Exhaust 1.3

[Steve126]

Can I just pick your heads a min?
We have to run the standard manifold so not good !!! But we have a straight pipe from the cat back but the box we have has no baffle! Would this effect the performance? Do these engines rely on back pressure? Thanks

 

[infinity]

Wouldnt say they rely on it but it helps low end torque although suffocates at high revs

 

[frank]

nah, backpressure on a 4 stroke is a myth

 

[Steve126]

So do

nah, backpressure on a 4 stroke is a myth
What do you think is best to do at the moment I have the standard manifold with the cat on the down pipe then a small box with no insides. I have emptied the cat. The exhaust stops just under the front foot wells just Incase he takes a hit!!

 

[frank]

you need an optimum gasflow/exhaust speed and minimum restriction steve, the system needs to be small enough dia to keep it flowing at speed (for extraction) but big and straight enough to limit restriction/backpressure
the stock downpipe is quite puny, so that is your limitation really