Need advice from racers / time trialers

[Orange Crush 1LE]

Hi all,

I had been having so much fun at HPDE days in my Camaro that I recently decided to compete in NASA time trials, and perhaps some day do wheel-to-wheel racing. I fit perfectly in NASA's TT2 class, which is an unlimited class that controls almost nothing but weight/RWHP ratio. Here's what I discovered:

In my NorCal and SoCal regions, there are very few TT2 cars, but lots of TT3 cars. If you place 1st or 2nd in your class, you can win free tires from Hoosier as well as free brake pads from Hawk. Awesome, those are the most expensive part of racing! The catch? Hoosier requires at least 5 cars entered per event. So bottom line is that if I want to make racing affordable I should detune my car and compete in TT3.

I'm currently at about 500 RWHP, but would need to detune to 430 RWHP to be in TT3 class. I don't know if I want to do that, because I just love the raw power and torque this thing has now. It is a beast on the track.

And here's another twist- my engine blew up (another long story), and will be rebuilt in the coming weeks. I could detune my engine by putting the stock cam in it, or perhaps I could do a restrictor plate but that might give me a less than ideal torque curve. Or I could have this motor fixed, pull it and set aside for the future. Then I could purchase a stock crate engine and tweek it with minor mods to get it up to about 430 RWHP (I wonder if my longtube headers and CAI with a tune would get a stock LS3 to this?)

If I do wheel-to-wheel racing one day, the ST2 class is more populated and I could use my 500 RWHP engine for it.

I'm currently leaning towards just staying in TT2 class, finishing out the points season and then deciding at the end of the year whether to stay in TT2 or detune to TT3 for next year's racing.

Not sure what to do, I would appreciate any thoughts you guys have.

[hcsi99]

I'd go with the stock crate engine just for the reliability factor, on the other hand if money is no object more power is always fun.

[Orange Crush 1LE]

Originally Posted by hcsi99

I'd go with the stock crate engine just for the reliability factor, on the other hand if money is no object more power is always fun.

That's good advice, and a good reason to consider moving to 430 RWHP which is class TT3. The rest of the drivetrain will hold up well with the stock crate engine.

In the short term, I already have the modified engine (once rebuilt, likely on the rebuilder's dime) so it would be less expensive in the short term to just continue with sticking with TT2 and 500 RWHP. That is, if drivetrain doesn't break.

[Jim968]

A few thoughts from someone who has competed successfully in a NASA weight to power class, GTS in my case…

Whatever you do remember that you need to be near the minimum weight/power ratio in your class if you want to be competitive. Just falling somewhere in the class range will make you legal, but it won’t make you competitive.

For the ST class scenarios make sure your math includes the impact of all of the safety items that will be required for W2W racing. Roll cage plus fire system and other safety equipment minus interior stripping and deletion of other interior items. Usually you end up with a small net weight gain when you prepare a car to go W2W racing.

Also make sure you’re considering the “modification factor” adjustments for weight and tires that apply to the adjusted weight/power calculation.

I can critique your weight assumptions and calculations if you want to post them.

Car counts matter more in W2W racing then they do in time trialing. If you don’t have critical mass ensuring that you always have someone in class to race with then you’re missing out on all the fun of W2W racing. Therefore its absolutely crucial to be 100% sure you’re building a car to compete in a popular class at the tracks where you want to run.

[MJanowich]

It would probably be more fun to have more competition in the TT3 class. Plus, the opportunity to win free tires and pads makes TT3 sound that much better.

[Synner]

Wheel to wheel with a new car? Hopefully you own a body shop or have a ton of cash to burn, unless you just don't care about it.

[Orange Crush 1LE]

Originally Posted by Jim968

A few thoughts from someone who has competed successfully in a NASA weight to power class, GTS in my case…

Whatever you do remember that you need to be near the minimum weight/power ratio in your class if you want to be competitive. Just falling somewhere in the class range will make you legal, but it won’t make you competitive.

For the ST class scenarios make sure your math includes the impact of all of the safety items that will be required for W2W racing. Roll cage plus fire system and other safety equipment minus interior stripping and deletion of other interior items. Usually you end up with a small net weight gain when you prepare a car to go W2W racing.

Also make sure you’re considering the “modification factor” adjustments for weight and tires that apply to the adjusted weight/power calculation.

I can critique your weight assumptions and calculations if you want to post them.

Car counts matter more in W2W racing then they do in time trialing. If you don’t have critical mass ensuring that you always have someone in class to race with then you’re missing out on all the fun of W2W racing. Therefore its absolutely crucial to be 100% sure you’re building a car to compete in a popular class at the tracks where you want to run.

Thanks Jim, appreciate these insights. A couple of questions for you, I'm new to this so I have a lot to learn. Yes I realize that I need to be near the minimum weight:power ratio to be competitive.

For TT2, at my current weight of 3920 Lb w/driver and running on fumes, max power = 529 RWHP. (For TT3, 445 RWHP max.) Any thoughts on how far below those max numbers I should be? My engine builder uses a Dynapack dyno, and NASA uses a Dynojet to test cars. I had heard dynos vary by +/-2%, so if I wanted to be conservative I'd have my engine built at 529 RWHP - 4% = 508 RWHP. Any advice on this?

Regarding weight, NASA gives help to porky cars like mine. Because my car weighs more than 3800 Lb with driver, the minimum TT2 weight:RWHP = 7.4, whereas if my car were as light as 3,000 Lb, my weight:RWHP = 8.0. The net result is that I'm allowed to run 40 RWHP more at my current weight. I'm hoping this handicap will make my car competitive. I know lighter is better on everything- brakes, tires, cornering, but will this 0.6 point advantage help level the playing field to the point where heavier cars are competitive? I have to make a decision whether I want to rip out my AC, heater core, stereo, interior, Etc., to get the car lighter. I have to say that for recreational time trials, I'd like to keep the car comfortable with climate control. I have removed the stock seats and have Sparco Evos, and have installed a welded roll bar, which is legal for time trials but not wheel-to-wheel. If I do wheel-to-wheel, then out goes the interior and in goes a cage and fire system (which I plan on getting anyway).

I've looked at past NASA results and my car would have likely won most TT2 competitions at Buttonwillow (but would have been mid-pack at many of the ST2 wheel-to-wheel events), so at my current skill level my car is competitive at least at the track I have the most experience at. So I'm hopeful that even with a heavy Camaro, it can do reasonably well.

I have considered all modification factors and reviewed them with the local NASA competition director, so I'm good there. Because TT2 is nearly unlimited, there is no penalty for running a big wing and splitter, the 315 Hoosiers, or any of my other mods. If I run in TT3 however, there's a 0.4 point penalty for running non-OEM aero. This is another reason that I like TT2 class.

At this point I'm leaning towards continuing in TT2 for the remainder of the year and learning. Then next year, I may detune or swap the engine so that I can run the more-populated TT3 class. But at least I will have some perspective after running four more events this year.

Feedback welcome from all, thanks.

[Orange Crush 1LE]

Originally Posted by MJanowich

It would probably be more fun to have more competition in the TT3 class. Plus, the opportunity to win free tires and pads makes TT3 sound that much better.

Yes I agree, likely next year I will switch to TT3 but it sucks that I already built my engine and it's ideal for TT2. I just hate the idea of detuning it because with the drag from the big wing on the back this car really benefits from the added power in the straights.

[Orange Crush 1LE]

Originally Posted by Synner

Wheel to wheel with a new car? Hopefully you own a body shop or have a ton of cash to burn, unless you just don't care about it.

Agreed, no wheel-to-wheel racing for now, that's why I'm doing time trials. However I'm keeping an open mind to the future, perhaps a couple of years down the road. Plenty of time to learn and think that through in the meantime.

[Synner]

I'd just buy a dirt cheap spec miata for wheel to wheel. You don't care if it gets trashed, plenty of events, and its all about driving the perfect line since you don't have the horsepower to make up for poor choices. There's some decent cash prizes too from what I've been told.

Keep the camaro high hp and have fun with it in events that fit its "intended" purpose.

[Jim968]

Originally Posted by Orange Crush 1LE

Thanks Jim, appreciate these insights. A couple of questions for you, I'm new to this so I have a lot to learn. Yes I realize that I need to be near the minimum weight:power ratio to be competitive.

For TT2, at my current weight of 3920 Lb w/driver and running on fumes, max power = 529 RWHP. (For TT3, 445 RWHP max.) Any thoughts on how far below those max numbers I should be? My engine builder uses a Dynapack dyno, and NASA uses a Dynojet to test cars. I had heard dynos vary by +/-2%, so if I wanted to be conservative I'd have my engine built at 529 RWHP - 4% = 508 RWHP. Any advice on this?

Regarding weight, NASA gives help to porky cars like mine. Because my car weighs more than 3800 Lb with driver, the minimum TT2 weight:RWHP = 7.4, whereas if my car were as light as 3,000 Lb, my weight:RWHP = 8.0. The net result is that I'm allowed to run 40 RWHP more at my current weight. I'm hoping this handicap will make my car competitive. I know lighter is better on everything- brakes, tires, cornering, but will this 0.6 point advantage help level the playing field to the point where heavier cars are competitive? I have to make a decision whether I want to rip out my AC, heater core, stereo, interior, Etc., to get the car lighter. I have to say that for recreational time trials, I'd like to keep the car comfortable with climate control. I have removed the stock seats and have Sparco Evos, and have installed a welded roll bar, which is legal for time trials but not wheel-to-wheel. If I do wheel-to-wheel, then out goes the interior and in goes a cage and fire system (which I plan on getting anyway).

I've looked at past NASA results and my car would have likely won most TT2 competitions at Buttonwillow (but would have been mid-pack at many of the ST2 wheel-to-wheel events), so at my current skill level my car is competitive at least at the track I have the most experience at. So I'm hopeful that even with a heavy Camaro, it can do reasonably well.

I have considered all modification factors and reviewed them with the local NASA competition director, so I'm good there. Because TT2 is nearly unlimited, there is no penalty for running a big wing and splitter, the 315 Hoosiers, or any of my other mods. If I run in TT3 however, there's a 0.4 point penalty for running non-OEM aero. This is another reason that I like TT2 class.

At this point I'm leaning towards continuing in TT2 for the remainder of the year and learning. Then next year, I may detune or swap the engine so that I can run the more-populated TT3 class. But at least I will have some perspective after running four more events this year.

Feedback welcome from all, thanks.

Its critical to get your car dyno’ed on a Dynojet for your calculations. Preferably find the dyno shop that shows up the track you want to run and have them do it. Having an accurate number before you start messing with the car will be well worth the hassle. There is a wide variation among dyno manufacturers, and even some variation among different Dynojets. I have no experience running on a Dynapack, so I can’t help with a variation %.

My objective has always been to target coming off the track with a 20 lb. buffer over my minimum weight. So far in in 12 years of competing with NASA and PCA I’ve never been DQ’d for weight, so I’d have to say that works. If you translate that into your TT2 scenario that only drops your allowable RWHP by 2.7 HP. So rather than trying to fine tune the engine to match the weight it is much easier to fine tune the weight to match RWHP. This is done with fuel level, and/or carrying a small amount of ballast. This ability to easily adjust weight becomes very important because scales can vary, sometimes significantly, from event to event and you often end up having to make weight adjustments during a race weekend.

Is your allowable RWHP right for TT3? I’m getting 3,920/(9.0-.6) = 467 hp

I think the .6 adjustment for > 3,800 lbs. is very fair. With it I’m confident you’ll be competitive with lighter cars, but as you noted your bill for consumables will be higher. If you’re planning to drive to the track I wouldn’t sacrifice creature comforts to reduce the weight. When you get to the point where you’re always trailering the car to the track, and are expecting to eventually install a full roll cage then I’d say it’s time to start getting rid of any extraneous weight and getting as close to 3,800 lbs. as possible.

Sounds like you’ve done a thorough review of the rules and run everything by your comp director. Excellent! You’d be surprised how many people don’t do this and receive a rude awakening when showing up to have the car teched for their first event.

It sounds like you’re closer to TT2 in your current trim, so it will probably be easiest start in that class. Once you start running you’ll get a better idea of which way you want to go. For maximum fun W2W racing is where it’s at, so if ST2 where you eventually would want to race, then running in TT2 will be perfect for car and driver development.

[Orange Crush 1LE]

Originally Posted by Synner

I'd just buy a dirt cheap spec miata for wheel to wheel. You don't care if it gets trashed, plenty of events, and its all about driving the perfect line since you don't have the horsepower to make up for poor choices. There's some decent cash prizes too from what I've been told.

Keep the camaro high hp and have fun with it in events that fit its "intended" purpose.

Can't race a Miata, that's just not me. I won't judge those who do, but man they are so slow in the straights when on track with anything with power. I have friends that love theirs. True that they are fantastic momentum machines, I've heard how much they do for your car control skills, learning how not to scrub speed. But tracking is an emotional thing, and I think we all have different passions. For me I grew up with muscle cars, so my choice would be a Mustang, Camaro, Viper or Vette.

[tw78911sc]

Most IMSA/Tudor/LeMans classes make performance adjustments between mfg's by restricting air. Cheap, easy to restore, and saves your internals since it never gets near the peak HP/torque ... They should be able to swap out restrictors on the dyno until you hit your hp/wgt sweet spot.

[Orange Crush 1LE]

Originally Posted by Jim968

Its critical to get your car dyno’ed on a Dynojet for your calculations. Preferably find the dyno shop that shows up the track you want to run and have them do it. Having an accurate number before you start messing with the car will be well worth the hassle. There is a wide variation among dyno manufacturers, and even some variation among different Dynojets. I have no experience running on a Dynapack, so I can’t help with a variation %.

My objective has always been to target coming off the track with a 20 lb. buffer over my minimum weight. So far in in 12 years of competing with NASA and PCA I’ve never been DQ’d for weight, so I’d have to say that works. If you translate that into your TT2 scenario that only drops your allowable RWHP by 2.7 HP. So rather than trying to fine tune the engine to match the weight it is much easier to fine tune the weight to match RWHP. This is done with fuel level, and/or carrying a small amount of ballast. This ability to easily adjust weight becomes very important because scales can vary, sometimes significantly, from event to event and you often end up having to make weight adjustments during a race weekend.

Is your allowable RWHP right for TT3? I’m getting 3,920/(9.0-.6) = 467 hp

I think the .6 adjustment for > 3,800 lbs. is very fair. With it I’m confident you’ll be competitive with lighter cars, but as you noted your bill for consumables will be higher. If you’re planning to drive to the track I wouldn’t sacrifice creature comforts to reduce the weight. When you get to the point where you’re always trailering the car to the track, and are expecting to eventually install a full roll cage then I’d say it’s time to start getting rid of any extraneous weight and getting as close to 3,800 lbs. as possible.

Sounds like you’ve done a thorough review of the rules and run everything by your comp director. Excellent! You’d be surprised how many people don’t do this and receive a rude awakening when showing up to have the car teched for their first event.

It sounds like you’re closer to TT2 in your current trim, so it will probably be easiest start in that class. Once you start running you’ll get a better idea of which way you want to go. For maximum fun W2W racing is where it’s at, so if ST2 where you eventually would want to race, then running in TT2 will be perfect for car and driver development.

Good advice on doing the Dynojet. Because my car doesn't run until the engine is fixed, I'm stuck with dynoing it after the engine is fixed. My plan is to take it to a Dynojet after getting the dyno results at my engine builders and adjust weight as required. I'm currently at 3950 Lb and could easily drop to 3920 by running a Braille battery. I have a few other ideas on dropping weight if need be. Hopefully I won't have to add ballast, but will if need be.

I wish I could run 467 RWHP in TT3, it would be a no-brainer. For TT3, there's a 0.4 point penalty for running non-OEM aero, so the calculation for max RWHP is 3,920 Lb / (9.0-0.6+0.4) = 445 RWHP. There's no such aero penalty for TT2, which is another big advantage to that class.

And I am so glad to hear that you wouldn't sacrifice the creature comforts since my car's a driver. Two of my favorite tracks are 3 to 4 hours away, and this is supposed to be fun, right? And yes ST2 is where I'd like to end up, and it's well populated.

Good news, even though my engine blew up during my first NASA time trial and they weren't able to observe me on track for more than 5 laps, they just sent me my time trail license in the mail today.

Thanks, this his been really helpful, your feedback has helped me clarify what to do. I'm going to stick with TT2 for the remainder of the year. If I can get the engine fixed in time, there will be some fun races. Next race is Laguna Seca, then Thunderhill, Sonoma, Buttonwillow, and finally the Western NASA Championships at Sonoma. Kinda cool to have it here in my backyard, Sonoma is about an hour from me although I've been avoiding it because I know so many people that have totaled their track cars there. Lots of walls to hit.

Here are a couple of shots of the Camaro in race trim, just before the engine decided to puke. I picked up the car after having a new set of heads installed and dyno tuned, and the car started with the dreaded blue smoke on the third lap of my first session. Even with the engine going away and just warming up, it was fourth fastest out of 70 cars. NASA put the HPDE4 cars on track with all of the time trial cars for the first warm-up session, so traffic was extremely heavy. They gridded me 30th initially, I was working through traffic when the engine went. So I think when I get it repaired, it should be competitive. There are a few guys though that are in another zip code than me, so I've got plenty to learn and tweak on the car.