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I was told yesterday that the new Z will WAY under rated. That many cars have dynoed around 460rwhp/425rwtq ! Could GM be doing what SVT did with the Cobras ?
 

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azzkiknZO6 said:
I was told yesterday that the new Z will WAY under rated. That many cars have dynoed around 460rwhp/425rwtq ! Could GM be doing what SVT did with the Cobras ?
I hope so. :sneaky:
 

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azzkiknZO6 said:
I was told yesterday that the new Z will WAY under rated. That many cars have dynoed around 460rwhp/425rwtq ! Could GM be doing what SVT did with the Cobras ?
It would be sweet indeed if more #'s show up than GM stated.
 

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azzkiknZO6 said:
I was told yesterday that the new Z will WAY under rated. That many cars have dynoed around 460rwhp/425rwtq ! Could GM be doing what SVT did with the Cobras ?
No way GM is very honest ( maybe a little to honest sometimes). It's not under rated it's undertuned, big difference. IMO the new Z06 will Dyno at around 440RWHP. I know it seems very low to us when many members with 427's have Dyno numbers 70 to 90 RWHP more. This gives GM the potential to increase HP in future years very easily.
So with a set of Headers and camshaft change the new Z06 will right back up there with big time numbers of 500 plus RWHP.


I found your comment about the Mustang a little amusing. After all the years of Mustang lying about HP they finally went legit. A stock Cobra Dyno's at 350 RWHP. If you are hearing bigger numbers it's from bench racer's
 

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From what i understand the small cam is holding the ls7 back so a new cam alone should make BIG gains.
 

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IT L GO said:
IMO the new Z06 will Dyno at around 340RWHP. I know it seems very low to us when many members with 427's have Dyno numbers 70 to 90 RWHP more. This gives GM the potential to increase HP in future years very easily.
Surely you mean 440rwhp?

Geoff
 

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IT L GO said:
No way GM is very honest ( maybe a little to honest sometimes). It's not under rated it's undertuned, big difference. IMO the new Z06 will Dyno at around 340RWHP. I know it seems very low to us when many members with 427's have Dyno numbers 70 to 90 RWHP more. This gives GM the potential to increase HP in future years very easily.
So with a set of Headers and camshaft change the new Z06 will right back up there with big time numbers of 500 plus RWHP.


I found your comment about the Mustang a little amusing. After all the years of Mustang lying about HP they finally went legit. A stock Cobra Dyno's at 350 RWHP. If you are hearing bigger numbers it's from bench racer's
My stock '03 Cobra dynoed at 372...some people with no more than a CAI top out right @ 400. Mine is currently 460hp/458 tq at the wheels. As you well know manufacturers rating is based on being measured at the flywheel (this is what is confusing to the "Average Joe" consumer) as opposed to being measured at the wheels (standard dyno measurement). Drivetrain loss can be 10% on most vehicles.

BTW....03-04 Cobra's were/are under rated.....Marketed at 390 hp...actually @ 420 at the flywheel.
 

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azzkiknZO6 said:
I was told yesterday that the new Z will WAY under rated. That many cars have dynoed around 460rwhp/425rwtq ! Could GM be doing what SVT did with the Cobras ?
I have a buddy with the new Cobolt SS rated at 205hp and put down 214 fwhp stock.......Figure that one out!!!!!!!!!! :jawdrop: :jawdrop:
 

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we will find out soon...I doubt it tho

maybe few cars here and there will dyno 450-460, but most will be 440 rwhp range....
 

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Assuming the standard 15% drivetrain loss the rwhp should be 429 not 440, given a bhp of 505.

If you increase the rwhp figure to 440 then the bhp would be 518 (or the drivetrain loss less than 15%). Recall that virtually every rwhp figure on this forum has been calculated based on a 15% drivetrain loss.
 

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No Doubt said:
Assuming the standard 15% drivetrain loss the rwhp should be 429 not 440, given a bhp of 505.

If you increase the rwhp figure to 440 then the bhp would be 518 (or the drivetrain loss less than 15%). Recall that virtually every rwhp figure on this forum has been calculated based on a 15% drivetrain loss.
You know I have often read this figure of 15% drivetrain loss but I don't understand how this can hold true.

Can someone explain how/why an engine rated at 505hp SAE (accessories and exhaust included) can lose a fixed percentage of power through the same driveline as power increases?

For instance, using the example that a 505hp SAE engine would dyno 430rwhp (delta 75 hp assumed 15% drivetrain loss.) However, adding 100 hp to the same engine without making any driveline changes; would equate to 514rwhp using the 15% (a delta of 84 hp).

Why wouldn't the difference remain constant with an engine using the same driveline??? Do frictional losses increase that much as power increases??? Why?

-RR
 

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No Doubt said:
Assuming the standard 15% drivetrain loss the rwhp should be 429 not 440, given a bhp of 505.

If you increase the rwhp figure to 440 then the bhp would be 518 (or the drivetrain loss less than 15%). Recall that virtually every rwhp figure on this forum has been calculated based on a 15% drivetrain loss.
Early Engine Dyno tests shows that many of the new LS7's were producing numbers around 513 HP give or take a few. The General decided to advertise the HP as 500HP then latter changed to 505 HP. This would insure that everyone got at least 505 HP plus. I used 515 HP minus 15% drivetrain loss to arrive at my figure of 440 RWHP. I guess I should have said 437.5: :D
 
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