F prepared Boxster

[Bigsmoothlee]

I've been giving some thought to building a F prepared Boxster to compete with fast guys in SCCA Solo, because there's no way a 986 can compete in B street or A street prepared at a national level. Your choices are to either get picked on by S2000s in B street, or have your ass handed to you by tuned Evo's and STI's. Lets not even mention the horrors of going to SSM

F prepared seems like its the only route to take to be nationally competitive... I see the minimum weight is 1900lbs, and I'd have to use a 2.5l engine. How close has anyone come to 1900? Any insight would be appreciated.

[stjoh]

Mine's totally gutted with mostly carbon fiber panels and I'm at 2,400 lbs. I may be able to knock another 100lbs off but that's probably it. I don't think 1,900 is doable.

[thstone]

My Spec Boxster is 2450lbs with several opportunities to lose more weight. I think that I could get to 2200 with some work and an affordable investment. But the path from 2200lbs to less than 1900lbs will be expen$$$ive. Remember, at 1900lbs, you're talking about losing 1/3 of the original weight and there is only so much you can jettison; then you have to start replacing steel with aluminum and aluminum with carbon fiber.

[Bigsmoothlee]

2400lbs is plenty light, especially since I'm probably at 3100lbs with driver.

Aside from the obvious stuff, like carpets and the convertible top, how far did you have to go? Are the doors gutted? Is the HVAC unit gone under the dash? Did you remove your fuel tank and install a fuel cell?

[stjoh]

It's got gutted CF doors, CF fenders, front bumper cover and both hoods. Hard top is fiber glass. All AC components are removed. Wiring harness is stripped. I did not replace the tank. The only other items I can think of to lose more weight are:

- radiator fans still installed, could be removed
- wipers still installed, easily removed
c- ross bar in cabin could be cut (assuming the cage provides sufficient stiffness)
- Techart tail mounted above OEM tail could be removed
- upgraded (big red) brakes replaced by OEM brakes
- smaller gains could be had by replacing engine covers, seat etc with lighter CF versions but that's pretty pricey
- passenger side seat pan could be removed, cheap but fairly time consuming
- standard dash could be replaced by AIM or similar

[j.fro]

I'm running in F Prepared in my Boxster S. My first question is why you are going with the 2.5. Per SCCA, I think you have to stick with the stock engine, but can go up if a larger engine was offered later. My biggest FP competititor runs a 71 911 with a 3.6 from a 964.
I'd be really happy if I could get around 7lbs/hp.
I'm at 2637 with full doors & passing VA state inspection. I think I could get down to 2500 and still pass, but it would be $$$

[thstone]

My car is a Spec Boxster so its fairly easy to search and find what can be removed and what has to stay.

[Bigsmoothlee]

Originally Posted by j.fro

I'm running in F Prepared in my Boxster S. My first question is why you are going with the 2.5. Per SCCA, I think you have to stick with the stock engine, but can go up if a larger engine was offered later. My biggest FP competititor runs a 71 911 with a 3.6 from a 964.
I'd be really happy if I could get around 7lbs/hp.
I'm at 2637 with full doors & passing VA state inspection. I think I could get down to 2500 and still pass, but it would be $$$

The rules are very confusing, I'd love to run. 3.4 or larger in F prepared. It looks like the larger the engine is, the higher your minimum weight goes... Do you have a link to the rules?

[goldsc_78258]

basically the rules are your weight is 75% of your displacement and you can put any engine that is on any boxster or cayman in the same line as yours plus 100# for wheels over 10"

SCCA has a rules page on its website

hope this helps

[itsnotanova]

Fred, The craftsmanship to loose weight on your car is amazing. I don't want to divulge any "trade secrets" but what are you down to now?

[goldsc_78258]

Down to 2160 but I have to run at 2500 because the 3.2l engine, but this lets me shift the weight around where is needed. Planing to move to XP with a 4l engine and get rid of all the balast