joytown

L.A. Performance Division here in Los Angeles had a "grand re-opening event" yesterday. Buncha vette folks (and a few others) getting to hang out. Great shop and great folks BTW: http://www.TheLAPD.com

Here are some pics from that event:
http://forums.corvetteforum.com/show...1&postcount=47
http://forums.corvetteforum.com/show...2&postcount=49


Anyway, as part of the event, the fine folks at LAPD were offering free Dyno pulls so another CF LA guy, LexAudio, and I decided to do an experiment and do back-to-back dyno pulls. Same day, same dyno, same temperature, same everything.

The Cars:
Joytown: 2008 C6 LS3 A6 NPP - Stock
LexAudio: 2006 C6 LS2 MN6 - Varam, B&B Bullets


My results for the LS3:
378.48 RWHP / 362 TQ!

Now, the dyno guys said that it needed some calibration so the numbers showed a bit low and called it an even 380HP. What's amazing about this number is if you do some math. The rule of thumb on an Automatic is a 20% loss from the crank to the wheels. Plugging in the numbers gives you a whopping 475HP! This from a car pretty much straight off the lot with an official rating at 436HP!! Awesome.

So now -- I'll get Lex to post his numbers for comparison - we felt that his two mods made the two cars comparable. Will the numbers bear out?

Meanwhile, here's my sheet:




Cheers all - and thanks again to L.A.P.D in Chatsworth!

-jon

maxp

thanks for the numbers LS3/A6/NPP here also

Wicked C5

Not for a Vette your about 15% drivetrain loss a little less with a manual. Rear tranny helps the numbers. Your numbers would be about spot on with 15%

Boomer111

Joytown..........You are dreaming if you think your 436hp rated engine is doing 475hp!!

Remember I am only the messenger

joytown

15% loss with a 380 RWHP = 447 HP still not too shabby -- Thanks for the clarification - was just going on what I was told yesterday as a rule of thumb.



-jon

joytown

Just ran the numbers using the 20% drivetrain loss on an Automatic guideline.

475*20% = 95
475-95 = 380

I'll certainly stand corrected!

-jon

C6~Missle

great numbers... is that stock?

carlrx7

unless your engine is out of the car and on an engine dyno, the flywheel number is gonna be wrong. just stick to the rwhp numbers. thats the actual power moving your car..

FM

Sounds like one case where the rule of thumb doesn't work.

It's always seemed strange to me that, for example, a Honda Accord with 150HP loses 30HP (20%) in the drive train, but a Corvette with 436HP loses (following the ROT) 87HP.

I would expect a somewhat greater loss with a heavier duty drive train, but 3 times as much? Doesn't seem possible.

OTOH, a loss of 56HP (436-380) compared to the Honda's 30HP seems much more likely.

talon90

Nice numbers. As others have indicated, you do not have a 475 hp LS3, hate to burst your bubble. The LS3 motor is SAE certified and as such they will all be 430 plus or minus. The 2008 and LS3 have lower driveline loss figures than previous generation Corvettes. The manuals are seeing loss in the 43-48 hp range and the automatics roughly 60 to 65. While fun for benchmarking the "percent loss" calculation is a total misnomer.

A driveline should lose horsepower fairly consistantly across a wide range. Meaning, if you make power adders under the hood they will not change the hp loss of the driveline. Slop, tolerance and friction of the driveline will not change just because you got a tune or an intake. Using percentages will result in expectations of artificial loss and unrealistic gains.

For example:

Stock LS3 and driveline on a T6060 mn6 transmission would expect to have a RWHP of approximately 385 (430-45)

If you take that same engine and driveline and add a supercharger you should expect that your RWHP is 430+150=580, subtract driveline loss (585-45=535.

If you did the same thing using the percentage calculations you would see 526.6 (585-58.5). How would the same driveline lose more horsepower just because the engine produced more power from an external source. The friction and loss of the driveline hasn't changed. If you change the cam, the clutch, the differential or the gearing then yes it will affect the driveline loss but stock to stock the percentage game just doesn't play out. While the super charger is an extreme example and due to some parasitic loss may not be the best example to cite it still shows that with percent calculations larger gains produce larger losses and this just shouldn't be the case.

The only way to know what the car has for driveline loss is to dyno the engine (BHP) and then dyno the driveline (RWHP) and measure the loss. Once you know that loss number you can then determine what your power adders have done to your baseline RWHP number. Other than that is is purely fantasy. Simply stated no one knows what the current mechanical efficiency of the newer drivelines are but if you must use a "percentage for comparison than in stock trim on the manual it looks like it is about 10-11% of stock horse power and the auto is about 14-15%.

need-for-speed

Well it sounds like you went to the same HP Back Calculation class that that LexAdio went to

I traded several IM's with him about the numbers his LS2 was making and his attempts at back calculating (a very optimistic) number for crankshaft HP. I finally gave up.


Also, if you are going to compare an LS2 to an LS3, it would be nice to have both with the same tranny.


BTW - your number look to be right on the money for an A6 car.

'06 Quicksilver Z06

Well put.

jrpedraza

Ummm, where are Lexaudio's numbers? I was expecting both in the post.. Definitely impressive numbers.

lexaudio

Can't get the scanner to work. Jon will vouch.

370 RW
370 TQ

LEX

'06 Quicksilver Z06

Nice numbers.

joytown

I thought it seemed a little high - although I'm a board certified n00b when it comes to a lot of this stuff. Thanks for the informative post. One of the great things about this forum is how much you can learn!

Cheers

-jon

joytown

Bottom line:

Joytown: 2008 C6 LS3 A6 NPP - Stock
380 RW
362 TQ

LexAudio: 2006 C6 LS2 MN6 - Varam, B&B Bullets
370 RW
370 TQ

Thought it makes an interesting comparison, although I agree that it would be nice if they both had the same tranny.

-jon

danl72

Good numbers.

Patman

I know it's not a direct comparison since one is a manual and one is auto, plus the LS2 is modded, but I do find it interesting that even though the LS3 in this case makes more power, it doesn't make as much torque as the LS2.

FloydSummerOf68

Go race em and I bet the LS2 with those mods would outrun the LS3.

I'm insanely impressed the LS2 made those numbers with 2 mods that dont show much power increase on a dyno. Is his car tuned also?

Dyno numbers mean very very little. Go to a track if you want to know what kind of performance your car has. A dyno just gives you a sheet of paper that you can brag about to others who dont understand.

Nice numbers though.