Racing Beat Roadrace Header
06-04-08, 02:09 PM
#26
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I guess it would be kind of a pita to jack it up just to measure them out. I can check mine when I get home and try to get an overall difference in the length of the pipes. I wonder if they will be within that 5" spread, and also fall within the range given previously before collecting.
Last edited by djjjr42; 06-04-08 at 02:20 PM.
06-04-08, 06:11 PM
#27
If you think that then why the hell did you buy it, Einstein? Maybe you should start your own company, and dream that it was at least 10% as successful as theirs.
Dumb question. But isn't the center section of the RB RR system made in a manner that causes one pipe to be longer than the other, thanks to the fact they both have to make a bend? Perhaps this has been taken into account by RB, and is the reason for the unequal length pipes on the header.
I don't hace access to an RB RR system, but I'd be willing to bet that by the time you measured from the engine flange, to the rear of the center section, they would be much more closely matched in length.
I don't hace access to an RB RR system, but I'd be willing to bet that by the time you measured from the engine flange, to the rear of the center section, they would be much more closely matched in length.
"Headers -- Primary Pipe Lengths
Misconceptions concerning exhaust pipe lengths are widespread. Take for instance the much-overworked phrase "equal-length headers." More than the odd engine builder/racer, or two, have made a big deal about headers with the primary pipes uniform within 0.5 inch. The first point this raises is whether or not what was needed was known within 0.5 inch! If not, the system could have all the pipes equally wrong within 0.5 inch! Trying to build a race header for a two-planed crank V-8 with lengths to such precision is close to a waste of valuable time. Under ideal conditions it is entirely practical for an exhaust system to scavenge at or near maximum intensity over a 4,000 rpm bandwidth. Most race engines use an rpm bandwidth of 3,000 or less rpm. If the primary pipe scavenging effect overlaps by 3,000 rpm then it matters little that one pipe tunes as much as 1,000 rpm different to another. Since this is the case, then all other things being equal, pipe lengths varying by as much as 9 inches have little effect on performance. A positive power-increasing attribute of differing primary lengths is that it allows larger-radius, higher-flowing bends and more convenient pipe routing to the collector in often confined engine bays."
Misconceptions concerning exhaust pipe lengths are widespread. Take for instance the much-overworked phrase "equal-length headers." More than the odd engine builder/racer, or two, have made a big deal about headers with the primary pipes uniform within 0.5 inch. The first point this raises is whether or not what was needed was known within 0.5 inch! If not, the system could have all the pipes equally wrong within 0.5 inch! Trying to build a race header for a two-planed crank V-8 with lengths to such precision is close to a waste of valuable time. Under ideal conditions it is entirely practical for an exhaust system to scavenge at or near maximum intensity over a 4,000 rpm bandwidth. Most race engines use an rpm bandwidth of 3,000 or less rpm. If the primary pipe scavenging effect overlaps by 3,000 rpm then it matters little that one pipe tunes as much as 1,000 rpm different to another. Since this is the case, then all other things being equal, pipe lengths varying by as much as 9 inches have little effect on performance. A positive power-increasing attribute of differing primary lengths is that it allows larger-radius, higher-flowing bends and more convenient pipe routing to the collector in often confined engine bays."
It's that kind of ******* bs that is chasing people away from here. A forum is supposed to be an environment for people to learn. I posed questions and wanted explanations. I wasn't looking for you to just sit up on your high horse and look down upon us like we're a bunch of retards. Where the hell do you get off? That being a moderator stuff has put you on an unrealistic power trip man. Get a grip.
2 Sorry if you took offence I mis-readwhat you were asking, and I came across too strong. I thought you were just challenging me and not actually asking a question. I'm happy to help and I think I do a lot.
We can look at why people are always talking crap about the pacesetter header. There are 3 design flaws with the Pacesetter header. It's not equal length, It turns to early from the block, and it has a terrible collector collecting two 1-7/8" pipes into one 2" pipe. Now lets look at the RB header. We now know there are 3 design flaws with the RB header. It's not equal length, It turns to early from the block, and it has a terrible collector collecting two 1-7/8" pipes into one 2" pipe.
I bought the header in an attempt to correct these design flaws. I had no idea the header wasn't equal length I was trying to correct the problems in the center section and collector.
They did a good job of trying to make it look equal length.
Last edited by Hyper4mance2k; 06-04-08 at 06:19 PM.
06-04-08, 06:31 PM
#28
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Apology accepted. I kind of got hot myself and had a knee jerk reaction to your responses, and I apologize for that.
Now back on topic. I know that we can't just apply all rules for a piston engine to a rotary, but to me it seems like in the case of things that are outside the engine, like an intake or exhaust system, there's not really any difference. I mean, in an exhaust pulse from either, aren't the same physics at work? The logic about the scavenging operating at or near maximum for an extended rpm range just rings true to me. If you disagree, please post your reasoning behind it so that we can all understand and make this a thread worthy of referencing in the future.
Now back on topic. I know that we can't just apply all rules for a piston engine to a rotary, but to me it seems like in the case of things that are outside the engine, like an intake or exhaust system, there's not really any difference. I mean, in an exhaust pulse from either, aren't the same physics at work? The logic about the scavenging operating at or near maximum for an extended rpm range just rings true to me. If you disagree, please post your reasoning behind it so that we can all understand and make this a thread worthy of referencing in the future.
06-04-08, 06:49 PM
#29
No because a rotary with stock ports has as much intake and exuast over lap compairable to a piston with a 280* cam. The only guys running those big of cams are seriously spending hundreds of hours designing a perfect exhaust to scavange everylast breth of exhaust to make peak power. Once you start porting a rotary it gets even more important. That's why companies like speed source and SDJ spent the time properly designing a better header and it showed with 10WHP gains and much flatter wider torque curves than the RB systems. Since both of those products only appealed to the very few who really care about extracting every last HP the demand was low and the price for such products was driven up to compensate for R&D. And now neither of those products are made any more. hense my attempt to correct the problems by using what we have available to us now.
SDJ Header
SDJ Header
06-04-08, 07:40 PM
#30
You're always welcome to weld up a header yourself and build a better mousetrap. I need a new header for an old school 13b 4-port and I just don't like how the RB header as bends right after the engine flange. YAW made some sweet headers too.
06-04-08, 08:16 PM
#31
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Well, poo. I forgot that the longer header tube also went into the longer center section tube. It's been awhile since I *really* looked that close at an RB RR system.
I'm not a huge RB fanatic myself. I do have one of their street headers on my car, but I bought it barely used, with the presilencer, for $100. Presilencer is still laying in the back of my truck. The rest of my exhaust is custom stainless pipe and a stainless "fart cannon" that came with the car. I simply shortened the pipe, and welded a homemade 1/4" flange to the pipe, and bolted it to the RB header. It *does* flow *much* better than the stock manifold, which is what I was after.
I'm also one that usually makes most of my own stuff, and almost built my own header, till I ran across a deal too good to pass up on the *barely* used RB stuff.
I'm not a huge RB fanatic myself. I do have one of their street headers on my car, but I bought it barely used, with the presilencer, for $100. Presilencer is still laying in the back of my truck. The rest of my exhaust is custom stainless pipe and a stainless "fart cannon" that came with the car. I simply shortened the pipe, and welded a homemade 1/4" flange to the pipe, and bolted it to the RB header. It *does* flow *much* better than the stock manifold, which is what I was after.
I'm also one that usually makes most of my own stuff, and almost built my own header, till I ran across a deal too good to pass up on the *barely* used RB stuff.
06-09-08, 10:28 AM
#32
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Are there any more pictures of the SDJ header? I keep seeing that one over and over. Also, rotary motors are like a two-stroke in a lot of ways. If you get all the harmonics lined up you're going to make more power and have a better curve. That's just how it is. If you read up on how kart and moto-cross guys tune their exhausts you're going to learn a TON about how a 12a/13b exhaust should be designed. On our motors equal -length exhausts are not over-rated.
Last edited by Brian558; 06-09-08 at 10:40 AM.
06-09-08, 05:31 PM
#35
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That's what I'm saying. If you have a MIG welder you could make one in a jiffy. All you really need to know are the pipe diameter at the ports, length to the y and the pipe diameter at the collector.
06-09-08, 07:35 PM
#36
Pics of the Racing Beat Long Primary Exhaust System...
Not sure if these photos are of any value; however, it was convenient to take the photos: Racing Beat Long Primary Exhaust System.
