Best way to make less power?

[largeorangefont]

Yes the thread title is odd.

I want to start racing time trial in the NASA series. Right now my car would be classed as a TT1, and TT1 has a maximum power to weight ratio of 5.5:1. TT2 has a maximum power to weight ratio of 8:1.

Right now based on the allowances for the car's weight and tire sizes, I am at a power to weight ratio of 7.43:1. I would undoubtedly be killed in TT1, but if I add a little ballast, and drop about 30 HP at the wheels, I can be just over 8:1, and hopefully classed in TT2.

What is the best way to do this? Put a restrictor in the intake? Back off ignition timing? Lower the rev limiter? I don't want to change anything mechanically in the engine if I can avoid it. Ideally I would like to just build a tune and use an intake restrictor plate to make less power.

Ideas? Thoughts?

[Skeltic]

the patented wood under the gas pedal would work.

Serious though, you want as much power in your torque curve as possible, so something to cut power at the top end would be ideal, I think there is a way in the ls ecu that you can set max torque, so I would look into that, I know that you can program it to throw a code and go into limp mode if you go over the set torque number, I am unsure weather you can change it from throwing a code to just cutting spark, like the rev limiter.


Good luck

[Speedfab]

If they are only looking at PEAK power, don't restrict a damn thing - kill it by retarding timing just where you need it to lop the peak off the power curve and make it nice and flat there.

[largeorangefont]

I have a pretty broad powerband, but looking at my dyno graph I won't drop the peak power unless I do something other than dropping the rev limiter. That is a good point on the torque management, that might be worth playing with.

[largeorangefont]

If they are only looking at PEAK power, don't restrict a damn thing - kill it by retarding timing just where you need it to lop the peak off the power curve and make it nice and flat there.

Thanks Tracy.

Yea they are just looking at peak, but my peak is more like a mesa. If I can get there just by dropping timing, I am all for that. I am running 25 degrees up top now, I can see what 20 or 21 degrees would do.

[twokrx7]

Find a stingy dyno??

[Speedfab]

If they are only looking at PEAK power, don't restrict a damn thing - kill it by retarding timing just where you need it to lop the peak off the power curve and make it nice and flat there.

Thanks Tracy.

Yea they are just looking at peak, but my peak is more like a mesa. If I can get there just by dropping timing, I am all for that. I am running 25 degrees up top now, I can see what 20 or 21 degrees would do.

Where do you need to be?  I could make that power curve a nice flat line at 370 in about 10 minutes.

[Bowtie7]

Can you race it with the timing yanked out? Won't the egt go high? Am i just thinking in rotard tunology?

[Bowtie7]

Ash, the other option would be to run in NASA-SE region where rules are merely a suggestion.......

[mattster03]

How do they check your HP?  Do they actually check your HP?

[MPbdy]

How about we make MORE power and go into TT1 

[largeorangefont]

Where do you need to be?  I could make that power curve a nice flat line at 370 in about 10 minutes.

365-370 WHP should do it. I still need to get the car weighed to figure out the specific power number.

If I am under 3000 lbs race weight (wet with driver) I take a slight hit as well. I am thinking I'll be around 2900 race weight, but if I am within striking distance of 3000 I'll add a bit of ballast and run a full tank of gas.

The good news is that I can run up to 275mm tires for free, and I am planning on going to 275s all around anyway.

[largeorangefont]

How do they check your HP?  Do they actually check your HP?

You dyno your car, submit the plots and paperwork to NASA and the dyno operator signs off on it. It is largely an honor based system.

It has to be a Dynojet, Mustang or Dyno Dynamics, and they tell you the settings the output needs to be.

[largeorangefont]

Can you race it with the timing yanked out? Won't the egt go high? Am i just thinking in rotard tunology?

I don't think I'd have to pull that much timing where EGT would be an issue. I'm going to look at a stock timing map from an Fbody here shortly.

[largeorangefont]

How about we make MORE power and go into TT1 

Lol. That's just what I need.. To spend MORE on tires and brakes!