ESE's works engine tuner

[jonny quest]

See if this works. .. Some of my work

[mr bucketracer]

It works on the 4strokes.

I use to build 2 stroke exhausts for a living. I was put out of business by the 4 strokes in the MX market. ... I may get whipped for saying this here... but glad I did. Business has quadrupled because of all the extra moving parts.

I taught myself how to make cone pipes. ... spent the last year teaching myself cam design. It's a lot easier grinding a cam than cutting, hammering out a pipe. (Labor wise)

But I bought myself a fun little 2 stroke to play around with again. A newer CR125. Having fun playing. ... and it really is amazing how that technology applies to both.

so who do you cam grind for? no work here unles you grind cams for boring cars lol

[TZ350]

Something I have just seen on the net. Valves dimpled on the head like a golf ball for better air flow over there surface, so clever I don't know why it had not been done before.

[Haufen]

Something I have just seen on the net. Valves dimpled on the head like a golf ball for better air flow over there surface, so clever I don't know why it had not been done before.

Maybe because valves, unlike golf balls, rotate with a far lesser speed (if at all) and thus the effect does not work?

[fixer]

My beloved Aprilia RS50 acquired a new Doppler Vortex 50cc kit recently. I bought it because I liked the look of the wide bridged exhaust port and the wide and (I believe) nicely-angled transfer ports. It's advertised as a road kit so it (as I have discovered) has relatively mild port timing. There's a video showing the inside of the kit here: https://www.youtube.com/watch?v=mUeeycpkpc8.

The standard Aprilia top end with some exhaust port mods made a bit over 11hp on the ESE dyno. So we put her back on the dyno and, lo and behold, with the Doppler kit she was making just under 10hp with a dip in the power band the size of the Grand Canyon.

But ... we took advantage of the large number of exhaust pipes to be found in the ESE workshop to see if a different pipe might conjure up another pony or two.

So the Conti pipe (which had been largely responsible for an earlier increase from 5hp to 8hp) came off and another pipe went on. Still a large dip in the power band, but substantially more power. Back up to just over 11hp. This pipe was a bit large and only fitted a couple of mm into the barrel. So we shaved a bit off the OD so it would fit in better. It was probably about 10-12mm shorter when properly fitted, and was a disaster. Back down to just over 10hp. What??

Okay ... so we tried a different pipe. The result was MUCH better. Nearly 12hp with a much nicer looking power curve.

And then for the hell of it, we tried the original Conti pipe with a shorter adaptor between the pipe and the barrel (probably by about 12-15mm). Based on our previous experience of a longer pipe being better, I bet that this shorter adaptor would make things worse. WRONG!!! There was still a chunky dip in the power band, but it was back up to nearly 12hp.

The moral of the story ... the proof is in the dyno! Below centre is a photo of the 5 dyno charts. You can see the range of different results obtained from 3 different pipes, with two of them tried twice each with shorter or longer adaptors. The maximum power varies by around 20 percent, but 4 out of 5 have a similar dip. One doesn't. This is very promising.

The photo on the left illustrates the huge difference that just having a 10mm or so longer adaptor between the pipe and the barrel can make. The photo second from right shows the two adaptors.

So on went the degree wheel (see photo on right), and some considered measurements were taken (see photo second from left), with the result being that we're going to raise the barrel a bit with a spacer, machine the head to fit it into the top of the cylinder, tweak the squish band and stick her back on the dyno. More exhaust port duration is apparently what is required here.

Two-strokes and dynos ... a match made in, well, if not Heaven, then at least Wonderland.

Tim

[jonny quest]

Very clever detective work TZ350

[TZ350]

very clever detective work tz350

.......

[wobbly]

Simply lifting the cylinder to get 115 on the transfers and 192 on the Ex means you will have shit loads of STA on both, but the thing will then be severely blowdown limited.
It may in fact make better power than what you have now - but such a STA mismatch will always mean narrowing of the useable power and probably even
more issues with big torque holes.
115 is what you would run on a full noise road racing setup, 192 is what a much lower power hot road bike might need - so the resulting power will always be compromised by the missing blowdown
that matches neither the transfers nor the Ex STA.
Just coz its easy dont mean its right - it aint.

[Grumph]

Something I have just seen on the net. Valves dimpled on the head like a golf ball for better air flow over there surface, so clever I don't know why it had not been done before.

Well....I don't know....If it is that good why is the exhaust valve dimpled more than the inlet ? I look at where the dimples are on the inlet and wonder about turbulence at low lift...and how it may limit flow. I suspect the weight saving may be of more benefit then anything else.

Back to 2 strokes please.

[FastFred]

Just coz its easy dont mean its right - it aint.

You are sort of right but there is not enough information to make quick judgments as one would need to know the exhaust port shape/area to know the actual blowdown STA.

I am picking that they have half a clue about what they are doing and possibly think there was excessive blowdown with the standard setup and that by raising the barrel and RPM ceiling that what was excessive blowdown STA at lower rpm is suitably adequate for the higher rpm they are aiming for. So it could be they are tuning for the blowdown area they already have. And yes the spacer plate is easy but it also makes things easily reversible, so easy could be good if they are wrong.

Anyway I am sure there will be a dyno graph in due course.

[F5 Dave]

Well....I don't know....If it is that good why is the exhaust valve dimpled more than the inlet ? I look at where the dimples are on the inlet and wonder about turbulence at low lift...and how it may limit flow. I suspect the weight saving may be of more benefit then anything else.

Back to 2 strokes please.

Yeah I'd file that along with Rifled Banshee comustion chambers (can't find a pic & too lazy to search for more than 30sec).

[husaberg]

me i'm still trying to get my head around this...........


Jess ...................

[Drew]

me i'm still trying to get my head around this...........


Jess ...................

That makes sense to me. Once I figured out what 'squish' was, were I in to fucking about with 2 strokes I'd maybe even have given it a go.

[Grumph]

[QUOTE=Drew;That makes sense to me. Once I figured out what 'squish' was, were I in to fucking about with 2 strokes I'd maybe even have given it a go.[/QUOTE]

Do you really want to squirt wet mixture at the plug ? refer wobs post a few back about unburned mixture left in crevices and the probs it causes.

[Drew]

Do you really want to squirt wet mixture at the plug ? refer wobs post a few back about unburned mixture left in crevices and the probs it causes.

I wouldn't think it through that far. My mind would get stuck at 'turbulence' and the possibility of more.