813KR$

I have heard many times that the further straight the exhaust goes coming out of the exhuast ports, the better scavenging effects? For example RB vs ISC headers. Resulting in more power. If this is true, what are the thoughts on creating a header spacer similar to a carb spacer. I was thinking, by using a header gasket for a template, their could be a spacer machined to add a couple or few(as much as you can go with out clearence problems) inches to straighten out the RB headers, so they wont turn as quickly.

Good Idea, Bad Idea?

Why?

mwatson184

You might be better off just building a custom header with a racing beat flange. A couple or few inches?? That would be one thick heavy spacer.

-Marques

chairchild

I think i remember reading that it's best to have a 3" straight section from the flange. But the ideal setup would be a section of straight pipe that leads directly to the edge of the car.

This would then give you the problem of trying to dump a load of gasses into a high-pressure area, but if you fed the exhaust into a venturri, the faster you go, the faster the gasses would be "sucked" out.



Hmmm.... That's got me thinking now

813KR$

I like that venturi idea ! ! !

But sounds expensive and also time consuming with many dyno tunes with different venturi sizes and lenghts to perfect! Something RB should have been doing, slackers! Ha, ha . . .

PPC-Racing

you still need to put a 90 degree radius into the header, instead of trying to go striaght out THEN go 90 degrees on say a 2" x 2R elbow, come off the header flange with a 2"x4R elbow.. if you feel the need to reduce inversoin, then put in simple anti reversion plates. A longer, transition and reduced inversion will do more for flow then trying to go out straight for 3" then turn.

chairchild

The general rule of thumb for this kind of useage, is that the restriction wants to be 1.5x diameter of the main pipe,
the restriction want to be 3x diameter of the main pipe,
and the entry/exit points need to be as large as possible (minimum 3x size)

And they shouldn't really be put in the same ventuuri either, so two venturis at different heights should do the job

here's a pic of what I mean

PPC-Racing

throwing a venturi in is just going to destroy any flow you have, ( unless you can find the room to put in a max 15 degree taper in line ..?)

chairchild

That was only a quick sketch, a proper version would be angled at around 45 degrees, with corresponding entry and exit allignment tubes. Which would mean that you'd have a pipe which starts off close to the car, which would then turn out (smoothly) to 45 degrees. The exhaust pipe would then link into the ventuuri, and amother 45 degree turn would be after the venturi, placing the final exhaust position around 6" away from the bodywork

nimrodTT

I see a few probable issues with this concept. First, you can potentially remove a portion of the force pushing on the rotor by creating a vacuum to suck the expanding gasses out before they can act on the rotor face. Second, you may have a hard time getting past the critical point where you transition from positive exhaust pressure to equal pressure to negative pressure - the equal pressure phase will stall your engine because you achieve zero flow out of the port. You could of course cap the venturi inlet till after you are past this point and you may be able to avoid that entirely. Third, the venturi would have to flow a very large amount of air to compensate for the exhaust flow which will cause an aerodynamic drag on the car that may defeat any gains you would see from this setup.

It's late and I'm just brainstorming, so hopefully that makes a little sense. For what it's worth, I don't think it can work in that configuration. Maybe you could focus in on an H-pipe configuration header design.

chairchild

H-pipe? whats that?

813KR$

JESUS, GOD! Where did this thread go wrong ? ? ? You guys have lost me. Why dont we try to concentrate on the "Header Spacer"? There is no venturi design here, just a simple and straight forward RB header fix!

chairchild

Well, quite simpy because if you were to make a spacer that would even make a difference, it would throw out the placement of the exhaust by MILES.



unless you "coaxed" it with a large hammer and a big foot of course........

813KR$

chairchild:

?Huh?

Cant follow you on that one?

5 point whoa

I think you should cut of the flange, and put a few iches of pipe before it turns to go off behind the car. that would be the best way to do it, because if you put a thicker flange it'll be heavy, and if you add a few inches of pipe it would be light. anyone have any idea how much you could add on to it??? plus, it wont throw off the placement of the exhaust , if your running true duals you have to customize it anyways, so it is a good idea, but I dont know how good it would work. It would be good for a racecar, but you dont wanna have to go through all of that work of moving around the exhaust and stuff on a street car

chairchild

813KR$, you'd pertty much be moving the ENTIRE exhaust over towards the wheel-arch by at least 3", you'd need to bend it a fair bit to get it in-line with the stock exhaust hangers (without stressing them)

that's why you'd need the hammer and a foot - to force it into position

813KR$

Exhaust, hangers are not ****. my exhaust is light and doesnt take much to hold it up. Iam good at making **** fit, Iam heavy handed!

chairchild

I pity your girlfriend

813KR$

HA, Ha, ha ! ! !

They Love It !