Lef16, possibly you are misunderstanding the term "trombone pipe," . . . or maybe I am (anyway, one of us will learn something here). I believe the term refers to an expansion chamber that can be slid in and out, like a trombone, changing the tuned length. This is the universal practice in outboard racing (although we call them "slider-pipes"), but it's a lot harder to accomplish on a motorcycle, sled, kart, jetski, etc. The sliding section is (except in some old karts) in the header area close to the cylinder. The trombone pipe(s) could have any number of diffuser sections, any number of baffle cone stages. The point is that it slides in and out, usually over a roughly 10cm range.
(Now we'll see if the others agree with my use of the term . . . .)
As I said before,my English is not perfect.By trombone I meant the typical-header -> 3stage diffuser where every diffuser has steeper angle than the previous part-2 stroke pipe.
Anyway,I think wobbly or Frits understood what I wanted to say and I'm waiting for their answer with suspense!!
Cheers
False. A better descrition is given in the second page that Husa posted above. In case you missed that: each gear has its own centrifugal clutch, and all gears except the highest gear have unidirectional freewheels (called dog-bone clutches because of the shape of the locking elements in them) so they can be overriden by a higher gear.
No news about the FOS cylinder, except that everything takes way more time than it should.
The trombone pipe works a treat and the sealing is bullet-proof now, but with a six-speed gear box you hardly benefit as far as lap times go. On our kart tracks fewer gears might actually yield better lap times; Richard Maas is investigating that now.
Originally Posted by RAW
Just been re- reading and couldn't help but wonder if the system is fully functioning, did anyone solve the sealing issue of the sliding surfaces.
Further with the aprilia RSW / RSA exhaust port, the exhaust stub fitted to the barrel is approximately 40mm long and roughly has an internal diameter of 43mm, the port shape within the barrel is not round leaving a large step upon the upper and lower surfaces, how,why what is going on here ? I'm aware this is common to several engines but I have never spent the time to ask myself as to what may be the reason for this, I can only imagine there must be a good reason for this but I'm unable to think of one
Originally Posted by Frits Overmars
With a variable header length you do not need to artificially raise the exhaust gas temperature, so you need neither the power jet nor the ignition retard.
The 50 cc engine with trombone pipe that I wrote about some time ago, runs strongly from 7,000 to 17,000 rpm without power jet and ignition retard.
Note: the power jet in the Aprilia RSW / RSA is gradually closed and the ignition is gradually retarded till 10° before TDC. These engines rev to 14,500 rpm. But I am convinced that with a trombone pipe they would function much better still.
Originally Posted by TZ350
I am very taken with the Trombones possibilities and after using EngMod2T to simulate it, it looks like the Trombone is much better at extending a pipes upper range than plumping up the lower part of the torque curve below the pipes natural operating point.
So if you have an engine with a pipe good for 13K and a mechanical limit of 14 then its not much point in making a 13K trombone that can run 6K from 12 to 18.
After looking at the EngMod simulation results I think it makes better sense to discard my 13K pipe and design a pipe that’s a strong torque monster at 8K with the trombone effect extending its range out 6K to the engines 14K limit.
That’s the approach I am going to take when I make one of these for Beast-2.
A trombone and power valve combination would be even better.
Originally Posted by Frits Overmars
More news from Richard Maas. Did his trombone pipe give the desired results? O yes. At 10,000 rpm it gives 4 HP more than the same engine with a fixed pipe. It runs over 17,000 rpm without the need for a powerjet and with a fixed ignition timing. It is miles better than an engine with an exhaust power valve. And the mapping of pipe length, ignition timing and powerjet pulse width has yet to be carried out. Maybe the powerjet can disappear altogether.
Only problem so far: the piece of pipe that is fixed to the cylinder, is shrouded by the pipe that slides over it, so it gets very hot. Too hot for the Viton O-ring that is taking care of sealing. Any bright ideas, anyone?
Originally Posted by Lef16
As I said before,my English is not perfect.By trombone I meant the typical-header -> 3stage diffuser where every diffuser has steeper angle than the previous part-2 stroke pipe.
Anyway,I think wobbly or Frits understood what I wanted to say and I'm waiting for their answer with suspense!!
Cheers
Here is a WR200 pipe used with a 196 Ex, simmed at around 78 crank Hp @ 10250.
The pipe that was posted has a too short and too shallow header length, and isnt fat enough to get a good diffuser action.
The two stage rear does nothing of any use I can figure out.
A nozzle on the front end needs to start at around 75% of the port effective area, with the header starting at 100%.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
Yes, not a typo - and translated into a real 67RWHP on a DynoJet.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
My setup is 194* ex,boost ports to open 87 atdc,125* main tr,128* secondary and boost,14.5 compression ratio,also the YPVS will be disabled.
Wobbly,does the power band in your engine starts at 8000rpm?
I designed this exhaust for public street daily use,with long power band,thats why the shallow header and thin pipe,and also because of a little bit crap transfer ducts.Shall I try your exhaust with my setup?
What if I try a Blair type or a modern(according to engmod) pipe?
Cheers!
Here is a WR200 pipe used with a 196 Ex, simmed at around 78 crank Hp @ 10250.
The pipe that was posted has a too short and too shallow header length, and isnt fat enough to get a good diffuser action.
The two stage rear does nothing of any use I can figure out.
A nozzle on the front end needs to start at around 75% of the port effective area, with the header starting at 100%.
WR 200 as in small yamaha trail bike or is there another WR 200 I haven't heard of?
That was a big bore for drag racing engine.
The pipe is designed to work with all the other components and cant simply be fitted to any old WR200 and work correctly.
Blair or "modern " derived pipes in EngMod are simply a place to start, get the full code and start learning what does and doesnt work well.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
I thought that only here in Greece wr200 engines or moped engines with wr200 crank/cyl(73 or 74mm) were tuned for drag racing
Anyway,what about this design for public road use with a wide power band?I don't think my crap transfers will work with a very fat pipe.
Would seem to be a considerable improvement on, say 1/2 a CPI RZ400. I remember Chris Sayle thinking about trying to find a couple or WR barrels with the notion trying to fit to Anstey's TZ.
Don't you look at my accountant.
He's the only one I've got.
The CPI cylinder is hamstrung by the 102 bore centres of the RD/RZ cases, the WR has super swoopy transfer ducts by comparison.
That later pipe is better, but the header is still too shallow, and the basic design is derived from a full noise road racing type pipe.
To get a wider range the final diffuser needs to be the steepest, as having the steep mid diffuser helps to put the max BDC Ex port depression
earlier in the cycle - increasing the overev power.
Not what you want in the application.
Ive got a thing thats unique and new.To prove it I'll have the last laugh on you.Cause instead of one head I got two.And you know two heads are better than one.
The guy that did the American tzr400 or whatever it was mentioned WR200 as it I think had aux exhaust ports.
Originally Posted by HPbyGD
Hi Guys
It was one of those projects where the guy came to me wanting to put a big bore job on his stock barrels. My thinking was that a lot of the big bore kits I have seen end up not making much of an improvement in the peak horsepower without LOTS of work. I started looking around for some cylinders to use that were already a bigger bore. That is when I found the DT 200 cylinders and after looking at one I thought that I could get two of them on the TZR 250 lower end. I would have liked to use WR 200 cylinders with the triple exhaust ports but they are a lot harder to find. The crank was stroked to 56 mm and 110 mm were installed. I did some dyno testing with a DT 200 lower end and was able to get 40 horsepower and a nice spread of power with the power valve. I know that the stroke on the DT was 1 mm longer but I thought it would give me at least a good indication of what the twin would be like. It wasn't to far off even though the guy didn't want to have me build a set of pipes like the one I used on the dyno and he decided to use the Jolly Motos that he all ready had. I didn't do much porting on the cylinder just a good clean up. The reed valves are for a Blaster and the carbs are 34 mm flat sides. I made a head for the DT that uses replaceable combustion chamber inserts. When I built the twin I made a head for it also. Makes it easy to try different combustion chambers or repair it if there is something damaged. I order to get the cylinders to fit on the lower end I had to cut the sides of the cylinder and then weld up the holes that appeared. Linking the power valves together took me a while to figure out. What I ended up doing was making a piece that fit into each end of the power valves and making a stud that went all the way through both power valves to hold every thing together. I made the stud out of drill rod and so far it has held up fine. That is most of the info and if you have any questions let me know and I will try and answer them. One other thing that I forgot to mentioned is that I have actually built two motor that were kind of similar. The other one the guy wanted to use big bore Athena TZR 125 cylinders. The guy went through some teething problems with the plating on the Athena cylinders. I don't think that the guy with the Athena cylinders ever pu tit on a dyno that I know of. Both of the motors used a Zeel ignitions.
Would seem to be a considerable improvement on, say 1/2 a CPI RZ400. I remember Chris Sayle thinking about trying to find a couple or WR barrels with the notion trying to fit to Anstey's TZ.
From memory someone tried a tz v twin big bore with Dt200 or something bits, I think it was Ansteys, pretty sure Kicka or Grumph posted something about it.
Oh it was You Dave Grumph and Kicka
Originally Posted by F5 Dave
A mate was looking at building a 400 twin from a (think it was his old B model) TZ back in the day (for Anstey) in a similar fashion, but it never really got past planning stage.
Originally Posted by Grumph
Yeah, you must have an eidetic memory, W. That TZ when it was sold was probably the best in NZ....but it went downhill quickly.
If the present owner of the barrels can find a V twin TZR, there's an F3 bike to fit the current regs. And there are aftermarket pistons available for the 200 which weren't about at the time the barrels were done.
PS you must go into a lot of sheds too......
Originally Posted by Kickaha
I will suggest it to him, Brian still had the barrels a while back , although the 3XV V Twin goes for silly money if you can find one
Originally Posted by Grumph
Last i heard Brian was working in Akl....but his son had started junior MX. At the speed he does projects the boy may be old enough to ride it if it ever gets done.
Originally Posted by Grumph
I have a memory of Mark telling me Antspiss had asked him what was involved - and being severely discouraged when he was told how much work it took.
These two were unusual in that they had the TZ bits, enough money, enough time,the right equipment and motivation...
The motivation was to show the "diesel tuner" - me - that they could do it and it would work. All I had to do was taunt them occasionally that it would never run....
Kinky is using a feather. Perverted is using the whole chicken
Taking the NZ Bucket rules, where it states “Engines must be derived from non-competition motorcycles,” could someone:
a. Extreme ask. Melt down a non competition cylinder, eg a H100 or Suzuki A100 and cast an entirely new design cylinder with that molten material?
b. Less than extreme ask. Completely remove the guts of an appropriate cylinder, probably water cooled, and refit an entirely new internal port set and cylinder arrangement, the external sort of resembling the original?
c. Mild ask. Remove the CI liner and then fit a plated aluminium liner?
"Success is the ability to go from one failure to another with no loss of enthusiasm.”
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Originally Posted by seattle smitty
can't find the post either ROB but found these.........
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