low compression 548 dyno testing has begun!!
03-30-2017 | 02:39 PM
#261
Charter Member#568
Joined: Dec 2000
Posts: 2,171
Likes: 17
From: Western N.Y.
No big deal.Just making sure. I haven't sent the final ones yet due to a scanner issue. Save time if you want and just look at these final ones and just refer to the earlier ones if you feel the need.
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Straight bottoms and flat decks
Straight bottoms and flat decks
Last edited by bck; 03-30-2017 at 02:42 PM.
03-30-2017 | 06:51 PM
#262
Charter Member#568
Joined: Dec 2000
Posts: 2,171
Likes: 17
From: Western N.Y.
so a 700 hp motor at 1.05 cf has a friction factor of 5.25 hp added to cf vs observed? sounds about right compared to depac
I think the depac friction factor is slightly more generous or motor doesnt have quite 15% friction as at 2.8% CF am gaining 28 hp from CF at 663 observed when it would be 18.56 actually.
What this means to all the normal guys reading this who are scratching there heads: the higher your CF is on dyno, the less accurate your numbers are PERIOD. At one point Roccard came on here showing a 454 or 502 making 710 + hp w edelbrock 9-1 290 cc heads on 91 octane for sale, problem is he showed bsfc and lbs hr fuel used, motor used like 290 lbs per hr fuel at hp peak at .5 bsfc, he did NOT show CF used. So doing some real easy math, 290 x 2 (being bsfc was .5) is 580, thats how much hp worth of fuel he used at .5 bsfc, the numbers dont lie, so motor made 580 observed hp and was corrected 22.4 %, you would have to be dynoing in a monsoon at 5000 feet elevation to have a 22.4% CF, totally lies and BS, he quickly got ran off this board. You will ALSO notice that some very good looking dyno sheets from well known builders have been posted on OSO thru the years and you will OFTEN see BSFC and lbs per hr whited or blackened out, why, whats to hide??
I think the depac friction factor is slightly more generous or motor doesnt have quite 15% friction as at 2.8% CF am gaining 28 hp from CF at 663 observed when it would be 18.56 actually.
What this means to all the normal guys reading this who are scratching there heads: the higher your CF is on dyno, the less accurate your numbers are PERIOD. At one point Roccard came on here showing a 454 or 502 making 710 + hp w edelbrock 9-1 290 cc heads on 91 octane for sale, problem is he showed bsfc and lbs hr fuel used, motor used like 290 lbs per hr fuel at hp peak at .5 bsfc, he did NOT show CF used. So doing some real easy math, 290 x 2 (being bsfc was .5) is 580, thats how much hp worth of fuel he used at .5 bsfc, the numbers dont lie, so motor made 580 observed hp and was corrected 22.4 %, you would have to be dynoing in a monsoon at 5000 feet elevation to have a 22.4% CF, totally lies and BS, he quickly got ran off this board. You will ALSO notice that some very good looking dyno sheets from well known builders have been posted on OSO thru the years and you will OFTEN see BSFC and lbs per hr whited or blackened out, why, whats to hide??
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Straight bottoms and flat decks
Straight bottoms and flat decks
03-31-2017 | 05:51 PM
#263
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From: frankenmuth michigan
Sounds like we need a thread devoted just to dynos and correction factors. So if you know the weather conditions you should be able to tell what the correction factor should have been? With the understanding that there are a couple acceptable standards they could be corrected to.
03-31-2017 | 06:33 PM
#266
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From: frankenmuth michigan
03-31-2017 | 08:01 PM
#267
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Joined: Jul 2004
Posts: 11,332
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From: chicago
685 x 1.0736 = 735hp
685 x 1.0836 = 742hp
685 x 1.0936 = 749hp
685 x 1.1035 = 755hp
Seems like while the correction factor was 1.0736, it actually added about 9% to the observed number with Depac. Air Temp listed at 84.6 F, 29.211 baro, SG .751,
Lets go 
