Draw-Thru ( Turbocharging your carbed accord )

[2oodoor]

I have wanted to say that cliche for a long time to certain members, thanks
Your idea is not too far off base I guess, Ive seen turbos way back further than that before.

[turabaka]

As much as I'm interested in this idea. I'd really rather try to find a supercharger that could work with our engines. I just don't like the idea of fuel going so close to the hot ass exhaust. Maybe it's just me, but heat + flammable stuff = fucking eek.

[89T]

funny how we hate what we dont understand!

has anyone ever played with the idea of using the stock exhaust manifold, or possibly an aftermarket header, and cutting it right before the firewall for turbo placement? the intake tube could draw air from the vacated black box area, and your charge pipe would only have to be like 2'-0" in length, if going sans intercooler. just a thought, especially since finding a turbo header is almost impossible.

i have done that before on a past turbo project with good result.the turbo seemed to spool very quickly almost at idle and the turbo was high enough to drain oil back to the pan. the car was throttle body injected though.

i remember reading somewhere that there are a few shops in Cali that specialize in draw-thru set ups on sand rails. i am thinking there using Holley 4 barrels on 4 Cly. applications.

[colinnicholson86]

funny how we hate what we dont understand!

has anyone ever played with the idea of using the stock exhaust manifold, or possibly an aftermarket header, and cutting it right before the firewall for turbo placement? the intake tube could draw air from the vacated black box area, and your charge pipe would only have to be like 2'-0" in length, if going sans intercooler. just a thought, especially since finding a turbo header is almost impossible.

Yep I saw it quite a few years back on a 3rd gen accord. (I'm sure it was on here) Turbo mounted at the back of the engine bay and it was carbed too

[Accordtheory]

funny how we hate what we dont understand!

Well, I for one, understand. I also understand how easy it is to convert to obd-1, and how the improvement from doing so is exponentially better than a carbed setup.

Usually when you deliberately set out to half ass something, it costs more because you have to completely redo it in the future. Almost everything automotive you buy and sell, you only make a small percentage of what you paid back. You also have the original time invested, which is just wasted. The only good that comes from it is knowledge, but why not just read more instead..

A slightly cheaper initial investment, but offset by less accurate fueling and ignition, drastically less reliability , driveability, and fuel economy, no intercooling (resulting in very limited boost, and therefore power) and still requiring some type of ignition control box, ($) and still requiring a wideband for tuning. Why not just convert to obd-1, run a freeware rom editor, and have actual potential, for not even spend much more money. It's 2008, for fuck's sake, why use technology that hasn't been used in most regular production vehicles for about 30 years. Or you could build a carbed setup and blow your motor while getting your ass handed to you by a completely stock pontiac g6 driven by some hot girl laughing at you like you just left the special ed class for building cars.

[ghettogeddy]

Well, I for one, understand. I also understand how easy it is to convert to obd-1, and how the improvement from doing so is exponentially better than a carbed setup.

Usually when you deliberately set out to half ass something, it costs more because you have to completely redo it in the future. Almost everything automotive you buy and sell, you only make a small percentage of what you paid back. You also have the original time invested, which is just wasted. The only good that comes from it is knowledge, but why not just read more instead..

A slightly cheaper initial investment, but offset by less accurate fueling and ignition, drastically less reliability , driveability, and fuel economy, no intercooling (resulting in very limited boost, and therefore power) and still requiring some type of ignition control box, ($) and still requiring a wideband for tuning. Why not just convert to obd-1, run a freeware rom editor, and have actual potential, for not even spend much more money. It's 2008, for fuck's sake, why use technology that hasn't been used in most regular production vehicles for about 30 years. Or you could build a carbed setup and blow your motor while getting your ass handed to you by a completely stock pontiac g6 driven by some hot girl laughing at you like you just left the special ed class for building cars.

well played my good man well played

[2oodoor]

Could have done without your input/comments AccordTheory. We all know what you said probably holds water ok, that is not even the point here. This is not a FI vs carb *thread my friend. I appreiciate your knowledge (no doubt you are a smart mofo ok bro) and vague intellectual transfer of knowledge via talking down to anybody that may be opposite the debate table from you, I say vague because half the time you mix it up with so many emotional triggers it often becomes offensive to read.
Some of us are pretty resourceful and can achieve these projects without paying top dollar. We can barter and trade and hell just give uneven trades sometimes in the name of commeradery to keep each other's dream cars going. So the name of the game is fun, originality, and making friends who are also into cars. If we want to love blown carbed cars, is that so wong (jon lovitz)

Edit: *ok fair enough I did mention something about carb haters, maybe I bent a obd 1 nerve..... But my statement stands ^^

[Accordtheory]

Could have done without your input/comments AccordTheory.

half the time you mix it up with so many emotional triggers it often becomes offensive to read.

So you liked my comment about getting smoked by the hot girl in the g6?

No one has really gotten into the drawbacks of the carbed setup. I'm just bringing the big picture back into focus. Also, why the thread is emphasizing draw through, a clearly inferior setup compared to blow through? Draw through has inferior fuel distribution/atomization/keeping the fuel in suspension/whatever, the lack of intercooling possibilty, and the requirement that the compressor side of the turbo can tolerate vacuum. People on this forum seem to love ITBs, for what reason I still don't know, but this is one case where I agree. 4 individual boost referenced carbs would work a hell of a lot better than one big one before the turbo.

So let's say you can tune that to run at 14.7 for most of the part throttle, get it to idle, start, rev and run right, and then enrich to about 11.8:1 for most of the boost, (how well can you really do that? To how many pounds of boost/how much hp?) Then what about the ignition part of the equation. What type of ignition box gives you a 3d map of rpm and manifold press? How else would you do it? An msd boost timing retard? Not very good. I think msd makes a programmable box, but I also think it's more expensive than a chipped obd-1 computer + the obd-1 distributor.
So you have the cost of the carbs (how much is that realistically? And you know they don't just bolt up to the a20 head..more fab work involved there..) + the ignition setup, + the wideband, + all the turbosystem components, and the tuning.
I just really don't think there is going to be much of a difference in cost between the 2 setups, and one of them provides a much better result. You do have to build a subharness for the obd-1 wiring, but there's fab work for carbs too. For instance, how would you even connect them to the intake piping?
What kills the idea for me is mostly the ignition thing. Whatever you use to (accurately)control that can also control the fuel for probably the same cost. I also doubt you'd be able to make the carbs run right across the motor's wide variety of operating conditions while accomodating more than about 10lbs of boost, but I don't really know.

[Accordtheory]

Another thing, just an example of carbed vs injected, look back at the buick grand nationals of the 80s..they started out carbed, but then the injected setup came out, and it was a world apart in terms of performance and function.

[AccordEpicenter]

carbs are the suck when it comes to turbo setups, the tunability and driveability leave alot to be desired when it comes to suck through and blow through setups. Ive seen some really fast blow through turboed race cars which is fine (only thing you care about is WOT tuning) nobody gives a damn in those cars about driveability. If you want a cheap turbo header, (like, flat rate styles) you can make an up pipe going from the stock exhaust manifold pretty much making a u turn and then up to the front of the engine or trans into a turbo flange. Not the greatest setup but it will work, probably better than a log manifold, but will work fine for budget setups if you can make it fit. Big thing is having clearance in the engine compartment so you dont start fires

[2ndGenGuy]

Blah blah blah... fucking seriously.

[2oodoor]

Another thing, just an example of carbed vs injected, look back at the buick grand nationals of the 80s..they started out carbed, but then the injected setup came out, and it was a world apart in terms of performance and function.

good example, I was going to use that myself. Those first t types were the shizzle weren't they I guess that is why they continued development on the Grand National since it was such a success out from the get go ( in carbed form, you said it)
I for one would appreciate any positive feedback, experiences, and information of builds on any forced induction carbed powerplant. It may not be the latest and greatest but it is the topic of this thread.

[Accordtheory]

Well, you're not really going to get that, because it doesn't really exist. Standards are higher nowadays, and that's a good thing. Look how nicely even the previously mentioned mass marketed non particularly performance oriented new g6 v6 drives. My point was the carbed GN/t types were a joke compared to the SEFI distributorless MAF car of 86/87. The 86/87 GN was one of the few times GM actually let their engineers build something they wanted to build. They showcased the latest technology at the time, and it made the carbed version obsolete. And that was 21 years ago. Another example, obviously not as good, but Nissan's Z cars first came out with carbs, then they went to efi with their turbo versions in the late 70s. Even back then with their extremely primitive efi, they knew it was better than carbs. Anyway, that's not even my main point. My main point was about cost vs function, and that you still need expensive electronics for ignition control, so why not use that money and get fuel control also.

But seriously, whatever, like 2ndgenguy said, who cares. Like anyone on here is actually going to build a carbed turbo setup anyway.
That's like using your head to break a brick wall instead of a hammer. This whole thread should just be deleted. Sorry if anyone finds that offensive, but seriously.

[2ndGenGuy]

That wasn't what I was trying to say at all. Mostly that this was an informational thread and not yet another carb'd vs EFI thread. Some people aren't always looking for what's the best most high tech, and what's far superior... or are worried about what everybody thinks of them if they don't come in first place.

For people like us, this is fun to read about. Good, insightful information about alternatives is always welcome, but the "holier-than-thou" attitude toward not running the latest and most high tech "far-superior" stuff is irritating... It's just the same annoying crap you see on so many other forums that makes them just god awful to read.

[turabaka]

^^ I'm with ya 2ndgenguy. Although, I'm wondering something. If FI really is the best thing ever, then why do so many of the guys on onecamonly talk about using carbed setups? I mean they may not be the best for boost, but you can make some pretty good power with a carb.

[Accordtheory]

the "holier-than-thou" attitude toward not running the latest and most high tech "far-superior" stuff is irritating... It's just the same annoying crap you see on so many other forums that makes them just god awful to read.

I'm not advocating an i-vtec k20 swap with a garrett twinscroll ball bearing turbo, am I? I wish someone would have told me everything I did wrong or should have done differently when I was 21 and built my first turbosystem. Yet when I post shit that is true and will actually save people regrets, I'm referred to as "holier than thou"? Fuck that.

[colinnicholson86]

Well, you're not really going to get that, because it doesn't really exist. Standards are higher nowadays, and that's a good thing. Look how nicely even the previously mentioned mass marketed non particularly performance oriented new g6 v6 drives. My point was the carbed GN/t types were a joke compared to the SEFI distributorless MAF car of 86/87. The 86/87 GN was one of the few times GM actually let their engineers build something they wanted to build. They showcased the latest technology at the time, and it made the carbed version obsolete. And that was 21 years ago. Another example, obviously not as good, but Nissan's Z cars first came out with carbs, then they went to efi with their turbo versions in the late 70s. Even back then with their extremely primitive efi, they knew it was better than carbs. Anyway, that's not even my main point. My main point was about cost vs function, and that you still need expensive electronics for ignition control, so why not use that money and get fuel control also.

But seriously, whatever, like 2ndgenguy said, who cares. Like anyone on here is actually going to build a carbed turbo setup anyway.
That's like using your head to break a brick wall instead of a hammer. This whole thread should just be deleted. Sorry if anyone finds that offensive, but seriously.

Wow so arrogant.

If you don't like the thread then why post.
As you can see on the first page I DID build a carb turbo setup - Although it diddn't last as long as I'd hoped, It really was more a case of inexperience with tuning that caused its short life.
Plus there is also a few others that have done it as I stated earlier.

Mitsi built a carbed turbo car OEM as have a few others car manufactures - And they were reliable, and driveable.

Yea sure PGM-Fi is better because of blah, blah, blah. We all KNOW that. Sometimes it's nice to step outside the box every once in a while, and try something new.
Its like saying Why would you ever want to build that RWD Accord, that Vector is building? - Its not because you think its a dumb idea, but because HE WANTS to.

[oscwrestler]

why do these always turn into arguments? seriously accept the ideas or keep quiet.

[Hauntd ca3]

draw thru turbo set ups work fine
seen it heaps and no horror stories
blow thru would be the way if you want to intercool but otherwise draw thru is cool
just have to make sure the carb is far enuff away from the compressor so that the fuel doesnt errode the wheel away
dont laff, seen people do just that with water injection.
they had the nozzle to close and guess what
after a while they had bits of compressor wheel flyin thru there motor

[2oodoor]

bump

[oscwrestler]

what is better for reliability? draw or blow through?

[A20A1]

This thread is about draw-tru which is why there is more one sided approach. I seperated it from the other thread that talks about blow-tru... I think that was my intention when making this thread, but I did it a while back so I'm not sure.

[oscwrestler]

can you post the link for the blow through? i search and it was no dice

[Hauntd ca3]

what is better for reliability? draw or blow through?

dont really think there is much dif betwen the two
before aftermarket ecus came along, everyone just used an su or 45dcoe in a draw thru set up and had no worries with reliablity either way
a draw thru would be easier for an experianced tuner to set up as they can look down the carb while its runing and see how the fuel is atomising and the god ones can make decisions on what jets and what not to use

[89T]

dont forget that the turbo acts like a blender also.
the only real problem would be fuel pooling in the turbo at idle if you use too big of jets.