HP Gain

[brix542]

Im looking for ways to gain HP on the Pathy. Not looking to be the baddest or anyhting just a little more power. Im going to get the CAI kit from ebay and exhuast ran. For the exhuast I plan to run 2" duals with nothing but mabey cats. Would that be good or would it not give anough back pressure? Are there any other add-ons for the wd21 that would give HP gain? Thank You

[synthetic]

avoid stock airbox imo it's tiny, if i can get to it ill send a pic of the cone assy. i run.

[Precise1]

You can do CAI, cams, headers, ECU reprogram, and exhaust for power. Exhaust is recommended to be 2-2.5" single pipe depending on configuration. I have headers, high flow cat and a Flowmaster Delta 60 with 2.25" piping and that is almost too much IMHO.

 

B

[Kingman]

You'll flow more exhaust and be more efficient with a single large pipe than you will with duals. 2.5" from the y-pipe back, headers, cold air intake, cams, etc. The less back pressure you have the better, zero is best.

 

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[MY1PATH]

Not having enought back pressure is a misconception.

What really happens when you run duals or the pip is too large is that the exhaust gasses expand too fast causing them to cool down and slow down. This creates turbulance and disrupts the chain of flow for the exhaust pulses behind the expanded cooled gas.

 

2.0 or 2.25 pipe is pretty ideal and works even for modified VG engines. Intake Is good, headders are better and JWT S1 cams do lots! For more mild gains up top the Eurospec cams from the dealer are also a good option.

[nismothunder]

0 back pressure is best? Maybe WFOT yes but with duels no, its not on a small engine. I ran true 2 inch from the manifolds back with a thrush glass pack and it worked good, I never wished for more power since its a little engine.