Garrett Gt35r Install
12-09-2006, 11:44 PM
#77
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Originally Posted by Dave951
West Windsor is where all the hot cars come out to play! 
Raj
12-11-2006, 06:44 AM
#79
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It seems necessary to give a few more explanations about my set ups as I was asked to.
Fisrt point is that you see actually two different configurations: One uses the 16V head, the other relocates the turbo but keeps an eight valve head.
16V head
The head I used is a S2 head. The 928 heads don´t help you, would not be different to a S2 head just smaller valves. The heads are symetric so you just flip around the cams and mount them back in. The idea was to swap intake and exhaust side. If the exhaust ports are where you have the intake ports on a stock engine, you can make a very nice header and you only have to worry about the down pipe (instaed of routing two thick pipes and the steering column in that area). You can even retain the stock exhaust and downpipe if you want to.
The difficulties with that set up are that nothing on the head fits to the block (besides the head studs). You have to make a dry deck conversion (this is what I meant by saying that the head was already weld up) and all water and oil passages have to be routed externaly. That is quite some work but not too complicated jobs. What finally stopped me persueing this route was that I did not think passing the cam drive which unfortunately compromises the intake plenum. I tested everything without the cam sproket beeing mounted. This can be avoided by driving the (new) exhaust cam. By doing so I would have to cut a hole in the bonnet which I did not want to do on this car. So there are two ways to avoid the trouble with the intake mani but both were no goes for this car and this is why I put it on hold. I might come back to this and digg the parts out again once I am building a "flat out" motor. What is slightly anoying about all of this is that I think Porsche should have done it like this in the first place. Would have been very easy for a manufacturer with only a minimum of effort.
That is how I ended up with the stock 8V turbo head and a turbo relocation as seen on the other pictures. I tested that all will fit and it is going into my track day car. It is a simple solution and irons out the miserable design of the crossover-to-turbo joint, needed to do something different for the GT turbo anyway. I am currently waiting for some tubes to arrive but I hope to make quick progress once they are here.
Fisrt point is that you see actually two different configurations: One uses the 16V head, the other relocates the turbo but keeps an eight valve head.
16V head
The head I used is a S2 head. The 928 heads don´t help you, would not be different to a S2 head just smaller valves. The heads are symetric so you just flip around the cams and mount them back in. The idea was to swap intake and exhaust side. If the exhaust ports are where you have the intake ports on a stock engine, you can make a very nice header and you only have to worry about the down pipe (instaed of routing two thick pipes and the steering column in that area). You can even retain the stock exhaust and downpipe if you want to.
The difficulties with that set up are that nothing on the head fits to the block (besides the head studs). You have to make a dry deck conversion (this is what I meant by saying that the head was already weld up) and all water and oil passages have to be routed externaly. That is quite some work but not too complicated jobs. What finally stopped me persueing this route was that I did not think passing the cam drive which unfortunately compromises the intake plenum. I tested everything without the cam sproket beeing mounted. This can be avoided by driving the (new) exhaust cam. By doing so I would have to cut a hole in the bonnet which I did not want to do on this car. So there are two ways to avoid the trouble with the intake mani but both were no goes for this car and this is why I put it on hold. I might come back to this and digg the parts out again once I am building a "flat out" motor. What is slightly anoying about all of this is that I think Porsche should have done it like this in the first place. Would have been very easy for a manufacturer with only a minimum of effort.
That is how I ended up with the stock 8V turbo head and a turbo relocation as seen on the other pictures. I tested that all will fit and it is going into my track day car. It is a simple solution and irons out the miserable design of the crossover-to-turbo joint, needed to do something different for the GT turbo anyway. I am currently waiting for some tubes to arrive but I hope to make quick progress once they are here.
12-11-2006, 11:41 AM
#80
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Relocating the Turbo:
Anyone considered doing a rear mounted turbo???
I have read/seen this approach a lot more lately (and not just on trucks) and it seems there is not any additional lag or pressure drop that most front mount systems. Also, I have seen numbers of the intake temp drops from the turbo to intake alone being 100+ degrees; NOT including the temp drops from the IC itself. So that makes your IC running the the 90% + effeciency range.
Anyone considered doing a rear mounted turbo???
I have read/seen this approach a lot more lately (and not just on trucks) and it seems there is not any additional lag or pressure drop that most front mount systems. Also, I have seen numbers of the intake temp drops from the turbo to intake alone being 100+ degrees; NOT including the temp drops from the IC itself. So that makes your IC running the the 90% + effeciency range.
12-11-2006, 12:44 PM
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12-11-2006, 01:08 PM
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There are two other locations that I considered more closely before I arrived at the above two which I already explained:
- One is to place the turbo where the batterie used to sit, quite easy install, biggest problem beeing the wastegate placement. Needs moving the batterie into the back if not already done anyway.
-Two would be to put it in the passengers footwell. This is quite close to the pictures Marcus sent besides the fact that I would place it INSIDE the car, much cleaner pipe routing and more easy too. That is still one of the best positions I found. Very easy install, even possible to keep the stock headers and close to optimum exhaust routing. I tried this position (only for installation tests) on one of my cars. It needs cutting a hole in the footwell but I really liked it. Would like to hear the sondtrack....The air filter can be mounted in place of the batterie. Drawbacks are the oil drain of the turbo (but seems to work on hondas and mitsubishies) and the longe distance to the intercooler with even beeing very close to the very hot exhaust. This does not necessarily need to be a penalty as you can install a big air to water intercooler on the passenger side (like the big boys do) but would not make a good race set up just something for drag racing.
- One is to place the turbo where the batterie used to sit, quite easy install, biggest problem beeing the wastegate placement. Needs moving the batterie into the back if not already done anyway.
-Two would be to put it in the passengers footwell. This is quite close to the pictures Marcus sent besides the fact that I would place it INSIDE the car, much cleaner pipe routing and more easy too. That is still one of the best positions I found. Very easy install, even possible to keep the stock headers and close to optimum exhaust routing. I tried this position (only for installation tests) on one of my cars. It needs cutting a hole in the footwell but I really liked it. Would like to hear the sondtrack....The air filter can be mounted in place of the batterie. Drawbacks are the oil drain of the turbo (but seems to work on hondas and mitsubishies) and the longe distance to the intercooler with even beeing very close to the very hot exhaust. This does not necessarily need to be a penalty as you can install a big air to water intercooler on the passenger side (like the big boys do) but would not make a good race set up just something for drag racing.
12-11-2006, 04:28 PM
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would it be possible to place the turbo on a shorty exhaust manifold going strait down from the head and then strait back out the exhaust. Like in the pictures above but higher, coming off the headers.
You would think that this would allow better spool-up and possibly being a shorter distance to the intercooler.
But the more i think about it, i think the biggest factor is space and you probably couldnt fit the turbo there...
take it with a grain of salt, just an idea.
-Jace
You would think that this would allow better spool-up and possibly being a shorter distance to the intercooler.
But the more i think about it, i think the biggest factor is space and you probably couldnt fit the turbo there...
take it with a grain of salt, just an idea.
-Jace
12-11-2006, 04:35 PM
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something like this, but a 951 engine obviously. I guess you could also maybe possition the headers to go forward so that the turbo fitted in the spot for the windsheild washer reservoir.
God i feel like im treading on thin ice with these ideas haha.
and using DSM pictures as reference....how could I?
-Jace
12-11-2006, 08:46 PM
#87
Originally Posted by JE_951
something like this, but a 951 engine obviously. I guess you could also maybe possition the headers to go forward so that the turbo fitted in the spot for the windsheild washer reservoir.
God i feel like im treading on thin ice with these ideas haha.
and using DSM pictures as reference....how could I?
-Jace
Nothing wrong with that - I have more than 1 piece on my car that was made for the 4G......
12-11-2006, 09:11 PM
#88
Drifting
Originally Posted by JE_951
...I guess you could also maybe possition the headers to go forward so that the turbo fitted in the spot for the windsheild washer reservoir...
12-11-2006, 09:42 PM
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PLEASE STAY AWAY FROM YOUR CAR!
Skip Wolfe: Exactly like that. Is this your car? do you know if that set-up worked very well?
12-11-2006, 10:27 PM
#90
Drifting
No its not my car, it's Bob Howard's. I was written up in Excellence, and from what I've heard has had it share of problems, although that is only through the grapvine and no idea if it is true or if it relates to the turbo placement. Seems like it would be a good setup to me.
http://www.lindseyracing.com/Merchan...TCARSBOBHOWARD
http://www.lindseyracing.com/Merchan...TCARSBOBHOWARD