Exhaust header: help or hurt f/e

[MetroMPG]

So the concensus seems to be: "it depends".

... and the only way to know for sure would be to dyno test the header against the stock manifold.

[Chalupa102]

Originally Posted by MetroMPG

So the concensus seems to be: "it depends".

... and the only way to know for sure would be to dyno test the header against the stock manifold.

That's probably what i'm gonna try to do now, because there is mixed opinions.

The guy said he has the stock exhaust manifold lying around in his storage unit and would give it to me. He also said he wants to buy the header that i have on now if i decide to sell it.

I'll see if i can get the stock one to test and if i get better f/e with it, then i'll sell the aftermarket header to him.

[gone-ot]

...should really depend upon how well the tuned pipe LENGTHS match with the FE-engine RPMS...if a multiple of the max RPM tuned length (or very ± close) the cylinder breathing and scavenging is helped, which benefits torque.

...however, the "got'cha problem" occurs when FE-engine RPMS fall "...in between..." and approaches a 'Helmholtz' quarterwave length, then the exhaust is trying to be stuffed back into the cylinder instead of being pulled out of the cylinder---bad,bad,bad.

...header pipe DIAMETER at lower RPMs shouldn't be a problem.

[Christ]

Originally Posted by rgathright

I have a Mopar hot rodding magazine that detailed the same changes to a Dodge Neon. They were able to find an additional 37lbs of torque by doing this to the 2.4L engine. I have since dreamed of this doing this to make a FE NEON.

The question is not whether they made more torque, but where the bulk of it was made.

You have to remember, we're operating under 3,000 RPM most times. Most things that increase high RPM power also decrease performance in the lower RPMS, which could have an adverse effect on economy.

[Tygen1]

My expirience was that it did not help or hurt my FE, in general. However, if I were able to pulse and glide, then having more torque below 2500 rpm would help. I'm ATX, so when I "pulse and coast" I can't stop the engine from reving up past 2500, so for me I felt (this was pre scan gauge) that there was an increase in torque during this spirited acceleration, and it seemed to make the pulse length shorter. No real testing was done, more of a subjective feeling. I went with a 4-2-1 header, but it has very large primaries.
Hope this helps your decision.