Makenzie71

You said that if all things remain equal that it would flow the same. But if the dual runners have the same volume as a single runner, then the restriction at the "Y" it's self would hinder flow.

Which is why I repeatedly asked for clarification...lol.

Yes I was referring to same muffler design, tubing volume, etc.

NZConvertible

You mean weak point? Sorry, but that's wrong. Go back and read my earlier post about this.

EDIT: Oops, just realised I made that point in a different thread. It you restrict a system slightly at one point, it doesn't make the system flow as if the whole system were that size. Otherwise there'd be no point at all in putting a 3" exhaust on a turbo for example, as the turbine outlet is much smaller than 3". But we know it make doess a huge difference.

More retarded logic. The pipes can be whatever size you want. If you want to keep the same size pipe after the Y you can. Even if you reduce the pipe size, they'll still flow more than the single pipe before the Y if there big enough. To repeat an example again, two 2.5" pipes flow a lot more than a single 3".

You guys have got to get the stupid idea that "single flows better" or "dual flows better" out of your head. It all depends on the pipe sizes, not just the number of mufflers.

88convert

If you go with bigger piping, then you decrease your exhaust velocity. Which in my mind is kinda redundant unless it's being forced out, ie a compressor.

2.5" would be and ideal pipe size

rotarygod

iTrader: (1)

If you have a 2.5" single pipe before the Y, you have all the tuning and velocity you need to make good power. The pulses from each rotor have been collected for a long time. After this point it is irrelevant. It doesn't matter if it splits to 2-2" pipes or 2-3" pipes at this point.

The argument is getting so technical and detailed about which one will flow the most right down to that last tenth of a cfm. Assuming a single exhaust and a dual exhaust are both designed properly, you will still see no difference in power between the 2 systems. Argue all you want you can not prove it. I challenge anyone to prove this wrong. The weight difference between each system will also not be enough to affect performance. Again I challenge anyone to prove this wrong.

As far as I am concerned, anyone who says that a single can be more powerful than a dual system (or vice versa) had better provide a direct back to back dyno comparison between the 2 systems, both of which are properly designed and show a greater than 5 hp difference between them. I say 5 hp because conditions between dyno runs can easily change. Even back to back runs on the same system can yield different results. Until I see this proof (video proof would be better) there is no argument that is rational for or against any 1 system.

I'm surprised that NZ hasn't asked for proof yet. Let's face it, one person's education vs another person's experience don't mean **** on a computer screen. Let's see a nonbiased result such as a dyno.

Makenzie71

I wish the nearest dyno to me wasn't 400 miles away...not to prove anyone right or anyone wrong, I'd just love to see back to back results.

Not that "prove it" would ever mean anything significant on the internet...:/

NZConvertible

When?! I keep asking you to prove all these supposed quotes of mine, but so far nothing. Since that one is completely out of context it doesn't mean much.

No, actually that's wrong. Any divirging juction of a particular angle is at it's least restrictive if velocity remains unchanged, i.e the combined exit area is equal to the inlet area. Increasing or decreasing the velocity actually increases pressure drop. The problem is that the "perfect" Y would make the outlet pipes very small and restrictive, e.g. splitting a 3" pipe into two 2.12" pipes give the same area and practically no loss through the Y but those pipes are way too small and hence the whole system will flow poorly.

None of this changes the fact that a well-built Y is only a small part of the total restriction of the system, as is easily countered by correctly sizing the two rear pipes.

Radial GT

iTrader: (16)

Good thread

vice

this is a dumb discussion because you could make a single outlet that is just a straight tube and ofcourse it will flow better than a split pipe. the only difference between a single outlet and dual should be the Y. true duals on an N/A dont cout becaust those are just 2 single outlets.

there are too many variables. we should discuss strictly if a Y pipe or single pipe flows better.

-no cats or mufflers,

-2.5" piping on the single outlet. and 2.5" piping on the dual untill the Y.
-after the Y, the area of the pipes(when looking into the end of one side) should be cut in half.
-single outlet should have same ammount of total degrees bent as the dual outlet.

if all the variables are the same the only difference is the Y-split.

Makenzie71

I'll admit I probably justmisunderstood you and leave it alone...

But how can velocity remain uneffected when you introduce varying tubing diameters and throw a splitter right in the path of flow. As you said (quoted below), a direct transition from size "A" tubing to two sections of size "B" tubing, if the volumes remain constant (area of B*2=area of A), would be rough and create a bottleneck. Gradually changing from size A to the two size B's would require a small section with a volume greater than that of A. Introducing this cavety and then flowing back into smaller diameter runners would also create a bottleneck.

Can you explain this more?



IMHO, I just don't think the perfect Y could ever be built with steel runners. Possibly cast molded, but even then I have my doubts. But I do understand the minimal loss/gain in that area alone.

True duals....best of both worlds...kinda...

NZConvertible

I see your point, but I don't entirely agree. There's nothing stopping you splitting a 3" pipe into two 3" pipes and mufflers, and I'm pretty sure you'd agree that this would be less restrictive than a single 3" system. You said nothing about pipe sizes, which as I keep saying is far more important than just configuration.

I haven't asked for proof because I don't need any to prove my point. I have never said that one is better than the other. My whole agument right from the beginning of this thread and others is that you CANNOT state one configuration is better than the other. That is all. You can't make stupid blanket statements like "single flows better than dual" (or vice versa) because there are too many other variables to consider. You might remember that this all started because of the comment "single is better for performance".

I would be very interested to see back-to-back dyno testing, but I don't believe I'll ever see it. To do it properly you'd need to build two cat-back systems using the same style mufflers (but in two different sizes), and test them on the same car and preferably on the same day. Who's gonna do that?

No we shouldn't, that would be very stupid. Like I've already said, the Y is only a small part of the total restriction of the system.

You're thinking way too hard about this. For starters, you seem obsessed with the "splitter" in the middle and I don't know why. The air is being divided and diverted at a pretty shallow angle (15deg each side). This only causes a bit more of a loss that a bend of the same angle. Most of the loss actually comes from the change in velocity, because most of the time the pipes are sized in such a way that velocity drops. Going from 3" to dual 2.5" the velocity drops by ~30%.

As for the rest, who really cares? The only important point is (once again...) the Y is only a small part of the total restriction of the system. Concentrating on this one point and ignoring the rest is just nonsense.

It's just the way fluids work. Any time you force the fluid to change direction or velocity, there's a loss involved.

Who cares? There's no such thing as a perfect anything. You just need to accept the fact that a decent Y is nowhere near as restrictive as you think it is.

TurboIIGuy

I dynoed about 10hp less than the claims on one car 3 years ago and 4hp more on a car this last summer.

tecknomage

ahhhhhhh poor college art student can't stands no moreee techinicallll data can't even spell write all i know is that i have the stock 2.5 inch pyping comming from the headder and the orginal Y with 3 inch piping after the Y and it sounds nice deap tone under 2 grand and high pitched above 2 grand and proforms quite well.

MPM

Many people will think the single exhaust is going to make more power because its louder. Its a ricer thing, of which I don't subscribe.