I've just purchased a 1985 Mazda Rx-7 GSL-SE from a friend of mine for $700.00...the car has 157000 miles on it but the motor was replaced around 110000 miles with brand new motor from mazda. The car is in fairly decent shape. I am looking forward to restoring it and wanted to know things I can do to increase horsepower and such. I know the basics about Rx7's (1st gen) but have only previously owned 12A versions. I do not want to port the engine since it is still pretty much new but would like other suggestions on how to gain horsepower. Any help is appreciated. Thank you.

 

extractors, exhaust. (remove the cat), get a full twin 2" system to the diff, with a resi on each pipe, and then a 3" over the diff and into a straightthrough muffler.

ditch the airpump when you do the exhaust.

Get an aftermarket computer, and get it tuned properly

Get the diff gears dropped, to a lower ratio, put low profile tyres on the stock wheels to lower the final drive even more.

Get a superlight flywheel, and a heavy duty clutch.

Remove the aircon, all unessary items under the bonnet, pull out all the interior behind the seats and drive without a spare tyre. Only put 30 or so litres of fuel in her to keep weight lower....

 

or if you're on a budget..........
*Run a full exhuast, this is always key to making power on a rotary as we all know. I am running headers with 2.5 inch single piping to the back into a racing beat power pulse muffler. I think dual piping is not necessary unless all you are looking for is top end power. YOu will loose some torque and increase a lot of noise with duals. Single pipe is fine for street driving.
But don't forget the secondary actuators on the intake manifold are controlled by the back pressure from the exhaust system via a small hose.
When running a full exhaust system on an SE if you connect a Apex AFC and a wideband O2 sensor you will noitice that the car runs slightyl leaner now on top end and also starts to max out the injectors. Not severely but its noticeable. I had some brand new RC 850cc injectors lying around so I threw them on my SE to try them out and was pleased with the power increase at top end.
*Low Profile tires are a good thing but also make it easier to spin wheel(loose traction) so it comes down to prefference.
*Light weight flywheel is a nice upgrade, I did it, but I use the stock clutch still since I am street driving it and it never sees any track time so its perfect. It never slips on me.
*get rid of the A/c if you don't need/want it.
*Air pump can go if you are using a modified exhaust or you can use it to open the secondary actuators on the intake manifold....There are several right ups on here for how to do that...It's rather simple and straight forward.
Well that's my 2 cents....Good luck

 

I appreciate the suggestions and will try them as my budget allows. If anyone can think of anything else let me know. I've been searching the forums looking for tips too. Any other comments are welcome. Thanks again..

 

do you have any pics of it? just interested in how it looks for 700$

 

I'll try and post some pics in the next week or so. Car is being kept in storage for next few days until this stupid hurricane ophelia decides where it wants to go. I've read alot of posts here about the 13B engine and alot of references to 4 port and 6 port engines. My question is this; is the 13B in my 85 GSL-SE a factory 6 port or 4 port? How do I tell? I never realized there was a difference. Also, I believe the stock horsepower for a 12A is around 105hp...what's the rating for the 13B?...

 

The 13B in your car is a 6port stock any way... The 4 port were much earlier (in the rx-3 and the repu as I recall) and then later when the turbo was added.

 

the 13b in the gsl-se rated at about 135hp stock out of the factory....