Low power for a 408 stroker/F1R?

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Sep 20, 2020 | 03:48 PM

Red02ss35th

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Low power for a 408 stroker/F1R?

Hey guys I have a question. I have a 408 stroker/stock ls3 top end studded w/ ls9 gaskets with a F1R procharger and a 4" vs racing intercooler. M6/9" 3.50 gears. With 11.1:1 compression on e85. I made 16lbs with a 7.65/4.25 pulley setup and only made 703whp. Is that low for such a big blower? Cam spec is for NA stroker 242/248 636/636 112+3LSA 20* overlap. Also after a several pulls iat goes to 150*. Normal?

Sep 20, 2020 | 09:46 PM

AwesomeAuto

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I think my junkyard 4.8 made more than that at that boost level and through an auto trans. It does seem pretty low.

Sep 22, 2020 | 03:50 PM

blackdak318

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I would say that is very low for that combo, yes. I'd say you're about 100-150 RWHP short. I'm not a centri cam guru but 20 degrees of overlap seems like a lot?? May be bleeding a lot of boost off in the motor. Something to check.

Sep 22, 2020 | 04:31 PM

BCNUL8R

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I'd have to guess it's the cam if you are actually at 16 lbs and pulling clean all the way up.

Sep 23, 2020 | 01:59 PM

V8sounds

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What does Timing and AFR look like?

Sep 23, 2020 | 03:12 PM

Red02ss35th

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Timing I'm not sure I'd have to ask my tuner. Afr in WOT is like 12.7 the dyno graph I don't have but didn't really drop until about 6500rpms and didn't drop didn't have any belt dust near the blower/bracket

Sep 23, 2020 | 03:46 PM

SLOW SEDAN

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Quote:

Originally Posted by Red02ss35th

12.7 A/F on 16lbs and 11:1 comp? Sounds like you need a new tuner.

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Sep 24, 2020 | 10:53 AM

ddnspider

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Quote:

Originally Posted by SLOW SEDAN

12.7 A/F on 16lbs and 11:1 comp? Sounds like you need a new tuner.

What in the actual crap?!

Sep 24, 2020 | 11:59 AM

#10

AwesomeAuto

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Yeah, new tuner, immediately.

Sep 24, 2020 | 12:57 PM

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SLOW SEDAN

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Quote:

Originally Posted by AwesomeAuto

Yeah, new tuner, immediately.

The tuna's are running wild!

Sep 24, 2020 | 01:39 PM

#12

Forcefed86

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Ever run it on motor? How high are they revving it? I'd agree to get it to a well known LS "boost" tuner, but something still sounds off.

Sep 24, 2020 | 04:30 PM

#13

Kfxguy

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If your afr was 11.7, I would still be concerned. 12.7 is a inevitable catastrophe. that needs to be in the LOW 11's....I've had mine around 12.0 before (2nd pump was off by accident) and it lost ALOT of power.

Sep 24, 2020 | 04:41 PM

#14

ddnspider

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OP stated it's on E85 which is the only reason it hasn't melted itself to death.

Sep 25, 2020 | 08:56 AM

#15

BCNUL8R

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Quote:

Originally Posted by ddnspider

OP stated it's on E85 which is the only reason it hasn't melted itself to death.

Correct low 12’s even at 11 to 1 compression will be fine on E if timing isn’t stupid. It might not make max power that way but it will be ok.

I think running too hot of a plug with E is more problematic to risk preignition than running a little lean.

Last edited by BCNUL8R; Sep 25, 2020 at 09:01 AM.

May 4, 2021 | 11:10 PM

#16

41off

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Did you ever get an answer as to why your numbers were at least 150hp low? Those are awful numbers for the size of the engine and blower.

May 5, 2021 | 10:09 AM

#17

Black_Sunshine_99

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Quote:

Originally Posted by Red02ss35th

Maybe your tuner is from the old school where the thought process was "lean is mean" lol.
But seriously, find a new tuner.

May 5, 2021 | 11:13 AM

#18

Pro Stock John

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I am wondering about timing as well. 12.7:1 AF WOT is risky. The higher your compression goes the smaller the tuning window.

IAT's to 150 on a pull, and that's without load. Maybe that intercooler kinda sucks.