Ok, I have this idea about making a true dual exhaust for a 4cyl. 2 cylinders into one pipe and 2 into the other.
BUT, which way: 1 and 3 in one and 4 and 2 into the other one;
OR 1 and 4 into one and 2 and 3 into the other.
firing order 1342
1 & 3 and 4 & 2 would make one pipe go pop-pop then the other would go pop-pop
1&4 and 3&2 would pop once per side .
some questions that have come to mind are what kind of exhaust turbulence would either combination cause. would the alternating pops cause back pressure issues? would it sound stupid? which way would be better?
Oh yeah this exhaust idea would be fed into side pipes.
Why do you want to do this?
It will actually hurt your engines performance.
IF I were to do it, I would go 1-4 and 2-3 to even out the "pulses" like a tri-Y header.
Bill
I have many hours to think of dumb shizod, while im at work, driving down the highway for hours and hours and miles and miles. and its something ive thought of that has me curious.
as far as" it will hurt my engines performance" I see 4 cyl motorcycles like this all the time that go really fast.
Its just a what if at this point, i didn't know if anyone had fooled around with this in the past, so I figured id throw the question out there.
If you are already running a hedder, you will notice a difference. Hedders are designed to "scavenge" air out of the engine, meaning crating a sort of vacuum in the tubes. If you lose this scavenging effect, it will most certainly "hurt your engines performance" from where it is now. Go ahead and try it, you'll see. I know a guy who tried this and it did just as I have stated. Exhaust manifolds also work in this same way. :hypno:
So somebody already tried this, How did they make them? Im not planning on building another 4 cyl, ever(i hope). But I lost enough sleep on this one over the years I would like to Mind dyno it a little. Do you know any specifics about the exhaust your friend built? Pipe diameters; were all tubes equal length; did they try an "H" pipe design to try to compensate for the loss of the scavenging effect; which cylinder combo did he try; what size pipe did he run the 2 cylinders together into??
If you dont know, would you be willing to ask?
My one friend seems to think it would sound like it had dual briggs and strattons. Just cause one person had no luck doesn't mean I'll quit thinking about it, Does Bill Nye have a pinto????
here's an idea. quad exhaust, the tubes set up so the they fire in sequential order. put flame throwers in and they'll spit fire from front to back out of the boom toobs! jist an ider.
krazi
ps, don't drink and type! :drunk:
ROFL. T.U.I. typing under the influence, you should be ashamed. Scott whats the legal limit, should he be arrested??? hmmmm, theres still a bottle of bacardi gold from new years.....................naah better not.
i don't care who ya are, that 's funny right there! what seems to be the officer, problem? :drunk: mmmm beer!!
Quote from: dirt track demon on March 14, 2006, 12:17:55 AM
ROFL. T.U.I. typing under the influence, you should be ashamed. Scott whats the legal limit, should he be arrested???
It has been about 15 years ago, but I believe it was a gutlees Chevy Luv he did this to. It had a dual outlet cast manifold, and had the same size pipe all the way out. I think it had a glass pack style muffler with 1 3/4 inch pipe, and it did sound kinda funny. He thought it did lose some power,but not alot seeing as they are a gutless turd anyways. The motorcycle exhaust spoke of earlier, generally goes from small pipe to a larger muffler, which I believe will crate the vacuum effect that is needed to make it run good at all RPMs.
So your friend built an exhaust with no back pressure and wonders where his performance went.
I was planning on being a little more inventive here. My whole idea in a nutshell:
starting at the head, stainless plate steel for the parts that bolts to the head. tube steel the diameter of the ports and all tubes being the same length(hence the term equal flow headers), then where the 2 pipes meet into one (the collecter) the diameter of that pipe will not exceed 85% of the value of the 2 combined pipes:
explanation: if both pipes can flow 100 lph per pipe than that would be 200lph for the 2 together if I run both pipes in to a pipe that is 85% of the combined value then the single pipe would have a 170 lph rating therefore i would be running 200 lph into a 170 lph thereby giving me adequate back pressure.
then as the pipes come back and are routed their separate ways they will do a 180 bend and go around the back of the front unibody subframe, at this point I was planning on placing the small flomasters, then another 180 bend into the side pipes running down the car.
In the event that not enough alternating vacuum pressures(your scavenging effect) are present Then I would try implementing an H pipe to try to regain some vacuum loss if any. But depending on how you angled your H pipe you can vary your flow exchange. an h pipe with a low angle v bend in it can be more effective than one with a straight pipe, if angled in the right direction.
Im not going to abandon the idea because of one previously failed attempt(it might have worked but you said it yourself it was tried on a chevy). If the wright brothers gave up after the first time they flapped their arms and fell down we wouldnt be where we are now.