Dyno Print out Help

[Chris Bruce]

I would appreciate any help reading my dyno sheet.
My understanding is RWHP is about 15% less than cranck horsepower?
If that is the case am I correct [*]465 RWHP = 550 [*]490 RWTQ = 575

Dyno Sheet

Also when is the ideal shift point? At 5000 RPM horsepower peak or 4300 Torque curve peak?
Thanks for any input.

 

[GR8_ASP]

The 15% number is overestimared. More like 12% for the Viper drivetrain and hp amount.

Best shift speed is the maximum area under the hp curve from shift point to shift point. It is almost always beyond the hp peak. How much depends on how quickly the power drops and how wide the gear spacing is. For the SRT the best shift point is as close as you can come to redline without hitting the rev limiter. GenII and Gen I are both lower (approx 5600 and 5200 respectively). Your peak hp should be more like 5600 rpm.

 

[NoRice]

Is that normal for the tq to drop like that?

 

[Cris]

Yes, but note the drop is only to 350 ft-lbs.

Your peak hp is also in the 5600 to 5700 rpm region, not 5000 as you indicated.

 

[Kai SRT10]

Is that normal for the tq to drop like that?

I've not seen that before.

 

[NoRice]

Yes, but note the drop is only to 350 ft-lbs.

Your peak hp is also in the 5600 to 5700 rpm region, not 5000 as you indicated.

I meant at the beginning.

 

[quick2tr]

How did you get one of those runs past the 6200rpm fuel cutoff?

 

[FikseGTS]

what mods are on your car?

I would appreciate any help reading my dyno sheet.
My understanding is RWHP is about 15% less than cranck horsepower?
If that is the case am I correct [*]465 RWHP = 550 [*]490 RWTQ = 575

Dyno Sheet

Also when is the ideal shift point? At 5000 RPM horsepower peak or 4300 Torque curve peak?
Thanks for any input.

 

[Chris Bruce]

West Coast Viper did teh following:

[*]Full B & B exhaust system with the factory converter
[*]Re-modified the computer to the exhaust mods
[*]Green Filters

It only has 1500 miles and more power than I can use on the street.
Looking forward to my first track day.

 

[Viper X]

Chris,

HP / TQ loss seems to be lower in a Viper than most cars. I'd use 12% as GR8ASP states.

As far as shift points in a relatively stock engine with only 1500 miles on it, I wouldn't push it past the shift light on the track or at the drags. No real benefit in most cases.

As far as power goes, get some stickier tires. Your power level is relatively low in the Viper world and you will get accustomed to it quickly. The first time you get "pulled" by another car, and you will get pulled, you will want more power.

Dan