I have an 81 rx7 that I bought a hear ago, and have been itching to start tinkering on it, but don't know Where to start. I want more power and more torque but do not want to suffer low MPG. What can I do that will not kill by MPG?

 

In all honesty as boring as it sounds, get your running gear up to scratch first - a decent setup will make it feel so much more fun anyway and then you'll be set for bigger power. Unless you've already done that then apologies - then it depends if you want to stay NA or go turbo.

MPG will go to ratshit regardless as you'll be loving it too much lol.

For what it's worth I did it the wrong way round and got decent power in the first incarnation of my car then worried about how well it stopped.

 

I don't know your starting point exactly, but if you like the car and want to keep it a while you can do this.

1. Put the car on stands.
2. Drop and clean the tank, replacing the fuel lines and putting a sock on the fuel pickup.
3. Flush cooling system, replace hoses.
4. Replace bushings, brake lines, steering idler arm.
5. Replace shocks/struts maybe even springs.

At this point your platform is ready for

6. Install exhaust header and silencers to meet your noise requirements.
7. Modify your Nikki carburetor to flow a little better
8. Go to one of the direct fire ignition mods talked about in many threads.

That's my 2 cents.

 

1-full tune up (plugs, wires, cap, rotor, air filter, fuel filter, oil, coolant, belts, hoses [fuel, vacuum, coolant])
2-remove emissions (if you dont have to test)
no REAL power is gained from this, but it eliminates man problematic systems, and reduces the chance of a vacuum leak
4-strip your Nikki!
5-MSD coils
6-full exhaust (RB of course, unless you can fabricate or find a coveted MindTrain exhaust)
7-intake (RB filter kit is cheap, looks nice, sounds nice, and might ad 1/2 a horsepower )
8-remove unused things for weight. If it is not in use, remove it. An ounce hear and a pound there adds up to quite a lot. (AC, emissions, RB exhaust etc can lead up to a 70ish pound weight loss)

Dont forget brakes and handling! New struts, shocks, and aftermarket springs will change the feel of the car. Replace you idler arm bushings for a tighter feel from your steering.