How much torque can the fd chassis handle?
 

I spoke with a guy who has worked on 7s for over 20 years and told me that the chassis on fd's can handle a lot of torque.

Anyone know how much torque the chassis can safely handle?

I'm not sure what your end goal is here. Unless you have mega $$, you'll never come close to "twisting" the "frame".

Assuming you are staying rotary, the factory motor and diff mounts wil tear. With those sorted, the PPF is next to die. Banzai racing makes a trans mount and diff brace to solve this issue.

I've seen the above issues on cars that are close to stock up to the BNR turbos or small single.

And once you make BIG torque, the differential will usually explode on launch with big tires. Swapping to a Cobra 8.8" IRS, custom axles and driveshaft will fix this.

These usually die with a BIG turbo, slicks, or LSX based engines.

I've never seen anyone complain that the chassis was tweaked as a result. So, with that being said, the sky (or $$) is the limit to what you can put in these cars.

Ruler_Mark has a Turbo LSX on E85 with >700LB/ft or torque.
ErnieT used to have a CYM 13B with BIG turbo >700HP.

Vince

how would you measure that?

i do agree, the FD is really tough. we raced an integra for years, and it isn't nearly as strong, it was tearing and popping spot welds and stuff, and that is WITH a cage

I hadn't ever heard of the chassis being weak either so I was a little skeptical. But, this was the guy over at pineapple racing telling me this, oh well. I guess everyone can have their own input on it! Thanks for the information, definitely made me feel better about my ls project ha!

I blew a stock diff at only ~330whp in my FD.

I have cut an FD in half with a sawzall. And seen one flat dropped 2 storeys on its nose onto a concrete road (shooting for a film) and also seen one flip over about 4 times, end over end on grass.
The spaceframe is very stiff- if you cut one in half around the rear pillar area you will find they have three gussets inside the rear quarter panels- big ribs that are there for strength.
The weakest area of the chassis is up front where the light buckets are. These areas bend and deform easily.

The main cabin and floorpan is one of the most rigid bodies I've ever seen on a high volume mass produced steel car though.