ESE's works engine tuner

**koba** · 6th July 2009, 07:44

Originally Posted by TerraRoot

what about water injection? the nsr500's used it to cool the pipe which changed the speed of the reflecting wave, think it worked too because they keep it right up until they the 2strokes got ruled out.

hmm, youve got me thinking!
Possibly an easier way to do it than slippy pipes, dialing it in would be hard tho.
Modern fuel injection systems give us lots of appropriate parts to work with.

**TerraRoot** · 6th July 2009, 07:54

tbh, adjustable pipes or water injection are only gonna smooth the powerband not make more power, big strokers had em to tame there mighty horse's, are you lot scared with only 17 of em?

**F5 Dave** · 6th July 2009, 09:42

That isn't 'smoothing the power'. That is extending the torque curve, boosting the midrange, increasing the over-rev. All things small capacity bikes could use. Whether the complexity & weight is worth it is dubious.

Any manual system is just going to take your eye off the ball when trying to ride & do something else, which is why I posted the idea originally presented as I did. But go crazy.

**speedpro** · 6th July 2009, 18:56

Never EVER letting the clutch right out can help as well by giving an apparently very wide peak power, from a road-speed perspective anyway, eh Dave.

**F5 Dave** · 6th July 2009, 22:05

Yeah not so much a riding style as sloppy maintenance, I adjusted it like that & well,. . .

**bucketracer** · 9th July 2009, 12:40

Old (1975?) DKW 125 MotoX engine, check the size of the finning and the fins on the bottom end. Note the gap around the crankcase, I guess this is to reduce heating of the incoming air/fuel mixture. Didn't TZ say somewhere that a large part of an engines waste heat is dissipated from the bottom end.

**TerraRoot** · 11th July 2009, 21:20

how about this for fixing your powerband hi-tech style. e-tec 600 ski-doo.

First a video
http://www.youtube.com/watch?v=N_DexODwAb0

Ignore the environmental stuff, note how smooth it is? and all the oil is not ending up in the combustion chamber, upping the octane value to boot.

what can us guys in our sheds do? A company called envirofit is making a retrofit kit for small old aircooled two-strokes.

http://envirofit.org/?q=our-products/2-stroke-retrofit

Basically, doing this conversion to DI, you ought to be able to control every aspect of the engine, advanceing/retarding the fuel injection, smoothing out the powerband should be no problem.

God i just hope it's not vapourware.

**bucketracer** · 11th July 2009, 21:30

First a video
http://www.youtube.com/watch?v=N_DexODwAb0

Is it just me, or has anyone else noticed that there was much less snow on the Ski-Doo's seat and runners, suggesting it had already been run up/or was covered before the test?????

Direct injection into the cylinder, interesting idea though.

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**TZ350** · 12th July 2009, 10:06

Direct Injection is a serious idea that seems to be getting some traction, could be the revival of small 2-Strokes.

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**Chambers** · 12th July 2009, 12:09

Optimization of a Direct-Injected 2-Stroke Cycle Snowmobile
Document Number: 2003-32-0074

Date Published: September 2003

Author(s):
Walter Hull - Colorado State Univ.

Abstract:
A student design team at Colorado State University (CSU) has developed an innovative snowmobile to compete in the Clean Snowmobile Challenge 2003 competition. This engine concept was originally developed for the CSC 2002 competition and demonstrated the lowest emissions of any engine that competed that year. The team utilized a 3-cylinder, 594cc, loop-scavenged, two-stroke cycle engine (Arctic Cat ZRT600) and then modified the engine to operate with direct in-cylinder fuel injection using the Orbital OCP air-assisted fuel injection system. This conversion required that the team design and cast new heads for the engine. The direct-injection approach reduced carbon monoxide (CO) emissions by 70% and total hydrocarbon (THC) emissions by 90% from a representative stock snowmobile. An oxidation catalyst was then used to oxidize the remaining CO and THC. This combination of direct fuel injection and oxidation catalysts reduced CO by over 97% and THC by over 99% when compared to the 2002 SAE CSC control sled. The design discussed in this paper builds on the core technology developed in 2002 to improve performance and reduce noise.

The direct-injected engine and supporting hardware were transferred to a lightweight 2002 Arctic Cat ZL600 chassis. The modern suspension and the reduced weight of the chassis resulted in improved handling, increased acceleration and improved fuel economy.

The 2002 entry exceeded the competition noise limit by one dBA. A comprehensive effort was undertaken to redesign the exhaust system to reduce noise, improve power, and to more effectively accommodate the oxidation catalyst. Analytical and experimental techniques were used to redesign the exhaust system which demonstrated a 20% improvement in peak power and mid-range torque over the 2002 entry. Improved materials are utilized to withstand the high temperatures produced by the oxidation catalyst. The new exhaust silencer design combines a diffusive silencer, a side resonator, and an absorptive silencer. Intake noise is attenuated with a combined diffusive silencer and side resonator silencer. The exhaust and intake silencers were effective in reducing the engine?s firing frequency and the first four harmonics.

A cost analysis has shown that this complete design approach would add $473 to the production cost of manufacturing the snowmobile. The majority of this cost is incurred by the direct fuel injection system and the modifications to the exhaust system.

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**Chambers** · 12th July 2009, 12:16

Wait and there is more:-

High Specific Power Output Direct Injection 2-Stroke Engine Applications
Document Number: 2005-32-0066

Date Published: October 2005

Author(s):
Rodney Houston - Orbital Australia Pty. Ltd.
Greg Bell - Orbital Australia Pty. Ltd.
Steven Ahern - Orbital Australia Pty. Ltd.

Abstract:
Whilst direct in-cylinder injection is now common in both the automotive and non-automotive markets, the very high-performance, 2-stroke engines pose specific challenges to the application of direct injection due to the increased fueling levels, the high fuel turn down ratio requirements and the reduced fuel preparation times at high engine operating speeds.

In addition, a high-performance, 2-stroke engine will usually have a highly tuned scavenging system, which puts further demands on the fuel and combustion systems to achieve the desired performance. The fuel and combustion systems must also retain the low emissions to meet the relevant emissions legislation with a minimum level of aftertreatment. This paper briefly discusses the requirements for emissions reduction in high-specific-output, 2-stroke engines, whether it is for a high-performance motorcycle application that only uses relatively low loads across the emissions testing cycle or for a highly loaded and high speed snowmobile application.

This paper then reviews some of the specific challenges and latest developments for an Air-Assisted Direct Injection (ADI) system and the accompany combustion system to address the operating requirements of high-performance and high-speed, 2-stroke engines.

So Yes it looks like DI is being taken seriously and could be made to work with race 2-stroke engines.

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**TZ350** · 12th July 2009, 13:35

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In moments of desperation or bad judgement racing someone for the next corner I have often slowed myself down by holding a gear to long, and making the motor rev way past its power peak.

And later thought, if there was an automatic way to change gears when the motor touched peak rpm the bike could accelerate much more smoothly and quickly.

When I was in JayCar’s yesterday I spotted this kit KC5378. It’s a frequency switch that will switch devices on or off according to engine rev’s. This could trigger an electric door lock attached to the gear lever when the motor hits peak rpm.

I could control it by setting it up so that it only works when I have my thumb on the horn button. Then at the right times All I would need to do is have my thumb on the button and keep the throttle nailed for fast seamless acceleration.

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**Skunk** · 12th July 2009, 13:42

Or do it Sketchy's way... hold your foot on the gear lever (race pattern) and push the kill button to cut the ignition for a moment and the gear changes as the motor drops it's loading. Done.

I would, however, be interested in that kit to limit the revs.

**TZ350** · 12th July 2009, 15:45

Originally Posted by Skunk

Or do it Sketchy's way... hold your foot on the gear lever (race pattern) and push the kill button to cut the ignition for a moment and the gear changes as the motor drops it's loading. Done.

Next time out I will try that.

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