Turbocharger Math - Metric Fun / Turbo Calculations

**Versanick** · 05-04-2003, 09:27 PM

So I'm trying to figure out my setup for when I run my turbocharger on my accord. I'm having an 88 a20a3 to start with, and sending it to RPM to be fixed up with the turbo setup.

However, I can't find my real engine specs anywhere. I need the specs on the flow, intake and exhaust valve diameters, pressure ratio, the fuel pressure, eff, pressure ratio, surge flow...

and I haven't figured an intercooler or turbo yet. I have a dozen options shopping around (totally custom, not doing anything that might "close to fit"... we'll see) I'm supposing you all reccomend I'm using an intercooler (40%?) too. I want to top over 300hp to the wheels, and I want to do it before Carlisle next summer. I'm going to pull in madd $ this summer, and the accord's gonna be hot. I only saw ONE 3g accord at carlisle this weekend, and it makes me sick. If anyone has REAL information on the engine, let me know. I'm putting it through some tests through a program to figure out gains, what kind of boost I need to run, and all that crap. The more information the better. I've been looking all over for weeks, and I know ALL TOO WELL the hp@what rpm, torque, how many valves, and what kind of carb (or pgm-fi) every engine has. and I know the bore/stroke and compression ratios... I'm goign to run 7.8 or 8.0:1 pistons btw....

I just need SPECS... I figured the technical area would be the best place to look. thanks fellas.

**ACCORD EX** · 05-05-2003, 05:43 AM

here is what i found ( specs from teh service manual ! ) hope this helps ! other guys will help you more !

MIKE

**Versanick** · 05-06-2003, 09:16 PM

Thanks a ton, Mike... those numbers are a huge help. It's appreciated! I'm still looking around (not too successfully) trying to find what kind of turbos you people who have turbod your cars have been using... I found a guy on ebay who makes his own intercoolers from aluminum custom shape/size, 60-70%ers, and sells em for $250-275, pressure tested and all... I was looking to buy one from him that I can fit into my car, ... but I've lookd at 10 different turbos and have no idea what I should invest in. The place I'm going to take it (RPM it's called, might take it to Doug's Speed Shop, we'll se) I'm going to say okay I want 300hp at the wheels, here's the parts (turbo and intercooler anyway), do whatever needs to be done to this engine to make it hold up (rods, bearings, internals, bored out, etc) so I can get the whole package... and run probably 30psi....... we'll see. I'm taking out a $5000 loan for this (lol). So we'll see how it goes. I'm still looking for a new honda to do this. My 86 is a rust bucket and I'm trying to get a 1988 with low/no rust (I want to go to Carlisle next year... this year inspired me to sell my American piece of garbage and get a Honda again.) I am sure I can find an engine to send them, but I might want to just send the car and even let them custom mount/cut up for the intercooler and everything. Well I'll stop babbling.. there's people in this section with REAL problems.... thanks for the help once again! and I love this place!

Long live the 3g! (literally, mine has 230,000, my friend's has 280,000 running like a top)

peace.

**shepherd79** · 05-07-2003, 03:47 AM

you may want to buy new ECU kit from sean. it will help alot with tunning.

**turfnnsurf** · 05-07-2003, 08:10 AM

Hey Versanick,

Do you plan on this accord being a daily driver??? reason i ask you this is because i have yet to see any A20A motor run more than 160 hp to the wheels. I think Justin's turbo can do it, and his is street legal, but other than two other accords that are for the drag strip only. I have not seen or read about anyone having a streetable turbo A20A block..

Maybe im just playing Devil's advocate, but even with the time and money OpenLoop has put into the 88LXi they have, they are only making 140+ hp to the wheels... Maybe you should aim for 200hp to the wheels before trying for something so lofty as 300 whp... Just my humble opinion

**Mike's89AccordLX** · 05-07-2003, 08:25 AM

Well 200hp is easy to get to. I'm going to be getting 200hp with nitrous. I'm sure if he gets a nice turbo and intercooler and nitrous he will be close to 300hp. I have been reading turbo threads and I'm considering getting a nice turbo setup.

**Versanick** · 05-07-2003, 08:42 AM

I would be only considering 200hp if I was doing this all myself. I'm looking at such an ECU kit, 900cc venom injectors, a high-rpm fuel rail, forged rods/pistons, lowered compression, bearings, seals, rings, considering MPNI... how sweet would that be? I have, however seen motors with much weaker natural aspiration (before turbo) hit way over 300hp to the wheels using only turbos and the upgrades needed to go with it. This speed shop will do everything I need, and everything the car needs to handle the boost. If I didn't have the $, I wouldn't be considering this, but thanks for your input... if I only get 200 to the wheels... oh well. So I wasted $5000. I'm also planning on a boost controller (1-30psi controller) so that when I'm driving it all of the time, I can run real low boost, and when it's time to hit the drag strip (or race a 5.0), I can rip it up, and the engine will be built to handle it....

this is function over form btw... this car will NOT look pretty (lol) (probably if it's wrapped around a tree, that's a given.... <fear>)

thanks again...
more input the better...
it's appreciated fellas. you're great.

***88turboaccord*** · 05-07-2003, 02:34 PM

$5,000 will not get you all that man. for just building my block alone was $2500. A good turbocharger is going to run around $400-800, good intercooler--$350-$450. $5K just does not cut it unless you want just a simple kit. Before I really knew much and went with a simple kit, that was $4200 and that was with just 8psi. Once you go into the motor--look out, you are in to spend a lot of money. So be realistic, look for around 200-225 HP @8-10 psi and nothing more. That will play more realisticly into your budget.

**turfnnsurf** · 05-07-2003, 05:04 PM

So i guess my first reply was more realistic.... Sometimes it feels good to see that all the time i have spent researching the possibilities of boosting our A20 blocks has been worth it.

**bobafett** · 05-07-2003, 05:40 PM

w00tw00t.

never listen to people who think that 15+ psi and 300whp are "no big deal"

***88turboaccord*** · 05-07-2003, 06:07 PM

Try the 18-20 that I was running, The new set-up should be running 20-25 which is the max efficientcy of the turbocharger.

**superaccord** · 05-26-2003, 06:48 AM

turbo, what are you running(turbo wise) to be able to run high boost like that?

**AccordEpicenter** · 05-27-2003, 01:17 PM

what did you do to build up the block justin?

**Swap_File** · 07-24-2005, 10:01 PM

I have been going through the turbo charger maps found here:

http://not2fast.wryday.com/turbo/maps/

and using this:

http://www.turbofast.com.au/turbomap.html

to calculate what turbos would work the best with an A20A3 (in theory at least).

The problem I have ran into, is that half of the turbo chargers maps are in metric. To use the numbers from the turbo calculator I will need to convert pounds per minute of air (lbs/m) to meters cubed per second (m^3/s). How to do most of this calculation is shown here:

http://www.newton.dep.anl.gov/askasc...9/gen99510.htm

I have done the math several times, and I can't seem to make the numbers come out.

I get numbers that could be right, but are just to the extreme right on all the metric maps.

Anyone here know the trick to converting lbs/m to m^3/s? Or even just have a basic table or trick to use?

Thanks

**keruhas184** · 07-25-2005, 04:57 AM

Looking at this discussion: http://www.fridgetech.com/discussion...html?998477326

"To convert pounds of air per minute to standard cubic feet per minute, multiply by 13.3"

"According to ASHRAE Fundamentals Handbook, the density of standard air is 0.075 lbm dry air/ft3, which corresponds to 60°F air at saturation, or 69°F dry air at 14.7 psia. The reciprocal of this value is 13.33 ft3/lbm, which is where the conversion factor is derived."

So, we start out with lbs/m, multiply by 13.33 and get ft^3/m. Now we go here http://onlineconversion.com/flow_rate_volume.htm to finish the conversion to m^3/s

"13.33 cubic foot/minute = 0.0062911 cubic meter/second"

So, one lbs/m is equal to 0.0062911 m^3/s in ideal conditions. You would divide the m^3/s value by 0.0062911 to get the lbs/m units.

I'm not sure that if when dealing with turbos (and increasing pressures and temperatures) if the math has to be more complicated to get more precise values at different boost pressures...

**b8er** · 08-11-2005, 01:43 PM

holy crap, iv been around drag racing since i was 4 and have been racing since i was 8 and iv never been so lost with anything related to cars, ahaha

im sure if i slowed down and read it i could figure it but wow, im gonna leave this to you guys

***AZmike*** · 08-11-2005, 02:58 PM

You have a mass rate and a volume rate. The density of the air, which will relate a given amount of volume to a given amount of mass, will vary by temperature, altitude, etc. I can get you a conversion factor if you give me an altitude and a temperature or I can show you what equations to use if you want to work through a range of values yourself.