Percentage diff between a Chassis Dyno and an Engine Dyno - Page 2

Ed Wright · 04-04-2011, 03:59 PM

As with any dyno, the numbers don't actually matter, it's the DIFFERENCE you see from the changes that matter. The shops I was refering to had Super Flow engine dynos and Dyno Jet chassis dynos. Mustang dynos don't alwaye read lower. Depends on the operator and the load factors they use. When the ATI Procharger people hauled their prototype cars from my shop (Dynojet), after tuning, to their place (Mustang dyno) they typically picked up around 5%.

Mike Taylor 3601 · 04-05-2011, 02:26 PM

Only thing I can tell you is my car lost 28% on chassis dyno.It was automatic then. Dynoed engine on superflow SF900AT It was calibrated as close as possible,air corrected to 29.9 baro 60 degrees. Then later we got a Dyno jet chassis so my car used to test it lost
28%.
As Ed said don't compare your # to others,just look at gains from where you started.
I don't know about others but dyno jet has setting where you let car coast after pull and it calculates driveline drag or % of loss I can't remember term they use.
I don't have much chassis dyno experience but in my opinion they probaly not as repeatable as good engine dyno.
Mike Taylor 3601

Ed Wright · 04-05-2011, 10:06 PM

Mike your sure right. A race converter causes more loss, also converter & fluid temp changes effect slippage losses. Tire slippage is another variable. Had a 10.5 car bring his car two days after it was on Reher & Morrison's engine dyno. His showed a 28% loss also. Mine has never been on an engine dyno. Sure hope mine looses more than 28%! LMAO!

Adger Smith · 04-06-2011, 07:19 AM

Ed,
Good morning.
Are you saying the HP math on your car is: 0 - 28% = 0 ??? :~)

Ed Wright · 04-06-2011, 08:05 AM

Quote:

Originally Posted by Adger Smith

Ed,
Good morning.
Are you saying the HP math on your car is: 0 - 28% = 0 ??? :~)

Pretty darn close. :-(

Mike Taylor 3601 · 04-06-2011, 12:00 PM

Ed
Took a minute for that to register,your're saying you hope your driveline is worse than 28% so your engine is making more than what chassis dyno is telling you.I'm from Ky. takes me a minute or two sometimes.
I hope to have mine back on chassis dyno soon to test X pipe different mufflers,I'm interested to see how much less stick uses.
Mike Taylor 3601

Ed Wright · 04-06-2011, 12:45 PM

Quote:

Originally Posted by Mike Taylor 3601

Ed
Took a minute for that to register,your're saying you hope your driveline is worse than 28% so your engine is making more than what chassis dyno is telling you.I'm from Ky. takes me a minute or two sometimes.
I hope to have mine back on chassis dyno soon to test X pipe different mufflers,I'm interested to see how much less stick uses.
Mike Taylor 3601

Mike, that's what I meant. Maybe my Okie accent makes me hard to understand. LOL

04-04-2011, 03:59 PM	#11
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Percentage diff between a Chassis Dyno and an Engine Dyn As with any dyno, the numbers don't actually matter, it's the DIFFERENCE you see from the changes that matter. The shops I was refering to had Super Flow engine dynos and Dyno Jet chassis dynos. Mustang dynos don't alwaye read lower. Depends on the operator and the load factors they use. When the ATI Procharger people hauled their prototype cars from my shop (Dynojet), after tuning, to their place (Mustang dyno) they typically picked up around 5%. __________________ Ed Wright 4156 SS/JA

04-05-2011, 02:26 PM	#12
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,372 Likes: 354 Liked 307 Times in 103 Posts	Re: Percentage diff between a Chassis Dyno and an Engine Dyn Only thing I can tell you is my car lost 28% on chassis dyno.It was automatic then. Dynoed engine on superflow SF900AT It was calibrated as close as possible,air corrected to 29.9 baro 60 degrees. Then later we got a Dyno jet chassis so my car used to test it lost 28%. As Ed said don't compare your # to others,just look at gains from where you started. I don't know about others but dyno jet has setting where you let car coast after pull and it calculates driveline drag or % of loss I can't remember term they use. I don't have much chassis dyno experience but in my opinion they probaly not as repeatable as good engine dyno. Mike Taylor 3601

04-05-2011, 10:06 PM	#13
Ed Wright Veteran Member Join Date: Mar 2005 Location: Sand Springs, OK Posts: 8,132 Likes: 896 Liked 390 Times in 170 Posts	Re: Percentage diff between a Chassis Dyno and an Engine Dyn Mike your sure right. A race converter causes more loss, also converter & fluid temp changes effect slippage losses. Tire slippage is another variable. Had a 10.5 car bring his car two days after it was on Reher & Morrison's engine dyno. His showed a 28% loss also. Mine has never been on an engine dyno. Sure hope mine looses more than 28%! LMAO! __________________ Ed Wright 4156 SS/JA

04-06-2011, 07:19 AM	#14
Adger Smith VIP Member Join Date: Dec 2001 Location: Texarkana Ark/TX Posts: 2,446 Likes: 575 Liked 880 Times in 311 Posts	Re: Percentage diff between a Chassis Dyno and an Engine Dyn Ed, Good morning. Are you saying the HP math on your car is: 0 - 28% = 0 ??? :~) __________________ Adger Smith (Former SS)

04-06-2011, 12:00 PM	#16
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,372 Likes: 354 Liked 307 Times in 103 Posts	Re: Percentage diff between a Chassis Dyno and an Engine Dyn Ed Took a minute for that to register,your're saying you hope your driveline is worse than 28% so your engine is making more than what chassis dyno is telling you.I'm from Ky. takes me a minute or two sometimes. I hope to have mine back on chassis dyno soon to test X pipe different mufflers,I'm interested to see how much less stick uses. Mike Taylor 3601