valetudo

I am putting an LS1 into my 1987 RX-7 using the Granny Speed Shop conversion kit. My question is whether or not the catback that Borla makes for the RX-7 will be a suitable place to start as high performance exhaust system for my future LS1 modifications. Summit sells the cat-back here http://store.summitracing.com/egnsea...0&autoview=sku

I believe it is 3.5" piping, and I will be having custom piping fabricated from the LS1 headers or stock manifolds to the cat-back.

Would it be more feasible to use an exhaust system more aimed at the LS1? I do not know if this exhaust system made for a 1.3 L rotary engine will be suitable.

The reason I ask is because it would be much more cost effective for me to buy a prefabricated bolt on cat-back then to have the full exhaust fabricated.

~Bob

Z-286speed

I would go with a custom exhaust since your getting the headers done. Get some true duals and run those out the back with an x pipe.

Birdie2000

iTrader: (15)

That big pipe doesn't look 3.5" to me, but it's hard to tell from the pic. I'd find out how big the smaller pipes are that the mufflers attach to. If they're at least 2.5", I'd buy the catback and cut that y junction off and run the duals to an X pipe. That basically looks like a rear section kit, and you'd only be cutting off maybe 6" of pipe off the system. Plus it'll fit good at the bumper, and borlas are generally very good mufflers. You could easily adapt that system to duals if the pipes are big enough.

valetudo

Okay, thanks for the information. I am thinking the pipes on the individual mufflers look smaller than 2.5", but I will call borla and find out. I will just cut off the Y-pipe and install an X-pipe if they are 2.5". If they are smaller I am just going to have a full exhaust with true duals and an X pipe fabricated and use a single cat with flanges that can be swapped for a straight piece of pipe.