midnightride42

i was reading over ones post and got a little confused, so here is my ?

i just resently put on two N1 style mufflers. just cut the stock mufflers off and replaced them with N1 style mufflers i bought. to me it seems like she has little more top end power not but im sure it couldnt be that noticable. but to my ? , i came across someone saying it could have a effect on the ports not opening or something in those terms. can someone spreak some light on this please.

i was going to do a search but didnt really know how to search for that by using key words.

i didnt replace the old exhaust piping only mufflers and bit of the piping to angle the mufflers a bit.

i have a 87 N/a

thanks
andy

Icemark

do you have your cats still on? if so then there probably is still enough back pressure to open the ports.

YearsOfDecay

in Effect.... 86-88 N/A's use the backpressure of the exhaust system to move the 6-port actuators. If you open up the exhaust system, you will not have enough backpressure in the system to make the 6-port actuators operate.

As Icemark said, if you still have your cat on, it should still have enough exhaust backpressure to open the 6-ports.

Mazda got rid of this problem in 89-91 cars by operating the 6-ports off of the air pump and using a computer controlled solenoid to operate them, thus making it necessary to leave the air pump on even if you remove the cat...

The most effective way of runing an open exhaust on an 86-88 that I've tried is the Summit RPM switch tied to a 3way solenoid which is hooked to the air pump and the 6-port system..

do a search for s4 6-ports and you'll find a lot of info.