Time to start the chump car FAQ with injectors rated between 230cc and 265cc. People will be scavenging pull-a-part for the rare sets.

Adjustable fuel pressure regulator would be better than trying random injectors. Just tune it on a dyno (or road tune with a wideband) and be done.

I'll argue power level is meaningless (obviously to some extent) in chump/lemons racing. Strategy (protecting the vehicle) is your top priority. There are plenty of yahoos that will make clean laps difficult to come by and jeopardize the car's safety simultaneously making that last drop of hp useless. Consistent, "fast" laps that aren't throttling the equipment for every oz of effort and avoiding flatspotting tires will get you into position for the last few hours. Then you make the push.

Wanna burn less fuel?

https://www.miataturbo.net/showpost....4&postcount=17

Nope. If saving fuel is higher priority that power in endurance racing, then you simply short shift and slow down. You never want to go slow, you simply want to use less fuel while going fast.

It boils down to this:

Endurance racing is gaining as much track position for fuel mass burned. Everything else is secondary.

Just going slow and high mileage is as pointless as hauling ass and getting terrible mileage. Track position:fuel mass used

Agreed. It seems to be a careful balancing point and having limited resources is mildly frustrating, but breads ingenuity.

That's too lean for my liking in an endurance car. If I could find a way to stay around 12.5 on the oem ecu I would be golden. Based on that graph it gets even richer than I thought at high rpms

I don't recall ever recommending going slow? I read some of the posts as "use up every bit of the vehicle at all times" and responded accordingly.

I could have sworn I posted our rpm regulated strategy earlier in this thread that the team I was on for an Oct Chumpcar event used. I even suggested consistent fast laps which is what we aimed for. Maybe I missed something? I guess it worked for us?

I'm all ears to learn and be corrected but it seems as there was some misinterpretation.

"I'll argue power level is meaningless (obviously to some extent) in chump/lemons racing." I interpreted that as an argument that you thought reducing power to gain mileage was OK. Also that adding power was less useful that increasing mileage due to difficulty in using the gained speed in traffic.

On our team, we go fast in traffic both being passed and passing. We spend a lot of time and money training our team drivers, poring over data. This is part of enduro winning strategy. If we can get power we take it. In NASA PT however, we have a lbs/hp cap so any extra power means more ballast. The lower weight helps more than the power does. If we weren't lbs/hp capped, we would weigh the same and definitely make more power. In Chump, we want as much power as possible.

FWIW we won a 24hour chump car in our first try with a 95whp street car on Flex's and junk tires. We were in EC class but actually a tad slower than Eyesore. They broke, we didn't.

Another reason we use chump for training because we like to learn to pass in turns. We're not always the fastest car in a straight line in Chump believe it or not.

Flex is certainly a step up from our Chump suspension setup. Can you say kyb gr2's, no front springs, BMW 5 series bumpstops, and rears were random H&R race springs. :rofl:

Anyways, what you said makes sense. I appreciate the insight and can certainly attest to the "we're not always the fastest car in a straight line in Chump". At PIR (a relatively HP advantageous track) we had our work cut out to keep up with the faster cars.

In the end though protecting the vehicle (not getting collected up in those large clusters of cars where chaos happens), 4 cyl fuel economy aided by 6500 rpm limit (extended driver stints to the full alloted 2 hours) and tire conservation (not flatspotting Star Specs) kept the machinery relatively "fresh" for the last few hours of the race where we really made up in the position department. That was my reasoning. Not pedaling your way around the track as perhaps it come off as.

You have the right idea. Keep pace without using up the car. In the my pre-race drivers meeting, rule #1 is "protect the car". Every other goal is subservient to that.

I think the real focus for me on this needs to be for me to get all the "spare" weight I can out of the car. As it sits now, it's around 2025 caged and I am not sure how much else I can take out, but I need to take a second look. That will really be having my cake and eating it too.

Rarely are we held up by traffic and use 95% of the car 95% of the time. I am amazed at how well chump and lemons have taught us to pass in the turns and how to do aggressive but safe passes in traffic.

Looking at the data for our last race has helped us understand the line even more. I thought after a good 500+laps at TWS I wouldn't have much room to grow, but the data doesn't lie. The more experience we get with this, the more time we find ourselves spending trying to understand how to get all we can out of the car. It really bumps it up a notch.

At TWS we top out around 108 on the front straight while others are hitting 140, so the frustration is very high to have to turn around and pass them again 2 turns later.


Same thing I say to them is that the #1 rule is to keep in a position to where you are in as much control as possible of your safety and the cars safety. You can't win a race in a car that is wadded up.

Really appreciate the reading and input in here. We'll be taking the Piñata down and adding a Civic Si to the mix for the 24 hour LeMons race in May @ ECR.

At TWS we put down some quick laps, but 7 trips to the penalty box pretty much killed any hopes of a top-10 finish. :(

Can you run lean and use water injection?

NASA yes, Chump it might be hard to show it doesn't add value. Wouldn't help mileage though. Do the math for latent heat vs BSFC. You lose more than you gain. Plus you would need a might big tank and safeties built in. Relying on water level to keep your engine from exploding, well, lets just say that's it's not an optimum strategy. Myriad other ways to improve the TP:FMB

btw, that Miata was DRIVEN to the race track....
it is a daily street Miata.

later, 949racing / 2nd Chance Roadster built a dedicated Chump car. This Miata was faster, due to 300LB less weight.. It won the last Chump race by 6 laps...

I think that is about as succinct as the situation can be described. Word.

Robert our rule has always been shift at 6500-6700. Period. In the BMW it was shift @ 3800 (325e).

Another thing I'm a believer in is the underbody aero. I think a flat airdam front, sideskirts and whatnot helps. Anything to keep air from going under the car. :)

I have done 3 races in our 1.6L (2 LeMons and 1 Chump) all with a dyno proven 84 whp. I have never seen over 1.5 hours out of a tank, how are you getting 2+? Is the early 90's tanks smaller? I dont think ours holds 12+ gal. I also think timing your stops in the long haul will be more beneficial than anything, we lost 3 spots in the last 45 minutes of a 24 hours race at VIR to come in for a splash of fuel...not cool. Still 7th made us happy!

I've never weighed our car, now knowing yours I have a benchmark. I bet due to the E-30 front end on our car it will be heaver. We also contended with 100*+ heat both days at VIR last summer and I dont think any of us could have lasted 2 hours even if we had gas. Thermo in the car was always over 140! The cool shirt was the best invention EVER!

90-93 had a 11.7 gallon tank and 94+ had a 12.7 gallon tank. Where you guys driving until you got fuel starve or until it read empty on the gauge? We found it still had about 2+ gallons when the gauge read empty. You can recalibrate the gauge and we will probably do that for the next race.

next time. during one of the track day. drive the car till fuel light comes on (if you have a NB), start your count. next drive till car hiccups...write down how many laps that was. then drive till the car stutters so bad that you are losing 5+ seconds. write that down.

my point is, ignore the fuel level gauge...it really is irrelevant...