Your header pictures.
03-04-11, 12:12 PM
#5
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check out dj55b's header and um rx7gto's headers.
https://www.rx7club.com/showpost.php...36&postcount=1
https://www.rx7club.com/showpost.php...36&postcount=1
03-04-11, 12:36 PM
#6
Building a copy of a downing designed header for my Monster Port 12A.
Using regular ol' stainless, and a munch of tubing I have lying around. Won't really matter.
And yeah, I'm building it simply cause I can, I don't care for RB headers, and my exhaust ports are ported so large that they're about 1/4 bigger round than the RB primaries, at least. Running a ported manifold ATM, going with a large primary header now.
Not sure on the primary size, at least 2 1/4".. 3 1/2" collector all the way back to the stock muffler.
Using regular ol' stainless, and a munch of tubing I have lying around. Won't really matter.
And yeah, I'm building it simply cause I can, I don't care for RB headers, and my exhaust ports are ported so large that they're about 1/4 bigger round than the RB primaries, at least. Running a ported manifold ATM, going with a large primary header now.
Not sure on the primary size, at least 2 1/4".. 3 1/2" collector all the way back to the stock muffler.
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03-04-11, 07:59 PM
#8
its supposed to do that
Holy short primaries batman!
A ported rx with any sort of overlap is going to want long primaries to do any sort of scavenging. Old school BP and PP race cars typically had ~102" before the collector. Coming straight out of the block before curving has shown impressive gains over the headers that start to curl just out of the flange (this is the problem with the RB header).
Isaac
A ported rx with any sort of overlap is going to want long primaries to do any sort of scavenging. Old school BP and PP race cars typically had ~102" before the collector. Coming straight out of the block before curving has shown impressive gains over the headers that start to curl just out of the flange (this is the problem with the RB header).
Isaac
03-04-11, 09:23 PM
#9
Holy short primaries batman!
A ported rx with any sort of overlap is going to want long primaries to do any sort of scavenging. Old school BP and PP race cars typically had ~102" before the collector. Coming straight out of the block before curving has shown impressive gains over the headers that start to curl just out of the flange (this is the problem with the RB header).
Isaac
A ported rx with any sort of overlap is going to want long primaries to do any sort of scavenging. Old school BP and PP race cars typically had ~102" before the collector. Coming straight out of the block before curving has shown impressive gains over the headers that start to curl just out of the flange (this is the problem with the RB header).
Isaac
If you think you're right, great. I won't argue.
I'll stick with my 7" inch primaries on my overly overlapped 12A.
03-04-11, 09:37 PM
#10
its supposed to do that
Isaac
03-04-11, 09:56 PM
#11
Do you have any data to back that up? In my own personal experience primaries that short have resulted a significantly noticeable loss in low/mid range torque. I am running a large SP 4-port 13b, and even the standard RB header worked better than a similar header to what you have there.
Isaac
Isaac
But I have the opposite experience, everytime I go long primaries, I lose sooooooo much low end. With these short primaries, broad power becomes friendly. Keep in mind, these primaries are extremely short, straight as my dick and the collector is also massive. And it stays 3.5" all the way through the muffler.
This specific header was designed by Jim Downing( I **** you not) for a tube chassis car with my Monster Port in it, that tube chassis car now has a 13B PP with another downing designed header with even shorter primaries, but, the length from the collector to the header is much much longer in fact it actually has a U-Bend in it solely to increase length, therefore improving torque.
A while back I and my Grandfather tried building a long primary header with a H-Pipe Balancer in it, and, it did exactly what u describe a short primary system should do.. I just posted pictures of these headers I describe in the 'how much can a rotary take?' Thread in the non tech section..
I've also tried running a RB header on my monster port in my DD and was unpleased with the results so I went back to my heavily ported manifold and open downpipe.
Sorry for the horrible post, I do everything from my phone.
Just stating my experience. I very much lovee this header design inparticular. And really hope I can keep it very similar even though it's going in my unibody car.
03-04-11, 10:38 PM
#12
its supposed to do that
I have no data.
But I have the opposite experience, everytime I go long primaries, I lose sooooooo much low end. With these short primaries, broad power becomes friendly. Keep in mind, these primaries are extremely short, straight as my dick and the collector is also massive. And it stays 3.5" all the way through the muffler.
This specific header was designed by Jim Downing( I **** you not) for a tube chassis car with my Monster Port in it, that tube chassis car now has a 13B PP with another downing designed header with even shorter primaries, but, the length from the collector to the header is much much longer in fact it actually has a U-Bend in it solely to increase length, therefore improving torque.
A while back I and my Grandfather tried building a long primary header with a H-Pipe Balancer in it, and, it did exactly what u describe a short primary system should do.. I just posted pictures of these headers I describe in the 'how much can a rotary take?' Thread in the non tech section..
I've also tried running a RB header on my monster port in my DD and was unpleased with the results so I went back to my heavily ported manifold and open downpipe.
Sorry for the horrible post, I do everything from my phone.
Just stating my experience. I very much lovee this header design inparticular. And really hope I can keep it very similar even though it's going in my unibody car.
But I have the opposite experience, everytime I go long primaries, I lose sooooooo much low end. With these short primaries, broad power becomes friendly. Keep in mind, these primaries are extremely short, straight as my dick and the collector is also massive. And it stays 3.5" all the way through the muffler.
This specific header was designed by Jim Downing( I **** you not) for a tube chassis car with my Monster Port in it, that tube chassis car now has a 13B PP with another downing designed header with even shorter primaries, but, the length from the collector to the header is much much longer in fact it actually has a U-Bend in it solely to increase length, therefore improving torque.
A while back I and my Grandfather tried building a long primary header with a H-Pipe Balancer in it, and, it did exactly what u describe a short primary system should do.. I just posted pictures of these headers I describe in the 'how much can a rotary take?' Thread in the non tech section..
I've also tried running a RB header on my monster port in my DD and was unpleased with the results so I went back to my heavily ported manifold and open downpipe.
Sorry for the horrible post, I do everything from my phone.
Just stating my experience. I very much lovee this header design inparticular. And really hope I can keep it very similar even though it's going in my unibody car.
That is actually pretty neat, it shows the difference between what two different ports apparently like as far as exhaust tuning.
Isaac
03-05-11, 07:00 AM
#13
I'll post my results when I finish this header. I'm afraid I won't be as sucessful because the amount of 'room' I have to work with and I won't be afraid to admit failure if I do fail. But, all in all, it'll be loud. That's the most important part.
03-05-11, 08:51 AM
#14
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over here loud = big ticket, but may you have the best of luck, because that would be pretty cool
03-05-11, 05:30 PM
#15
ACBron Motorsport
Here's some i used to own.
They were on a frontrunning Improved Production car (IPRA) here in Australia and the car held several lap records while wearing these. The engine was a 13b J-port with quad t/b's.
The're pretty simple in design. keep them straight as long as possible as they come out of the engine, then route the bends so thety are equal legnth.
They were on a frontrunning Improved Production car (IPRA) here in Australia and the car held several lap records while wearing these. The engine was a 13b J-port with quad t/b's.
The're pretty simple in design. keep them straight as long as possible as they come out of the engine, then route the bends so thety are equal legnth.
03-06-11, 12:09 PM
#25
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step 2 would be to try some different lengths, but geez for something off the shelf its good!