DO you Need it or not with a 13b cuz i dont mind noise and or the cops so can i run a straight pipes ? or cut off the stock mufflers and leve the cats on and run a straight pipe where the old mufflers went? oh i have a 86 N/a?

im a piston guy trying to figure out these wankles

 

hey,

welcome the the rotary world ... backpressure is required to push the low end performance ... it won't hurt anything though. It will help more if there's no backpressure in the top end rpms. depends on how much you'r pushing, most people go with a 2.5" straight pipe and that provides and good high and low rpm power. 3" will start hurting it more unless you have turbo, or supercharger, or some sort of proting job done to the engine.

 

ok well i have the stock system with 2 cats and a 2inch exhaust and i cut off the 2 mufflers and ran 2 pipes to tips to ther rear whair the mufflers use to be if you catch my drift yea i bought the fc for 400$ the guy(adoctor$$$) took the car to the mazda dealer and said it said that the exhaust was running to hot because the muffler shop said he went throw cats to fast and so he took in and the dealer said he needed to rebuild the hole thing because of a blown seal and qouted him 4000$ to fix so he put it up for sale and i found it looked at it and its in great shape with 105000 miles on it and nuthin rong at all on it i did a compression chek to it and that was perfict and as of right now i am putting stuffer ajustibull sway bars drilled and slotted rotors and ceramic break pads and the car has the hard sispention with the 4 piston calipers oh it an 86 but Thanks i love this car one of my favorits

 

if you talk to anyone on this forum, mazda dealerships always do the exact same thing ... they tell you your engine is blow and they have to change everything. They do this because they don't know how to fix rotary engines themselves but thye know how to get a new on and install it ... hence the whole job being redone .. never trust a word the dealer ship says ... they're always wrong

 

oh yea dealers suck in know this for a fact so you think if i run a 2inch str8 pipe with the 2 cats thats fine? or could i cut the cats off too? oh yea i have an
N/A 13b i might supercharge it

 

now when you say that you have 2" pipes going to the back do you mean it 2 seperate pipes, going ie from the the header which would have 2 outlets, and then each one of those pipes has a cat? if the thats the case, i would remove the car, but at the end of it I would install like SS magnaflow muffler which would have 2 inlets and 2 outlets. Personally i've had better performance installing a high flow muffle over cats. I know it might be only one or 2 pony's but thats still something.

But now if you have just one pipe that 2" dia connected to 2 cats (so basically stock setup) i would remove both cats .. .replace the piping to 2.5" and connect that up to a high flow muffler. I will hopefully be getting my muffler and pipes in today, and i will try to have them installed as soon as possible to send you some pics.

 

best NA exhaust (IMO):

short header to collector to 2.5" or 3" pipe then split again and dual 2" pipe to performance mufflers.

BUT on a 86-88 NA, you cannot modify the converter system without making the aux intake ports quit working. there are many threads on other ways to actuate the ports, and if you do one of those, then you can do whatever you want with the exhaust.

pat