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Discussion Starter · #4 ·
chimmike,

12.5 is safe huh? That's good because I'm around 12 and below for the most part. I'm very happy with my car. 245-250 WHP is where I've always wanted to be. It's a fun car.

Shane
 

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below 12 is too rich imo...you'll probably start building carbon deposits on the pistons.

keep in mind if you get a 2.5" or 3" exhaust, you'll probably jump up to 260-270whp...that stromung is holding back a lot.
 

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IMO, I'd keep it around 12:1 on pump gas...You could lean it out and make more power, but is the risk worth it?
 

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it's been covered before that on 93 octane gas, 12.5:1 is still a safe level. Even then, it's a bit rich...and you still have a safe backup.
 

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Discussion Starter · #8 ·
Cool thanks guys. Remember though, you can't say that 12.5 is safe on pump gas for ALL engines. It matters what the compression ratio is right?

Shane
 

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it's been safe on engines running 9.5:1 and 10:1. just watch for pinging, but I am 99% sure you won't get any pinging at even 13.0
 

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Discussion Starter · #10 ·
I didn't have any pinging what so ever. We even pulled my spark plugs after about 7 runs and looked at them and they looked great. There were no signs of detonation.

Remind me: What is the compression ration on the QR25DE?

Thanks, Shane
 

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Southern Shift Racing
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chimmike said:
below 12 is too rich imo...you'll probably start building carbon deposits on the pistons.

keep in mind if you get a 2.5" or 3" exhaust, you'll probably jump up to 260-270whp...that stromung is holding back a lot.
Maybe true, but consider that he's running on stock internals. IMHO ~250whp is downright perfect for the internals on the qr25, so long as the tuning is right and power doesn't come on too strong below 3krpms. I'd just start to get nervous about the internals once the power levels get close to 275whp.
 

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NG Autoworks
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chimmike said:
it's been safe on engines running 9.5:1 and 10:1. just watch for pinging, but I am 99% sure you won't get any pinging at even 13.0
Well, I don't blame you...since you have obviously never tuned an EFI car. 13.0:1 is way too lean for a turbo car,....and that's a fact.
 
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