MarkPcar

After spending the weekend running the 25 Hours of Thunderhill, I got to thinking about Spec Boxsters at the 25.

A Cup car was the overall winner again, congrats to Mercer Motorsports. However, in the race BMW's out number Porsches about 10 to 1 and Mazdas probably 15 to 1. Miata variants won four of six classes!

Based on my current PTC NASA class, a Spec Box would run the 25 in the P1 class. Competitive fast laps in P1 were in the 2:00 - 2:04 range with the bypass.

Does anyone know what good Spec Box lap times are when using the bypass?

jrgordonsenior

At POC"s event a few weeks back the fastest SB's were in the 2:02-03 range going over the top so it appears they'd be competitive. I think a 996 like mine would absolutely kill in E0 where I'd run based on NASA's ST2 class. Maybe next year....

jakermc

How is it that a GTS4 car runs in ES but ST2 is in E0, given that a GTS4 car can easily class into ST2 and they seem to run the same lap times on track?

Cory M

was that on Toyos or Hoosiers?

MarkPcar

Received a PM from another member about NASA's Performance Touring classing for Spec Boxster.

Running at 2,822 lbs, SBOX could get into PTD which would move it to E2 for the 25. Running on RA1's, I think the car would be very competitive in E2.

CAM14

I’m surprised that a Spec Boxster has not entered yet, I would think it would be a good platform for this event. How long can a Spec Boxster run on 10 gallons of fuel?

One of the reasons Miata do well at the 25 is that they are easy on equipment. 10 gallons of fuel lasts over 90 minutes in green flag conditions, usually end the race with the same brake pads it started with, and does not go through tires as quickly as some of the other quicker car do. So over the course of the whole event, the Miatas start to bubble up the finished order.

jrgordonsenior

I don't believe a GTS4 car can easily run in ST2 without making some major changes in weight or WHP. The classification differences between GTS and ST are that the GTS class parameters cover anything you can do to the car while in ST you have a smorgsboard of penalties and deductions for modifications including tires types and sizing.

The ST2 multiplier starts off at 8.7 but by the time I add in the penalty for slicks (.75) and weight (.3) I'm at 9.75 while I would still be 9.0 in GTS4. That .75 difference translates into 200lbs in my case (270whp), or an additional 20 rwhp (2625 lbs.) either way a huge advantage. The top GTS4cars should be faster than the top ST2 cars but the weather at Mid-O was a significant factor in those results. I would have loved to have raced that ST2 Mustang at Mid O, then run against Jay. Would have been interesting if the track was dry...

jrgordonsenior

They have a 16.9 fuel tank IIRC....

jrgordonsenior

I believe R6's....

BGB Motorsports

I have done this event 5 years in a row and have always done it in a Honda. Given that we are a Porsche team, I have always wanted to return with one of our former Grand-Am Caymans or 997s. The event though is far and we are always on track in December.

The problem with running a Spec Boxster is that I don't know if a Boxster trans would hold up for 25 hours. The most reliable trans we have seen to date is the Getrag in the Cayman S cars. Who wants to donate their Cayman Interseries car to the cause?!?!?

It might be something where everyone on the team gets together and promises to skip all 3-2 downshifts and any usage of 2nd gear at all. That would certainly open up a window.

GTgears

How about I be the gearbox sponsor and just bring a spare gearbox in return for my seat in the car?

eric523

Fastest lap of the weekend in my specbox was a 2:02:2 over the hill with some fresh Hoosier R6's.

dp35

Our E2 MX5 Cup car averaged 70-75 minutes per 10 gallon stint. The 949 Team's 1999 Miatas that we were racing seemed to go longer, maybe 80-90 minutes.
We had to change front brake pads twice. However I believe some Spec Miatas can make it without any pads.
Overall weight is critical when it comes to other parts lasting, such as wheel bearings. But Porsche is fairly good in these areas.

Because the rules only allow 10 gallons to be added per stop, that's the measuring stick.

jakermc

So the difference is slicks, since R-compound on an ST car leaves it at 9.0? Running R-compound in a 25 hr race wouldn't really hurt results. Might even help if you put on BFG or some other long lasting tire and cut down on the tire changes. Seems to me that a GTS4 car looking to run an enduro with NASA should take the ST route every time. Sure beats trying to compete with GTS5 and ST1 cars in ES!

CAM14

I was refering to the earlier model Miatas which are smaller, lighter and generaly slower. I've done this 25 hour race 7 times now in a early model Miata and never had to change brake pads yet. That includes 4 podium finishes.

That is correct, NASA has an odd rule that only allows 10 gallons per pit stop. In my case, it is an advantage because that is all the fuel I can hold anyway.


But I still think a Spec Boxster would be a good fit for this race, would be cool to see one out there next year.