94StinkinLincoln

Well just b/c you do not see it, doesn't make it anything more or less than what it is.
Do some searching, i doubt this has been covered on this board though...

OnyxCobra

okay and do you have any information to back up your claim? Dr. Gas puts their crossover as close to the headers as possible because they believe that's the best place for it, surely if they could have painted a pipe to find the IDEAL location they would have done that, no?

94StinkinLincoln

Its going to be different for each car. The Primary tube length and size, collector length and size, possibly the "firing order" of the tube configuration, and the motors compression, a/f ratio; which changes how hot the exhaust temp is.

http://sbftech.com/index.php/topic,1...html#msg177836
[quote author=Jay Allen link=topic=19097.msg177843#msg177843 date=1245692731]
[quote author=Sixtyninemercury link=topic=19097.msg177836#msg177836 date=1245690479]
No argue there, Jay. I was wondering when this motor is finished and in Red Death -- are you going to use a crossover? All the way back or dumps?
[/quote]

Cross overs (X or H) are just too hard to figure out. These one piece pipes that are made and one piece fits all mentality is wrong.

My exhaust will be just straight pipe.
[/quote]

Somewhat relevant: [quote author=Jay Allen link=topic=11796.msg113162#msg113162 date=1202763446]
Let's make this easy.

If mufflers made power, they would be on Cup cars, Pro Stockers, and Comp Eliminator engines.

Far, far, far too many variables to say a muffler makes power or not. If the headers is FUBAR, then whatever is beyond it is irrelevant.

[/quote]

[quote author=Jay Allen link=topic=11796.msg113173#msg113173 date=1202764595]
Art, I have an X-pipe, an H-pipe, and straight pipes. Do not make any changes to the engine, just change the days and the conditions. Some days the H was faster than the X. In the end, the straight pipes were quickest. I took the mufflers off and the engine immediately needed more fuel. More fuel means more air, more air is more power.

Does this help Art?
[/quote]

[quote author= Outlaw Bill
"X-pipe or H-pipe is used for street cars. If the race car needs exhaust, then I use what ever yields the best results. If I can run the them open, then no cross over." [/quote]

[quote author=Is1BadFord link=topic=15667.msg152787#msg152787 date=1236647338]
[quote author=gtvert90 link=topic=15667.msg152782#msg152782 date=1236646537]
[quote author=Captbb56 link=topic=15667.msg152768#msg152768 date=1236644419]
I called Mac and they said they have a 3 inch flange to match my headers with 6 inches of pipe for $29 plus shipping. They said I would loose HP not having a h pipe to equalize exhaust gases.
Barryb
[/quote]

Some very smart people have done track tests and straight pipe ended up faster than the x or H.
[/quote]

The average user doesn't have the ability to tune the crossover to his combination. EVERYTHING plays into it...so don't think Edelbrock, Flowmaster, Mac, or Bassani has the ability to either.

Cris :smile
[/quote]

http://sbftech.com/index.php/topic,1...html#msg176792

x-pipe or h-pipe... discuss
http://sbftech.com/index.php/topic,2210.0.html
[quote author=Jay Allen link=topic=2210.msg21681#msg21681 date=1163174247]
Back when I was sponsored by Flowmaster, I was part of a series of exhaust test on the dyno and on the track. I'll tell you what, I was more confused after the test than before it began. There were no clear cut better exhaust. It was dependant upon where the *X* or the *H* was located. If it were wrong, then the straight pipe was better. Then with the same cam, we changed rocker ratios to alter the camshaft a tad. Guess what? It only changed everything.

The answer here is, it depends. If you want maximum power, you'll test all 3 with your completed combination and see what the engine wants or needs.

:Gluck:
[/quote]

[quote author=fast88 link=topic=3418.msg33419#msg33419 date=1168428830]
Different motors with different combinations are gonna want different things.....What works well for one just may hurt the other.....but we're only talking 5-10 hp. For a streetcar I would make my choice primarily on tone.

......Im partial to X-pipes myself
[/quote]

http://sbftech.com/index.php/topic,2....html#msg24598
[quote author=Jay Allen link=topic=2493.msg24598#msg24598 date=1164832709]
First off.......Its a 302/302. It isn't a 306.

I did rebuild the shortblock. I fixed what I thought needed to be fixed. The GT-40 heads have an aftermarket valve job and have been converted to stud mount. I have played with various springs, locks and retainers. It has been a SR and it has been a HR. I have used just about any and every HR lifter just to see. It had 1 5/8 BBK headers with 2.5" exhaust with louder than hell Flow-Masters on it. I tried an X pipe. I tried an H pipe. I ran it with straight pipe. The straight pipe was the quickest, and loudest. When it ran 11.19, it weighed 3160 with me in it. I was able to manage a 1.47 sixty foot. This was with 4.56 gears and a 26 X 10 M/T slick. It ran 7.09 at 97.7 to the 1/8. I had too much gear and not enough clutch in it. It was fast to the 1/8 and it should have been quicker out back.

It made 305 RWHP and 317 RWTQ.

I have sold the EFI. I have a buyer for the GT-40 heads. The shortblock is now garbage. I have a vibration now. But if you had your brains beat out for 15,500 miles and shifted as high as 8000 RPM, you'd vibrate too.
[/quote]

http://sbftech.com/index.php/topic,8184.0.html

[quote author=Jay Allen link=topic=8184.msg74070#msg74070 date=1187355563]
I tested them all. The results changed from day to day and from cam to cam. There is no absolute. Those posts are here somewhere.
[/quote]
[quote author=347HO link=topic=8184.msg73810#msg73810 date=1187276838]
Just as you... I need to brush up on Subject Theory here.

Right off the batt, I really can't see anything happening with an X pipe. The gases collide or merge in this case.... big deal huh?
The H pipe I can see how the connector pipe would dampen exhaust pulses and improve or hurt performance.
As we all know, exhaust gases cool as the distance increases from the Head. So Yup... placement is probably very important in tuning.
[/quote]

Yes i am partial to Jay's advise. Whatever is said about him set aside, he still knows how to go faster than I do.

67mustang302

Paint burning off the pipes seems anecdotal at best(but perhaps not entirely without merit either), because temperature can change with a whole wide variety of things, but once the pressure wave is created it continues through the system at the local speed of sound. As the gas exits the primary and into the collector it will undergo the Joule-Thompson effect and as it expands freely the temperature can drop considerably. The less the difference in size between the primary and collector the less the temperature drop, the greater the difference the greater the drop(temperature also drops with distance traveled). And the drop in temperature as the gas enters the collector may or may not equate to ideal placement for an energy wave that's already moving through the system. One thing that can be said in support of the paint idea though is that as the temperature drops the local speed of sound in the system drops as well, which will slow down the speed of the energy wave, even if only to a minor degree(from say 780mph down to 750mph or whatever the case may be). So there may be some element of scientific truth to the paint idea, but again it's anecdotal at best and only backed up by the claims of some people that found it to be true(which is to say that it may be true in some cases, but not in others). It may be that something about the temperature change effecting the speed of the energy wave plays into it, though I imagine the length of the headers would play a great deal as well, since the energy wave has to travel that distance at a given speed etc etc.

I do agree that ultimately to get best power requires testing the different combinations on the vehicle to yield the best power in the range where it's needed. That's exactly what the Cup and F1 guys do, they start off with what they think is in the ballpark of what they need and test from there, sometimes it changes a little, and sometimes it changes a lot.

If you can find where the ideal spot for a balance pipe is and fab it in for your vehicle, then more power to you. This whole thing is actually the reason that many Ferraris as well as Formula 1 cars use the 180* single plane crankshaft design, to eliminate the need for crossovers in the exhaust to pulse tune a cylinder from the opposite bank. They can accomplish all of their tuning with a single 4-1 or 4-2-1 design on one bank, since the engine essentially functions like 2 inline-4 engines that share a common crank.

lxman1

I have also heard of the paint method of finding the ideal location.
In most cases, it comes down to where you can fit it and still get to parts that need to be accessed.
Oh, by the way, the last set of Hooker Mustang shorties that I tried to put on my old 77 F150 302, did not clear the frame. They angled out from the engine too far.
Might fit a later model frame though.

I would suggest making your H-pipe a slip fit. It will make the exhaust easier to drop in the future if it needs to be removed for tranny work or whatever.

F150 StrokerCobra

thanks for all the replies and ideas guys... im gonna start with true duals first... if i dont like the sound then i will try H pipes but what i will do this more for the sound becuase the difference between the X H or true is less then 5 Hp i believe so its isnt that big of a deal...