Thread:

8-71 Blown 540 questions

Originally Posted by racinjason65

I think you are "correct"...

Hey, just run the hell out of the thing first thing in the morning and your chances of seeing it all 1050 HP are pretty good.

Originally Posted by gn7

I could be wrong, but if you look that is the STP correction and was figured into the STPtrq and STPpwr. You would have to multiply your numbers by .949 or .95 to get your uncorrected Trq and HP

Not quite that simple.
Corrected power (CBHp) = (OHp + FHp) x CF - FHp
CBHp= corrected brake hp
OHp= observed hp
FHp= friction hp
CF= correction factor

You would need to know what the friction hp factor is.

This is true. Was trynig to make a seminar here But you arte 100% correct. SOOOOOO when the questions start flying, you better stick around to answer that can of worms you just tapped. LIKE, would that frictional HP include the blower?

He still stands his best chances of seeing the whole 1050 at 6:00 on a nice crisp dry morning. 110 in the middle of the day on the 4th of July in Havasu, not so much

Originally Posted by gn7

This is true. Was trynig to make a seminar here But you arte 100% correct. SOOOOOO when the questions start flying, you better stick around to answer that can of worms you just tapped. LIKE, would that frictional HP include the blower?
He still stands his best chances of seeing the whole 1050 at 6:00 on a nice crisp dry morning. 110 in the middle of the day on the 4th of July in Havasu, not so much

Depends on the FHP information. If there is a number in the data for that combination which inculudes a blower, then yes. That is, if they used a FHP number at all in the power calcs. I know when we did the 509 at Vrbancic's, they didn't include a FHP factor since it's a an "estimate" at best and can push the power numbers around considerably. They don't go for that.
With an .05 cf, the weather was decent that day...you're right...you won't find that at 2:30 in July on the river...am or pm

Given a choice, I'd rather know the observed numbers and accurate conditions, rather than corrected numbers.

Its not all that common in most dyno tests. Its imperitive if you're doing any comparitive testing. You know the Nascar and ProStock boys are doing it. You're right, I didn't mention it in my post to racinjason, but it would only muddle the thread I am still reeling from last INFORMATIVE dyno thread. I am still trying to figure out if I shuld build my jet boat engine for torque or HP.

Originally Posted by gn7

Its not all that common in most dyno tests. Its imperitive if you're doing any comparitive testing. You know the Nascar and ProStock boys are doing it. You're right, I didn't mention it in my post to racinjason, but it would only muddle the thread I am still reeling from last INFORMATIVE dyno thread. I am still trying to figure out if I shuld build my jet boat engine for torque or HP.

Yes.

Scott the OP with a hotrod 8:71 and 3 little strips of teflon isn't going to give huge power #s...you would have to spin that blower to the point of beating air...lol

Originally Posted by Michael Thomas

Scott the OP with a hotrod 8:71 and 3 little strips of teflon isn't going to give huge power #s...you would have to spin that blower to the point of beating air...lol

He will certainly run out of blower before he runs out of octane with that compression, but he can easily see that number. 8-71s pump just fine at 35-40 over and make 24-25 lbs of boost on that size engien. I think he will hit his number before that.

Originally Posted by Fast9SecChevelle

Hello, It seems that I have to turn to the boat guys again for some motor info. I'm close to finishing the build, and am concerned that I may not make the power I want. The combo is: 540 short block (8.5), total seal rings, ported RHS 320 heads 390 intake, 298 exaust @.800 lift, Super Chargers USA H.A. three point teflon stripped 8-71, two 1000 HP boost referenced Holleys,solid roller 736-727, 276-285 @.050 114 lobe sep, 2 1/8 headers with 4" exaust. Boost will be whatever it will take on race gas. Looking for somewhere near 1200 hp around 7200 rpm. Back up plan is of course an F2 procharger, but the hood already has the hole, and the blower is setting on the bench.

Looking for, and appreciate, any and all info or comments, combos or "I gotta buddy with a motor close to that that makes XXX horsepower" stories.

What ingnition are you running???? with the right ing. you should be able to make that hp no problem at all.

Originally Posted by jimclauss

not really

Whats not "really" the correction not being IN THERE? Or the using the inverse to figure the uncorrected. I not going to have to go thru the frictional correction with you too am I?

Originally Posted by gn7

Whats not "really" the correction not being IN THERE? Or the using the inverse to figure the uncorrected. I not going to have to go thru the frictional correction with you too am I?

No, How much dyno time do you have? Do you have your own Dyno? I've seen some strange suff with correction factors..