Cut Out Dyno on a Camaro 2010 SS LS3 ...
04-03-2011, 10:46 AM
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Staging Lane
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Cut Out Dyno on a Camaro 2010 SS LS3 ... We've done a dyno day yesterday near Paris, France.
14 Cars, I've tuned a camaro 2010 SS on the street and then get to dyno.
Here is the comparaison dyno sheet. (The 2 two best of 6 runs (3 cut out closed, 3 cut out open).
(Tq is in NM, flywheel numbers on the comparaison sheet, the rwhp numbers don't appears on the sheet, a stock C5 is .. 349 fwhl this day, superflow dyno)
the PROBLEM is ... the higher numbers are CUTOUT CLOSED !
Too much back pressure ? we were shocked !
Mods : K&N airbox, ARH 1-3/4 headers, stock catback
any explanation ?
14 Cars, I've tuned a camaro 2010 SS on the street and then get to dyno.
Here is the comparaison dyno sheet. (The 2 two best of 6 runs (3 cut out closed, 3 cut out open).
(Tq is in NM, flywheel numbers on the comparaison sheet, the rwhp numbers don't appears on the sheet, a stock C5 is .. 349 fwhl this day, superflow dyno)
the PROBLEM is ... the higher numbers are CUTOUT CLOSED !
Too much back pressure ? we were shocked !
Mods : K&N airbox, ARH 1-3/4 headers, stock catback
any explanation ?
04-03-2011, 10:56 AM
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Staging Lane
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04-03-2011, 11:09 AM
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I don't have the logs.
I've street tuned with cut out open. Playing with timing on the dyno (15 minutes) and then we have dynoed with cut out closed.
I was so surprised !
I've just paid for dyno and the owner of the dyno shop's owner let me play a little with timing.
Has anyone the same results or I am the only one ? What are 'regular' gain ?
I've street tuned with cut out open. Playing with timing on the dyno (15 minutes) and then we have dynoed with cut out closed.
I was so surprised !
I've just paid for dyno and the owner of the dyno shop's owner let me play a little with timing.
Has anyone the same results or I am the only one ? What are 'regular' gain ?
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04-03-2011, 02:09 PM
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Staging Lane
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No it's not a temperature variation, we made 6 runs, same data (cut out open / close) and no dyno manipulation.
The real difference is cutout opened/closes. For information cutout closed are the last runs.
I've got 3 runs cutout opened, the data are the samed within 1-2 hp.
My best shot cut out opened is 438 fwhp ! it's a 15 rwhp loss !
I am the only one to have tested cut out on a LS3 ?
I think I have to rent the dyno 1 hour and find the reason.
04-03-2011, 02:16 PM
#10
"My best shot cut out opened is 438 fwhp ! it's a 15 rwhp loss !"
Could be the location of the cutout. It might be in the worst posible location for exhaust wave tuning. Then again it could be something else.
Hard to say without seeing it.
Could be the location of the cutout. It might be in the worst posible location for exhaust wave tuning. Then again it could be something else.
Hard to say without seeing it.
04-03-2011, 02:17 PM
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If I had the data ... I don't need to post question on a forum.
No it's not a temperature variation, we made 6 runs, same data (cut out open / close) and no dyno manipulation.
The real difference is cutout opened/closes
I've got 3 runs cutout opened, the data are the samed within 1-2 hp.
No it's not a temperature variation, we made 6 runs, same data (cut out open / close) and no dyno manipulation.
The real difference is cutout opened/closes
I've got 3 runs cutout opened, the data are the samed within 1-2 hp.
And it's difficult to not say impossible to technically be affirmative on your case if you have no data to provide...and you can't be sure of temp/MAP/Dyn Airflow/Inj Duty cyc/IAT as long as you can't check them...
Christian
04-03-2011, 02:20 PM
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The curves shape are so parallel (from 2000 rpm to 4500 rpm...) that it is really looking like the Dyno Operator modified/adjusted the calibration between the runs...by purpose or by accident...it's a classic for anyone used to work on a dyno to see this figure.
And it's difficult to not say impossible to technically be affirmative on your case if you have no data to provide...and you can't be sure of temp/MAP/Dyn Airflow/Inj Duty cyc/IAT as long as you can't check them...
Christian
And it's difficult to not say impossible to technically be affirmative on your case if you have no data to provide...and you can't be sure of temp/MAP/Dyn Airflow/Inj Duty cyc/IAT as long as you can't check them...
Christian
1 minute after the best run with cutout open. I told him : let's test without the cut out closed !
and here are the results !
I am agree with you but .. do you mean all the dyno sheets on the forum section are a total non sense without datalogs ?
04-03-2011, 02:56 PM
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Got it !
http://www.camaro5.com/forums/showth...t=53251&page=2
"I got a dyno tune and I lost power (5-10 hp) over the curve with the cutouts open vs the 419/401 with headers and tune, but that's not why I got them. I'm certain you would see more power over the stock tune on a stock exhaust"
http://www.camaro5.com/forums/showth...t=53251&page=2
"I got a dyno tune and I lost power (5-10 hp) over the curve with the cutouts open vs the 419/401 with headers and tune, but that's not why I got them. I'm certain you would see more power over the stock tune on a stock exhaust"
