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Engine vs chassis dyno numbers

Old 11-09-2018, 10:16 AM
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EuroRod
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Default Engine vs chassis dyno numbers

Has anyone had comparable figures between an engine dyno and a chassis dyno for the same engine? Just curious how much is lost from the drivetrain ? Iíve heard 12 to 18% and wondering if there may be some real world figures out there?
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Old 11-09-2018, 11:01 AM
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Turbo6TA
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12-13% for the manual transmission

15% for the automatic
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Old 11-09-2018, 11:04 AM
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Pekka_Perkeles
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Some things to consider:

- STP vs. SAE
- measured vs. unmeasured losses
- correction factors
- unlocked vs. locked converters
- requested and real AFR
- requested and real timing
- etc. etc.

Logs from the dyno runs are essential be be able to compare any dyno runs.

Without those provided, comparing is pretty useless.

Just my 3 cents.
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Old 11-09-2018, 11:10 AM
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Originally Posted by Turbo6TA View Post
12-13% for the manual transmission

15% for the automatic
Very good.

But how many have actually measured those losses.

With or without lockiing converter? Do you release converter at the redline with tuning sw? Etc. etc

.
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Old 11-14-2018, 01:51 PM
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algZO6
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Blue line locked Red unlocked

Last edited by algZO6; 11-14-2018 at 01:52 PM.
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Old 11-15-2018, 05:25 PM
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farmington
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Dynojet dynos read about 10% higher than a Mustang dyno. So thatís something you need to consider also.
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Old 11-16-2018, 08:38 AM
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Unreal
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It isn't a set percent. It is a percent+fixed number, depending on drivetrain.

Kind of a pointless thing to chase down anyways. Seen a rock crawler do 900hp on engine dyno, then 600rwhp on a dyno.

Seen a c6z lose 25rwhp just swapping wheels/tires. Plus dyno to dyno variation, dyno type, etc etc

Figure anywhere from 10-40% or set number to spin certain parts + percent for friction/pumping/etc losses.

Last edited by Unreal; 11-16-2018 at 08:39 AM.
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Old 11-16-2018, 10:34 AM
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Originally Posted by Unreal View Post
It isn't a set percent. It is a percent+fixed number, depending on drivetrain.

Kind of a pointless thing to chase down anyways. Seen a rock crawler do 900hp on engine dyno, then 600rwhp on a dyno.

Seen a c6z lose 25rwhp just swapping wheels/tires. Plus dyno to dyno variation, dyno type, etc etc

Figure anywhere from 10-40% or set number to spin certain parts + percent for friction/pumping/etc losses.
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Old 11-17-2018, 07:59 PM
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stevieturbo
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Originally Posted by EuroRod View Post
Has anyone had comparable figures between an engine dyno and a chassis dyno for the same engine? Just curious how much is lost from the drivetrain ? Iíve heard 12 to 18% and wondering if there may be some real world figures out there?
Whichever gives the highest number to keep them happy down the pub.

Very pointless exercise.
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