dkirvida

Has anyone run a RSR-style/straight pipe exhaust on a M64/03? Any loss of low-end torque due to lack of back pressure?

Want to remove center muffler on US Cup Car and the car already has dual exit cutouts.

Thanks

964George

I'm pretty much running a straight through on my M64/01 engine and appear to have a loss of torque.
I'm running billy boat heat exchangers directly connected to a 997 GT3 rear silencer via the lower straight through section.

It's a healthy modified engine with 300bhp and 239lbft at the flywheel, it doesn't feel down on torque, goes really well and sounds glorious.
But other owners I know have torque between 260-275lbft with similar spec engines, but more conventional exhausts, so just by the figures alone I would say mine is down on torque.

They do say that the 964 standard exhaust is very good and hard to be improved upon.
At some point I plan to rework the exhaust and use standard 993 heat exchangers.

I know it's not a M64/03 engine but hope this helped.

kos11-12

Agree with George, the 964 with cat bypass and cup or cat bypass and second muffler delete is very good .
It looks like the next upgrade will be 993 collectors, cat less , with turbo mufflers or C2 reworked as RSR witch from my understanding are same as the turbo mufflers.