i was told that the rx7 needs alot of back presure to run properly i was wondering if it would hurt my car to remove the cats and run a straight pips and just mufflers i have a 88 rx7 gtu

 

if it is an n/a then yes it will "hurt" it persay .. ur secondary ports will not open due to they need back pressure from the cat to work .. i think ... im preaty sure thats what it is .. i could be wrong ...

 

Your 5th and 6th ports will not operate and will have a decrease in HP and torque across the power range if you choose for a straight pipe.

You can rig it, buy a RB presilencer, or run a cat with a split air tube.

 

so basically i sould just replace my cats and be happy

 

or get the Racing Beat presilencer with split air pipe.

 

Just gut out your existing cats with the split air pipe.
Or go with a rpm activated port set up. (Search)
If your going to do more mods like specifically to injection you might want to consider headers.


Almost all the backpressure is made at the mufflers, so the cat removal will not noticably effect this.

 

backpressure is needed, but only for the s4 my s5 opens automatically w/o backperssure so I could drive it with no exhaust but it would sound like ****

 

thanks alot

 

so basically mufflers that specificaly say reduce back presure is a stupid idea?

 

Reducing backpressure can increase power a lil. but youll have to rig up your 5th and 6th ports to open another way. There are a couple articles on how to do that if you search around a lil. I have a 88GTU strait pipes all the way back and rigged the 5th and 6th ports to open as described in the threads(cant really remember how it was done imma a lil drunk) and i couldnt have been happier(I am half death so the sound didnt bother me) it felt as though it had more power and it reved more feely. But if someone says other wise(like someone that knows there ****) that you should leave them do it...this is just my own experience on this subject.

 

do what I did, use a rpm switch and airpump to open ur ports. This is called the electric conversion for the ports. My setup work perfect with NO problems. (search the tread is out there). Ive showed everyone how to do this plenty of times. Goodluck!!

chris

 

BS to most of you guessers.

I have headers, an HKS midmuffler and aftermarket mufflers. My aux ports open nicely just using a fitting tapped in the rear header pipe, and an 1/8" copper tube going to the stock rubber tube coming off of the ports. Everything bought in the plumbing supply section at Ace Hardware. This setup works fine on my S4 and a GSL-SE I have worked on.

 

I wasn't guessing, you just did what I said in my first post by "rigging something up".

Btw, it is a header, we have only one.

 

thanks to all i was kinda wondering about the HEADERS thing i was starting to wonder where the second one goes

 

any suggestions on if my damn air pump is locked up

 

i searched the threads for about 2 hours and cannon find anything on riging the ports open could some one enlighten me on how ths is done remember im a new 2nd gen owner 88 gtu

 

Are you talking about just leaving them open, cause if you are then your losing HP and lowend torque. This is a bad idea to wire then open I did it and it suxd, mys well by a honda. Anywho lemme see if I can find my original post on the electric conversion.

 

http://www.teamfc3s.org/forum/showth...threadid=42367

This is what I did and make sure you use a fused power source, like using the battery for power not random power sources like plugs.

 

thanks alot

 

apprechate the help but i dont have the msd ignition all stock however i found a archive that a guy used some plumbing parts and the air pump think im going to give that a try

 

um....dude thats a RPM switch not an ignition. I got mine off ebay for cheap, when I did this mod and used a Ford expedition lumbar airpump which I also got off of ebay for cheap.

 

my bad wasnt thinkin so basically an air pump form about anything will work

 

yea compack style not too big,just enough to push 4 psi max.

 

You do not loose horsepower by wiring your ports open. .you lose some low end and that's it. the ports are open by 3800rpm anyhow. It really isn't that bad driving with them wired open, I did it for a while when I had an n/a. No analagy to a honda at all either. . lol

 

how do i wire them open ??