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GA16DE
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606 Posts
Discussion Starter #1
I found this:
http://home.att.net/~jason510/turbo.htm
I am only considering a draw through config
My plan is to use my current stock e16 (9:1 cr), a stock e16 intake manifold with a ga16 carb (blow through - all vents sealed I know) with this mentioned bov and fixed ignition advance, maybe around 20 crankshaft degrees btdc, and this ct9 turbo
I want 6 - 7 pounds of boost for this entry/learning project
I'll build a 8:1 e16 for more boost if things go as planned
I would like to hear your comments
Thanks in advance
 

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Banned
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velardejose said:
I found this:
http://home.att.net/~jason510/turbo.htm
I am only considering a draw through config
My plan is to use my current stock e16 (9:1 cr), a stock e16 intake manifold with a ga16 carb (blow through - all vents sealed I know) with this mentioned bov and fixed ignition advance, maybe around 20 crankshaft degrees btdc, and this ct9 turbo
I want 6 - 7 pounds of boost for this entry/learning project
I'll build a 8:1 e16 for more boost if things go as planned
I would like to hear your comments
Thanks in advance
The problems I know of with draw-through include excessive wear on the turbo compressor blades, which are constantly being bombarded at incredible speeds with what basically amounts to solid particles (atomized fuel). I saw what happened to a turbo compressor blade in a setup which used water injection pre-turbo (basically the same thing, though water is a bit heavier), there was almost nothing left of the compressor blade after 6 months time. I think your best bet is blow-through, at least for turbo longevity.
 

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Icy Hot Stunta
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2,366 Posts
The problems I know of with draw-through include excessive wear on the turbo compressor blades, which are constantly being bombarded at incredible speeds with what basically amounts to solid particles (atomized fuel). I saw what happened to a turbo compressor blade in a setup which used water injection pre-turbo (basically the same thing, though water is a bit heavier), there was almost nothing left of the compressor blade after 6 months time. I think your best bet is blow-through, at least for turbo longevity.
Don't even attempt to turbo a carburated engine.
 

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Viva el iPod
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1,232 Posts
morepower2 said:
Don't even attempt to turbo a carburated engine.
Why even say that? Its not impossable, in fact its not even that complicated. Granted, for most people Turbocharging an EFI-equipped engine is easier, but lots of carb'd cars are turboed, some from factory (like the Corvair).
 

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GA16DE
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606 Posts
Discussion Starter #5
Thanks for the data ;)
Look at the Renault 5 Alpine, it was a draw through config
I found a place where I can have a copper 2.5 mm thick headgasket made
As much as I know the stock headgasket has 1 mm height (after torque is applied)
I need 1.5 mm more height to drop the cr from 9:1 to 8:1
That would allow more boost
 

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Icy Hot Stunta
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2,366 Posts
bII said:
Why even say that? Its not impossable, in fact its not even that complicated. Granted, for most people Turbocharging an EFI-equipped engine is easier, but lots of carb'd cars are turboed, some from factory (like the Corvair).
Sure its posible but the results will absolutly suck, go ahead and do it, don't say I didnt warn you. The driveabilty will suck, maintaining the proper a/f ratio will suck. The engine will drive poorly and be unreliable. It won't make much power. Port fuel injection is what made turbocharing practical.
 

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Icy Hot Stunta
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2,366 Posts
velardejose said:
Thanks for the data ;)
Look at the Renault 5 Alpine, it was a draw through config
I found a place where I can have a copper 2.5 mm thick headgasket made
As much as I know the stock headgasket has 1 mm height (after torque is applied)
I need 1.5 mm more height to drop the cr from 9:1 to 8:1
That would allow more boost
That is the wrong way to drop CR. You loose all the quench in the cylinder and increse the propensity to detonate at a given compression ratio. Get proper piston made.

Your project is looking for trouble. You would be better off and spend less money going NA.
 

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GA16DE
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606 Posts
Discussion Starter #8
You are right...
I'll think things twice before jumping in...
Maybe a fuel injected ga16 could do it
Thanks for answering
 

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morepower2 said:
Sure its posible but the results will absolutly suck, go ahead and do it, don't say I didnt warn you. The driveabilty will suck, maintaining the proper a/f ratio will suck. The engine will drive poorly and be unreliable. It won't make much power. Port fuel injection is what made turbocharing practical.
I´m sure that mpfi is better, but not sure that its easier, you guys have to understand we have different realities, and there are places where carburated is better. A carb is easier to fix and lot cheaper.
My setup is starting to work out very well and its a e16s turbo with carb.
I had a chevy 350 efi, and after it stopped working here there wasnt anybody who could fix it, so it went carbed and it never stopped working.
Sorry, but a carb is better sometimes!!!
 

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GA16DE
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606 Posts
Discussion Starter #11
Its still related to force air into an engine, be it carbed or not
(please apologize me for my english)
 

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Viva el iPod
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morepower2 said:
...The driveabilty will suck, maintaining the proper a/f ratio will suck. The engine will drive poorly and be unreliable. It won't make much power. Port fuel injection is what made turbocharing practical.
Its driveability is no worse than any carb'd car, which with a properly tuned carb is fine. The engine will not run poorly or be any more unreliable than any other well-tuned vehicle. As far as power, there's plenty of Corvairs, Volkswagens, Toyotas, Datsuns, etc. that would very much disagree.

Carburation is simply another way of delivering fuel, granted its much easier to swap out bigger injectors and send your computer out to get reprogrammed when turbocharging, but there's no rational reason to firmly assert (as many many do, not just you morepower) that carb + turbo are incompatable, impossable, or "unreliable."
 

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morepower2 said:
That is the wrong way to drop CR. You loose all the quench in the cylinder and increse the propensity to detonate at a given compression ratio. Get proper piston made.

Your project is looking for trouble. You would be better off and spend less money going NA.
Not to mention, the thicker the headgasket, the easier it is to blow. Some exceptions can be made for metal HGs, though. The only correct way to lower CR is to replace pistons.
 

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bII said:
Its driveability is no worse than any carb'd car, which with a properly tuned carb is fine. The engine will not run poorly or be any more unreliable than any other well-tuned vehicle. As far as power, there's plenty of Corvairs, Volkswagens, Toyotas, Datsuns, etc. that would very much disagree.

Carburation is simply another way of delivering fuel, granted its much easier to swap out bigger injectors and send your computer out to get reprogrammed when turbocharging, but there's no rational reason to firmly assert (as many many do, not just you morepower) that carb + turbo are incompatable, impossable, or "unreliable."
Even if reliability and driveability be left out, it's still a poor choice for a performance application..........
 

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Icy Hot Stunta
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velardejose said:
You are right...
I'll think things twice before jumping in...
Maybe a fuel injected ga16 could do it
Thanks for answering
You are way better off doing that.
 

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Icy Hot Stunta
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2,366 Posts
dburone said:
I´m sure that mpfi is better, but not sure that its easier, you guys have to understand we have different realities, and there are places where carburated is better. A carb is easier to fix and lot cheaper.
My setup is starting to work out very well and its a e16s turbo with carb.
I had a chevy 350 efi, and after it stopped working here there wasnt anybody who could fix it, so it went carbed and it never stopped working.
Sorry, but a carb is better sometimes!!!
A carb is never better under any circimstances. Your turbo carbed E16s is not fast or reliable. EFI can always be fixed as long as competent people are around to fix it.

This sounds harsh and I don't mean it to be that way but thats how it is.
 

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Icy Hot Stunta
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bII said:
Its driveability is no worse than any carb'd car, which with a properly tuned carb is fine. The engine will not run poorly or be any more unreliable than any other well-tuned vehicle. As far as power, there's plenty of Corvairs, Volkswagens, Toyotas, Datsuns, etc. that would very much disagree.

Carburation is simply another way of delivering fuel, granted its much easier to swap out bigger injectors and send your computer out to get reprogrammed when turbocharging, but there's no rational reason to firmly assert (as many many do, not just you morepower) that carb + turbo are incompatable, impossable, or "unreliable."
Bullshit. A draw through system needs a huge disproportionate accelerator pump shot to avoid bogging. Once you get the pump shot high enough and thats a big if, it runs all eraticaly for quite a while due to huge wetting issues. You can't intercool a draw though system and you have compressor blade damage issues. Distribution problems are severe as well.

I don't think you have ever turbocharged a car otherwise you would know not to argue. Ever drive a datasun with a crown turbo kit or try to get it to run right? Ever work on a Rockstock ford drawthrough turbo kit? Or a BAE for that matter? What company made a carburated toyota turbo kit? maybe BAE? I am old enough to have worked on these.These things would never run with any sort of reliabilty or boost levels as todays turbo systems. None of these could even run with a well built NA motor and a modern turbo system could bite these up chew them up and spit them out.

Carburators must be so extensivly modifed to run draw through that their air bleeds and emulsion tubes as well as main jets must be totaly altered to work even halfway right. On carbs besides webers, del ortos and mikunis, this means soldering up holes, redrilling them and a whole lot of grief even if you know what you are doing. This is not stuff for a beginner on his first turbosystem and no one in their right mind would even do it today.

Tell you what, bring out a draw through crabed, or even blow through turbo anything that you built, lets go to to the track, turn the boost up to 20 psi or heck lets be fair, even 10 psi and see whos car is still running after 20 minutes of running.
 

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Here is a page on blow-through and draw-through applications. Nice little article, it even touches on some points that Mike did not.

HERE
 

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chimmike said:
close to the combustion chamber won't work as well as equal length simply because, as you know, not all of your cylinders fire at the same time.

the equal length takes those individual pulses and smooths them out into useable flow and thermal expansion for spinning the turbine.

just because it's close to the combustion chamber doesn't necessarily mean it'll spool faster because the flow will be turbulent from the ports.

another, better design, is the pulse converter design, which essentially makes the length of each runner according to the firing order of the cylinder so as to make the flow to the turbine equal, as if all the cylinders were firing at the same time, perpetually.
Someone actually tried this on a SR20. The stock manifold VS shortest possible VS equal length, and the equal length not only spooled faster, it made more FLAT torque and FLAT HP all across theRPM range. There is a reason that the really high HP NA cars have equal length tubular manifolds, to increase the scavengine effect. On a turbo car this is not as important, but still useful. If you want a higher EGT, wrap your exhaust. Wraping it actually works BETTER than a ceramic coating, but it corrodes the manifold faster, as it will hold moisture. Equal length SS manifold=Teh hotness.
 
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