fatbillybob

John,

In another thread you posted:"Anything in front of or behind the suspension points should be left to crumple as it was intended to.
__________________
John Hajny
Central NY Region PCA Chief Instructor - PCA National Instructor/Mentor
REDLINE Rennsport Services Performance Driving Preparation & Education"

I completely agree with you on this point but can you clarify this as it pertains to fuel cells? I have seen many fuel cells places fore and aft of suspension points in crumple zones. I have seen many 911's with front cells forward of crumplezones and boxed in with tubes therby negating the engineered crumple zone but presumably protecting the fuel cell. Are fuel cells so special with the internal rubber bladder and foam that having one get smacked in the crumple zone is no big deal? In a 911 for example are you better off doing your cell and tubing it for protection and viaolating the crumple zone or sacrificing the cell since it won't burst into flames and leave the crumple zone forward of the suspension intact?

RedlineMan

Hey;

I think you need to look at the speed potential of the car. What we know is that the fuel tank of any early 911 (pre 964) is pretty vulnerable because the front unibody is utterly flimsy. Now, adding a fuel cell to ANY 911 is a massive improvement in fire safety in any event.

However, you can see an obvious difference between a 2-2.4L car vs- a GT3 class car. In the higher speed potential car, you might be well advised to create at least a rudimentary structure out front to attempt to equalize the protection value a bit between the two.

Build to suit the real need, and if you're not sure, over build it! The worst you'll be is a little heavy. Better heavy than pan fried.

Noel

So is the recommendation that in an early 911 (Pre 89) that the spare tire remain in place as it may aid in the crupple protection?

kurt M

I can peg the 120 MPH speedo on my 912 when I put my mind to it and have a good tail wind. The 76 912 is the only 911 bodied Porsche with less HP. Hit something hard at 120 and you are looking at North of 100Gs. 60s and 70s 911s have poor protection and are not up to that kind of G load. Few if any cars are. I would think that there is a compromise between protecting the tank and absorbing Gs. I'll take keeping the tank in shape and requiring a better seat and body (and appendage) retention system.

I built a smaller dia tube X sided box for the cell in the 911 I am buiding. It is conected to the front a arm pickups and to the towers but not to the front corners.