Do dyno #'s lie?
Nov 5, 2007, 05:53 PM
#19
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Without going into a(nother) lengthy discussion, a dyno result should be taken as an indicator and not an absolute. Furthermore, a dyno doesn't tell us anything about things like boost recovery and time to rpm.
The same can be said for calculated estimations, which must fudge on a number of important factors, such as drag coefficients. I know of at least three different ones that give three different results. They are educated guesses, nothing more, nothing less.
Lastly, the one thing that can be said for Dynojets is they are relatively consistent. Eddy current dynos such as Mustangs and DD are better for emulating real-world conditions, but user-defined changes to a simple 'correction factor' and/or different mode settings will give different numbers as compared to another, otherwise identical machine.
The same can be said for calculated estimations, which must fudge on a number of important factors, such as drag coefficients. I know of at least three different ones that give three different results. They are educated guesses, nothing more, nothing less.
Lastly, the one thing that can be said for Dynojets is they are relatively consistent. Eddy current dynos such as Mustangs and DD are better for emulating real-world conditions, but user-defined changes to a simple 'correction factor' and/or different mode settings will give different numbers as compared to another, otherwise identical machine.
Nov 5, 2007, 06:05 PM
#20
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I feel lucky to be tuned on one of those unmolested mustang dynos
Also, I agree with Ted B regarding gearing. From my observation, 350z with 400whp on a Dj only traps 113-114, but on evo, it typically translates to 118
Nov 5, 2007, 06:09 PM
#21
Many if not most shops that use low reading dynos use them as-is. The ones that alter the correction factor usualy do so only because they fear their clientele are somewhat unfamiliar and may be disappointed with the lower numbers as compared to a Dynojet. The problem comes about when the client isn't aware of this, or doesn't know what the correction factor is, and tries to draw comparisons elsewhere.
Last edited by Ted B; Nov 5, 2007 at 06:13 PM.
Nov 5, 2007, 06:10 PM
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It would be nice to get some real world dyno/track comparisons posted... there has to be a bunch of racers on here that have gone to the track after a getting dynoed.
Nov 5, 2007, 06:17 PM
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regarding mustang dynos not reading as low as it supposed to be, I agree. Alot of shops/tuners just wanted to make themselves look better, instead of trying to learn how to tune, in order to satisfy all the hp savvy customers nowsdays.
I feel lucky to be tuned on one of those unmolested mustang dynos
Also, I agree with Ted B regarding gearing. From my observation, 350z with 400whp on a Dj only traps 113-114, but on evo, it typically translates to 118
I feel lucky to be tuned on one of those unmolested mustang dynos
Also, I agree with Ted B regarding gearing. From my observation, 350z with 400whp on a Dj only traps 113-114, but on evo, it typically translates to 118
Nov 5, 2007, 06:29 PM
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Better yet, shops should dyno their shop cars and then bring them to the track. They should try to average the trap speeds and adjust their dynos accordingly.
Nov 5, 2007, 07:22 PM
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I am sure many dynos aren't as accurate as they seem, but the purpose of a dyno is to see gains, that is why a baseline is important. Anyhow I think your numbers do match up, 400-410whp is about 119-121mph traps in my opinion and that is about what you ran 118.8mph right? I'm sure if you continued running your EVO over and over again you could get a little higher traps and even better E.T.s
Nov 5, 2007, 07:30 PM
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Ah for comparison sake-
EVOs making 400-410whp with 20% lost at flywheel it is about 480-492hp and trap 119-121mph.
C6 Corvette Z06 is rated at 505hp and has better top end and aerodynamics and around 15 to 20hp advantage and traps 120-124mph on the average.
By the way both cars weigh similiar, actually I think Z06 is a little lighter.
HP calculators are neat tools, but not accurate.
EVOs making 400-410whp with 20% lost at flywheel it is about 480-492hp and trap 119-121mph.
C6 Corvette Z06 is rated at 505hp and has better top end and aerodynamics and around 15 to 20hp advantage and traps 120-124mph on the average.
By the way both cars weigh similiar, actually I think Z06 is a little lighter.
HP calculators are neat tools, but not accurate.
Last edited by 3000ways; Nov 5, 2007 at 07:42 PM.
Nov 5, 2007, 07:47 PM
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Many if not most shops that use low reading dynos use them as-is. The ones that alter the correction factor usualy do so only because they fear their clientele are somewhat unfamiliar and may be disappointed with the lower numbers as compared to a Dynojet. The problem comes about when the client isn't aware of this, or doesn't know what the correction factor is, and tries to draw comparisons elsewhere.
Nov 5, 2007, 07:55 PM
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On a DD i have seen 309whp on pump
On the strip i have seen 12.14 @ 114 on the same map...
At the track i did a 12.07 @ 113 on a really bad clutch (slipping all gears and smelling really bad) @ 26psi boost on Sunoco 116 and adjusted map...
On the DD i saw 330whp @ 26psi on racegas on a new clutch though and a bit better map...
Weight the lightest i have ever weighted is 3480 pounds...
Now all you guys that are goon in Math or have good horsepower calculators can play...
Nov 5, 2007, 08:01 PM
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A Dyno is a tool for tuning.
ALL (even mustang) have a correction funtion.
A dyno can be fooled if the power comes on strong and "over rev's" the dyno drum/wheel even if the correction setting is accurate.
Fun tip: HP=TQ x RPM/ 5252
If the hp and tq curve do not cross at 5252 rpm there has been a correction or fraud
ALL (even mustang) have a correction funtion.
A dyno can be fooled if the power comes on strong and "over rev's" the dyno drum/wheel even if the correction setting is accurate.
Fun tip: HP=TQ x RPM/ 5252
If the hp and tq curve do not cross at 5252 rpm there has been a correction or fraud