8 replies to this topic

[av8tor]

Hey guys, a little off target but not much.  I'm introducing a PCA/PBOC friend of mine to SCCA and spec miata racing by doing the Bracket Enduro at Sebring next month.  There is no rule regarding tires.  2 questions:

1. Can a SM 1.6 liter do 1hr45min on the Sebring short course without running out of gas

2. What tire would you use and would you swap/rotate etc at the half way pit stop?

 

Trying not to break the tire budget goofing around on a "fun" race also considering the likely hood of rain, do you run something like an RA1?

 

Appreciate all the years of expertise this crowd has to offer.

 

Kevin

121

[Steve Scheifler]

I haven't driven Sebring but averaging our burn rate lately, ~75lbs of fuel in a 1.6 averaging ~L0.85, I would estimate 62-68 minutes. If it's tuned leaner and/or you aren't pushing quite as hard being an enduro, maybe 75. If the short course is really slow it will be somewhat more, but seems really unlikely that you can approach 105 minutes. Figure on two stops.

[Ron Alan]

We averaged 80-90 minutes on 10 gallons in the 25hr this year in the 1.6 car. Depending on the year of the car you might make it. The very early cars(89-90) had a 10 gallon tank...not sure when but it was bumped to about 11.5 to 12? I think this is accurate but will gladly be corrected. My point is if the car is a 91+ 1.6 and you can stuff 12 gallons in it...at endurance pace you might easily make 105 minutes?

 

With rookies at endurance pace you should get 5-6 hours out of tires so no problem on 1 set...RA1's will be fine if its wet and last you the next 4 years! But if you can find a set of 1 or 2 cycle Hoosier wets from someone who wont use them again...cheap or free have those ready if its really wet! But not if there is any sort of dry line!

 

BTW...if you have a mandatory pit stop and driver change that is timed(say 5 minutes?)...dont worry about fuel, you will have plenty of time.

[Brandon]

I'm not familiar with Sebring short (typical lap times or types of turns) but my point of reference on enduro type racing would be here in the NE, NJMP-Thunderbolt (Devil in the Dark).  

 

Seconding Ron's note about the year & fuel tank capacities.  In terms of fuel stops, the 1.6 I drove (with 1:38-1:40 lap times on the track noted above) we were able to get nearly a full 2 hours on a single tank.

 

 

It has predominantly right-hand turns and most teams can go nearly 6 hours on Hoosiers (essentially the 2nd or 3rd stop of the 12-hour race is when they change left side tires, some teams do all 4).

 

IMO, I think you'd be fine having a total of 6 (new) tires and a full tank of fuel for a less than 2-hour enduro in a 1.6.

[av8tor]

Good info from all - thanks.  The car is a 91 (bigger fuel tank). Gonna keep the Hoosier wets ready and try to do back to back 3.5hr enduros on 6 new Hoosiers with 1 stop each day, short shifting the whole way.

[Brandon]

Winner winner yardbird dinner.

[Steve Scheifler]

Wow, you guys get the MPG award! No way we get that kind of mileage in a sprint race. Even at the annual Loooong (sprint) race at Blackhawk when we were getting started with the Council we could just manage the 100 miles on a tank. of course we had less control of AFR then so it probably ran richer. But 2 hours? What was that, a fall color tour?

[Brandon]

It was a few years back - 2012 I believe, April race...

 

Believe me, we certainly got some accusatory looks and questions when we weren't pitting come 1:50...then 2:00....if I recall we were well into 2:10 before the car burped (our cue to come in).

It was the first stint of the race, we were on R888s too, so I think it was a nice mix of conservative driving, the tires not supporting a much faster pace, and the car being absolutely packed with fuel!

 

Most folks were around 1:45-1:55 for the first fuel stop but these guys were pushing consistent 1:37s for lap times in 99s with only a few 1.6s getting anywhere close to 2-hours on a tank.

 

Go us?

[shedguy]

Figure 1 gallon per 10 minutes and you'll be in the ball park