toddah

Hi all,
I have a stock 93 Touring I purchased a month ago, I am looking for some advice on exhaust combinations. I have just put 4 S02 PP tires on after a alignment and replaced the fuel filter, plugs, wires, oil, air & oil filters. I have purchased a SS M2 DP and a SS midpipe. The question is, should I put both pipes on now or the DP only and wait for replacememt of the ( new by former owner ) muffler system. I don't want to create imbalance and hurt the great driveability of the car. I will replace the catback but I need to save some more money for the catback and ECU before I can proceed. Any advice would be great. Still reading posts about noise levels and street use trying to decide on the correct catback combo. I park across the street from the local Police station at work
This site is great and discounting the sometimes pretty harsh flaming by some members it's the best auto related tech site I have ever found.
Have a good one !!!!!!

the_saint

Do not put on the midpipe until you get an ECU, and port your wastegates (or find some way of preventing boost creep)!

thesaint

Zoomspeed

I think you might want to stay away form the MP w/o an ECU, the cat is probably the biggest restriction in the exhaust, so you still ahve a possibility of getting some creep. I would go with the DP, and the catback, then just save the MP for when you get and ECU.

1FAST7

Downpipe + Midpipe = ECU Needed

with dp and mp, you will most likely have boost creep. To resolve that you need to port your wastegate. ECU will also help. but one thing for sure is, that you need a ecu if you have a midpipe. dp will be fine without an ecu.

1FAST7

RecKleSs

The downpipe and midpipe is a great mod for the RX-7. You will definitely feel a difference in hp and is also a great reliability mod. As for the exhaust go with the GReddy exhaust, it's not really too loud and has a great sound. You might want to contact Rotary 93, I think he wants to sell his GReddy exhaust, but I'm not too sure. DO NOT get the A'pexi exhaust, because it will be too loud for you.

As for your ECU, you will actually be fine with the OEM ECU if you put on the downpipe and midpipe on your car. However, make sure you have a good boost gauge, you don't want your boost to go over 10 psi. I don't know why some members are telling you to port the wastegate to solve boost creep, which you don't even have. Put on the mods first then see if you have some boost creep. Some RX-7 don't experience boost creep with these mods and some do.

rynberg

Well, the difference between the other members and your post is safety. On some FDs, putting on a downpipe and midpipe w/o ecu or porting the wastegate will lead to dangerous spikes and boost creep. You state that yourself. Why risk that when's it easy to wait until he gets an ecu. There is no reliabilty improvement from a midpipe unless the stock cat is really clogged up. But there are plenty of POTENTIAL problems.

I would think in the "ideal" upgrade scheme for FDs, that a mid-pipe would come after:

*downpipe
*cat-back
*intake
*ecu
*fuel pump

Then get the midpipe and install larger secondary injectors to keep duty cycles low.

Just my 0.02

Rotary93

Yes. Greddy SP catback for sale! Contact me if your interested.

BrianK

also know that if you put on the DP, MP, & CB, your low end torque goes in the *******... which means you'll only be hitting the good power up in the range where it's important that you have enough fuel getting in the motor. Make sure your injectors are working well in addition to a new ECU - if you've got lots of miles (read: over 60K), you should look into rebuilding the injectors for extra added safety.

... and, if you're only getting 10-12 psi with DP & MP, there's something wrong with your plumbing - in other words, be safe, assume everything is working properly & get an ECU.