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Old 09-10-2018, 10:31 AM   #26
smoky
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On pump most people will say to stay under 8.5, but on E85 people suggestion vary and higher CR seems to work quite well. Waiting to see how response feel on autocross event. If response is good, I might try higher CR on my next build, if not that great I'll get back to a 2.5. I'm experimenting over the years.

On a Cobb 20g turbo with a 2.5 a friend of mine was running 8.75 and got back to 8.2 on his latest rebuild. He loss almost 500rpm spool on the dyno, but he gained some power and was able to run more boost on pump (94 octane canadian fuel). It also makes the build safer, expecially if you have high IAT.
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Old 09-29-2018, 09:25 AM   #27
Daggernomad55555
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Somebody knows water meth injection with higher CR

Last edited by Daggernomad55555; 09-29-2018 at 09:32 AM.
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Old 10-01-2018, 01:48 PM   #28
Homemade WRX
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Yeah, more cylinder pressure always narrows the safety range for timing.

Bugbomb and Konkilr (Mike and Jake) Suxass car is running 14:1 on E85. I drove the car back in it's 10:1 autox set up and still 28 psi on an FP green IIRC...the throttle was a light switch.

The 14:1 switch was supposed to come with a larger turbine to mellow out the lightswitch a bit in lieu of more power. I ought to call them and see where the car is now. I know the old chassis died in a wreck (street driving) and they bought and swapped to a new chassis.

The TIC car lives on ethanol now and is a 10:1 2.5 bottom end, living on a mellow 32 psi from a GTX3582R. So it doesn't have the lower RPM high cylinder pressure issues. It wasn't at peak torque until ~4100 RPM IIRC. Then again, it's a TA car, so top end is much more of a concern.

I think most people are afraid of higher CR with boost, or are tuner limited.
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Old 10-10-2018, 11:57 PM   #29
smoky
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Quick update, turbo response on the track is very good. Powerband is also very nice, getting up to the end at 8k. Quick video of the last event of the year:
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Old 10-11-2018, 10:58 AM   #30
subydude
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It does sound like good response time on the throttle. Looks like another option potentially on the market
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Old 10-11-2018, 03:50 PM   #31
Homemade WRX
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I'm still curious to see what the next size up G-series will look like. Should be a nice fit for my 2.43 (4" bore) destroker.
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Old 10-11-2018, 05:47 PM   #32
undyjr
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I'm curious as well. Currently looking into options for a larger turbo on my FA20.
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Old 10-18-2018, 01:10 AM   #33
Krang
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I run an AWIC, previously with a EFR 6758 and now with a 6258. It's been great.

Very little weight difference, and the heavy stuff is where I want it (tmic location AWIC, and resiviour in the trunk)

https://www.iwsti.com/forums/gd-memb...-ftd-time.html
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Old 10-19-2018, 12:25 PM   #34
Homemade WRX
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Quote:
Originally Posted by Krang View Post
I run an AWIC, previously with a EFR 6758 and now with a 6258. It's been great.
Didn't realize you'd changed turbos. I just got four more of the IRL 0.64 AR 6758s if you want to switch back
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Old 10-20-2018, 04:02 PM   #35
spdracerut
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Quote:
Originally Posted by smoky View Post
Quick update, turbo response on the track is very good. Powerband is also very nice, getting up to the end at 8k.
Nice run! Smaller diameter wheels = lower inertia = good response
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