[M12LRV]

I just threw 15% out there because it is a typical ball park number and using that it is still far off. It shows a 10% drivetrain loss, not 12%, which seems like something is up to me.

Edmunds gets 411hp/ 407tq on 91 octane

http://www.edmunds.com/car-reviews/t...dyno-test.html

[fradaj]

I doubt the LT1 is underrated in the Corvette. But there could be differences in the output of the LT1 in the Camaro. I do remember the LLT V6 was rated at 304 in 2010 and then 312 in 2011 after it was re-certified.

[Bhobbs]

Originally Posted by M12LRV

I just threw 15% out there because it is a typical ball park number and using that it is still far off. It shows a 10% drivetrain loss, not 12%, which seems like something is up to me.

Edmunds gets 411hp/ 407tq on 91 octane

http://www.edmunds.com/car-reviews/t...dyno-test.html

Chassis dynos are not very accurate. They are all different. Do you want to say SAE is not right because one dyno showed a number that was used with a WAG for the drive train loss, which came up with a more or less horsepower than SAE said?

[DGthe3]

Originally Posted by M12LRV

I just threw 15% out there because it is a typical ball park number and using that it is still far off. It shows a 10% drivetrain loss, not 12%, which seems like something is up to me.

Edmunds gets 411hp/ 407tq on 91 octane

http://www.edmunds.com/car-reviews/t...dyno-test.html

Dynomometers can easily vary by 10% (probably more) in a given city, depending on type & operator. Some read high, some read low. Then there are correction factors which can further nudge the numbers one way or another. Thats why I don't like using them as a tool for comparison, they're too unreliable.

Its widely believed that Edmunds uses a 'happy dyno', ie a dyno that makes the customer happy because they get a nice big number.

Originally Posted by fradaj

I doubt the LT1 is underrated in the Corvette. But there could be differences in the output of the LT1 in the Camaro. I do remember the LLT V6 was rated at 304 in 2010 and then 312 in 2011 after it was re-certified.

Except that GM has already said that the LT1 is certified to make 455 hp in the Camaro. I don't think they were advertising the 304 hp on the 2010 Camaros as being SAE certified, because that would be inaccurate.

[whiteboyblues2001]

Originally Posted by fradaj

I doubt the LT1 is underrated in the Corvette. But there could be differences in the output of the LT1 in the Camaro. I do remember the LLT V6 was rated at 304 in 2010 and then 312 in 2011 after it was re-certified.

The LLT was never "rated" at 304, that was an estimate. Once it was certified, it was published at 312. Back then, the 2010 Camaro guys were wondering if the 2011 LLT had changes that lead to the increase in HP. Chevy came out and stated that the 304 number was an estimate, and that all LLT Camaro owners (2010 and 2011 at that time) had a 312 Certified HP engine.

[SpeedIsLife]

I think in 2009 they were saying "estimated 304"

[GretchenGotGrowl]

Originally Posted by whiteboyblues2001

The LLT was never "rated" at 304, that was an estimate. Once it was certified, it was published at 312. Back then, the 2010 Camaro guys were wondering if the 2011 LLT had changes that lead to the increase in HP. Chevy came out and stated that the 304 number was an estimate, and that all LLT Camaro owners (2010 and 2011 at that time) had a 312 Certified HP engine.

Originally Posted by SpeedIsLife

I think in 2009 they were saying "estimated 304"

Exactly. The 304 HP number came from the SAE rating for the LLT in the Cadillac. There were some changes to the exhaust (probably some accessories as well) when it went into the Camaro that bumped the output up a bit.

[High Magnitude]

Originally Posted by Jeffro19

Wow not even broke in. Either they are overrated or they have the most efficient powertrain ever, I highly doubt that though.

The ZF gearbox is amazing at putting power to the ground.

[titanfan]

Originally Posted by IOMike

Why do people think that drivetrain loss is a static number?

It boggles my mind. You guys are way over simplifying it.

And if you know anything about chassis dyno's, they all read differently, even if they are made the same manufacturer.

[Fraxum]

What difference do dynos make? They will all tell you something different.

Let's see some 1/4 mile MPHes. Then we will have a better idea.

[ULTRAZLS1]

Originally Posted by Z_Rocks

I agree. I met a guy last week who just picked up his new Challenger M6 and after 38 miles, had it dynoed in the hot humid weather in Florida and got 640 RWHP. Even at 12% loss, that 727 to crank.

Dude. That car still lost 70 hp through the drivetrain.

Just think about it for a minute and realize why applying a percentage is just that much more inaccurate with a high hp car.

It's a random guess based off of a chassis dyno reading with a shit ton of variables. It's a crap shoot.
Personally I think the sae certification is more accurate.

But everyone wants to think their car is special lol.

Every motor put in the hellcat makes between 700-715 hp. Around plus or minus 1% of 707.

[VADER SS L99]

Its funny how every few years a engine comes out and people think its underated. This is not the 50's-2000's anymore. Chassis dyno's are a tuning tool and can be a good power measurement for adding aftermarket parts on the same day. Otherwise there are wayyyyyyy to many variables to get a accurate crank power rating from it. I have seen some shops report a measurable change in rwhp on the same exact car, dyno, everything, only days apart.

[laborsmith]

Originally Posted by VADER SS L99

Its funny how every few years a engine comes out and people think its underated. This is not the 50's-2000's anymore. Chassis dyno's are a tuning tool and can be a good power measurement for adding aftermarket parts on the same day. Otherwise there are wayyyyyyy to many variables to get a accurate crank power rating from it. I have seen some shops report a measurable change in rwhp on the same exact car, dyno, everything, only days apart.

So true. As someone who in the past dyno tuned, I know whereof VADER speaks. Hours apart, not days. Late afternoon/early evening low humidity days return the better results when compared to a early afternoon quick showers on the same day.

My two cents.

Laborsmith