new to mr N/A, i swear, this car is faster than it should be..

[te51levin]

Originally Posted by 4W4K3

What's a book?

It's a kind of analog internet device, made of "trees" (I can explain them too if need be), used back in the cowboy and Indian days, back before DSL was widely available. Some old farts like me still like them because they are not subject to misapplication and misinterpretation by every kid with a keyboard and the desire to see his own thoughts on a forum or Myspace page.

Things ain't like they used to was...

[Recklesss]

why write a book when you can pee in the snow?

[TechX]

It is undeniable that backpressure robs horsepower, but as Aaron stated before cutting off your exhaust to make an annoying bumblebee will not help your horsepower either. The correct ways of raising your performance without becoming annoying is very simple. Create a better breathing atmosphere, colder cleaner and more air is the key. Give it a nice sound, if your stuff is old you run the chance of leaks, cracks, and low performance. Headers, decent exhaust pipe, and reliable/tested performance muffler. Change the oil, oil filter, fuel filter, plugs, wires, cap and rotor. Then have it tuned(by someone who knows what they are doing) and you will notice a great improvement.

If you are looking for anything more, then be ready to shell out the money. Your options range from 20v or 16v smallport topend. The lower end will cost you considerable more to change, just keep in mind, it was already stated a 4agze lower willnot increase power by itself. Changing the pistons, crank, and rods in the bottom end will however give you a larger HP curve to add to, and will in itself give you more options based on the compression ratio you build towards.

As another form of performance you have turbo, super, or twin charging your N/A, or just stop wasting time and do an entire engine swap and possible transmission as well if you are looking for a different gear setup.

There are limitless options as to what you can do with your car, it just depends on how much money you have and do you have the time and knowledge to do it yourself or money to pay someone. One of my boys is currently finishing up a 1jze(jap spec supra engine) into a Mazda RX-7. There are a lot of swaps that have been tried with the MK1, but feel free to explore and fill in the rest of us. Thanks.

[4W4K3]

From what I've heard on the forums and seen from a few dyno graphs upgrading to after market headers gives you little to no performance gains. At best I think I've seen 3WHP. If yours is cracked or rusted then by all means get new ones, otherwise I wouldn't spend the money.
Speaking only from a stock perspective. If you have other modifications that have increased power then the stock headers may turn into a bottleneck, but you'd have to be well over stock performance.

[TechX]

Your entirely right, the upgrade of headers alone isn't viable for the money you will spend, it would only be a "good" upgrade if you were applying more than just that individual upgrade. Performance is the key, and as it does open up the flow of the exhaust, the rest of the exhaust and the amount of exhaust coming out if the head make a difference, again most of the upgrades you make are very slight for each individual upgrade and even tuned only make a difference when you add all the +3, +7, +?? up in the end.

[F0Bman]

I agree.

[LokiRx7]

This debate is much like the intake porting depate, mostly because what is true with the intake is largely true with the exhaust.

Too small of a port, or exhaust port (same applies to exhaut pipe and intake pipe) Will cause excessive backpressure. No engine 'requires' backpressure. Anyone who tells you that you need backpressure knows nothing about what they are talking about.

What an engine needs is exhaust velocity, and with too large of an exhaust you will lose exhaust velocity. Some engines have very little exhaust velocity to help high rpm power at the expense of low end torque. We drive street cars and need to find a healthy medium.

The same rings true with porting, there is a such thing as too much porting or too big of an exhaust. I have read on some japanese 4A-GE specific tuning sites that the optimum exhaust diameter for this engine is between 2 inch and 2.5 inches. That was for an AE86/AE92. Depending on the length of your exhaust and the amount and severity of the bends is what should determine the diameter.

Alot of bends will make for a longer exhaust, it will probably be good to err on the larger side of 2.5 inches. Fewer bends will make for a shorter exhaust, I would shoot for around 2 inches. Also, I personally wouldnt use a glasspack on our cars. I would look for a nice chambered muffler, I have a Flowmaster, and I would have to reccomend it.

[TechX]

Agreed. Also, good information on exhaust sizes, my entire exhaust was rusted, and my engine hadnt run in 7 years, but I finally got the fuel pump replaced, and took the entire exhaust from the flex pipe to the muffler off. Broke bolts all over due to the severity of the rust. I'm going to cut the flex loose and cat, check inside the cat to make sure its not collapsed or anything and then I'm going to reassemble an exhaust with the flex and cat and just port it out the back so I can finish all the other work then I'll put a muffler on it. I'm going to pop a post up about the engine though, I'm having some probs and I think someone might be able to answer... stalling out it's broke, help...