mattorx7

Hi i have an ls1 in an rx7 it made 440.4hp and 492 lbsft i am having a new wiring loom built and using a stand alone ecu so the MAF sensor will go, my question is should i run a 102mm pipe from the tb to the filter or should i leave it in 89mm as it was up to the MAF previously?

Also my exhaust comes of in 3" to a y pipe where it increases to 3.5" then decreases back to 3 inch would it be better to continue in 3.5?

What would be the effects on power and torque with regard to changing the bore sizes?

01ssreda4

iTrader: (96)

When you increase the diameter of the piping, low and/or mid typically suffers and top end gains. Your exhaust is effectively 3 inch, the small section of 3 1/2 isn't benefiting you at all. To maintain flow off your headers but in one single pipe you would need to merge into a minimum of a 4 inch pipe, and even that wont flow as good as your 2 three inch pieces but it would be close. As for the intake track, if you are ditching the MAF, by all means up the intake piping as big as the next smallest restriction.

mattorx7

ok thanks would there be any advantage increasing the exhaust to 3.5 or even 4 inch?
also the tb is a standard ported one so i guess at 78mm that would be the next restriction so my 89mm pipework shouldnt be holding it back?
thanks
matt

mattorx7

anyone? my actual id is 85mm on the intake pipework