranny cause 2drse-i mantioned it did.

[2drSE-i]

I don't know if the B16 LSD will fit. I was asking if it really did fit into the A20 tranny cause 2drse-i mantioned it did.

According to Quaife, who are very well known lsd manufacturers, the B16 LSD fits with the A20 speedometer gear.

[hammer3rd]

I don't know if the B16 LSD will fit. I was asking if it really did fit into the A20 tranny cause 2drse-i mantioned it did.

Sorry. All clear now.

[hammer3rd]

According to Quaife, who are very well known lsd manufacturers, the B16 LSD fits with the A20 speedometer gear.

Cool. Now thanks for the info on the lsd. LOL.

[hammer3rd]

Let me ask this. Has anyone had good/bad luck with the b16/18 intake mod. And if so do you have any hp numbers to go with it.

[88lxi-shortram]

idk if anyone has numbers but i know plenty of people have had luck. i myself plan on doing it once my cars up and running.

[hammer3rd]

idk if anyone has numbers but i know plenty of people have had luck. i myself plan on doing it once my cars up and running.

Thats what I thought from what I had read. I am not wanting to make a ton of power just a little tweek. As I said if I can get 140 to the wheels I will be very happy.

[stat1K]

hammer, you dyno'd it yet to see where you're at now? i know 120 was the stock flywheel measurement i'm curious how much it's at now, because if you're like most of the stock cars i've seen, 95-100 is about what you will be running, so a 40% increase might be a little much to hope for without major work. i know you mentioned that you are willing to do major work but i dunno if you wanna do this much.

[mushroom_toy]

hammer, you dyno'd it yet to see where you're at now? i know 120 was the stock flywheel measurement i'm curious how much it's at now, because if you're like most of the stock cars i've seen, 95-100 is about what you will be running, so a 40% increase might be a little much to hope for without major work. i know you mentioned that you are willing to do major work but i dunno if you wanna do this much.

I think 140 whp is attainable. With a fresh engine with some timing and fuel mods im pretty sure you could see up to 120whp. My 440k mile motor with bad compression and shot rings on 2 cyls. was putting down around 92hp and 95 ft lbs. to the wheels. That was with just an intake and running rich.

I think it really all depends on how fresh the motors gonna be. Im hoping to get about the same whp out of my motor, but mainly looking for more torque. Im doing a little bit more than just manifolds, etc. No headwork though minus springs and cam, and hoping to rev to about 7200.

[stat1K]

i believe that the motor is fully capable, however, i haven't seen a car dyno over 120 without some decent modding. it makes me wonder if it's worth it since you can in fact buy b-series mounts now, throw in a b20b throw a vtec head on it and hit the 200 mark without a crazy bill.

i will say, lx-incredibles car, lx-i coupe with the integra tranny mod - obd1- cold air-header-2.5" catback and high flow muffler, is probably the quickest 3g i've driven and it didn't feel terribly fast, he has said on numerous occasions that my crx felt faster and it was rocking a 1.5l with only i/h/e.

in summary, 140 is attainable, but is it worth it on the A? i guess if you're keen on keeping wiring stock, not welding, and not mixing and matching axles it is.

[2ndGenGuy]

87roach put down 129whp on a stock ECU, cam, I/H/E and 1mm oversize exhaust valves and otherwise stock internals. That's a bit over 150bhp. I imagine with ITBs, you would open that intake up a bit more, and with a tunable ECU you might be able to squeeze out another 10hp.

[mushroom_toy]

87roach put down 129whp on a stock ECU, cam, I/H/E and 1mm oversize exhaust valves and otherwise stock internals. That's a bit over 150bhp. I imagine with ITBs, you would open that intake up a bit more, and with a tunable ECU you might be able to squeeze out another 10hp.

Ill be dynoing my motor as soon as I drop it in and break it in...so Ill give you a head up guys. Ill be dynoing first without the itbs, injectors, and my settings adjusted all the way. Then once im on the money tuning wise Ill be swapping everything out, tuning and going back to the dyno. SO 1st dyno will be stock motor bored .20 over stock head with bisimoto springs and delta 272, running an obx manifold, and probably 2.25 into a straight pipe. Probably tuned a little rich with carbed 5spd and spec stage 2+ clutch.

[hammer3rd]

Thanks guys for all the help and input. I dont want a very lopy cam/idle
for my car. I wont mind a little but dont want a lot.


Here is a little of what I am thinking of doing.

83 mm pistons in a 10 1/2 CPR Or what ever it takes to get 10 1/2 CPR
Colt stage 1 triflow cam/Bisimoto stage 2 cam??? Dont quite know which one yet. Any personel experience would help.
Mild P&P head with 1 mm bigger valves,bisimoto springs and bronze guides.
B16/18 intake and throttle body.
OBD1 conversion.
Some kind of header(choices are slim)and exhaust.
And a good quality bottom end rebuild.

So tell me what you guys think. Looking foward to hearing what you think.

And tell me about the delta 272 cam. Does it have a very bad idle?

[stat1K]

i haven't heard anyone complain about the 272, it's pretty mild, most people say they notice a gain but i'd doubt if you actually felt one right off. maybe combined with the others. the biggest thing is to have someone tune the whole setup, the problem is literally NO ONE knows what the a20 wants, most of those dudes are used to tuning 16v sohc or 16v dohc honda motors, 12v sohc is kinda different. i'd imagine if you got the most competent tuner out there that might help some guys were supposed to do lx-incredibles but they kinda had a falling out with their tuner and he doesn't work with them anymore, otherwise i would have more info on that.

the basemap from the pr4 seems decent on his mostly stock motor but it richens out a little at bottom end and leans out some at top. so some tweaking or a street tune would do wonders.

i think your build sounds pretty good. i'd go with a skunk2 b-series manifold and port it to a slightly larger TB. I've read tons on TB sizes and it doesn't seem like the biggest is always the best, now that's from an sohc standpoint (d-series) a lot of guys lost more hp with a large tb and gained more hp with an appropriate size (58-60mm). granted that's a significantly different power band as there is absolutely no low end torque in a d-motor and they don't start power until at least 3.5k.

camming a 4cyl isn't a lot like camming with a huge duration cam in a big block, you hardly ever will get cam lope until you're up in the stage 3 zone from what i've seen/heard/dealt with.

[87roach]

Thanks John, I was also running the colt stage 1 cam, and the head has been ported too.

On the tuning note, it would really nice to know more.. I'd like to delve into it but it's a bit scary. Although it would be sweet to get some more jam by just switching up a few numbers..

[stat1K]

roach, get yourself a wideband, a data logger, and a chip burner and you'll be good to go.

i myself would like to go this route so i could start making my own maps and testing shit out, theres even a guy selling a wideband w/ datalogging output in one right now on craigslist for 100. i just don't have the money. if i could get a hold of the stuff i'd just send it to lx-incredible to let him tinker because i know he's more than capable.

[mushroom_toy]

^Or wideband and piggyback, thats what im running at the moment. Works perfectly fine.

[hammer3rd]

i haven't heard anyone complain about the 272, it's pretty mild, most people say they notice a gain but i'd doubt if you actually felt one right off. maybe combined with the others. the biggest thing is to have someone tune the whole setup, the problem is literally NO ONE knows what the a20 wants, most of those dudes are used to tuning 16v sohc or 16v dohc honda motors, 12v sohc is kinda different. i'd imagine if you got the most competent tuner out there that might help some guys were supposed to do lx-incredibles but they kinda had a falling out with their tuner and he doesn't work with them anymore, otherwise i would have more info on that.

the basemap from the pr4 seems decent on his mostly stock motor but it richens out a little at bottom end and leans out some at top. so some tweaking or a street tune would do wonders.

i think your build sounds pretty good. i'd go with a skunk2 b-series manifold and port it to a slightly larger TB. I've read tons on TB sizes and it doesn't seem like the biggest is always the best, now that's from an sohc standpoint (d-series) a lot of guys lost more hp with a large tb and gained more hp with an appropriate size (58-60mm). granted that's a significantly different power band as there is absolutely no low end torque in a d-motor and they don't start power until at least 3.5k.

camming a 4cyl isn't a lot like camming with a huge duration cam in a big block, you hardly ever will get cam lope until you're up in the stage 3 zone from what i've seen/heard/dealt with.

I am afraid of big intakes. Dont want to loose any more bottom than I have to is why I am looking at the stock B16/18 intake and throttle body. And as far as tuning goes anyone with the propper setup can tune any engine. It requires the propper censors tuning equipment and a dyno and I forgot a lot of dang money LOL.
Oh and look at this old thread and see what you think of the products Thanks again for all the input, It really helps when you have never built a motor of this kind. http://www.3geez.com/forum/showthread.php?t=72262

[87roach]

roach, get yourself a wideband, a data logger, and a chip burner and you'll be good to go.

i myself would like to go this route so i could start making my own maps and testing shit out, theres even a guy selling a wideband w/ datalogging output in one right now on craigslist for 100. i just don't have the money. if i could get a hold of the stuff i'd just send it to lx-incredible to let him tinker because i know he's more than capable.

I've got all that man, and more. I just haven't had the time to install it yet. I'll be getting all that installed over the winter!

[hammer3rd]

roach. Did you say you had a colt cam. If so how does it perform.

[cygnus x-1]

can we use b16 ITBs?... it may be the same as the manifold right?


^ this would be correct, however, most itbs kits are either too expensive or just plain junk in the lower end. you'd be better off getting a manifold and cutting it up to adapt a set of itbs to.


The biggest issues with ITBs are sticking throttle plates, bore size, and tuning. The cheaper ones tend to have problems with the throttle plates sticking at idle. Not a big deal for racing but for street driving it sucks. The bore size needs to not be so big that they dump in tons of air as soon as they're cracked open. For an A20, no bigger than 45mm. Tuning is also essential for them to work properly. A standalone ECU (or OBD1 conversion) is required because the fueling needs to be controlled by throttle position instead of manifold pressure at mid to high throttle.
Hopefully I'll be able to get mine running right next spring. I just didn't have the time to put into them last fall.



i haven't heard anyone complain about the 272, it's pretty mild, most people say they notice a gain but i'd doubt if you actually felt one right off. maybe combined with the others.


For reference, the Colt stage 1 is 260/270 on the intakes and 274 on the exhaust. These are ok but the lift is not much over stock. The Bisi/Web cams use a higher lift, which I think should be better with the A20 (my own theory based on the short rod/stroke ratio creating high piston speed and a strong intake suction).



the biggest thing is to have someone tune the whole setup, the problem is literally NO ONE knows what the a20 wants, most of those dudes are used to tuning 16v sohc or 16v dohc honda motors, 12v sohc is kinda different.

The process of tuning would be the same but as far as knowing what parameters make best power, you're right. From my own tuning I can tell a couple things though. For one these engines LOVE cold air. Anything you can do to get colder air in the engine means more power. They also need lots of timing. The wider combustion chamber makes for a longer burn time, so it needs to start sooner. 35 degrees is good at WOT above 3500RPM. At light throttle having the advance come in strong at 2000RPM makes the throttle response much more snappy.

These engines don't do well with lean mixtures either. 16:1 is about the leanest you can go without getting significant misfiring. 15.5 is good for light throttle cruise. 13.0:1 is a good target for WOT and also for idle. Although mine seems to like low 12s at idle for some reason.

The best I was able to do with my old intake setup was 120WHP, calculated from datalogs from the Megasquirt. That was with a fresh stock A20 bottom end, stock head with minimal head work, Colt stage 1 cam, B18A intake manifold, and S&S header. I never did make up a proper cold air intake though so it might have squeaked out a little more.



the basemap from the pr4 seems decent on his mostly stock motor but it richens out a little at bottom end and leans out some at top. so some tweaking or a street tune would do wonders.

For timing I started with a stock P75 map and added more advance at WOT and right off idle. That worked pretty well.



i think your build sounds pretty good. i'd go with a skunk2 b-series manifold and port it to a slightly larger TB. I've read tons on TB sizes and it doesn't seem like the biggest is always the best, now that's from an sohc standpoint (d-series) a lot of guys lost more hp with a large tb and gained more hp with an appropriate size (58-60mm).

As long as the TB isn't a restriction there's no reason to go bigger.




On the tuning note, it would really nice to know more.. I'd like to delve into it but it's a bit scary. Although it would be sweet to get some more jam by just switching up a few numbers..


Do it man! As long as you have a backup of a good working tune you can always revert to it if you mess something up.

I'll tell you though, tuning timing on the street is difficult if you're trying for best power. It's best to do it on a brake dyno so you can get a simulated constant load.


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[87roach]

Some great info there Chris!

The thing for me is, I seem to have all the right gear to tune my machine but no experience in what these engines want. So really I am just going on what everyone has been posting.

My point being is that yes dyno is the best, but when I don't know how to tune that seems like a money pit! I'd be better off playing around on the street to get a feel of things before getting on the dyno, then again I might just take it to someone.. I'll have to see how it is once I get that far.

As for the colt cam I think it's pretty good, Chris had a good post before where he said pretty much what I think of it. Once you get to 3k it feels good haha :)

I'm not sure I'll be using the colt for turbo though, maybe one of the bisi cams?

[hammer3rd]

The biggest issues with ITBs are sticking throttle plates, bore size, and tuning. The cheaper ones tend to have problems with the throttle plates sticking at idle. Not a big deal for racing but for street driving it sucks. The bore size needs to not be so big that they dump in tons of air as soon as they're cracked open. For an A20, no bigger than 45mm. Tuning is also essential for them to work properly. A standalone ECU (or OBD1 conversion) is required because the fueling needs to be controlled by throttle position instead of manifold pressure at mid to high throttle.
Hopefully I'll be able to get mine running right next spring. I just didn't have the time to put into them last fall.


Man thanks a bunch for all this info. I dont care what cam I use as long as it idles well. A little bumb is ok but not much. And I want a higher CPR to boost low end power around 10.5. And am going to have a wad in the head. A P&P and larger valves with bronze guides. Everything else will be pretty much what you guys say works best.


For reference, the Colt stage 1 is 260/270 on the intakes and 274 on the exhaust. These are ok but the lift is not much over stock. The Bisi/Web cams use a higher lift, which I think should be better with the A20 (my own theory based on the short rod/stroke ratio creating high piston speed and a strong intake suction).




The process of tuning would be the same but as far as knowing what parameters make best power, you're right. From my own tuning I can tell a couple things though. For one these engines LOVE cold air. Anything you can do to get colder air in the engine means more power. They also need lots of timing. The wider combustion chamber makes for a longer burn time, so it needs to start sooner. 35 degrees is good at WOT above 3500RPM. At light throttle having the advance come in strong at 2000RPM makes the throttle response much more snappy.

These engines don't do well with lean mixtures either. 16:1 is about the leanest you can go without getting significant misfiring. 15.5 is good for light throttle cruise. 13.0:1 is a good target for WOT and also for idle. Although mine seems to like low 12s at idle for some reason.

The best I was able to do with my old intake setup was 120WHP, calculated from datalogs from the Megasquirt. That was with a fresh stock A20 bottom end, stock head with minimal head work, Colt stage 1 cam, B18A intake manifold, and S&S header. I never did make up a proper cold air intake though so it might have squeaked out a little more.




For timing I started with a stock P75 map and added more advance at WOT and right off idle. That worked pretty well.




As long as the TB isn't a restriction there's no reason to go bigger.





Do it man! As long as you have a backup of a good working tune you can always revert to it if you mess something up.

I'll tell you though, tuning timing on the street is difficult if you're trying for best power. It's best to do it on a brake dyno so you can get a simulated constant load.


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Man thanks a bunch for all this info. I dont care what cam I use as long as it idles well. A little bumb is ok but not much. And I want a higher CPR to boost low end power around 10.5. And am going to have a wad in the head. A P&P and larger valves with bronze guides. Everything else will be pretty much what you guys say works best. And which obd1 box is best I have heard po6 but idk.

[87roach]

I believe the OBD1 PR4 seems to run the best without any tuning, however it's made for a different engine so some tuning on it would get you better results.

[hammer3rd]

I believe the OBD1 PR4 seems to run the best without any tuning, however it's made for a different engine so some tuning on it would get you better results.

Thanks. Got a long parts list and a bunch on notes.

[cygnus x-1]

Some great info there Chris!
My point being is that yes dyno is the best, but when I don't know how to tune that seems like a money pit! I'd be better off playing around on the street to get a feel of things before getting on the dyno, then again I might just take it to someone.. I'll have to see how it is once I get that far.

That's exactly why I've never been on a dyno, it costs too much. And I've been able to do well enough on the street so far. But with the ITBs, street tuning is proving to be quite a challenge. I think whenever I get the big valve head put on that will be the end of the major engine upgrades for awhile, so then I'll probably hit the dyno and get a good solid tune down.

The shop I go to will let you do your own tuning on their dyno if you know how to run your own tuning software. In my case it's the only option since I doubt they know anything about Megasquirts. With an OBD1 conversion you can likely get more knowledgeable help.

But yeah, get that thing out on the street and have a go yourself.



As for the colt cam I think it's pretty good, Chris had a good post before where he said pretty much what I think of it. Once you get to 3k it feels good haha :)

I remember once when I still had the Weber 38, I was able to get the idle down to under 500RPM, and it was still smooth! I could almost read the writing on my adjustable cam pulley it was turning so slow. That carb had unbelievable mixture quality. I miss it sometimes. Anyway that was with the stage 1 Colt, so I'm sure even with a stage 2 you should be able to get a nearly stock idle.



Man thanks a bunch for all this info. I dont care what cam I use as long as it idles well. A little bumb is ok but not much. And I want a higher CPR to boost low end power around 10.5. And am going to have a wad in the head. A P&P and larger valves with bronze guides. Everything else will be pretty much what you guys say works best. And which obd1 box is best I have heard po6 but idk.

Which B series pistons were you going to use? You'll need to check for piston to valve clearance since the valve reliefs won't be in the right places. Not a big deal, just something to watch for. You could also use stock pistons and mill the head 1-1.5mm. That would get you to low 10s for CR.


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[MessyHonda]

I believe the OBD1 PR4 seems to run the best without any tuning, however it's made for a different engine so some tuning on it would get you better results.

yea...even with my performance engine the stock pr4 runs good...i need money and time to go tune..i first got to fix my oil leak from the front main seal.

[87roach]

The shop I go to will let you do your own tuning on their dyno if you know how to run your own tuning software. In my case it's the only option since I doubt they know anything about Megasquirts. With an OBD1 conversion you can likely get more knowledgeable help.

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The only dyno we have in the near area to me also offers this, I better get to know what I am doing before I go in haha.

I also asked if someone could tune my car for me. They told me that they have a guy who will come in and you can pay him to work on it for the day, I think he told me around $600. Which I then said ok, so what software does he use so I can make sure he can just dive in? Well I was told that he doesn't disclose that for business or some shit? So that doesn't really help me. I may have to find another shop at some point.

[cygnus x-1]

The only dyno we have in the near area to me also offers this, I better get to know what I am doing before I go in haha.


Even if you pay someone else to tune it you're always better off knowing as much as you can. That way you're more likely to smell BS.



I also asked if someone could tune my car for me. They told me that they have a guy who will come in and you can pay him to work on it for the day, I think he told me around $600.

That doesn't sound too bad for an entire day. For an 8 hour day that would be $75/hr. Does that include the dyno as well or is that just for "the guy"?

The place by me I think is $75/hr in the summer or $60/hr in the winter. That includes the dyno and an operator. The operator won't necessarily be able to run your software though. I think they do more domestics than imports. I seem to remember the owner telling me that they were Ford factory certified to do some kind of upgrade to the new Mustangs, a turbo/supercharger of some kind.



Which I then said ok, so what software does he use so I can make sure he can just dive in? Well I was told that he doesn't disclose that for business or some shit? So that doesn't really help me. I may have to find another shop at some point.

Proprietary information? :bs: That sounds like he just didn't know and was feeding you a line. If you have any kind of skills that you intend to make a living from you WANT people to know what they are. It's just like a resume.

You know, there's an interesting thread over on Preludepower in the tuning section about this guy in Argentina that decided he wanted to become a tuner, because there weren't any tuner's in the area. He describes how he got started and actually presents quite a lot of information. It's worth checking out.

http://www.preludepower.com/forums/showthread.php?t=330807


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[2drSE-i]

You know, there's an interesting thread over on Preludepower in the tuning section about this guy in Argentina that decided he wanted to become a tuner, because there weren't any tuner's in the area. He describes how he got started and actually presents quite a lot of information. It's worth checking out.

http://www.preludepower.com/forums/showthread.php?t=330807


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its an awesome read either way

[87roach]

I actually just stopped in there for the first and only time a while ago and asked a few quick questions, so I don't know all the details. Thank you for pointing out what I need to find out!

Thanks for the link man, I will have to do some reading in the morning.

[hammer3rd]

Thanks cyngus for all the info. I dont know what b pistons I was going to use. Was going to use them because they were cheep. Not trying to sound like I am building cheep, just no need to pay if you dont have to.

So whitch cam do you guys think is the best. And do does anyone have a compant that is better than another for the bottom rebuild. And any tips and tricks that make HP and is reliable. Thanks again guys for all your help.

[rjudgey]

Not sure why you would want to waste money on rods and pistons, whats the mileage on current engine and is it rebuildable and hasn't suffered bent or worn out crank etc.
I've used stock rods upto 8k rpm and never had any fail, only time I've had them go was when the rod bolts came undone, if you get them stress relieved and shot peened, use stock honda bolts but just do them up a little tighter and use thread lock it's no longer an issue. And the stock pistons are a strong design, if anything just get Diamond to make you some forged ones to fit the stock rods, the lighter piston will make it easier on the rod, and if you really wanted titanium wrist pins. If your not turbo charging for huge boost then this setup works best as the stock rods are a lot lighter than anything aftermarket and nearly as strong! Trouble with the B series pistons is that the valve pockets aren't in line with our valves so you may have piston to valve clearance issues with aftermarket aggressive cams, stock or mild one would be ok though.

Whats the rpm limit your setting yourself and bhp goals with or without a turbo? My engines run 200bhp and spin upto 8k rpm depending on cam choice. And I've had quite a few builds like this, most the issues i get are from over heated pistons as i used cheap patent ones that trapped the rings and then caused a fracture which creeps across the crown and then eventually holes it causes loss in compression big style! Just one other tip i use Federal mogul wrist pins which are a few grams lighter than the Honda ones which are thicker I've not had any issues with them being thinner. The whole setup which i run picks up revs extremely quickly especially with my new 10lb machined stock flywheel (use a Prelude 1.8 ET lighter)

[cygnus x-1]

Thanks cyngus for all the info. I dont know what b pistons I was going to use. Was going to use them because they were cheep. Not trying to sound like I am building cheep, just no need to pay if you dont have to.

So whitch cam do you guys think is the best. And do does anyone have a compant that is better than another for the bottom rebuild. And any tips and tricks that make HP and is reliable. Thanks again guys for all your help.


Really the first thing to do is to get the block measured to see what size pistons you need. OEM pistons are the ones to use of the block doesn't need to be bored out to more than 83mm. If it's worn beyond that then you're only options are the not so great aftermarket A20 replacement pistons, way oversized B series pistons, or custom forged pistons. Custom forged pistons will cost somewhere in the $500-$600 range as I recall. Any of the custom piston companies can make them, Diamond, JE, Arias, Venolia, etc. Rich covered the rest pretty well, although you can use ARP rod bolts instead of the Honda ones if you're paranoid. I used them on mine. I can look up the part number if you want.

For cams, depends on how much extra go you want. Colt stage 1 is very conservative and ok with stock fuel injection. Bisi/Web stage 1 would also be ok for a mostly stock setup but a bit more aggressive. Any of the stage 2 cams would be good for a more serious build, with the Colt being more conservative again. Beyond stage 2 cams you need higher compression, headwork, intake/exhaust, aftermarket ECU or carb setup, and forged pistons.

Other tips... mostly just attention to detail. You can get rings one size larger than you need and hand gap them. A high volume oil pump gives you a little more insurance for good oil pressure. Balancing the pistons, rods, crank, and flywheel will make the engine smoother and more reliable. If you have small scale you can balance the rods and pistons yourself. Make sure you have the factory windage tray. There is also a company out there that make a crank scraper for the A20. You can add baffles to the oil pan to prevent oil starvation if you like to drive fast around corners. Lightening the flywheel is a good way to make the engine rev a little more freely. It does not reduce low end torque like some people say, but it does make it a little more touchy when taking off from a dead stop because you don't have as much stored energy in the flywheel to give the car that initial bump to get it moving. I had my stock flywheel lightened (not that much really) and it's not that hard to drive. The aftermarket aluminum flywheels will affect this more.


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[WorkHardPlayHarder]

Sorry if some questions sound dumb I am new to the Honda community. I have the mechanical background just not up on all the parts for them. On the A20A3 what year intake mani/throttle body would i need to be looking for from the b16/b20's?