Offroad-Express

Its time to sort my exahust on my r rover .its 3.5 mild cam two barrel holley,ported heads.extractors.....but do i go big single pipe with a free flow muffler .or twin pipes with a coby type resinator on each pipe.this truck is not a hard out off road more a tow wagon/run around.what are the pros and cons for both..

Hello. Had twin pipes on a classic . Dont think it went any faster but sounded great. Am about to do the same to my p38 which has a high torque cam and other shit. Dont expect any performace gain but the noise should blend in with the 20" chromes etc.

Twin pipes with cobys will be quite loud.

The system I just put onto my Landy is headers into 2 & 1/4 pipe. Y section changes to 2 & 1/2" pipe at transfer case. Then through coby and small free flow muffler and out the back all 2 & 1/2".

You could probably ditch the resonator in the single system and just have the muffler (which I might do yet) and still be quiter than twin pipes with resonators.



I would have preferred twin pipes myself because lets face it, there just better

I didn't go for them because it was to tight getting it past the handbrake drum on the drivers side at the back of the transfer case.

The RR might be different though.

Your both right there is nothing quite like the sound of twin pipes with the uneven idle of a lumpy cam.....

Definately go for "long" resonators though. Those short buggers do stuff all.

I did a Bathurst style side exit on a worked holden 202 in a Holden HZ ute. Twin 2inch with a short coby in each pipe. It was stupidly loud.

The fact that the length from the extractors to the side exit was about 1.5m didn't help

Sold the ute and the exhaust was still on there two years later

Whatever option you choose, put a reasonator (or 2) up near the front to make it sound good and a muffler near the rear to keep the noise level down.

You get more performance from a single larger pipe than twins. And a smoother more even sound.

My uncle has a worked 331 Chev with gene extractors into a single 3inch pipe. The performance is actually better than a twin. sounds very nice, but 3inch gets expensive and will sound louder without the correct muffler.
3inch mild steel, HPC coated looks better than chrome

I'v always wondered how to make an exhaust system sound either:

deep/rumbly

or

Raspy/Angry

If you know what I mean.

I like the Raspy/Angry sound myself, especially if you can keep it reasonably quite until it gets onto the cam...

just a matter of picking the right pipe size (gas speed) and resonator/muffler(s) to make it resonate at the right frequency.
two mufflers works better than one single. but it depends on what space you have for mufflers. you don't want the first muffler/resonator to close to the Y join.