ESE's works engine tuner

**Sketchy_Racer** · 14th February 2010, 12:00

This Plenum thing is very very interesting!

Kind of an odd question, but has it been thought to put a slide on the intake to the motor and leave the carb completely open all the time? or maybe have a cable split and have two throttle slides opening, one on the motor intake and one on the carb??

**TZ350** · 14th February 2010, 20:37

Links from the last ten pages, other link collections can be found on pages 80, 90, 100, 110 120

This is my favourite photo of Avalon, at the BOB,
https://secure.sportzfotoz.co.nz/pop...?imageid=45555

Tuning Keihin Carbs:-
http://www.carbparts.com/keihin/need...hin_tuning.htm

The jet size problem, interesting info on jets posted by SS90.
http://rd500lc.free.fr/technics/jet_size_fr.htm

All sorts of info on tuning carbs here:-
http://www.sudco.com/mikuni.html

Some interesting info on hydroformed expansion chambers from Bert.
I though it might be useful; if it hasn't been posted before.
http://ypvsbox.free.fr/pipedesigner_en.html
and this
http://www.gifford.ca/hydroform.html

A digital/programable DC-CDIP 2 Race 2-Stroke IgniTech ignition, there are also units for 4-Strokes, they can be purchased from The Two-Stroke Shop or directly from IgniTech. http://www.ignitech.cz/english/aindex.htm

The setup info was found on the Two-Stroke Shop www.twostrokeshop.com site.

This is about the latest RACE Ignitech and our ignition systems: http://www.twostrokeshop.com/ignitech_race.htm

Here is an article showing how to modify the RZ hardware to allow use of the Ignitech twin cdi module, eliminating the wasted spark system and giving full control over all electronic functions. http://www.twostrokeshop.com/ignitech.htm “.

For 2-strokes just half the runner length.
http://www.not2fast.com/gasflow/Lecture08.ppt

Maybe more for 4-strokes but lots of interesting stuff here:-
http://www.not2fast.com/

Resonant Airboxes: Theory and Applications:-
http://motorcycleinfo.calsci.com/Airboxes.html

The volume of the plenum:-
http://www.jagweb.com/aj6eng/technics.php

More on Plenums from:-
http://urbanracer.com/articles/anmvi...sp?a=3344&z=38

All you want to know about physics and resonance
http://hyperphysics.phy-astr.gsu.edu/Hbase/hframe.html

Automotive Calculators, lots of fun things to play with:-
http://www.wallaceracing.com/Calculators.htm

Some theory to help you in putting it all together:-
Power…………………. http://www.bgideas.demon.co.uk/tmanual/Tm_Ch1.pdf
Breathing & Induction.. http://www.bgideas.demon.co.uk/tmanual/Tm_Ch2.pdf
Combustion…………... http://www.bgideas.demon.co.uk/tmanual/Tm_Ch3.pdf
The Exhaust System…. http://www.bgideas.demon.co.uk/tmanual/Tm_Ch4.pdf
Camshafts…………….. http://www.bgideas.demon.co.uk/tmanual/Tm_Ch5.pdf
Ignition Systems……… http://www.bgideas.demon.co.uk/tmanual/Tm_Ch6.pdf
Turbo or Supercharger.. http://www.bgideas.demon.co.uk/tmanual/Tm_Ch7.pdf
Engine Reliability…….. http://www.bgideas.demon.co.uk/tmanual/Tm_Ch8.pdf

Interesting dyno results here:-
http://www.factorypro.com/dyno/true1.html

**TZ350** · 14th February 2010, 20:47

Originally Posted by Sketchy_Racer

has it been thought to put a slide on the intake to the motor and leave the carb completely open all the time? or maybe have a cable split and have two throttle slides opening, one on the motor intake and one on the carb??

This is a good idea, I am not sure how to work it, but reducing the port size into the motor some how at lower revs to get the gas velocity up, would probable overcome the fuel blowback problem.

**TZ350** · 14th February 2010, 21:07

Testing at MtWelly was difficult on the wet track, there was not a lot of traction, open the throtle and the back wheel would just spin up. Then the motor would backfire as it climbed into over rev.

Why some motors do that, pop back through the carb when they have revved past peak power I don't know but two of Team ESE's motors have regularly done it on the dyno while the others dont?

After quite a few backfires the seal on the blow off valve gave up, ending the days testing. We haven’t got the thing working completely smoothly yet, but it looks like it will work.

It has some kinks to iron out, but it does run, didn't blow up and shows promise. I am looking forward to getting the beast onto a dyno soon to see if the gains make it worth persevering with and developing it further.

I had a look around the pits and there were only 4 2-strokes about 10 or 12 FXR's 3 CB125T's and a CBR. I think without the FXR's in buckets, buckets would be fading away, up here anyway.

**Yow Ling** · 15th February 2010, 11:22

Originally Posted by Sketchy_Racer

This Plenum thing is very very interesting!

Kind of an odd question, but has it been thought to put a slide on the intake to the motor and leave the carb completely open all the time? or maybe have a cable split and have two throttle slides opening, one on the motor intake and one on the carb??

I think there may be a downside to this, the carb is designed to give different mixture strenghts at different combinations of airflow and throttle position, running WOT will give correct fuelling at high rpm/power and then with low airflow through the venturi at lower speeds will screw up all the benifits gained from having a needle and needle jet.

Might work with a CV carb, as it adjusts to the engine load

**bucketracer** · 15th February 2010, 19:09

Or you could adjust the tuned length of the inlet port so the out of resonance point (the blarrrs) are moved to somewhere else...........

**SS90** · 15th February 2010, 21:33

Originally Posted by bucketracer

Or you could adjust the tuned length of the inlet port so the out of resonance point (the blarrrs) are moved to somewhere else...........

Or fit a reed valve.

**F5 Dave** · 16th February 2010, 11:50

Yeah but a reedvalve into a rotary input negates the benefit + he still needs that bit to be the 24mm restriction.

**SS90** · 16th February 2010, 13:02

Yes, but with-out the Reed Valve, the Plenum will never work, jetting up just softens the resonance problem/reduces power.

There is clearly an intake tract resonance issue here.

There are so many people before that have tried to compensate for problems that have found that larger jets "improve" things, only to find that, in the end, no jet in the world will fix things.

simple logic/experience says that the jet sizes he is using defy common sense

125cc Two stroke engines with pressurised airboxes producing over 40 PS and achieving in excess of 200KPH don't use jets the size Teezee is currently using.

I don't think the Plenum will be a worthwhile effort.

Never seen a 125GP bike with one, and that is always a good place to look for inspiration.

**TZ350** · 16th February 2010, 15:59

Originally Posted by F5 Dave

Yeah but a reedvalve into a rotary input negates the benefit + he still needs that bit to be the 24mm restriction.

Hi Dave my carb is 24mm, the duct from the plenum into the engine is 34mm, the theory being that at WOT the carb flows all the time and is able to refill the plenum to at least atmospheric pressure by the time the motor takes another gulp. I figure a 24mm carb can flow full time as much as a 34 that is only sucking for half the time. If I can get a beneficial resonance through the carb going I have considered a read valve after the carb to help pump the plenum up to higher than atmospheric pressure.

Originally Posted by SS90

Yes, but with-out the Reed Valve, the Plenum will never work, jetting up just softens the resonance problem/reduces power.

There is clearly an intake tract resonance issue here.

There are so many people before that have tried to compensate for problems that have found that larger jets "improve" things, only to find that, in the end, no jet in the world will fix things.

simple logic/experience says that the jet sizes he is using defy common sense

125cc Two stroke engines with pressurised airboxes producing over 40 PS and achieving in excess of 200KPH don't use jets the size Teezee is currently using.

I don't think the Plenum will be a worthwhile effort.

Never seen a 125GP bike with one, and that is always a good place to look for inspiration.

Hi SS you make a lot of good points, thank you. I will work through them so you can see my thinking.

A plenum, “Never seen a 125GP bike with one”, probably because they are not restricted to 24mm like I am, so don't need to look at different ways of doing things.

The reason for the plenum is so that the motor can suck through a 34mm straw in large gulps from a big reservoir of air/fuel at atmospheric pressure instead of trying to gulp outside air through a restrictive 24mm one.

“I don't think the Plenum will be a worthwhile effort.” You could be right, or wrong, and now that the engine pulls well on WOT, I am keen to get the bike onto a dyno to see if there is any real gain.

“125cc Two stroke engines with pressurised airboxes producing over 40 PS and achieving in excess of 200KPH don't use jets the size Teezee is currently using.” “simple logic/experience says that the jet sizes he is using defy common sense”

Those motors aren’t using a plenum between the carb and engine…….At the moment I put my bigger jet requirement down to the fact, that when my plenum motor is pulling there is no discernable standoff in front of the carb.

Unlike other motors where at resonance the air bounces back and forth in the inlet tract at least three times, picking up fuel each time it passes the jet, I think the air flow through the plenum carb is all one way, so it has to pick up all its fuel in one go on the way in, hence the bigger jet.

“There is clearly an intake tract resonance issue here.” The resonance issue is with the 34mm tract from the motor into the plenum.

When the inlet duration was 205 degrees the motor would suffer a bad case of the blarrrrs before hitting hard. With the duration reduced to 180 degrees the blarrrs have significantly decreased but the port/time/area is still excessive for an engine that makes max power at only 9000 rpm.

I would have to reduce the inlet duration to 160 degrees (135/25) to get the correct inlet port/time/area but this requires making a new rotary valve and that is a job of work in itself.

Another problem was, that the 34mm inlet tract into the engine had a tuned length more suitable for 11,000 than 9,000 rpm so we are changing that now.

The blarrrs or reversion at the bellmouth of the 34mm inlet tract, I believe is associated with the inlet closing point and tuned length. From the testing we have done so far, we know its not going to blow up. So all of this gives me hope that we can get on top of the resonance (blarrrs) problem and it will all be a big succes.

Yes, in the end it might not work, but I don’t think we have played it all out yet, and it performs better every day.

I remain optimistic.

**jasonu** · 16th February 2010, 16:10

QUOTE I would have to reduce the inlet duration to 160 degrees (135/25) for the correct inlet port/time/area but this requires making a new rotary valve and that is a job of work in itself.

Surely makeing a new disk valve would be the eaisest thing on your plate right now. That is the beauty of the disk valve motor, if you cock up a disk, unbolt it and try another.

**TZ350** · 16th February 2010, 16:35

Originally Posted by jasonu

Surely makeing a new disk valve would be the eaisest thing on your plate right now. That is the beauty of the disk valve motor, if you cock up a disk, unbolt it and try another.

Yes, its easy to increase the duration by cutting an existing disk but reducing the duration to something less than std requires putting metal back, it means drawing one in CAD then having it lazar cut, and getting the fine teeth with their little radiuses cut precisely right to match the driving dog, I have found to be a bit of a trick.