CIS Rear mount turbo?
#16
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Dan, that was hardly a fair fight! Funny has hell though! I am sure he was scratching his head wondering what just happened to him! LOL! Good stuff that!
#17
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I wanted to do a RMT for the 82. But I would run higher boost because of ethanol and EFI.
But I may just put the NOvi on it.
But I may just put the NOvi on it.
#18
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Since the air sensor plate and piston in the fuel distributor are designed/engineered/calibrated to operate in a vacuum, your turbo intake side should be plumbed between the air sensor plate and the throttle body. i.e. the lower plenum will need to be reengineered to route an inlet and outlet between the plate and throttlebody. Another option would be to move the fuel distributor/air sensor plate as was done by Porsche for the 930/931's. With the 79 compression ratio and cams, 8 psi would be safe and would provide 100+ HP gains at full boost. Anything more will require an intercooler.
The size of the turbo question should be left to your turbo supplier. Just be prepared to provide them with specifics on the engine/exhaust systems. Lag should not be as pronounced as it is on a lower compression engine.
Dennis
The size of the turbo question should be left to your turbo supplier. Just be prepared to provide them with specifics on the engine/exhaust systems. Lag should not be as pronounced as it is on a lower compression engine.
Dennis
#19
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The local rear mount turbo guys were looking into doing this mod. If I recall correctly one of the stumbilng blocks is finding room for the up pipe. On the S4's there's room between the driverside firewall and the motor, but I guess this is not the case on the 16v motors. Take a look and see if you see any room for it on your 928.
To LanceJ:
With all due respect. In my opinion, if you can't answer question #1, you shouldn't be tackling this project. Buy some books and read them until you almost have them memorized. There are calculations you can run to determine which turbo's will work for you. The more homework you can do now, the fewer headaches you will have later.
The person who knows the most about boosting CIS 928's is Carl, but in my experience, he isn't very eager to help unless you buy his S/C kit. Maybe if you buy some of his fuel enrichment parts he may help. Give him a try.
#20
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to fabio421 reading "Maximum boost"
Thinking
1st-3psi-stock untuned-
2nd-8psi tuned with Carl's fuel enhancement goodies
3rd- 12psi 93octance,with Meth/injection-
4th- 16psi e-85, EFI standalone, Meth/injection-
Meth/injection kit is in order for extra protection.
Thinking
1st-3psi-stock untuned-
2nd-8psi tuned with Carl's fuel enhancement goodies
3rd- 12psi 93octance,with Meth/injection-
4th- 16psi e-85, EFI standalone, Meth/injection-
Meth/injection kit is in order for extra protection.
#21
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Lance,
Before going to your 4th option plan on replacing the head gaskets with the thicker type, decarbonize the pistons and heads and run an intercooler. Lowering the charge temp is great but remember the age of the engine and its open deck block design.
Dennis
Before going to your 4th option plan on replacing the head gaskets with the thicker type, decarbonize the pistons and heads and run an intercooler. Lowering the charge temp is great but remember the age of the engine and its open deck block design.
Dennis
#22
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Before adding the supercharger I pulled the heads and replaced every piece of rubber on the car.
Unless your engine has less then 20,000 miles on it, I'm sure the valve guides / seals are waving goodbuy. Might not be an issue for the stock motor, the extra oil dripping down in to the combustion chamber is not a good thing.
#23
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When you get closer, post back. Hacker or myself can help you with some of the tuning on the 16v. Theres a neat little trick, shown to us by J. Kuhn, that allows you to pull ign. timing out of the stock distributor while under boost. The best part is that it doesn't cost any $$$. ![Big Grin](https://rennlist.com/forums/images/smilies/biggrin.gif)
Grab a book on the CIS injection system as well. Learn all about it. It will help you in the long run. There were a few factory CIS turbo cars. Pay attention to what they did and how it differs from the 928 setup.
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Grab a book on the CIS injection system as well. Learn all about it. It will help you in the long run. There were a few factory CIS turbo cars. Pay attention to what they did and how it differs from the 928 setup.
#24
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This is the CIS turbo set up on the 931. BTW this setup with a 928 fuel distributor and a top mounted IC developed 375 HP and won it's class in the 81 and 82 Lemans.
Dennis
Dennis
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Yes thanks Dennis and Fabio421 for all the advice. i will be spending some time replacing all rubber parts. it only has 72k miles on the clock. But it sat for 8 months.
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Carl Fausett is the guy for blown CIS motors--although he moving away from CIS (well, adding more stuff to his already large wealth of knowledge and products) to stand alone EFI, John Kuhn or Mark Robinson can guide you on turbos.
your biggest hurdle is the air valve/fuel distributor issue, as described above.
--Russ
#28
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What I've noticed over the years is that those, who sell boosted kits, are usually not that keen on giving out free information.
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Whatever happened to the remote CIS project?
I don't understand about the modifying the lower plenum. I thought I had read in more than a few places that CIS can be boosted w/ no mods to the fuel system up to around 5 maybe 7lbs.
Carl's stage one system does not include a "modified" anything that I can see of. Boost is boost, if you don't need to modify anything at 5lbs for a SC kit, why would it be different for turbo boost? Am I missing something? It should be very straight forward w/ a turbo positioned in the middle of the car, or a rear.
Stephen
I don't understand about the modifying the lower plenum. I thought I had read in more than a few places that CIS can be boosted w/ no mods to the fuel system up to around 5 maybe 7lbs.
Carl's stage one system does not include a "modified" anything that I can see of. Boost is boost, if you don't need to modify anything at 5lbs for a SC kit, why would it be different for turbo boost? Am I missing something? It should be very straight forward w/ a turbo positioned in the middle of the car, or a rear.
Stephen
#30
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The 924 turbo that Porsche ran in the 81 and 82 Lemans used a 928 fuel distributor to develop 375 HP, so I would expect the stock CIS would be good for up to 10 psi of boost.
The modification is required to place the turbo between the air sensor plate and the throttle body in the intake path.
Dennis
The modification is required to place the turbo between the air sensor plate and the throttle body in the intake path.
Dennis