ESE's works engine tuner

[F5 Dave]

The standard MB does too, I think I'm just being a scaredy pants.

Vibration can be a major concern. However Frits had posted up a version using an o-ring for a super short manifold, remind me sometime.

[TZ350]

Hi there,

1314ABUC.xls

the results of the 8^th & final round of the 13/14 season of AMCC bucket racing from today are attached, Tim will be updating the website.

Congratulations to the winners:
F4 Rick Ford
F5 Tim Fraser
B grade Pete Leahy
C grade Helene Conway
Sidecars Rick & Henk

No Diproses this season, even though Nathanael did win the last 10 F4 races in a row… (out of 16 total)
I guess if I want to win anything I should stop falling off my mountain bike.
Regards,
David Diprose

[TZ350]

Hi all,

The final round (round 8) of the Auckland Bucket Championship was held under sunny skies on Sunday June 15.

The detailed race results can be found on Mylaps here: http://www.mylaps.com/en/events/1034514

The final championship standings can be found on Mylaps here: http://www.mylaps.com/en/championships/31443

Congratulations to the new class champions:

F4 Rick Ford
F5 Tim Fraser
B-Grade Pete Leahy
C-Grade Helene Conway
Sidecars Rick & Henk

Two Strokes take out in F4 and in F5

[speedpro]

Two Strokes take out in F4 and in F5

and EVERY race on the day except sidecars

[TZ350]

The Beast is starting to snarl and it will pull away in top gear on the dyno from 3500rpm and WOT.

Attachment 292749

Red line is the best ever using a carb with this old cylinder and the Blue line is where I am at with fuel injecting it. In all fairness for a proper comparison it needs a new head and a generator for the EFI. I am pretty excited about the Ecotrons fuel injection system as its starting to be very easy to work with. I think this EFI business is going to work out OK.

Well, we have a good head and just about finished wiring the generator and installing the four channel temperature data logger.

Dyno time soon .... hopefully have the Beast track ready for the new season.

[TZ350]

Two Strokes take out in F4 and in F5

and EVERY race on the day except sidecars

A two stroke side car with CVT is being built. Shishhhh ... you did not hear that from me....

[husaberg]

Vibration can be a major concern. However Frits had posted up a version using an o-ring for a super short manifold, remind me sometime.

http://www.kiwibiker.co.nz/forums/sh...post1130375552

[TZ350]

Just musing, but I have seen 2 into 1 expansion chambers before, they make a real weird noise. Anyway I was thinking of something different, a 1 into 2.

Because the new engine will have a power valve that changes the exhaust timing from 80 deg atdc to 90 and back I have been thinking of two expansion chambers with a butterfly in the header that switches between them so that whatever the exhaust timing the working chamber suits it.

Possibly a step better than an ATAC valve. Anyway, like I said, just thinking about it but you can see how possible it would be to put a butterfly in the header to switch between chambers.

[Frits Overmars]

Because the new engine will have a power valve that changes the exhaust timing from 80 deg atdc to 90 and back I have been thinking of two expansion chambers with a butterfly in the header that switches between them so that whatever the exhaust timing the working chamber suits it.

I have been working on a ZABEL 700 cc two-stroke single for sidecar-MX. The guys with the heavy boots want power from 2000 to 8000 rpm, so I had to dive into power valve calculations once again (a trombone pipe would do much better, but I'm afraid it wouldn't last long in MX).
A good power valve may adapt exhaust timing to pipe dimensions and rpm; an average powervalve will spoil some of the exhaust pulse's energy so it won't do too much harm to the power curve when it returns too early at low revs, but all powervalves reduce the blowdown angle.area far more than is desirable, with consequent engine overheating.
A butterfly in the header to switch between chambers would be worth looking at. Ages ago I drew something along these lines for Solex racing, with a rotating drum, switching between a short and a long header. I can't find the picture any more but it was not unlike the variable-length inlet system found nowadays on some Audis.

[TZ350]

Thanks for the ideas .....

[wobbly]

In the testing I did using an ATAC chamber with a flat throttle plate close to the header gave just over 30% more power on top of the extra
we already had from the powervalve , at the bottom of the powerband.
I have operated them with a servo using a rotating throttle plate, or you can even use a Rotax type powervalve diaphram pulling a flat blade with a port in it.
This worked even better with its spring return and a small compressed air bottle to solenoid valve drive it with ECU control.

[TZ350]

Great, thanks for that....

[Drew]

Ummm, how do ya get an instantaneous transition from one pipe to the other? There's potential for a wicked dead spot at swap time, followed by a big power jump as the new pipe comes on.

How many cycles does it take for a smoker to come right after a miss? I think I remember Wob or someone saying ages ago, but I cant figure out how to search for it.

[Yow Ling]

Would switching to the cold pipe give an advantage as it would appear longer when switched over then as it heats up get shorter so kinda tracking the rpm , a bit like a power valve does , I guess after a wee while on the pipe this effect would start to decay but maybe of some benefit when exiting a slow part of the track

[Drew]

Would switching to the cold pipe give an advantage as it would appear longer when switched over then as it heats up get shorter so kinda tracking the rpm , a bit like a power valve does , I guess after a wee while on the pipe this effect would start to decay but maybe of some benefit when exiting a slow part of the track

Sooo, is it possible to just cool the pipe rapidly when the PV opens?