MarinS4

For those who have wondered about NA turbo conversions. I am still running stock 11.2CR and VRAM. It does require race gas though.

https://rennlist.com/forums/attachme...yno-10-psi.jpg

The Dyno run was done using 10psi springs. I normally run 7psi springs on the track etc.

Greg H.

Unfortunately, either MarinS4's car is faster than the UMW stage 2 kit, or my car isn't running properly. That's not dyno racing but according to the front and back straight at Thunderhill

Greg H.

MarinS4

I can help you with that.

I was running 7psi that day.

Basal Skull

nice numbers MarinS4!

well Greg, I'm pretty happy being able to keep up with the new gt3rs (our cars are 14 yrs old!). What gas are you using and what boost are you seeing?

Canadian money's doing good recently and I'm itching to do some upgrades/get my hands dirty ...

Greg H.

95 octane (actually 50/50 100 and 91). No idea, no boost gauge.

Greg H.

sonny1

Hope it lasts...I reallly do.,cheers.

MarinS4

5+ years on the setup. Lots of track days too. Leak down & compression were perfect prior to upgrading rods, cams etc. Lots of successful versions of this build floating around.

With high compression and 7psi of boost the corrected compression is the same as a low compression 993tt at 1bar.

sonny1

That's great!!!

pstoppani

His car was putting down some very good power at THill; surely 450HP at least at the crank.

I'd be very interested in seeing a 7psi dyno pull on that same dyno.

pstoppani

As in interesting comparison, TPC makes a 4.5PSI turbo kit for the Cayman S, which takes it from 295HP to 485HP (420WHP). The Cayman has a slightly lower, 11.1, CR.

MarinS4

When changing the springs to the 10's I pinched a diaphragm on one of the wastegates. I think this is why the boost readings were showing 8psi and tapering to 6psi. When I logged it the last time I ran the 10psi springs I did not have that problem.

I have since corrected the problem and reinstalled the 7psi springs. I would be willing to bet it still has 400+WHP on these 7psi springs.

Number be damned the car is a blast to drive! That's what really matters.

pstoppani

Indeed! And fast...

Jean

The peak torque numbers make sense at an effective compression ratio of 16.5 PSI (11.2:1 compression + 7 psi boost) with an intercooled twin turbo setup + cams and race fuel.

Any acceleration GPS logs you can share? A comparison vs. traditional setup would be interesting.

axl911

Martin,

One of the biggest issue /w boosting the NA engine /w its high compression is the amount of ignition timing normally run on the NA engine. Do you know how much timing are being pulled?

MarinS4

I don't have any timing figures. Protomotive did all of the tuning. I know the twin plug setup requires less timing than single plug because the flame travel time is cut in half.