HOW TO: Mod Stock Exhaust for High Flow.. The Right Way

[katoranger]

Well the reason I say it is because the escort is not a race car and needs to be driven in low-speed environments.

I read the article you posted in the other topic and that person only talked about high rpm. Very little about low rpm.

I am not saying you are incorrect about the need for backpressure on high rpm uses. Just that in my real world experience my car needed some.

These bikes diffinately benefit from opening up the exhaust and you are correct there. I don't mind needing to rev more to get out of my bike. The car was a pain to drive that way. The clutch would chatter like you were dumping the clutch.

I also have a minor in automotive engineering.

Allen

[katoranger]

Here is the flowmaster take on backpressure.

http://www.flowmastermufflers.com/backpressure.html

It never says that no backpressure is good, but does tell about what needs to be done when backpressure is reduced.

If you don't change other things when the backpressure is reduced is how you loose the low end torque.

My escort was not able to compensate for the loss of backpressure. That is why you need to rejet to adjust for more fuel do to more air.

So as I read more its not so much the backpressure, but the velocity of air moving through and keeping it moving.

Good point Porterz. I think I have a changed opinion. It you don't want to do other mods then you need backpressure, but if you can adjust the other systems to accomodate for the open exhaust.

Allen

[Gimpdiggity]

Originally Posted by PorterzCustomz

well.. not exactly it typically moves the powerband up to the higher rpms thats why all race cars run as free flowing as possible, some run open headers. It may take a little power away at low rpm but you gain much more on top end.

Isn't that exactly what I said earlier, when you called me a hater??

[PorterzCustomz]

Originally Posted by Gimpdiggity

Isn't that exactly what I said earlier, when you called me a hater??

It moves higher in the rpm range, it don't dissapear :wink:

[Gimpdiggity]

Right, like I said. You'd suffer a loss of power at low RPM, but flow better up high.

Semantics!!!

[katoranger]

I want my power at lower rpms where I tend to use it more.

I ride it more like a trials bike off-road.

Big power right off idle is what I want.

If you like going fast on open trails then get you power up high where it is more usuable.

You are right in the the power is not gone. Just in a different place.

Allen

[knothead]

I went the cheap/easy way and just drilled three 1/2" holes in the end of my muffler and into the baffle, I swear I lost power, mostly low/mid but also on top end. I don't like the sound either!

[katoranger]

You may get better results by installed a larger main jet with your drilled muffler.

Allen