• Required reading for all forum users!!!

    Welcome!
    Register to access the full functionality of the GSResources forum. Until you register and activate your account you will not have full forum access, nor will you be able to post or reply to messages.

    A note to new registrants...
    All new forum registrations must be activated via email before you have full access to the forum.

    A Special Note about Email accounts!
    DO NOT SIGN UP USING hotmail, outlook, gmx, sbcglobal, att, bellsouth or email.com. They delete our forum signup emails.

    A note to old forum members...
    I receive numerous requests from people who can no longer log in because their accounts were deleted. As mentioned in the forum FAQ, user accounts are deleted if you haven't logged in for the past 6 months. If you can't log in, then create a new forum account. If you don't get an error message, then check your email account for an activation message. If you get a message stating that the email address is already in use, then your account still exists so follow the instructions in the forum FAQ for resetting your password.

    Have you forgotten your password or have a new email address? Then read the forum FAQ for details on how to reset it.

    Any email requests for "can't log in anymore" problems or "lost my password" problems will be deleted. Read the forum FAQ and follow the instructions there - that's what we have one for...

  • Returning Visitors

    If you are a returning visitor who never received your confirmation email, then odds are your email provider is blockinig emails from our server. The only thing that can be done to get around this is you will have to try creating another forum account using an email address from another domain.

    If you are a returning visitor to the forum and can't log in using your old forum name and password but used to be able to then chances are your account is deleted. Purges of the databases are done regularly. You will have to create a new forum account and you should be all set.

Super Cool Patented High Performance Exhaust Available Now (Add echo effect here)

  • Thread starter Thread starter Guyver
  • Start date Start date
I know that on hotrod cars, the builders sometimes bring dual pipes together, and weld an X in them. Supposed to balance out the sound or some darn thing.

The reason Jetting may not be required, is that where the 4 pipes join, and then split off, is a large area. When a gas has that much room to expand, its velocity will slow down, thus bringing the soundwaves closer together. That will create backpressure, which everyone knows, is a restriction to the exhaust of spent gases from the cylinder. Some backpressure is a good thing, too much, and you don't get a good intake charge, and poor running. I will wait for someone else to try it. :)
 
I'd like to put my fist in Monty's mouth. He's a real smart ass.
I told him not to BS people and he started playing e-mail games.
He likes to talk but he can't really back it up. All he can say is how the pipe scavenges. Not much else that really matters.
 
Pan,

I support your logic on this.

Generally, standard exhaust systems operate effectively over a broad range of rpm. When we get greedy for greater performance we believe that we must go bigger. It is true that there is no substitute cubic inches.

The next move is bigger valves, race bred cams, bigger carbs, big bore exhausts etc, etc.
All these mods have an affect on each other. The trick is to maintain a balance, or we end up with a road machine that is totally untractable/unreliable.
I have experimented with performance road/race 4-1 and 2-1 exhaust systems, along with a few 2 stroke expansion chambers on bikes, go carts and yes, rotaries.
All these systems produced their broadest range of torque when the tuned length was calculated to coincide with around 3/4 of their usable rpm.
They all benefit greatly from pressure/sound pulses arriving at the port window/valve pocket at just the right moment. Scavenge is happening.

The early motorcross expansion chambers consisted of a series of inline cones with an expansion area in between and a presssure bleeder/stinger. They were baulky.
Then some tuner experimented with jinking the pipes aroung the engine and frame hoping to improve handing /weight, only to discover that this shape produced a greater range of power over the same tuned length. This was caused by the sound waves travelling back to the exhaust port window over a longer duration. The cones now had bevelled inlets.
A friend of mine rallied an RX3 with a 12A bridge port and a 2-1 extractor that branched just under the drivers seat. He blew his motor, and fitted a standard earlier twin distributor 12a until he rebuilt the race motor.
We chopped the extractor at the collector and fitted an expansion chamber. Surprisingly,the standard motor had far more low to upper midrange torque than the bridgeport. He refitted the bridgeport, but found that the chamber didn't work as well as with the standard ported motor.
4 stroke engines also benefit from longer duration sound waves travelling back to the valve pockets. The area behind the collector can be tappered or straight. The cross section area and lenght are inportant. The power band/torque range can be greatly increased by having the exhaust gases exiting through a bevel cut pipe. The bigger the bevel angle, the greater the range.
I run one of these pipes on my 850. It is moderately muffled but is a lot quieter than all other 4-1's I have heard. I still run the VM carbs and airbox.
Had I not been happy with my setup, I would have been tempted to give Monty's pipe a try.

Cheers
 
Ok, so I think I want to try one, if everyone here buys one of my new "Telcool MK5" oil cooler adapters, (still only $75.00, what a bargain!) I'll volunteer to buy the first X Pipe here, and do a full test, including a "before and after" Dyno report. Who's in? Cheers, Terry.
 
Yeah, I'm a starter Terry.

I wasn't planning on running an oil cooler on the 850, but it may be an advantage after raising the CR. I guess I'll know after its first mid summer run.
I'm picking that the X-pipe system hasn't taken off because of the oil changing issues and excessive heat build up in the sump area due to radiation off those close fitting pipes.
PM me for details if you decide to go ahead.
Cheers
Ian
 
I remember these from 'back in the day'. They never caught on.
Looks like someone bought some old inventory.
The theory was that they made more power over a wider revband. A 4-1 really only has an advantage in a very narrow range. This is why all the exhaust ystems emloyed by the oem's have several different exhaust valve arrangements to widen the band.
This thing is very similar in principle to an X-pipe that is found in most high performance automotive exhaust systems.
Seriously,aside from this guys goofy rhetoric(alot of whats is in his post is taken straight from the old ads)it may have been nothing more than 'fashion' that kept this design from going farther. The Codgers remember when everybody thought 4 straights were better than a 4-1.
Kevin Cameron once stated that if bikes were designed to be truly aerodynamic the oem's couldn't sell any because they wouldn't look like peoples perceived notions of what a bike should look like.
Underseat exhaust are a perfect example. The alleged aero advantages are minimal,they might aid cornering clearance,but a properly designed conventional pipe addresses those issues,the muffler that high and hung out past the back axle isn't helping handling and the several extra bends in the pipe ain't helpin' flow(on MotoGP bikes,the underseat pipes get a straight shot from rear cylinder banks).
Basically,they are on the bikes because 'they look cool'. The factory teams running production bikes have said its been a real bear to get the systems to work the way they want,but have to use them because CORPORATE has dictated there use and the rules require a stock configured system.
 
"I run one of these pipes on my 850. It is moderately muffled but is a lot quieter than all other 4-1's I have heard. I still run the VM carbs and airbox."


49er, do you have any pictures of the 850 with the above fitted?

Cheers,
Mark...
 
Pan,
I do have one pic that was taken just afer I bought the bike. It's taken with an SLR on film.
A mate has scanned it for me but it is way bigger than accepted on this site.
I need to work out how to digitally reduce its size and then I'll post it.
Any ideas?
Cheers
 
G'Day Ian, I'd love to see that pic too mate, I've got another friend in the US who's bought an "X" pipe for his Honda CB750 project bike, but hasn't fitted it yet, so I'm keen to see how it looks on your bike.

I think the pipes extend past the sump, so I can't see that being an issue, I've got an old set of 4 into 2 "drag pipes" (remember them?) on one of my CB750's, and they come out just past the engine, and I assume that the X pipes would be similar? Cheers, Terry.





49er said:
Yeah, I'm a starter Terry.

I wasn't planning on running an oil cooler on the 850, but it may be an advantage after raising the CR. I guess I'll know after its first mid summer run.
I'm picking that the X-pipe system hasn't taken off because of the oil changing issues and excessive heat build up in the sump area due to radiation off those close fitting pipes.
PM me for details if you decide to go ahead.
Cheers
Ian
Click to expand...
 
Terry
I'm posting a photo of my 850 with a 4-1 on it, not with an x-pipe.
It should be on site tomorrow.
Your'e right about the pipes clearing the sump area. There is still a big collector assy radiating heat right underneath the center of the sump and obscuring access to the drain plug.
Cheers
 
Ok, I think I've got my act together this time.
The pic was taken last summer, with part of the bike in the shade so bevel isn't that clear.
I believe this pipe was made in NZ and that they are still available.
Cheers
Ian
 
I was curious about them too. I never saw a bike that had 'em before.
 
You must log in or register to reply here.
Back
Top