Alternate Cooling Method.... Worth it or not?  By  mopojo (Read 2,079 times)

Wheelbender,

Trust me, I know the hoops you need to jump through for those coveted clearances...  I was in Karlsruhe, Germany at the time, attached to the 7th Special Forces, in psychological warfare.  As luck would have it, our unit was a repository for some nuclear weapons.

As such, we had the corresponding nuclear codes, today called the "football".  Anyone with access to the codes had to have a COSMIC clearance (above Top Secret back then) ours being COSMIC/CRYPTO designating access to actual geographical targets.  Pretty spooky stuff.

To get the clearance, I went through a whirlwind background check, GOING BACK 3 GNERATIONS!   The FBI and Army Intelligence showed me things about my ancestors even I didn't know.  (I have an obscure ancestor who married a Native American Indian who was at the time a member of a tribe which had not yet made peace with the government)  That fact almost kept me from getting the clearance!  Cheesh... I kept that clearance even after leaving that post, and I'm still proud today of the credibility it carried.

It still looks good on a resume, even though anybody younger than 60 or so will be quick to point out that today, "Top Secret" is the highest "normal" clearance... True.  But that was then.

This whole thread is beginning to smell, and it's not the spirit the site is built on.  I'm done with it.  I have more to worry about than an exhaust mod that I found to be great... I am 70, I'm starting to go blind, my Wife's meds now take more than my entire Social Security income and I'd like to keep my participation in the site friendly.  It's been that way for 8 years and this is the first time anyone has turned on me.  It's sad this thread came to a "he say-she say" tribute to total disrespect because of a simple post of mine which I had hoped might help when asked about the exhaust.

Ride safe,

And think twice before trying to give helpful replies.  No good deed goes unpunished...

Leo in Texas


     

I know chamber pipes on 4-strokes are not COMMON. But they do exist, engineered by both amateurs and pros...  Below, are some threads from sites featuring chamber pipes on 4-strokes.
_________________________________________________

Chamber pipes used in rally cars... Copied from enginetips.com 4-stroke chamber exhaust:
Artsi (Automotive)
(OP)
26 Sep 09 10:23
I spotted an additional exhaust runner resonance chamber on BMW 450cc motocross bike engine, see provided link.

I have tried to wrap my head around the design function of said chamber with no results. This does not seem to be an anti-reversion chamber.

I have however seen similar chambers on 4-cylinder naturally aspirated rally car engines. Chambers are there to even out torque curve. They're connecting cylinders 1-2 together, and 3-4 together (if my memory serves me right).

Would this BMW factory racing exhaust chamber serve same function?

Junior37c (Mechanical) answer:
27 Sep 09 16:53
My understanding from having run some simulations on those MX motors is that it's just there to smoothen the resonance action across the RPM band. Smoothen out the power delivery.

This is EXACTLY the results I obtained on my old Xingyue, and on numerous 4-stroke flatheads on our pit-bikes at the kart tracks in the early 1960's

Four-Stroke Expansion Chambers copied from thumpertalk.com:
By mikekay, Posted January 15, 2005
the answer is YES!
you CAN design 4 stroke pipes to extract performance....two ways to do it.
1) the FMF design as posted above.
2) Megaphone design. As used on F1 cars. a pipe that slowly expands in size right up to the muffler. If you ever get to look at Team Hondas Baja 1000 winning 650R note the custom made megaphone mid section...no one offers that for sale...yet. Not sure if anyone has combined the two technologies...
Neither will give you something as rad as a 2 smoke hit--but both will give added performance over the current total crap 4 stroke pipes on the market.

Many road racing and drag racing four strokes use exhausts with straight exhaust headers, followed by a tapered conical "megaphone" with gradually increasing diameter capped by a reverse cone on the end. Megaphone exhausts are the four stroke equivalent of an expansion chamber, in that they are tuned to utilize the pressure pulses of the exhaust flow to increase exhaust scavenging and HP. I believe this scavenging effect is tuned to a specific rpm range, the megaphone may reduce power somewhat outside the tuned range. Some dirtbike exhausts surely utilize megaphone desigh principles. The HP benefit for fourstrokes is likely less than two strokes.
www.mc-land.no/exhaust/muzzy_drag_race.htm
If you would like to get a bit technical, check this out:
www.cafefoundation.org/aprs/EPG%20PART%20IV.pdf
Aren't you glad you asked? :cry:

OK, there are a few public thread examples of EXACTLY what I'm talking about. And I PROMISE you that if you could bolt on that little stainless chamber pipe in my thread onto your nice scoot, it would perform every bit as well, or better than the nice performance setup you now have.

With that old thread of my setup, I was NOT interested in racing, or any sporting use. I simply recreated what I did 55 years ago at the track on our pit bikes and it worked BEAUTIFULLY on my street-150, just as I expected it to.  I thought others wanting a good-running, AFORDABLE setup for their 150 might enjoy trying it.  (An additional benefit is a BIG reduction in in-sprung weight on the rear suspension; enough to make a noticeable difference in handling, especially on a washboard surface.

I have no problem with you disagreeing with me. I have a problem with you demeaning me and calling me a liar over things I have done and shared with members. I wish you could have been there when my then gal-friend Janice "the Flying Squirrel" ran my chopper in the mid tens at over 140... sans all but her skivvies, laying on the tank, shifting no-clutch with her left hand on the shifter... Yeah, it happened, and nobody cares except that it's a neat, fun true story of long ago that would never happen today.

I'm very impressed with your escapades and I'd believe you without the pix... This is a fun and mildly educational forum, and most threads are honest. We're not building record-breaking rides, just making the best of our scoots, and that chamber pipe on my old GY6 worked GREAT. What I object to is your extremely demeaning criticism of things I've done, and others have enjoyed reading about, without even knowing me.

The chamber pipes on alky dragsters I saw in a magazine years back. I could not find current info on them.  Apparently they never caught on, but the article showed figures that they outperformed traditional zoomie headers by a good margin.  However, the forum posts I harvested above should show you that I'm NOT the only guy to find out they work, and work well.

The blue copy above (Many road racing and drag racing four strokes use exhausts with straight exhaust headers, followed by a tapered conical "megaphone" with gradually increasing diameter capped by a reverse cone on the end.)  Refers to the alky dragsters I read about.  Maybe the misunderstanding would b made clear by re-naming the devices.  On a 2-stroke, they ARE expansion/contraction chambers.  On a 4-stroke, they ARE free-flow, scavenging mufflers.

On a little 150, the stinger portion does little or nothing save make it a tad quieter.  The pigtail pipe is not small enough to create adverse back-pressure.

If I was to run that same pipe on a larger motor, like my 250, I would remove the pigtail and stinger, and cut the end of the chamber's reverse-cone to open it to an inch or so.  Then I'd have the exact same setup as referred to concerning piped "road racing and drag racing four strokes" above.

How about burying the hatchet and having a little understanding that what either of us posts is truthful? Other members would appreciate that, and those who try my chamber conversion will be impressed with the results.

Sorry about the jury comment, that creep SHOULD rot in jail. My comment reflected your complete lack of willingness to listen to someone relating a truth you disagree with.  Have a bone...

Sincerely,

Leo in Texas

Chopper dude this is the extent a "Chamber" is used in motorsports anywhere in the World, a Resonant Chamber, this is from Pipe God Mr Peyton at Pro-Circuit racing, Mr Peyton, Mr Emler ,Bill have spent thousands f hours in Dyno rooms.over the past 50 years or more. Your Stinger is like you Farting thru a Cocktail straw, it does create adverse back pressure for the GY-6 that like a HD loves to breath.
You would be laughed out of the office of any of the Gods of Pipes showing them the 2-T pipe on your GY-6 150, thats your prerogative.
I had and have had no ill will towards you that there is a hatchet to bury, Its all good and I would sit down and have a beer with you at Willhoits.
There is no way you could know I served on a jury back in of the Gangster who killed the little girl on Juneteenth in Stop-six, a apology was not necessary,but accepted.
Im moving forward and finished here.
Cheers