Hi again, you guys were so helpful to me the last time I was on here. I was thinking of a turbo for NASA PT class but am now sticking with the NA. I am still new to rotary so I am ingorant about a lot of things. I think I have an FC? It is a 1991 NA with the duat exhaust.

I am assuming that a racing dual exhaust would be the best(thinking about the Racing Beat) but after reading some posts on the subject there is talk about the need for back pressure and something about the actuators. Would I be doing the right thing to go with the complete RB exhaust from the header to the muffler or is this a waste of money and there is something better or just as good for racing applications out there? I intent to run some type of racing intake also.

Also there wqas also something about the air pump being needed for the engine to run properly with a racing dual exhaust. Is this true or do most guys take the pump, steering fluid pump and AC out?

 

You have an series 5 FC (89-91), series 4 is (86-88).. Racing beat is a very good company. Specializing in rx7s. there is a kid on this forum that is putting down 490 and running high 10's in the quarter with the RB dual exhaust. So is there better out there?? there are always better, but the racing beat is a really good quality exhaust, and for what your doing.. your not going to need anything to crazy.

 

The best exhaust for an IT/PT type car is the one from ISC Racing. It can not be beat, call Mike and talk to him. Custom header, front section, mid pipe and muffler. You are looking at about $800 + shipping.

I have not purchased the ISC one yet but am currently running an RB style header (from RX7.com years ago) that is ceramic coated and wrapped - 3" custom pipe (wrapped) - to a Dynomax SS Ultra Flo muffler. My system works good for me and is in excellent condition, I'm content with the power and have not switched to the ISC.

Take a look at the fastest ITS cars or even an EP car, I don't think you'll find many with a dual exhaust. Single 3" works fine.

As far as removing the other items.... that's the fun of PT!

 

SDJ is another good one ... if you can find someone selling one as they are NLA. I do know Rob from rotaryshack and banzairacing (I think thats his name) from this forum have both purchased the rights to reproduce them. This is mine:

From when it first came in (long primaries, O2 bung, collected into 2.5"):





To now with added EGT probes, and wrapped. Will do ceramic coating sometime:





And if anyone cares about the weight of them, they're only 8lb.

 

They're listed for sale here:

http://www.rotaryinnovation.com/headers.htm

 

thanks again, I am glad I asked I just assumed that a dual would produce better flow and less turbulance. I will take a look at single setups

 

Very interesting. I had no idea someone still produced this header. I have an old original SDJ 12a version. Anyone try to buy one of these from rotaryinnovation? Anyone familiar with them? The rumor was that these made the most power of any commercial header, although I have never seen back to back tests. The ISC was next.

 

I know you are asking about an FC exhaust system but you may wnat to check with Charlie Clark at KC Raceware (http://www.kcraceware.com/). They make a very good FB 12A/13B header for ported engines. He may have some ideas and suggestions for you.

 

Check out the Racing Beat web page. You should either look at a "single" (collected 2-into-1 around 2 feet from the ports) or a true dual (collected back near the rear axel).

Pay attention to the muffler. I have the Racing Beat headers and midpipe/silencer into a single Corksport "cat-back" exhaust and it's too loud for several of the tracks I run at. An uncorked rotary is a noisy beast!

As for back pressure, the S4 (see above) uses exhaust pressure to actuate and open the 5/6 intake ports at a certain RPM. The S5 uses air pressure from the air pump to accomplish the same thing. If you are looking at a true race car, you will almost never see the lower RPM range while on track, so the 5/6 port actuators should be removed and wired in the "open" position (or remove the valves from the intake tract entirely). The VDI system is also actuated by air-pump pressure and should just be wired open.

Hope this helps,

-bill

 

Ya not sure about the rotary innovation site. But I doubt it. Never hurts to give them a call though. But ya SDJ's are legendary.

EDIT:

Looking at the date that the site was last updated Nov 1, 2005 I would say they are not in business again, if they did work side by side with SDJ.