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Registered
Join Date: Apr 2009
Location: New Jersey
Posts: 62
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Max boost for stock compression
Pardon any ignorance but ...
What sort of boost can you run on a stock (U.S.) compression ratio of a 3.2? I know of turbo kits for other cars that run fairly low boost (about 5psi). My Scirocco with the Callaway kit is 8.2 : 1 and runs 14 psi+. Granted thats a water cooled head.
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1988 911 Carerra 1982 Scirocco, Callaway Turbo Stage II |
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08-14-2014, 09:33 PM
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Brando
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All of it.
Sorry, do a search on turbo 3.2. Sooooo many threads that are good. Short answer is about 6psi.
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Turbo powa! 1977 911s. it's cool |
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08-14-2014, 10:31 PM
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Slantnose from HELL
Join Date: Dec 2004
Posts: 888
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With a small turbo typically a T3 14+ Is at the upper limit with stock pistons. We are talking about a Scirocco which I have ALOT of experience with early water cooled VW's. If you start pushing boost higher then the turbo is over spinning and just super heating the charge. If you upgrade to a T4/T3 like a 60-1 compressor with let's say a T3 .63 Stage 3 turbine section. Then 12 psi is all the cast pistons can handle. The pressure from the higher air mass will break the ring lands on the pistons at about 13 psi. Forged pistons are required. I ran Wiseco and JE pistons with excellent results and over 30+psi. My last Scirocco made 485HP with AC and complete street trim. Needless to say the torque steer was challenging. A 3.2 has cast pistons as well and WILL have the same fate. Most 3.2 owners doing the turbo install will do a top end rebuild and exchanges the stock pistons and cylinders to a set of stock 930 P&C's. Usually with stock 3.2 pistons, 7lbs safely and a max of 12 psi.
Last edited by GJF; 08-15-2014 at 08:29 AM.. |
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08-15-2014, 08:23 AM
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Registered
Join Date: Oct 2013
Location: Seattle, WA
Posts: 1,086
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Just came in to post a pic of my old 87 Scirocco, was running 18psi.
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- 86 Porsche 930 - Mr.Hyde - 86 BMW 635CSi - Dr.Jeykell - 2006 Infiniti M45 Sport https://medium.com/@crashingdoor |
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08-15-2014, 09:24 AM
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Registered
Join Date: Apr 2009
Location: New Jersey
Posts: 62
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Very nice.
I can't see more than 250HP on those cars! The steering just gets horrendous. Plus they are very light cars to begin with. But that was the info I was looking for. I know the 930's have very low compression ratios and don't really run very high boost (stock) so it made wonder.
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1988 911 Carerra 1982 Scirocco, Callaway Turbo Stage II |
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08-15-2014, 09:34 AM
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Slantnose from HELL
Join Date: Dec 2004
Posts: 888
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Too much HP is a early MK chassis is definitely a challenge. I used to set my left arm on the arm rest, and once I had the car pointed, I used it as a prop to aide with the torque steer. I end up converting the car to RWD with a 9" rear. I set it up with a crossflow head mated to a T5 5 speed, ended up selling it as a roller, and then bought and built my current over powered Hot Rod
 Good times though
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08-16-2014, 05:04 AM
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