Power with basic mods

[Viper Scot]

What sort of power can you expect on a '96 RT-10 with headers, smoothe pipes, air filters, free-flow cats and cat-back performance exhaust?

Also, what exhaust is best for maximising power (rather than making a nice sound)?

Cheers,

Hamish

 

[Viper Scot]

Anyone? Even a ball-park figure?

 

[PhoenixGTS]

I spun 415/475 on a Dyno Dynamics machine couple of weeks ago with mods in sig. STFA and you will see 390-40 RWHP on Dynojet is normal range for mild-mod cars.

 

[Phil Lee 94 red RT]

I'm guessing 410 to 415. I do 396 with out headers.

 

[ruckdr]

Click on my photos and see my Dyno chart, (417/472).
Mods:
Late model stock (short) headers (Gen2).
Plug wires
Smooth tubes & filters.
Corsa Cat back (stock cats still)
Gen2 compression ratio:
(9.6,9.7 up from Gen1, 9.1,9.2)
Did this when replacing the head gaskets.
Later,

 

[Viper Scot]

Thanks for the info. I take it all those are wheel BHP figures? How do these relate to manufacturer flywheel figures?

 

[PhoenixGTS]

Thanks for the info. I take it all those are wheel BHP figures? How do these relate to manufacturer flywheel figures?

My dyno guy thinks there is about an 18-19% correction factor so take rwhp numbers and multiply by 1.18 or 1.19. Example would be my 415 rwhp = 490+ crank hp.

 

[ruckdr]

PhoenixGTS,
I think your Dyno guys are a little high in their "loss" value from engine HP to Rear wheel HP. We here and others use 15%, and the equation must balance between Engine HP and RWHP. Therefore you must DIVIDE the RWHP by .85 (assuming 15% loss)
EXAMPLE: 500 engine HP; loss of 15%,
500 X .85 = 425 RWHP (very close to Gen3 pulls)
425 / .85 = 500 engine HP
_____ Equations balance


Later,

 

[Supra]

Rule of thumb is ~15% loss. And the right way to calculate is to take the RWHP % and divide by .85 if it's 15% loss, .82 if it's 18% loss or .81% for 19% loss. This is because you are starting with X HP at the flywheel and losing power through the drivetrain, not starting with X HP at the wheels and generating extra HP through the drivetrain. So your 415 would be ~512 HP with a 19% loss or ~488 with a 15% loss.

Thanks for the info. I take it all those are wheel BHP figures? How do these relate to manufacturer flywheel figures?

My dyno guy thinks there is about an 18-19% correction factor so take rwhp numbers and multiply by 1.18 or 1.19. Example would be my 415 rwhp = 490+ crank hp.

 

[Supra]

Dang it, you beat me to it by 2 minutes

PhoenixGTS,
I think your Dyno guys are a little high in their "loss" value from engine HP to Rear wheel HP. We here and others use 15%, and the equation must balance between Engine HP and RWHP. Therefore you must DIVIDE the RWHP by .85 (assuming 15% loss)
EXAMPLE: 500 engine HP; loss of 15%,
500 X .85 = 425 RWHP (very close to Gen3 pulls)
425 / .85 = 500 engine HP
_____ Equations balance


Later,

 

[ruckdr]

Supre
We must have been reading each others minds - scary
Later,

 

[Viper Scot]

So, let me get this right... You're looking at a gain of about 70 bhp (flywheel) over stock then? Assuming a 15% loss from engine to road.

 

[ruckdr]

Yesssss...., if you pull 500 rear wheels, then 500 / .85 =588; a gain of 173 from the stock 415HP
if you pull 300 rear wheels (heaven forbid) then 300 / .85 = 353; a loss of 62 from the stock 415HP.
Later.

 

[PhoenixGTS]

PhoenixGTS,
I think your Dyno guys are a little high in their "loss" value from engine HP to Rear wheel HP. We here and others use 15%, and the equation must balance between Engine HP and RWHP. Therefore you must DIVIDE the RWHP by .85 (assuming 15% loss)
EXAMPLE: 500 engine HP; loss of 15%,
500 X .85 = 425 RWHP (very close to Gen3 pulls)
425 / .85 = 500 engine HP
_____ Equations balance


Later,

You guys are so right. Your math makes rwhp a corrected portion of crank hp where mine was deriving crank hp from rwhp. In any event, just you you never go fast as you should at the track, I think we can agree that you never spin as much power as you should ont he dyno.

This Saturday the AZ guys are having a dyno day on the same dyno I ran on, so perhaps some bone stock cars will go and we can get better information regarding a correction factor for Vipers. I hope my 415/475 is better than a stock Gen III will pull.

 

[ruckdr]

We had 2 Gen lll's, Dyno in 2003 before they did some mods. One pulled 442/483.4, another 440.2/480 at the rear wheels.
Have fun.

 

[Supra]

That was probably on a Dynojet right? The dyno day Phoenix is talking about is a different type that yields somewhat lower #'s.

Phoenix, I'm planning on dynoing the snake this Satruday, are you going? You should also come to our (lots of Supras, a few Vipers, one Lambo, etc.) Globe run on Sunday.

We had 2 Gen lll's, Dyno in 2003 before they did some mods. One pulled 442/483.4, another 440.2/480 at the rear wheels.
Have fun.

 

[ruckdr]

Supra,
Yes, Dynojet.