Originally Posted by C. Ludwig

Look under any of Mazda's race cars of the 80s and you'll find a collected header. Look under any ITS FC that's run up front at the ARRC or anywhere in SCCA and you'll find a collected system. It might be a long primary or a short primary but they're all collected. We've used long primary with RB uncollected header, Speedsource short and ISC short. The Speedsource combination made the most peak power. The ISC was best up to about 6000. We haven't tried the SDJ header but they have a good reputation. The RB headers are widely considered slightly sub-optimal because of the sharp bends directly off the flange. We have made 170+ whp with them though so they are not terrible. Truth is that all the good systems end up with power curves that pretty much fall within a couple horsepower here and there of each other. Speedsource has the RD and wins to back their product so it's hard not to go that route. You guys can debate theory all you want but at the end of the day there are a couple products out there that are all pretty similar produced by smart people that are winning all the races. If uncollected worked they'd be using them.

I really don't want to get into the arguement but... True there is no one perfect exhaust. But all ITS engines (should) have the same port configuration, intake configuration, trans gearing, etc., etc., etc. So in this particular context there can be a generalization made that what works on one car does work on another. And what has worked for multiple ARRC champs and best in our testing is the Speedsource exhaust.

For the record, best we've done was 174 whp (Mustang dyno) on a stock ECU with the Speedsource exhaust. That engine is currently leading the Mid-Div championship. Our own car reached 172 (Mustang dyno) with the long primary/RB combo with better low end. That car won the '05 Cen-Div title. With our ECU we haven't seen much in the way of peak HP gains over cars that previously had the fuel pressure regulators optimized for peak HP. You can get any one particular 500 rpm range right by tuning a fuel pressure regulator and the CAS. The gains have been below 7000 and past peak HP where compromises are made with fuel pressure tuning alone.

Also, seems I remember you saying something about your 6 port actuators working or not working in a previous post. For an ITS engine you need to ditch the sleeves and actuator rods. The point at which those sleeves pay dividends is well below the rev range of a race engine. The flow restriction of the actuator rods is real. They need to come out for an optimum build.

Originally Posted by phoenix7

why are you looking at the collected header?

If you're concerned about weight and taking advantage of every little bit of weight and power then why not start with the true duals? That's like saying "I want to lose weight. Let's go to KFC."

seriously guy, follow your own criteria.

Originally Posted by Black91n/a

The comments about the RB header stem from them having the exhaust turn immediately after the flange, you ideally want it to ge straight as long as possible from what I understand. So you won't see that difference from a side shot. The collector design is also really important, and can cost you significant power.

I've heard the Pacesetter isn't equal length, so it'll be inferior for that reason.

Originally Posted by rxtuner79

I know it's only a few pounds, but like I said it all adds up in the end. The dollar to benefit ratio of a custom setup is exactly what I'm looking for, which is why I made this thead.

Originally Posted by anewconvert

When puttin gmy header on my car that was the one thing I noticed and didnt like about the RB header. The primaries take a hard turn towarsd the rear of the car within about an inch of the ports. Ideally, on a piston engine, you want at LEAST 2 in or more of straight header primary coming off the port before turning. I would venture in a rotary, with the continuing expansion of the exhaust, you would want more than that if possible.


BC

Originally Posted by Black91n/a

I've heard the Pacesetter isn't equal length, so it'll be inferior for that reason.

Originally Posted by glhs0867

Like I said before "a modified RB header works the best." at all rpms.

Besides who races their RX7 below 4000rpms and not go over 6000 rpms? makes no sense.

All you gotta do is add the piping to the right places. Its not that hard to do.

Originally Posted by anewconvert

Wait, let me get this staight. You WANT to spend more money with little return for it? A custom header is going to be expensive compared to an off the self RB header unless you can cut and weld yourself, which you have said you cant. Most exhaust shops charge at least $70 an hour in labor, and you are looking at many hours of cutting, bending and welding to get a header to fit right in your car. That doesnt include materials and the time spent making a flange for the header. You are going to pay at least twice the amount for a custom header than an RB header than MIGHT make as much power and weigh only a few pounds less.


Its a waste of money man.


BC

Originally Posted by phoenix7

I heard nothing about porting so true duals seems like the best for this motor. And seriously, taking weight off the headers just seems ridiculous to me.

Did anyone bother to ask what this guy's mods are?