cmicasa

LS3 RWHP?
LS2 RWHP

then What have U fellas who put a Vortex, KillaBEE, Lingenfelter, or Vararam getting on the Dyno after the instal??

MNVette

Basically, a manual C6 will lose 15% or so from the crank to the rear wheels. An auto will lose 18-20%.

That means 400 hp at the crank will equal 340 rwhp or so on a manual, and an auto will be a little more than 320 rwhp. For 430 hp, the numbers would be about 365 rwhp or so for a manual and about 350 rwhp or so on an auto.

There is a great deal of debate over CAI's. IMHO, they don't add much of anything.

LostAngel

^A lot of stock MN6 LS2's i've seen are getting 350-360....stock MN6's ive seen are getting in the 390's that i've seen...

RACN1320

I believe stock LS3s dyno in around 385 hp and stock LS2s dyno in the 350 hp range

JSB LS3

Those numbers are low.

real world, most LS2s are in the 340-360 range. LS3s usually put down 370-390

wayback

here is my dyno. 2007 LS2 stock vs haltech cai, LG street series and tune.

HawaiiC6

Gotta disagree on your opinion on CAIs, the problem with a system like the Vararam is that it will show nothing on the dyno as it is a true ram air system. The dyno is done on a car not moving so therefore there is no ramming of air into the system which will not show any improvement on the dyno. But on the SOP and time slips being shown there are well documented improvements meaning that HP and TQ is being made by the system but at speed, the faster you go the more power you make.

siffert

For the LS2 off the production line, HP varies from 396 to 404 at 1% QC production difference. This equates to about 325-335 RWHP for the Auto and 340-350 RWHP for the Manual.

FloydSummerOf68

I always figured the manual LS2 to lose around 12-13% and the auto losing aronud 15-17%

jschindler

You have to be careful that you are comparing apples to apples. The new SAE rating system changed things on the 2008s.

My car dyno'd at 390.5 at MTI in houston (LS3 with NPP & manual tranny). Jayson overlayed a bone stock LS2 that they had dynod, and he said was very typical of LS2's. If I recall correctly, it dynod at 353. I'll try to find it and post.

lurtonk

Bone stock LS3 MN6, 400RWHP.
If the 15% allowance for transmission is right, the LS3 should be rated at 470 crank HP.

FloydSummerOf68

400rwhp isnt the norm.

I still say around 12% is an accurate figure for LS2 or LS3
I guess 11% might be more accurate for the LS3

That puts the LS2 around 350rwhp and the LS3 near 390

talon90

As others have indicated the age old Corvette estimated loss is about 60 hp for manuals (15%) and 72 hp (18%) for automatics on a stock C6. These losses have their roots in at least the C5 days if not earlier than that.

While commonly used the percentage is not totally accurate as the driveline loss is not linear as hp increases. The parasitic loss will not increase as you add performance mods unless you make additional modifications to the driveline. Meaning that you won't induce additional loss since the drag and friction will remain constant (with the exception of wear over the life of the car) for the most part as you make gains in horsepower.

For example:

baseline
400-60 (15%) = 340 on a stock C6 manual.

add intake and exhaust (gross about 15hp)
415-60 = 355 as the driveline didn't change so all the same friction and slop is present.

but using the conventional 15% it would show:

415-62.25(15%)= 352.75

Not too significant at lower hp ratings but think about as you begin to add a supercharger (150hp)

550-82.5 (15%)= 467.5 Why would the very same driveline now all of a sudden create a 82.5hp loss? No increased friction, so it should not.

For ease of calculations and a baseline to baseline comparison we have settled on these percentages but as you increase in horsepower gains the accuracy does drop off sharply. Basically we will only get one shot at flywheel to rearwheel comparison and that is from the factory. As we do anything to increase the hp at the flywheel we would need to measure it there and then compare to the rear wheels and that isn't very likely to happen.

The one other thing that we all need to keep in mind is that those loss percentages that people (myself included) throw around were originally intended to describe the "stock" drive train. I would say they are completely out the window as people have performance parts installed in the driveline as they increase horsepower.

More importantly, all cars have manufactured parts on them, obviously. All manufactured parts have tolerances. Most tolerance bands have upper and lower limits. As the tolerance band widens the potential for "slop" increases and with that slop should come additional loss. Furthermore, wear items will contribute to additional loss as well as they may begin to fall outside the original engineers design intent.

It should be used as a rule of thumb at best. A relative comparison from car to car to help understand the gains. I believe that from car to car even in the same manufacturing year this percentage will vary a bit and unless we can measure several cars at the crank and then at the rear wheels and compare older cars to newer cars the same way we will continue to have "real world" data from Dyno's that either support or dispute these numbers depending upon the cars being dyno'd.

It is also important to note that the 2008 Corvette and the LS3 opens a whole new realm of possibilities, why because the internals on the valvetrain have changed and in the manuals and automatics there have been hardware changes which will produce different amounts of friction, slip and loss. It has all ready been demonstrated that the LS3 is loosing less horsepower to the drivetrain because the only other explanation is that it is grossly underrated and with the new SAE guidelines that just can't be the case.

ATC399

Thanks for sharing your knowledge

Purdue

My 06 A6 dynoed at 345rwhp....however about a hour earlier another forum member bone stock LS3, manual with NPP put down 393 or 398rwhp .

Marina Blue

Another factor that makes a direct comparison somewhat more difficult is the rpm at which the two engines reach peak horsepower. LS2 is at 6,000 and LS3 is at 5,900. The difference is small, but higher rpm for LS2 contributes to a greater frictional loss. If what you are saying about drivetrain loss is correct, the combination may contribute to part of the rwhp gap between LS2 and LS3 and be the reason some think LS3 is making more than 430 or 436 hp.

HyperX

talon90

Good point. I've never seen that touched upon before when discussing LS2 vs. LS3 comparisons.

photoguy

Great posts guys!! This is THE place for information.

cmicasa

I have the LS3, Manual, NPP.. I like those numbers. I just ordered the Vortex CAI and will hopefully have it next week.

Thanks everyone for your informative post