Peak torque move puzzling?

General engine tech -- Drag Racing to Circle Track

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Frankshaft
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Re: Peak torque move puzzling?

Post by Frankshaft » Wed Dec 06, 2017 3:34 pm

So it's a super Stocker?

gtca9014
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Re: Peak torque move puzzling?

Post by gtca9014 » Wed Dec 06, 2017 3:45 pm

Frankshaft wrote:
Wed Dec 06, 2017 3:34 pm
So it's a super Stocker?
Yes, I thought I stated that initially.

1972ho
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Re: Peak torque move puzzling?

Post by 1972ho » Wed Dec 06, 2017 4:00 pm

GTCA seeing this is a superstock engine is there any reason you don’t ask some the racer and engine builders over on the classracer sight.

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Re: Peak torque move puzzling?

Post by gtca9014 » Thu Dec 07, 2017 10:08 am

1972ho wrote:
Wed Dec 06, 2017 4:00 pm
GTCA seeing this is a superstock engine is there any reason you don’t ask some the racer and engine builders over on the classracer sight.
I have talked with some over there and in person. Never got a definite answer so came here.

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Re: Peak torque move puzzling?

Post by LSP » Fri Dec 08, 2017 6:52 am

gtca9014 wrote:
Wed Dec 06, 2017 2:49 pm
mag2555 wrote:
Wed Dec 06, 2017 1:53 pm
Wishing for a peak in the 6500 to 6700 range with out a HP goal to shoot for makes it hard for us to help you .

Also with out knowing what cid motor we are talking about here asking Peanut port heads to HP peak at 6700 rpm could take a wapping big Cam!
It is a low compression 9:1 402 BBC with oval port, not peanut port heads. Cam is 288/284 and mid .800 lift although cam guy wants to try higher lift on next one. Should be 700hp if good. My old one goes thru at 82-8400 with peak power at 7300. would like peak hp at 77-7800 and cross at 87-8800.
Cam events and intake tract length will move the peaks, but you didn't change either so not sure how the peak shifts happened?

What lobe seperation and where is the intake centerline?

Which intake manifold and are the runners extended?

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Re: Peak torque move puzzling?

Post by mag2555 » Fri Dec 08, 2017 7:10 am

I have seen headers with rust scale in them knock a surprising amount of power off a motor at times.
So your old motor when dynoed hit peak hp above 7800, with regular Oval ports?

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Re: Peak torque move puzzling?

Post by gtca9014 » Fri Dec 08, 2017 8:44 am

LSP wrote:
Fri Dec 08, 2017 6:52 am
gtca9014 wrote:
Wed Dec 06, 2017 2:49 pm
mag2555 wrote:
Wed Dec 06, 2017 1:53 pm
Wishing for a peak in the 6500 to 6700 range with out a HP goal to shoot for makes it hard for us to help you .

Also with out knowing what cid motor we are talking about here asking Peanut port heads to HP peak at 6700 rpm could take a wapping big Cam!
It is a low compression 9:1 402 BBC with oval port, not peanut port heads. Cam is 288/284 and mid .800 lift although cam guy wants to try higher lift on next one. Should be 700hp if good. My old one goes thru at 82-8400 with peak power at 7300. would like peak hp at 77-7800 and cross at 87-8800.
Cam events and intake tract length will move the peaks, but you didn't change either so not sure how the peak shifts happened?

What lobe seperation and where is the intake centerline?

Which intake manifold and are the runners extended?
111 in at 106
Dart no extention of runners 1 1/8 QJet adapter/spacer

gtca9014
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Re: Peak torque move puzzling?

Post by gtca9014 » Fri Dec 08, 2017 8:46 am

mag2555 wrote:
Fri Dec 08, 2017 7:10 am
I have seen headers with rust scale in them knock a surprising amount of power off a motor at times.
So your old motor when dynoed hit peak hp above 7800, with regular Oval ports?
No, old motor 7300 with peak tq 6200. New motor cam was to move peak power to 76-7800 range.

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Re: Peak torque move puzzling?

Post by mag2555 » Fri Dec 08, 2017 8:57 am

How much Hg is the motor pulling at peak rev's?
You really need to test either with a dyno that can give you these numbers, or at the track.

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Re: Peak torque move puzzling?

Post by John Wallace » Fri Dec 08, 2017 9:22 am

X2!

The BSFC looks wrong.
Using the corrected numbers it looks like the thermal efficiency is around 35% at peak HP?
(way too good?)

Need uncorrected HP/Tq numbers.
If that last column is vacuum, you are running a very small carb.
(but the numbers don't seem to be for that)

Are you using a thermal barrier on pistons/heads?

:?:
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Re: Peak torque move puzzling?

Post by vortecpro » Fri Dec 08, 2017 9:34 am

I believe it has something to do with the start RPM difference of the two tests. One other thing to notice is the RPM this engine is run at....more converter more gear, faster car.
Racing a NA NHRA stocker should be mandatory before any posting.

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Re: Peak torque move puzzling?

Post by LSP » Wed Dec 13, 2017 4:36 am

PM sent

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