ESE's works engine tuner

[Gigglebutton]

Would it help if we cut a sectoin of frame rail away, where the Deltabox sticker is. Then weld the shock and swingarm mount back ??

Attachment 263422

[bucketracer]

I truly believe in the future it will be 30hp 2 strokes, but I am certain it won't be from engines with single exhaust ports, to get that power, serious blowdown is required, and therefore narrow power, requiring either a change in gearbox speed (primary ratio possibly) or somehow more, closer ratio gears.

You should look at TeeZees 30hp graph more carefully before talking any more about narrow power bands and the need to change the primary gear ratio or suggesting a closer ratio gear box because your way off the mark there.



TeeZees 30ps (DIN hp) at 12500 rpm with a useful 4k torque curve from 11 to 17.5Nm. (13 ft/lbs = 17.5Nm)

How wide do you think yours is? from your 20ps 8Nm graphs (attached below) and taken from engines similar to TeeZee's it looks like its 2.5k, 3k at best.

So that begs the question, how wide a torque curve does a 4 speed Vespa need?

If you know the rpm drop between gears lets see if TeeZees 30hp 4k curve would work ok on a Vespa too.

My guess is ... Yes ... and probably better than your race winning combos shown below.

What is possible is say 22-25 HP at 10,500, and that, from my experience is not only feasable, but race winning as well......

TeeZees Graph is 22+hp at 10,500rpm so your right, it is feasable.

The idea of lower rpm and a broad strong spread is not that silly and TeeZee posted his ideas 20 or so pages back on how it could be done and a pipe design to go with it.

[TZ350]

I think you can be very happy with your regulations, as it looks like they allow for a great amount of freedom of choice without any setups / directions being superior to the rest. Too bad I am living on the other side of the planet, if I were in NZ, I'd surely take part. Are there any european 125cc two-stroke street bikes available in NZ, for example Aprilia RS125, or Cagiva Mito (Evo)?

And, by the way, this thread is a great read! I really like the attitude of sharing experience and helping each other which is present here

Very few small European bikes available in NZ and they are relativly expensive. The bikes here are mostly the std Honda/Suzuki/Kawasaki's.

I am glad you enjoy the thread, I started it a while ago just to wind up the opposition before the annual Taupo Road Racing Spectacular, TRRS for short.

While I plod along diarying my own and something of Team ESE's success and failures with development other contributors have added their bit and it has morphed into something that’s both entertaining and useful.

And we are very lucky to have real technical and industry experience with Wobbly and Frits, their input adds real depth and understanding that’s invaluable and I am very grateful for what I have learned from them.

Even if someone does not want a 30hp engine like mine there is plenty of info posted by the community here, to help them make whatever they like.

If you would like to post about your projects it would be welcome as we are always interested in someone else’s work.

[TZ350]

Would it help if we cut a sectoin of frame rail away, where the Deltabox sticker is. Then weld the shock and swingarm mount back ??

Attachment 263422

I had gone off the idea of cutting the frame because the stearing head to seat length was already the same as a Honda RS125.

But now that I am changing the tank and set, frame cutting might be worth looking at again.

Kel is coming around Friday night, if you can, please pop in too and we can all look at whats possible.

[F5 Dave]

I'll bring the beers & the hacksaw.


oh hold on, you're 600 odd k away.

[TZ350]

I'll bring the beers & the hacksaw.

If you can get here we will shout the beers and lend you a hack saw.....

[F5 Dave]

Hmm, $91 grabaseat & I do drink a bit so it could be worthwhile to come get trashed & saw your bike to bits. Hmm, carry-on bag, would fit my 125 grinder & I'm dangerous with that.

[speedpro]

I can get an 8" grinder with cutoff discs. We'll have that thing in small pieces in no time

[TZ350]

Hmm, $91 grabaseat & I do drink a bit so it could be worthwhile to come get trashed & saw your bike to bits. Hmm, carry-on bag, would fit my 125 grinder & I'm dangerous with that.

I can get an 8" grinder with cutoff discs. We'll have that thing in small pieces in no time

Well OK beers for all, hopefully after an hour or two every one will have forgotten what they came for...

[F5 Dave]

or after a few hours when you come to weld it all back up again the wheelbase will be so short the back of the front tyre will rub on the front of the rear

[TZ350]

I see the four essential things for a winning formula as, Rider, Handling, Power and the way the power is Delivered.

If the opposition is a rider you can't out ride, and he has a good handling bike the equal of yours and you both have sufficient power then that only leaves "Power Delivery" as a possible advantage.



And usually 4-Strokers are better at that than 2-Strokes, and the reason 4's are so hard to beat.

So what to do????

SS90, TeeZees 30hp Graph is 22+hp at 10,500rpm so your right, it is feasible.

Your idea of lower rpm and a broad strong spread is not that silly and TeeZee has already posted his ideas, 20 or so pages back on how it could be done and a pipe design to go with it.

22-25hp at 10,500rpm is easily feasible but now that FXR150's are starting to creep into the low 20's and with some turning 25+ on the dyno a 22-25hp 2-Stroke might not be all that much of an asset.

But your right "lower rpm and a broad strong spread is not that silly" its just you may need to aim for 25-30hp to have a competitive stroker.

This is the original post.

After we get the triple port and Piranha pipe testing out of the way I want to try my hand at one of these Trombone pipes. They look like the key to making an all conquering 2-Stroke.

The plan is to make a pipe that works well down low and then use the Trombone effect to get lots of extension of the working range. Not so much about peak hp numbers, that 2-Strokes can be good at but dramatically increasing the area under the power curve.

After Frits revelled the Trombone concept I immediately could see that it had real possibilities if we could get it to work for us.

Using a traditional expansion chamber has its limitations because its limited to a relatively small range where its in resonance, 3-4K at best an the 4-strokes can pull 6k.

The Trombone Frits showed us I think was made to extend the range above and below a full race pipes natural resonance point.

Trombone simulated in EngMod2T and graphed in kW's

After doing some investigation it looked like the Trombone was better at extending a pipes range than lowering it.

So to get a better, broader power delivery my idea was to design a pipe more like a torquey MX one that works very well at relatively low rpm and use the optimal exhaust port duration for resonance that Frits has talked about.

Then use the Trombone principle to progressively shorten the header until the engine reaches its mechanical limits at 14,000rpm or so.

If extra power is only worth tenths of a second and handling whole seconds, but the other bike is as good as yours and the other rider is a mad psycho. What are you going to do, out ride him? I don't think so, then that only leaves Power Delivery as a possible advantage.

The trombone might be the answer.

[Farmaken]

What was that saying?- Measure once, cut twice

Good luck TZ

[TZ350]

Frits has motivated us into looking at the Beasts handling.



My CRM Tank and Seat arrived today and yes, it looks like I can use it to get the fuel and riders weight forward.

Make a light sub frame for the back and with a MX tail and number boards it should look quite the bizz, or at least pretty unusual, even for a Bucket.



Comparing the CRM tank and seat to an original FZR one, it looks like the rider will be able to move around and get their weight up front when needed OK.

When you look at the original (No 21) FZR, it looks so restrictive.



Yep, fits a RG50 too.



Getting the engine forward in a small race chassis makes it tricky building a good pipe. I am glad I have a roomy FZR chassis.



Stuff every where, house keeping is obviously not big around here.



And Bucket, the "Industrious Man" or is that Industry Man? is busy working on cylinders.

[F5 Dave]

Tell you something for nothing. the engine in the NX4 is too high.

[speedpro]

And Bucket, the Industrious Man is busy working on cylinders.

So that'll be a 500 V4 when finished?