that's even less than the minimum of 10% which would put me at 482 RWHP and 15% would be 502 RWHP 
Dyno conversion
Thread Starter
Le Mans Master
Joined: Mar 1999
Posts: 6,029
Likes: 85
From: Palm Coast, FL
Dyno conversion
I'm wondering what my dyno jet or dyno Pac number would be if I just put down 441 rwhp on a mustang dyno
Is there a good conversion number to use? I think I should be at or around the 500 mark, how close am I?
Is there a good conversion number to use? I think I should be at or around the 500 mark, how close am I?
Thread Starter
Le Mans Master
Joined: Mar 1999
Posts: 6,029
Likes: 85
From: Palm Coast, FL
Thread Starter
Le Mans Master
Joined: Mar 1999
Posts: 6,029
Likes: 85
From: Palm Coast, FL
I may have to actually make a pull on a dynopac at ECS when I find some time and find out. It's just funny how the owner of the Mustang dyno says it seems to vary between 10 and 15%. 5 % seems really low but it's just a number and I just picked up another 20 RWHP. I'm sure Tech section knows better, the car will run low tens all day, I haven't seen too many cars with 460 hp doing that ...
Are there any examples of the lower percentages as a standard or are these just "guesses" ?
recent facts:
Went to track in Nov ran 10.3's all day long in 60* weather
went on Dyno and put down 418
adjusted next pull 425
dialed in the vacuum pump and 436
I had a problem and took the heads off to find a broken spring, fixed car re dyno'd @ 441...so it's even harder to believe I was running 10'3's with 418 rwhp and at 5% correction to a dynojet would still only be 438. Crossing the stripe at over 130 MPH, it doesn't seem to be adding up.
Are there any examples of the lower percentages as a standard or are these just "guesses" ?
recent facts:
Went to track in Nov ran 10.3's all day long in 60* weather
went on Dyno and put down 418
adjusted next pull 425
dialed in the vacuum pump and 436
I had a problem and took the heads off to find a broken spring, fixed car re dyno'd @ 441...so it's even harder to believe I was running 10'3's with 418 rwhp and at 5% correction to a dynojet would still only be 438. Crossing the stripe at over 130 MPH, it doesn't seem to be adding up.
Last edited by Rob Petyo; Dec 12, 2015 at 10:57 AM.
Le Mans Master
Joined: Jul 2000
Posts: 7,635
Likes: 326
From: Greenville SC
Just guesstimating from #s I have seen over the years, but I really have never seen that many use Mustang dynos. I believe the Mustang dyno can also be set to simulate a dynojet, so that has to be considered too. Since you drag race, your ET is the important part, and it is very impressive, even if it is 500whp. You obviously know how to drive, and the car is set up correctly. I don't lke using ET to determine power, too many variables, a lot more than an SAE dyno #. Look at it this way, your ET is even more impressive with the lower HP number! 
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Thread Starter
Le Mans Master
Joined: Mar 1999
Posts: 6,029
Likes: 85
From: Palm Coast, FL
Don't want to sound like a wise-*** but understood mph has direct relation to HP... if that is the case, where I only have 470 rwhp then I would assume there should be a lot of cars running low ten second quarter mile times 
I can believe that this Mustang dyno is like many advertise, "stingy"
I can believe that this Mustang dyno is like many advertise, "stingy"
Last edited by Rob Petyo; Dec 13, 2015 at 11:37 AM.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Well, if you do find a "good" answer I would be curious as my car is just a few ponies less than yours on a Mustang dyno. We do have a local dynojet but I never took it there for a retest.
Thread Starter
Le Mans Master
Joined: Mar 1999
Posts: 6,029
Likes: 85
From: Palm Coast, FL
Have you ever ran the quarter and if so what were your times and mph?
got the impression from my tuner that making 441 NA from a 346 SBE wasn't common, remember I went 10.22 at what originally was a initial dyno reading of 418
It would be great if I could compare mph with others that have gone over 130 and ran under lets say a 10.5X qtr mile with or without an automatic and wasn't spinning at the big end
got the impression from my tuner that making 441 NA from a 346 SBE wasn't common, remember I went 10.22 at what originally was a initial dyno reading of 418
It would be great if I could compare mph with others that have gone over 130 and ran under lets say a 10.5X qtr mile with or without an automatic and wasn't spinning at the big end
Last edited by Rob Petyo; Dec 14, 2015 at 10:36 AM.
Drifting
Joined: Nov 2011
Posts: 1,377
Likes: 41
From: Chesterfield (St. Louis) MO
Do you have a dynojet nearby? If so, just get it dynoed there for giggles if you are concerned about it. If you trapped 131 in a full weight C5 ZO6, you are no doubt at around 500 to the tires (on a dynojet), IMO. Even more on a dynapack. The most important thing obviously, is that you are trapping 131 and are in the 10s.
Le Mans Master
Joined: May 2006
Posts: 9,993
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From: League City Tx
I've dynoed my 71' on a Mustang dyno and a Dynojet 248 dyno the same day, 2 hrs apart. 423hp on the Mustang, 460hp on the DJ.... That's roughly 8%..
But ofcourse you have variables in the dynos themselves that's easily + or - 5%....
I wouldn't put too much stock in numbers from either dyno....
Your 131 trap speed is all that's important.
For comparison, my best trap is 127.99 mph on a -300' DA night at 3660lbs on the exact same tune up that made 460 rwhp on the DJ.
But ofcourse you have variables in the dynos themselves that's easily + or - 5%....
I wouldn't put too much stock in numbers from either dyno....
Your 131 trap speed is all that's important.
For comparison, my best trap is 127.99 mph on a -300' DA night at 3660lbs on the exact same tune up that made 460 rwhp on the DJ.