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I'm trying to get conclusive evidence on what is the best gear to dyno our cars. My original thread is here where all my runs were done in 4th gear but my A/F ratios were off. Sal thinks the engine doesn't look loaded enough and suggested 5th gear, but others have chimed in that 5th could be too tall and others still have said they used 3rd gear.

SO, Dyno people what do you think? Also if others who've had their cars dynoed could chip in what gear it was done in perhaps that will help narrow down the issue.

Thanks all!
 

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I'm trying to get conclusive evidence on what is the best gear to dyno our cars. My original thread is here where all my runs were done in 4th gear but my A/F ratios were off. Sal thinks the engine doesn't look loaded enough and suggested 5th gear, but others have chimed in that 5th could be too tall and others still have said they used 3rd gear.

SO, Dyno people what do you think? Also if others who've had their cars dynoed could chip in what gear it was done in perhaps that will help narrow down the issue.

Thanks all!
3rd gear wont get sufficient load. 4th does, but 5th does so best (and is the 1:1 gear).
 

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Yes, 5th gear is 1:1.
 
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the "dyno in the 1:1 gear" is a bit of a misnomer considering the vast numbers of different final-drive ratios available. For a non-load-simulating dyno, loading the engine more (higher gears) will be of some benefit. Other dynos that allow you do adjust load can work within a few HP/TQ in different gears.
 

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1:1 means nothing.

Here are the facts:

1) Different dyno's will require different gears to be tested in
2) You cannot compare figures from one brand to another
3) As long as tests are performed in the same gear on the same type of dyno's - that's all that matters
4) Without correction factors being displayed dyno graphs belong in the bin as they mean nothing.

Consistency within dyno brands is what's important.

The Dyno Dynamics graphs need the most amount of sorting out. Dynojet - just dyno in 5th guys. It works and the consistent is nothing short of excellent. Figures are properly on the high side sometimes compared to others but that doesn't matter.
 

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the "dyno in the 1:1 gear" is a bit of a misnomer considering the vast numbers of different final-drive ratios available. For a non-load-simulating dyno, loading the engine more (higher gears) will be of some benefit. Other dynos that allow you do adjust load can work within a few HP/TQ in different gears.
This is very true. This is what leads to vast inconsistency between dynos and to other old wives tales about brand X reading low or high when trying to get real HP numbers. For tuning, it's essential to have a load simulating dyno and the "true" HP number is irrelevant. It's awesome that nowadays we can have machines that can do it all!



1:1 means nothing.

Here are the facts:

1) Different dyno's will require different gears to be tested in
2) You cannot compare figures from one brand to another
3) As long as tests are performed in the same gear on the same type of dyno's - that's all that matters
4) Without correction factors being displayed dyno graphs belong in the bin as they mean nothing.

Consistency within dyno brands is what's important.

The Dyno Dynamics graphs need the most amount of sorting out. Dynojet - just dyno in 5th guys. It works and the consistent is nothing short of excellent. Figures are properly on the high side sometimes compared to others but that doesn't matter.
Couldnt agree more. Except with the last statement, others read as the operator sets the load/weight/etc...dynojet reads true WHP w/o the load cell engaged (otherwise it's the same deal as other brands) :cheers:
 

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This is very true. This is what leads to vast inconsistency between dynos and to other old wives tales about brand X reading low or high when trying to get real HP numbers. For tuning, it's essential to have a load simulating dyno and the "true" HP number is irrelevant. It's awesome that nowadays we can have machines that can do it all!





Couldnt agree more. Except with the last statement, others read as the operator sets the load/weight/etc...dynojet reads true WHP w/o the load cell engaged (otherwise it's the same deal as other brands) :cheers:
Please elaborate.

I really like the dynojet for one major reason - it allows the engine to naturally deliver it's power rather than against a constant brake. Can totally screw up the torque calculations!
 

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Please elaborate.

I really like the dynojet for one major reason - it allows the engine to naturally deliver it's power rather than against a constant brake. Can totally screw up the torque calculations!
The dynojet uses a heavy drum vs the Dyno Dynamics/Mustang/etc that use an eddy current to apply load. For HP readings, you just use the inertia part (ie the weight of the drum). The sensors measure how fast the drum accelerates over a period of time and then combine that number with an RPM readout to get a torque figure. Then HP is calculated. If you engage the load cell/brake, you'll skew the torque numbers (and consequently HP #'s) down by whatever % load you decide to apply to the drum. You can fit all the same sensors that a DD has to the DJ, AND you'll get an electronic runfile you can share so that there is no way to hide any cheating. You've played with Winpep....there is a surprising amount of info you can tag into the runfile.
 

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The dynojet uses a heavy drum vs the Dyno Dynamics/Mustang/etc that use an eddy current to apply load. For HP readings, you just use the inertia part (ie the weight of the drum). The sensors measure how fast the drum accelerates over a period of time and then combine that number with an RPM readout to get a torque figure. Then HP is calculated. If you engage the load cell/brake, you'll skew the torque numbers (and consequently HP #'s) down by whatever % load you decide to apply to the drum. You can fit all the same sensors that a DD has to the DJ, AND you'll get an electronic runfile you can share so that there is no way to hide any cheating. You've played with Winpep....there is a surprising amount of info you can tag into the runfile.
I used a dynojet in Dubai and really liked it. The V10 I tuned and 30hp was gained. It gained it's power far more quickly than when applying a brake force and this really is down to the fact that the engine can deliver it's power naturally.

So, how do you know if someone has applied a brake force on a dynojet?

Also, I know that a correction is given but is the information on how that's derived available?

The only thing that bugs me is the vast difference in wheel HP between dynojet and dyno dynamics.... sometimes.

Thankfully the S62 power readings for stock cars atleast are quite close when comparing wheel figures but that really depends on what ramp rate was applied on a dyno dynamics which can massively vary from shop to shop unless they all start using shootout mode!

Winpep is pure brilliance.
 

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I used a dynojet in Dubai and really liked it. The V10 I tuned and 30hp was gained. It gained it's power far more quickly than when applying a brake force and this really is down to the fact that the engine can deliver it's power naturally.

So, how do you know if someone has applied a brake force on a dynojet?

Also, I know that a correction is given but is the information on how that's derived available?

The only thing that bugs me is the vast difference in wheel HP between dynojet and dyno dynamics.... sometimes.

Thankfully the S62 power readings for stock cars atleast are quite close when comparing wheel figures but that really depends on what ramp rate was applied on a dyno dynamics which can massively vary from shop to shop unless they all start using shootout mode!

Winpep is pure brilliance.

You can call up the load cell percentage/brake force in the runfile parameters. If the dyno is load cell equipped, the load will show up there. Also, the correction factors and smoothing play a big part in the number output. SAE reads the lowest, DIN/Japanese the highest. STD falls somewhere in the middle. We used to do SAE, smoothing 3 to compare graphs from different machines to one another.
 

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Short of re-writing the base code/tampering with the hardware in the stack, there is no way to cheat :blabla:



yup. exactly why NASA has mandated their use [as well as other sanctioning bodies] for enforcement of power-to-weight ratio rules.
 
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