Dynojet dyno's: All models should give the same RWHP / or RWTQ #'s?
06-06-2014, 05:17 PM
#1
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Dynojet dyno's: All models should give the same RWHP / or RWTQ #'s? Just as title says:
My modded Cad '09 CTS-V dynos 658 RWHP on 1 Dynojet & dynos 601RWHP on another, both supposedly SAE CF.
What gives?
My modded Cad '09 CTS-V dynos 658 RWHP on 1 Dynojet & dynos 601RWHP on another, both supposedly SAE CF.
What gives?
06-06-2014, 05:26 PM
#2
I've seen differences between the 24" and 48" diameter drum Dynojets. Usually if the drum diameters are the same they are pretty close. They will give different results even on the same dyno in different weather condition even with the CF adjusting for weather. Without seeing the data logs of both your runs it's impossible to say if it is entirely in the different dynos.
05-21-2015, 03:05 PM
#4
A dyno is a high precision piece of equipment that requires maintenance and care. This includes the weather station. The math behind it doesn't lie, it is quite stable for dishing out consistent numbers.
Do we see people complaining about vastly varying torque wrench values ? no. But if one guy drops his a bunch of times, dont expect it to be the same.
I usually see shops that have weather stations covered in dust and other items.
I see operators apply SAE or STD or DIN corrections for wategate controlled turbos (which is inflating the actual number by the correction factor).
There are many things to take into consideration here as well, such as.. it is an inertia or eddy current drum setup? Dynojet makes both types.
There are also drum grip/tires/ car drivetrain etc. that all inject err. to the total. Just doesnt help much when you compound poor or inaccurate weather station readings and operator error into the mix...
Operator error!
Do we see people complaining about vastly varying torque wrench values ? no. But if one guy drops his a bunch of times, dont expect it to be the same.
I usually see shops that have weather stations covered in dust and other items.
I see operators apply SAE or STD or DIN corrections for wategate controlled turbos (which is inflating the actual number by the correction factor).
There are many things to take into consideration here as well, such as.. it is an inertia or eddy current drum setup? Dynojet makes both types.
There are also drum grip/tires/ car drivetrain etc. that all inject err. to the total. Just doesnt help much when you compound poor or inaccurate weather station readings and operator error into the mix...
Operator error!
05-21-2015, 03:49 PM
#5
A dyno is a high precision piece of equipment that requires maintenance and care. This includes the weather station. The math behind it doesn't lie, it is quite stable for dishing out consistent numbers.
Do we see people complaining about vastly varying torque wrench values ? no. But if one guy drops his a bunch of times, dont expect it to be the same.
I usually see shops that have weather stations covered in dust and other items.
I see operators apply SAE or STD or DIN corrections for wategate controlled turbos (which is inflating the actual number by the correction factor).
There are many things to take into consideration here as well, such as.. it is an inertia or eddy current drum setup? Dynojet makes both types.
There are also drum grip/tires/ car drivetrain etc. that all inject err. to the total. Just doesnt help much when you compound poor or inaccurate weather station readings and operator error into the mix...
Operator error!
Do we see people complaining about vastly varying torque wrench values ? no. But if one guy drops his a bunch of times, dont expect it to be the same.
I usually see shops that have weather stations covered in dust and other items.
I see operators apply SAE or STD or DIN corrections for wategate controlled turbos (which is inflating the actual number by the correction factor).
There are many things to take into consideration here as well, such as.. it is an inertia or eddy current drum setup? Dynojet makes both types.
There are also drum grip/tires/ car drivetrain etc. that all inject err. to the total. Just doesnt help much when you compound poor or inaccurate weather station readings and operator error into the mix...
Operator error!
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05-31-2015, 10:50 AM
#8
There are outside factors as well, sure, 1-2% maybe. And this AGAIN would lie on the operator to do several runs, properly, to make an average on your supercharged examples.
e.g. Nothing worse than adding 20% fictitious power when one for example, applies a correction factor that happens to be 1.24 CF on a wastegate turbo controlled engine. this changes things by 100s of HP when getting up into big numbers.
05-31-2015, 10:52 AM
#9
as I originally said, its not the 5 figure precision instrument fault.. it is the shops and operators.
^^^^ this is why there are so much variances and the dyno gets the heat as being at fault for some reason. sad really...
06-01-2015, 09:54 PM
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It could also be the car, boosted cars dont always perform the same day to day. The dyno wont make up for horrible air in a boosted setup if it doesnt make the same amount of boost, belt slip, etc
06-02-2015, 08:20 AM
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OK, developments since original thread / post: I originally posted this thread as I had been shown a dyno chart by HPE that my car had made that during break-in of the HPE 700 build-up. They told me that they de-tuned the car down to 618 RWHP for the street. I later dynoed on two different Dynojets, both on SAE CF, & found out that I was actually making about 550 RWHP. I have since had D3, CMS, & Izzy's performance add some more goodies and a re-tune by Tom & I am currently up to 640 RWHP & 625 RWTQ on 91 pump but 680 RWHP & 650 RWTQ on a 50-50 mix of 91 pump & E-85. Many thanks for all the responses.
