Stock L99 Dyno #'s / Dyno #'s after K&N

[2010 2SS RS]

The best of three pulls while stock in my 2010 L99 was 342.9 RWHP and 357.3 RWTQ!
I was impressed to say the least, I expected more powertrain lose, anyways...

I exchanged my stock airfilter for a K&N air filter that fits right into my stock airbox and my best of three was 333.7 RWHP and 367.9 RWTQ!

I didn't expect to lose about 5RWHP but gain 10RWTQ ... I was hoping to even out my RWHP with my RWTQ rating (a long shot) or to experience a minor HP & TQ gain but I didn't expect to lose any HP or TQ...

What gives Any suggestions as too why , thoughts , whatever would be helpful as to understanding why this might have occurred. Minus a incorrect dyno cause the things a brand new DynoJet....

Thanks guys!!!!

[paultheman2007]

what i dont get is why chevy says the the l99 has 400hp when it doesmt that makes me mad why would chevy lie or what am i missing

[v6sonoma]

Originally Posted by paultheman2007

what i dont get is why chevy says the the l99 has 400hp when it doesmt that makes me mad why would chevy lie or what am i missing

Manufacturers give crank HP and TQ numbers from an engine dyno. These are chassis dyno's which give an idea of how much of that makes it to the pavement.

As for the differences it could be do to the newness of the K&N. I know they don't perform there best till they are run for a bit. Aside from that you probably won't see any huge gains off a filter alone. At best you might expect better throttle response.

[speedster]

Originally Posted by paultheman2007

what i dont get is why chevy says the the l99 has 400hp when it doesmt that makes me mad why would chevy lie or what am i missing

The L99 makes 400+ flywheel HP. Looks like he was getting ~342 at the wheels. Average drivetrain loss is about 17%, so 17% of 400 HP ~68 HP, 400-68 = 332 RWHP. The actual loss with a 6L80E, 2 piece driveshaft IRS and 20" wheels is probably closer to 20%. Therefore his motor is probably making > 420 flywheel HP.

P.S. Nice 2011 SIM 1SS you have there !!

[boltmark]

Originally Posted by paultheman2007

what i dont get is why chevy says the the l99 has 400hp when it doesmt that makes me mad why would chevy lie or what am i missing

Chevy isn't lying, you are going to loose HP from the flywheel to the rear on any Auto.

[10spokess]

Well chevy usually lies and under rates their cars. They rated my 2002 camaro at 325hp and i made 310rwhp stock so they really under-rated it

[TOMS1SS]

Originally Posted by boltmark

Chevy isn't lying, you are going to loose HP from the flywheel to the rear on any Auto.

What will make you even more angry....perhaps confused is that before 72 the automakers used to rate the engine with no attachments like (power steering, ect) at the fly wheel. That 450 horses in the LS6 in a 70 Chevelle was more like 360 horses at net and 270 at the rear wheel.

[paultheman2007]

so what will my car gain more hp wit shorty or long tube headers so the ls3 isnt making the 426

[TOMS1SS]

Originally Posted by paultheman2007

so what will my car gain more hp wit shorty or long tube headers so the ls3 isnt making the 426

Not sure about the headers but most L99s and LS3s I've seen on the dyno stock ran between 340 to 365 rear wheel horse power. Keep in mind there is a small discrepancy in the horsepower being bumped by the dyno itself, so figure the actual stock engines run 335 to 360 at the rear wheel. When you consider the drivetrain loss of 20% off an LS3 factory rating of 426 is 340.8 the numbers seem to be accurate.

[TOMS1SS]

Originally Posted by 10spokess

Well chevy usually lies and under rates their cars. They rated my 2002 camaro at 325hp and i made 310rwhp stock so they really under-rated it

Kind of. Don't forget the LS1 made 345 to 350 in C5 Corvette applications. Since there was virtually no difference in the LS1 in the Camaro, its safe to say GM lied to protect the Corvette hierarchy. I talked to an 02 SS owner last night and he pulled 314.6 on his car. The LS1 probably was pulling more like 375 horsepower.

[2010 2SS RS]

Originally Posted by speedster

The L99 makes 400+ flywheel HP. Looks like he was getting ~342 at the wheels. Average drivetrain loss is about 17%, so 17% of 400 HP ~68 HP, 400-68 = 332 RWHP. The actual loss with a 6L80E, 2 piece driveshaft IRS and 20" wheels is probably closer to 20%. Therefore his motor is probably making > 420 flywheel HP.

P.S. Nice 2011 SIM 1SS you have there !!

Thanks ... but she's a 2SS

I love how Chevy list the cupholders like it's a big deal... lmao

[TOMS1SS]

Originally Posted by 2010 2SS RS

Thanks ... but she's a 2SS

I love how Chevy list the cupholders like it's a big deal... lmao

Just like floor mats?

[Mr CLuTcH]

seats.......lol

[2010 2SS RS]

Originally Posted by v6sonoma

Manufacturers give crank HP and TQ numbers from an engine dyno. These are chassis dyno's which give an idea of how much of that makes it to the pavement.

As for the differences it could be do to the newness of the K&N. I know they don't perform there best till they are run for a bit. Aside from that you probably won't see any huge gains off a filter alone. At best you might expect better throttle response.

Yeah i did'nt expect to see much of a gain numbers wise, i mentioned my hope of evening out the HP and TQ #'s was a long shot, especially since i left the crappy stock airbox in there ... lol ... anyways what i also didnt expect was my HP #'s to drop by 5RWHP... all runs were done on the same day, same conditions.

So you suggest the newness of the K&N is dropping my HP, i can understand no gain but a lose ... really? wow ... i guess only time will tell, ill break in that filter a bit and run it again and see what kinda #'s i get. Its just hard getting similar weather conditions to preform a comp. in LA and having your and the Dyno dudes schedule match those conditions hahahahaha....

Thanks for the input ....