took my car to the dyno ***updated with a/f info***

Q&A regarding engines, turbos, and intercoolers and power upgrades

Postby Razzo » Tue Mar 21, 2006 6:41 am

I didn't realize he was talking about correction factors. But about the drivetrain loss i would really only give it 20-25%. 30% is just to much :shock:
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Postby Conan » Tue Mar 21, 2006 6:51 am

Razzo wrote:30% is just to much :shock:

It's the reality.
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Postby crazy_russian » Wed Mar 22, 2006 1:19 am

Why do you say that standard dyno correction factor for air density is invalid for turbocharged cars? I think the effects of thiner air are the same UNLESS boost controller operates in terms of absolute pressure and allows more boost at higher altitudes. My understanding is the stock wastegate does not do that. Would be nice if it did though, you would automatically get extra 2.5psi in Denver and extra 5.3psi in Rocky Mountains National park (12000ft).
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Postby SuperWhite92 » Wed Mar 22, 2006 1:38 am

crazy_russian wrote:Why do you say that standard dyno correction factor for air density is invalid for turbocharged cars? I think the effects of thiner air are the same UNLESS boost controller operates in terms of absolute pressure and allows more boost at higher altitudes. My understanding is the stock wastegate does not do that. Would be nice if it did though, you would automatically get extra 2.5psi in Denver and extra 5.3psi in Rocky Mountains National park (12000ft).


The correction factors used are not for turbo cars, they are for N/A cars, which are unable to help correct for less air density. A turbo compresses the air to what it's supposed to be, pressure wise, while an N/A or supercharger cannot. It takes a bit longer to hit the same boost level when compared to boosting at sea level.

Here's a thread from a local board comparing a sea level dyno, a denver dyno, and a corrected denver dyno. It shows how shops BUTCHER the SAE correction. Cool for bragging rights, I guess.

http://awdpirates.net/phpBB2/viewtopic. ... highlight=
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Postby Razzo » Wed Mar 22, 2006 3:44 am

Conan wrote:
Razzo wrote:30% is just to much :shock:

It's the reality.


Really, thats new news, fwd cars average about 10-12% so your saving just because of a transfer case and another 2 wheels in the back you lose another 20% ekkk i went through a bunch of forums and dyno sheets to only see 3 awd and 4wd cars dyno more then 30% drivetrain lose. just what i see all over, figures he has here are like 20% so. I don't believe in that much drivetrain loss its just to much man. That means a stock sti makes 210whp....i dont see no drivetrain in the world that should lose 30% of the engines force in just the drivetrain. Just to much power being lost
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Postby Denver_whiteST185 » Wed Mar 22, 2006 3:55 am

hey guys, i finally found my A/F ratios. here they are....

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I know, its bad. do you think this is also why my idle is kinda lumpy?

btw, my two cents, i think the drivetrain loss is around 20%. is there a way to get my car dynoed at the crank easily? maybe that will solve the discusion i just replaced my oil and differential fluids a few days before the dyno, so drivetrain friction shouldn't have been that bad. im getting my transmission fluid flushed too, so ill probably have a few extra horses after that too.
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Postby turbo4wd » Wed Mar 22, 2006 4:34 am

Denver_whiteST185 wrote:hey guys, i finally found my A/F ratios. here they are....


:shock:

whoa..
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Postby Conan » Wed Mar 22, 2006 5:30 am

Denver_whiteST185 wrote:btw, my two cents, i think the drivetrain loss is around 20%. is there a way to get my car dynoed at the crank easily? maybe that will solve the discusion

You think beacause you are using your own numbers ;) That's why I said the uncorrected graph is much closer to the truth. You can switch the lever on the tranny and dyno the car in FWD mode, see what the difference is.
I believe your car is fast an all that but I have seen it stated more than once, a stock ST185 makes ~100 kW (which is 136 HP) on all wheels. You can count drivetrain loss from that.
Last edited by Conan on Wed Mar 22, 2006 5:41 am, edited 1 time in total.
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Postby Conan » Wed Mar 22, 2006 5:38 am

Razzo wrote:That means a stock sti makes 210whp....i dont see no drivetrain in the world that should lose 30% of the engines force in just the drivetrain. Just to much power being lost

So how much do you think a stock sti is making? :) A dyno uses special brakes to simulate the load the car is getting when it's running on the road. On such dyno, your exhaust manifold and turbine housing will be glowing after 1-2 runs. There are dynos without brakes though, inertia type, they measure power at the flywheel because the load is minimal. Now it's the matter of how "dyno brakes" are adjusted, the car will put down different numbers under different loads. That's why it's best to comare results from same dynos.
And 20% drivetrain loss is more an FR car like RX-7 or 200SX.
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Postby Denver_whiteST185 » Wed Mar 22, 2006 6:08 am

Conan wrote:
Denver_whiteST185 wrote:btw, my two cents, i think the drivetrain loss is around 20%. is there a way to get my car dynoed at the crank easily? maybe that will solve the discusion

You think beacause you are using your own numbers ;) That's why I said the uncorrected graph is much closer to the truth. You can switch the lever on the tranny and dyno the car in FWD mode, see what the difference is.
I believe your car is fast an all that but I have seen it stated more than once, a stock ST185 makes ~100 kW (which is 136 HP) on all wheels. You can count drivetrain loss from that.


Hey, where on the tranny is that lever? if i switched it to FWD, would everything work fine to drive it on an everyday basis. by the way, the uncorrected graphs are at around 6,000 ft, so the car is not putting out 200 crank hp. thats why theres a sae corrected version. also, sense everyone doesn't think i should use a SAFC, what are some idea to fix the A/F ratios?
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(not really, i just own a completely UNmodified 91 civic dx that gets 45+ mpg now)
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Postby Razzo » Wed Mar 22, 2006 6:21 am

Conan wrote:
Denver_whiteST185 wrote:btw, my two cents, i think the drivetrain loss is around 20%. is there a way to get my car dynoed at the crank easily? maybe that will solve the discusion

You think beacause you are using your own numbers ;) That's why I said the uncorrected graph is much closer to the truth. You can switch the lever on the tranny and dyno the car in FWD mode, see what the difference is.
I believe your car is fast an all that but I have seen it stated more than once, a stock ST185 makes ~100 kW (which is 136 HP) on all wheels. You can count drivetrain loss from that.


Actually.... I have seen many dynos that say 136hp for a stock alltrac, but i've also seen many dynos like this before. All i'm trying to say is the drivetrain loss numbers are going to be close to 25 then 30.
Last edited by Razzo on Wed Mar 22, 2006 6:37 am, edited 1 time in total.
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Postby Razzo » Wed Mar 22, 2006 6:36 am

Conan wrote:
Razzo wrote:That means a stock sti makes 210whp....i dont see no drivetrain in the world that should lose 30% of the engines force in just the drivetrain. Just to much power being lost

So how much do you think a stock sti is making? :) A dyno uses special brakes to simulate the load the car is getting when it's running on the road. On such dyno, your exhaust manifold and turbine housing will be glowing after 1-2 runs. There are dynos without brakes though, inertia type, they measure power at the flywheel because the load is minimal. Now it's the matter of how "dyno brakes" are adjusted, the car will put down different numbers under different loads. That's why it's best to comare results from same dynos.
And 20% drivetrain loss is more an FR car like RX-7 or 200SX.


A stock sti makes anywhere from 230-250 awhp it has a 300 crankhp rating.

So that means the sti has about 20-25% drivetrain loss, i know 4wd/awd trannys haven't had much on the technology side of things within the last 15 years.

Also your off about the rx-7 and the 200sx they lose about 15%(many people have dynos of the ka24 engine showing less then 15% drivetrain loss. You can look if you want. I think people are a little to hard on the gt-four(4wd system), you would be surprised.
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Postby Conan » Wed Mar 22, 2006 7:22 am

Ok Razzo, I think we can reach an agreement for 25-30% ;) But less than 25 - no way! :D
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Postby Conan » Wed Mar 22, 2006 8:11 am

Denver_whiteST185 wrote:Hey, where on the tranny is that lever? if i switched it to FWD, would everything work fine to drive it on an everyday basis.

Here's a related thread:
http://www.alltrac.net/phpBB2/viewtopic.php?t=8880
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Postby Denver_whiteST185 » Wed Mar 22, 2006 3:57 pm

thanks conan
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(not really, i just own a completely UNmodified 91 civic dx that gets 45+ mpg now)
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