Im only alowing 2psi of boost right now, however even on that boost level I was able to keep up with a ls1 convertible vette with a really fat driver, he was PISSED OFF hahaha. That seems like low boost and it is, but the turbo im using is rather large, the pictures dont really do it justice. The car sounds rather stock until you floor it, then it sounds like a jet engine roaring down the street :) oh yea it runs very reliably and idles just like stock too

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question...are there any benefits to a rear mount? i know they make those kits for vettes, but i have never seen one in person. seems like a hell of alot of extra piping for the same result.

The turbo stays cooler and can be larger because its not in the engine compartment. I chose this route because it was the least amount of down time in the install for my car. Durring the install the most time the car was not able to run was 4 hrs. (I did the install in many parts) The underhood heat is also kept down. On the down side I did loose 2" of ground clearance but it hasnt been a problem yet, I can look past that for now.[/align]

nice :D has it been tuned or are you just running stock tuning?

Where is your turbo inlet at? Is it just the filter on the turbo, or do you have a sort of an intake tucked away into the bumper? Just a question since it's still not that great of weather permanately for the season

Is it possible to ummm...dent in the underside so you can have a nice channel for the boost tubing? I know it might sound barbaric, but it's just a question.

The engine has a piggy back apexi fuel computer. The charge piping does hang down some but not too bad. The filter is on the maf which is on the turbo inlet, and there is an air box around the whole thing.

if you have a safc i hope you are funning more that 2psi now. 5-7psi should be fine if you can tune it right. You may even want to up the fuel pressure to keep a/f around 11:1-11.5:1, which you should also be keeping an eye on.

All that & you have 2 psi?

I bet it takes some time to spool up & you must have massive lag. A turbo works off of thermal compression. Putting it way back there, the exhaust cools a LOT, causing the flow to slow down. That's why most turbo's are right off the manifold. yes, it will run cooler back there, but your getting far less efficiency from it.

Then you have all that piping, do you have a IC? I hope you never scrap anything on the underside of the car. Boost leaks are going to plague you.

You can gain more performance from one of the E-ram electric superchargers over your setup.

Sorry if you think I'm being a little mean, but if your not going to due it right, why even do it?

sorry but im going to have to refute some of these points

ORIGINAL: 2k S4

All that & you have 2 psi? Agreed

I bet it takes some time to spool up & you must have massive lag.

From the pic it looks like its before or replacing the cat

A turbo works off of thermal compression. Putting it way back there, the exhaust cools a LOT, causing the flow to slow down.

theturbo works on flow, thats why a larger displacement engine makes more exhaust flow spooling a turbo faster.

That's why most turbo's are right off the manifold. yes NO, they are there because of space and they spool faster., it will run cooler back there, but your getting far less efficiency from it. Not really,it gets a much more even flow like a equal lenght manifold. Which although slower in spool (pending how far back it is) you gain more high end hp.

Then you have all that piping, do you have a IC? I hope you never scrap anything on the underside of the car. Boost leaks are going to plague you. He is not even above 7psi. He would be fine until he passes that. Plus he would only need a smaller ic because he is using a larger turbo at very little boost causing very little heat.

You can gain more performance from one of the E-ram electric superchargers over your setup. I really hope that was a joke. A large turbo flows way more cfm then a plastic fan

Sorry if you think I'm being a little mean, but if your not going to due it right, why even do it?

ORIGINAL: cincyTT

A turbo works off of thermal compression. Putting it way back there, the exhaust cools a LOT, causing the flow to slow down.

theturbo works on flow, thats why a larger displacement engine makes more exhaust flow spooling a turbo faster.


[/quote]

Yes and no, the turbo works off of heat and back pressure. as the air enters the manifold the turbo traps the air creating back pressure. Meaning the pressure of the exhaust gas is higher than atmospheric pressure. A pressure and temperature drop occurs (expansion) across the turbine , which harnesses the exhaust gas’ energy to provide the power necessary to drive the compresso

so in turn by having that turbo way in the back you are loosing some of the ability of turbo to spool. Also since you have it feed by one chamber your exhaust gasses arnt working at full efficientcy because overlap is occuring. But despite all this i aplaud you for making it work. It is a good option if you do not want to run duel turbo's and im sure its mch cheaper.

ORIGINAL: Bondga

so in turn by having that turbo way in the back you are loosing some of the ability of turbo to spool. Also since you have it feed by one chamber your exhaust gasses arnt working at full efficientcy because overlap is occuring.


This is why a equal lenth manifold works so much better because when one chamber passes it creates a little vacuum for the next one creating greater flow.

*** AND TO THE OP, i hope you have your headers and exhaust to the turbo wrapped to contain the heat. Like said above heat is important, and by traping that heat in the exhaust preturbo will aide in your performance.

ORIGINAL: cincyTT

sorry but im going to have to refute some of these points

I bet it takes some time to spool up & you must have massive lag.

From the pic it looks like its before or replacing the cat

A turbo works off of thermal compression. Putting it way back there, the exhaust cools a LOT, causing the flow to slow down.
theÂ*turbo works on flow, thats why a larger displacement engine makes more exhaust flow spooling a turbo faster.

That's why most turbo's are right off the manifold. yesÂ* NO, they are there because of space and they spool faster., it will run cooler back there, but your getting far less efficiency from it. Not really,Â*it gets a much more even flow like a equal lenght manifold.Â* Which although slower in spool (pending how far back it is) you gain more high end hp.

Then you have all that piping, do you have a IC? I hope you never scrap anything on the underside of the car. Boost leaks are going to plague you.Â* He is not even above 7psi.Â* He would be fine until he passes that.Â* Plus he would only need a smaller ic because he is using a larger turbo at very little boost causing very little heat.Â*

You can gain more performance from one of the E-ram electric superchargers over your setup. I really hope that was a joke.Â* A large turbo flows way more cfm then a plastic fan


If you look at the pic, it loose like the back of the car, where the muffler was, the car doesn't look like a quattro, as I don't see any drive shafts.

Ok, yes, a turbo works off of exhaust flow. But the FLOW HAS TO BE MOVING FAST! As it cools, and moves away from the exhaust mani, it slows way down, and has less pressure on it. It's basic thermodynamics. This will spin the turbo slower, create much more lag, loose a lot of efficiency. Turbo's are mounted right off the exhaust mani to get max performance from it. Thats' where the gas is hottest, moves the fastest, and has the most pressure. Just about every turbo system out there is mounted off the exhaust mani. It's not for packaging, it's to get the least amount of lag, & to get the most efficiency. Also being way back there, it's also going to get the pulse waves from the exhaust, so it will get inconsistent pressure. Put your hand at the end of your exhaust, it's going to get pulsed, not a steady flow. The whole point of a equal length header, is to amplify the exhaust pulse wave, to create a low pressure area, that in turn pulls the exhaust gas out of the combustion chambers. It's has no applications on a turbo car, due to the turbo, cutting the exhaust pulse waves, and the turbo it's self forcing the gas out of the combustion chambers. Totally different theories.

Again from the pic, it looks like it's at the back of the car, so you have piping from the rear to the front, under the car. My point on the IC is this is not a finished system, and not very well thought out. Personally I would never go threw the trouble of adding a turbo to a car for 2psi. Hopefully there are plans to at least get to half a bar of boost.

ORIGINAL: Bondga
Yes and no, the turbo works off of heat and back pressure. as the air enters the manifold the turbo traps the air creating back pressure. Meaning the pressure of the exhaust gas is higher than atmospheric pressure. A pressure and temperature drop occurs (expansion) across the turbine , which harnesses the exhaust gas’ energy to provide the power necessary to drive the compresso


It's a air pump, it works off of one gas spinning a wheel to compress gas on the other side. The gas on the turbine must be higher then the gas on the compressor.
The turbine wheel creates the back pressure, that pressure drop @ the wheel is what spins it. Gas moves from high pressure to low pressure. The pressure & heat from the exhaust help create a higher pressure differential, that's what helps spool the turbo faster. The pressure doesn't really need to be higher then atmospheric pressure, it just needs to be higher then the pressure on the other side of the turbo.

What happens when you add a downpipe? The turbo spools faster, right? It does so, due to less restriction on the other side, meaning there is less pressure build up on that side of the turbo, meaning there is going to be more flow, & a greater pressure differential.

yeah the turbo is spolled by a change in pressure over the blades. Reducing the pressure on teh aft side of the turbine will cause the pressure difference needed to occur faster therfore spooling the turbo faster.

ORIGINAL: 2k S4
Personally I would never go threw the trouble of adding a turbo to a car for 2psi. Hopefully there are plans to at least get to half a bar of boost.




Looking at this pic

http://www.audiforums.com/upfiles/32036/365F1D4F265140CFB0FA34987E2F3510.jpg

I dont see garrett or turbonetics on the comp housing. Also that looks like a ebay wastegate and i know that isa ebay filter. Im just curious what this "kit" is really composed of.

that is a pretty nasty lookin snail there. you could probably dry ten camels with a hairdryer that size. He does have a point boost dosnt mattter. Its all about cfm. the more air you put into the cilinder the more power. but bigger turbo produces the same cfm at low boost as a sml one at high boost

the only thing taht woud really bother me about this setup is that low hanging intake pipe

Now what would be cool, is if someone went with the small turbine to spool up real fast, and that is connected to a big turbo to spool up quicker...all the power you need, haha, ok, temps would be high...but who cares, I just saved a bunch of money by switching my car insurance to Geico...Ok, I lie, but I did find out the Chevron by my house sells 100 octane gas...I thought that was pretty neat. Anyone know if I would notice if I filled up using it...30v 100% NA...Would be nice to see a little extra power

ORIGINAL: Bondga

that is a pretty nasty lookin snail there. you could probably dry ten camels with a hairdryer that size. He does have a point boost dosnt mattter. Its all about cfm. the more air you put into the cilinder the more power. but bigger turbo produces the same cfm at low boost as a sml one at high boost

the only thing taht woud really bother me about this setup is that low hanging intake pipe


There both needed. Think of it in terms of Volts & amps. You need the PSI to push the flow, of course the CFM is the amount of the flow. So if you have really high CFM but low pressure. THe cylinder charge will be much lower, and the air will get lazy & slow down even more in the intake track, in turn slow down the turbo. So you balance out the CFm with PSI, to push that air into the cylinders, do to the high CFM there is much more air in there, so the turbo will spin faster.

Back to the V & A. Think of a car stereo amp. They work off of 12v, that is the "pressure" of the power, this is what will "push" the flow of electrons. Then you have the Amps. This is the amount of flow. What happens when the radio is on, and you have a strong battery? It sounds great, but what happens as the battery starts to die, & goes lower then 12v? It sounds like crap, due to the lack of push on the low voltage. That's also why car radio's are louder when the car is running, it's now at 14.4v instead of 12v.

My point is, you need CFM & PSI in a symbiotic relationship.

wow. neat setup. But your pipes were lower than mine. Also, how are you oiling your turbo? I was too afriad to place my MAF back there so I ran a push through instead of your pull through...interesting. Well, like someone said earlier if you want do to it right, then do it right..dont bother with those ebay parts. I have high quality parts that are NEW!!!!! and willing to deal cuz I need them gone and I buying a G2 with water injection (320 is enough power for me for now). I will pm you prices and specs! I also have tuning available for you setup.....

ok guys here is a good problem for you to solve: I have a boost/vac leak somewherein the intake in the engine compartment. ive ruled out the turbo piping andall the aftermarket stuff, it is somewhere in the stock part of the manifold.I have also ruled out the wastegate andexhaust leaks, So without being able to look at the car and I havent been able to use a smoke leak detector yet, does anybody knowif there is a notoriousvac leak problemwith the 2.8 12v a4 that is big enough that i wouldnt be able to build more than 2psi at full rpm/throttle.(i already sealed up my plastic check valve for the brake booster because it was blowing apart under boost, sothat is not it either)

Hey, im very interested on all the stuff you need to do this.. and how if possible??? im going to go and pick up a turbo tomorrow and start this project. i was wondering if you could help me out at all.

ORIGINAL: asv4k8

ok guys here is a good problem for you to solve:Â*Â* I have a boost/vac leak somewhereÂ*in the intake in the engine compartment. ive ruled out the turbo piping andÂ*all the aftermarket stuff, it is somewhere in the stock part of the manifold.Â*I have also ruled out the wastegate andÂ*exhaust leaks, Â*So without being able to look at the car and I havent been able to use a smoke leak detector yet, does anybody knowÂ*if there is a notoriousÂ*vac leak problemÂ*with the 2.8 12v a4 that is big enough that i wouldnt be able to build more than 2psi at full rpm/throttle.Â*Â*(i already sealed up my plastic check valve for the brake booster because it was blowing apart under boost, soÂ*that is not it either)Â*Â*

I would look at the stock plastic intake to the throttle body, it's a weak part, and can leak on a NA car. Then I would check the EVAP purge system, then the vacuum lines that are right at the TB area. I don't think they would like boost much, since they suck air. My guess is you are now pressurizing the internals of the engine, instead of it running in vacuum. You might need to run a catch can, & put in some one way check valves.

your throttle body hose which is flexible and plastic NEEDS to be a hardpipe..trust me. I made that mistake and replaced it with a hardpipe, took it back to the tuner and everything worked out so much better.

ORIGINAL: Black97a4

Hey, im very interested on all the stuff you need to do this.. and how if possible??? im going to go and pick up a turbo tomorrow and start this project. i was wondering if you could help me out at all.


you can buy my set up and go from there. you will have a HUGE head start without all the headache and calculations I did for you already, and for a fraction of the price! You have a pm from me.

GreekA4, I'm pretty sure that if he has already made his own set-up, he's probably not going to want to buy yours. How bad for boost would a oval shaped pipe be? I know it wouldn't flow as good due to being squeezed, but in a low boost situation, would there be much of a difference? Just thinking ofa different way to save ground clearance

ORIGINAL: Hey_You

GreekA4, I'm pretty sure that if he has already made his own set-up, he's probably not going to want to buy yours. How bad for boost would a oval shaped pipe be? I know it wouldn't flow as good due to being squeezed, but in a low boost situation, would there be much of a difference? Just thinking ofa different way to save ground clearance



first of all, when i pmed himI was offering parts as well,if he wanted to upgrade and couldnt find any good deals on the turbonetics/turbosmart parts I have, or if he is looking to completely tune it sometime soon. Second, about the oval shaped pipe, depending on the where it is and how much it is squeezed, but for the most part if it is a portion of the charge pipes, then that wouldnt be a smart idea. Either way, in that section it will lessen the I.D. to a degree, and cuz too much air turbulence when air will flow back into a round pipe. If you are talking about trying to get down the firewall, a 2inch I.D. pipe clearly fits. I hope that helps all who are trying this set up now.

was your kit ever running? and did you build any pressure, if so what was the max pressure you were able to produce[/align]

the system is tuned to 7psi with the Unichip tuning. Before that I was only seeing 2-3 psi w/o tuning like you are, and rough idle. That was only for a few miles, until I programmed the tuning. The tuning portions still needs a bit more FINE tuning that a dealer can do with a dyno, because I do not have access to one.

Yea but the tuning should effect the boost really, I have my wastgate closed off it should be building lots of boost like thatassuming no boost leaks, im going to put the maf up front and run the motor na but with the turbo still on the exhaust, cap off the charge piping and measure the pressure that the turbo can produce like that. that should tell me if there is something wrong with the turbo, if it does make good pressure then I can narrow the problems to either possible boost leaks, or the turbo just doesnt flow enough on that motor to build pressure. Ill let everyone know how it goes.

It would not necessarily be worse for boost and flow. If you have a 2.5" round pipe that you want to replace with oval, use an oval pipe that's say, 3.5" wide and 1.75" tall (just as an example - I didn't actually calculate the volume but just threw the numbers out there for the sake of the argument). That way, you'd have a wider width but a lower "height" to the pipe. If you size it correctly, you could have the same flow volume.

sorry to bump an old thread, but that looks like a Gm-8 turbo, made by IHI for GM on their 6.5L turbodiesels from the mid to late 90s.

crap, greeka4, wanna help me out by telling me everything you got for it, i wanna do this to my A4, i already have a Ko3 and an oil kit.

lol did you say 2 inches of ground clearence.. thats alot IMO

lolz