I'm thinking about puting a exaughst system on my 88 fc, But I have been hereing a lot of different opinions about me losing power or gaining power, I'm wondering if I take cats out and put a high flow muffler on it my car will lose a noticble amout of get up and go

 

There may be a small increase of power but nothing drastic , if you want a real system buy at least catback exhaust or header.

Running straight pipe in place of cat or a gutted cat may increase peak power but may also decrease torque, I however have no proof but this is just what ive heard.

Simply gutting out the cat and putting a muffler on the car is going to make more of an increase on exhaust noise than hp , basically making your car sound faster than it really is.

If you want to put your money into something useful buy some kind of header, header will increase your power by about 15 hp where wat youre wanting to do will be lucky to give you 5 hp.

 

what about the aux exuaghst ports, would it slow me down I dont really understand the whole concept behind the aux ports?

 

The auxilary ports are ports that are made for high rpms that work like a hondas vtec does, basically they stay closed at any rpm under 3500rpm but after 3500 they open up. This is to give the car a better overall power without sacraficing power in the low end giving the car better overall average power throughout the powerband.

As far as your exhaust goes, if you get headers you can get headers that will work to make the aux ports open but it may cost a little more to get all the parts as racingbeat prices are not cheap, the other option is to open them through the airpump instead of opening with exhaust backpressure(granted you still have your airpump), the other option if you dont haver an airpump would be to get an electric airpump and rpm switch and have them open through that method.

Even if you dont want to go through all that racing beat even sells a downpipe/midpipe that just attaches itself to the stock manifold and will give you some better power without having to worry about making a setup to open your 5/6 ports but youll still get more power with a header.

Sorry if i am confusing you, but all in all the most restricted thing on any rx7 is the exhaust , freeing up the exhaust will give you more hp than any other bolton mod.


You can also get cheaper priced headers from pacesetter which have the pipe on it to open the aux ports (i think) , and they are also much cheaper than racing beat , pacesettter being 150$ and racing beat being 250$, another place that recently has started making header for na is http://www.corksport.com

 

I still have the air pump how could I make it to open the aux exuaghst ports?

 

Goto this page it explains everything, if you havent heard of RotaryResurrection.com its owned/maintained by kevin landers, so thank him for the writeup lol.

http://rotaryresurrection.com/2ndgen...actuation.html

Oh and by the way, they arent aux exhaust ports, they are auxilary intake ports.

The engine only has 2 exhaust ports, one per rotor :P

 

A nice full exhaust (cat and mufflers) is good for about 25HP, maybe a little less. The 5th and 6th ports are good for about 25HP.
So... yeah, hook up the aux ports to your air pump and get them working.

 

When i get ready to do my exhaust, i'm going to just do full racing beat exhaust. Mostly because i like the style. Call me crazy cuz its really expensive, but i like the idea of a full racing beat system on my car. I also have racing beat springs =D.

Anyway 5th and 6th ports open at 4400 rpms..........i think..... not totally sure but i think thats what i read.

Also you gain more power, the "rx7 vtec" at 3800 rpms, thats when ur secondary injectors kick in, if they're working properly. Sometimes they crap out. From my experience with rx7's (which hasnt been very much) i've had 3 people that i hang out with have their secondaries crap out on them.....no fun.