ESE's works engine tuner

[Henk]

Excellent excuse. I'll start looking for an RS.

[TZ350]

Other links collections can be found on pages 80, 90, 100, 110

From a link posted by Bert
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

Toyota turbo cheat, posted by Koba
http://worldrally.motorsportforum.co...d.php?t=121013

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

IgniTech programmable ignitions for race bikes
For 2-strokes get the SPARKER DC-CDI-P2 race http://www.ignitech.cz/english/aindex.htm because it is has all the bells and whistles

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

24mm carb for 30+ hp go-cart engines
Carb-01 http://www.out2win.com/catalog/images/ibeal5.jpg
Carb-02 http://www.out2win.com/catalog/ibea.html
Carb-03 http://www.j3competition.com/downloa...mologation.pdf

Expansion Chamber Design According to Blair:-
http://members.bellatlantic.net/~vze...es/expcham.htm

We see that the flow bends upwards and forward towards the exhaust port as the cycle proceeds and the piston rises to shut the port.
Abstract taken from http://www.lortim.demon.co.uk/vsih/pistons.htm

Port/Time/Area Jennings page 81-82 http://www.vintagesleds.com/library/...20Handbook.pdf

Two Stroke Tuners Hand-Book http://www.datafan.com/TunersHandboo...efiltered.html

The specs of Avalons Team ESE's BOB Suzuki GP125 20 rwhp engine:

Skim the barrel 1.5mm and “o” ring it, no head gasket, thin alloy spacer plate under the barrel and Suzuki RG250 pipe modified to RM125 specs, KX80 ignition. Raise the exhaust to open 83 deg ATDC, and widen to 70% of the bore, cut 30 deg from the closing point of the rotary disk, so inlet opens 145 BTDC and closes 85 ATDC. Champher the inlet side of the crank at 45 deg to aid inlet flow. Set the mj about 102.5 105 107.5 and ignition timing, 26-28 BTDC using a dyno. A link to Bells book and the RM pipe specs can be found on page 100 of this thread.

Cheep easy effective mods that most anybody can do and get 20 rwhp from a Suzuki GP125.

.

[TZ350]

.

Ilmor Engineering, http://www.ilmor.co.uk/ the British company that came to MotoGP briefly in 2006 and 2007, has now developed a turbocharged, 700cc, three-cylinder, five-stroke petrol engine which might someday be used on a motorcycle.

So Team ESE are not the only ones at the cutting edge of racing motor cycle technolagy.......

.

[SS90]

Other links collections can be found on pages 80, 90, 100, 110



We see that the flow bends upwards and forward towards the exhaust port as the cycle proceeds and the piston rises to shut the port.
Abstract taken from http://www.lortim.demon.co.uk/vsih/pistons.htm


.

I'm just having a look at this link Teezee, and it has some accurate information regarding scavnge patterns, but I just thought that people would be interested in this paragraph.

When a jet of gas penetrates an almost stationary medium, its velocity changes in accordance with Newton's law of momentum. The wave front takes on a mushroom like appearance, and when the overhanging edge curls round and enters the exhaust port then short circuit waste of new gas starts. The short circuit generally starts in earnest about 25o after port open, and continues for the remainder of the port open period. The minimum effective distance between the exhaust port and the transfer port has been determined at 6% of stroke (about 4.5_mm on our 72_mm stroke engines). This is some 50% larger than the rule of thumb passed down from an earlier era. Changing the primary compression ratio, or the main compression ratio, has no measurable effect of the swirl-scavenge action.

The last sentence is incorrect (in my experience), and it's quite important!

Lower primary compression reduces short circuiting dramatically, particularly when running large port area's.

Pretty much everything else they write is on par with my observations of my tests.

[koba]

Hopefully no dickhead will be in my grid position this year and I manage to finish the race this time, its not fun sitting on the infield watching.

19th December 2009

[TZ350]

I'm just having a look at this link Teezee, and it has some accurate information regarding scavnge patterns, but I just thought that people would be interested in this paragraph.
Changing the primary compression ratio, or the main compression ratio, has no measurable effect of the swirl-scavenge action.

Lower primary compression reduces short circuiting dramatically, particularly when running large port area's.

Pretty much everything else they write is on par with my observations of my tests.

...… it seems counter intuitive that changes in the primary compression ratio wouldn't effect the scavenge pattern.

The booklet is in part a re right of Blair’s work, and an account of how they have applied it to their racing engines.

I know, it's Villers Engines But it’s a good effort and I think very informative, it’s worth a careful read. Actually it makes Villers engines and vintage racing look interesting.

Here is a bit about the transfers much like the unmasking you encouraged me to look at earlier.

“The vast majority of the gas to be pumped up the transfer ports comes not from the crankcase but from under the piston as it descends, and the gas has to do a 180 turn to go up the transfers …………………… From this it can be seen that any tuning effort would be wisely directed to the underside of the piston, smoothing out any sharp edges on the gudgeon pin boss and particularly the transfer cutaway, which should accurately match the cylinder cutaways at BDC.”

http://www.lortim.demon.co.uk/vsih/pistons.htm

I couldn’t find a date but it looks to be written in the mid 90’s, what do you think?

[TZ350]

I had a bit more of a look at the web site and found the Villiers Singles Improvements Handbook can be purchased here using Paypal:- http://www.lortim.demon.co.uk/pdfbook.htm

From the induction section of the Villiers Singles Improvements Handbook:-
http://www.lortim.demon.co.uk/vsih/carburat.htm

“To achieve the nominal choke size the following formula should be used.
Nominal choke size (mm) = 0.8 x (swept volume x rpm/1000)^(1/2)
207 cc racing motor at 8500 rpm: 0.8 x (207 x 8.5)^(1/2) = 33.5 mm”

So for my Suzuki GP125 at 11,500 rpm the carburettor choke size required is
=0.8 x sqrt (125 x 11.5)
=0.8 x sqrt (1437.5)
=0.8 x 37.9
=30mm

For 9,000 rpm its 27mm and 10,500 its 29mm and 12,500 its 32mm

So according to the Villers handbook, even at 9,000 rpm the F4 rule of a max 24mm carb for a 125 2-stroke is way to restrictive for good power.

Luckily, like Black Adder I have a cunning plan, a plan so cunning that you could put a tail on it and call it a weasel.

.

[gav]

So according to the Villers handbook, even at 9,000 rpm the F4 rule of a max 24mm carb for a 125 2-stroke is way to restrictive for good power.

Luckily, like Black Adder I have a cunning plan, a plan so cunning that you could put a tail on it and call it a weasel.

.

Umm, so its taken you 120 pages to reach that conclusion then? Hehehe, thats why most go with a 100cc bucket.
Nah good to see your progress, has been very informative, thanks for your efforts!

[bucketracer]

You might not be that far off. I have had a play with the choke size numbers.

8K=25mm choke 12K=32mm choke

8K is 2/3 of 12K so if your using a plenum, and 8K passed air all the time wouldn’t it be able to keep up with the demands of 12K sucking from the plenum for only 2/3 rds of the time?

In other words through the use of a plenum a 24mm carb that’s open all the time could feed a 32mm choke that is only opened by the inlet rotary valve for 2/3 rds of the time and keep it supplied with all the air it can swallow.

I think you might be onto it.

[Buckets4Me]

You might not be that far off. I have had a play with the choke size numbers.

8K=25mm choke 12K=32mm choke

8K is 2/3 of 12K so if your using a plenum, and 8K passed air all the time wouldn’t it be able to keep up with the demands of 12K sucking from the plenum for only 2/3 rds of the time?

In other words through the use of a plenum a 24mm carb that’s open all the time could feed a 32mm choke that is only opened by the inlet rotary valve for 2/3 rds of the time and keep it supplied with all the air it can swallow.

I think you might be onto it.

Ok I get it

32mm choke = 12,000 x 125cc x 2/3 = .........…. 1,000l/m out of the plenum through the 32mm flow tube and into the motor.

25mm choke = 8,000 x 125cc = 1,000l/m x 3/3 = 1,000l/m flow through the smaller carb and into the plenum chamber.

Its all in balance because the 25 is flowing for1/3 longer than the 32

[=cJ=]

Only problem I see is persuading the engine to suck continuously, rather than just when the inlet port's open, though I am guessing this is where the tuning of the plenum comes in?

[Buckets4Me]

or the opening facing forwd
then engine would not have to suck so much as swollow or GULP at taupo

[bucketracer]

then engine would not have to suck so much as swollow

I have allways had a preference myself for engines that suck then swollow

[SS90]

...… it seems counter intuitive that changes in the primary compression ratio wouldn't effect the scavenge pattern.

The booklet is in part a re right of Blair’s work, and an account of how they have applied it to their racing engines.

I know, it's Villers Engines But it’s a good effort and I think very informative, it’s worth a careful read. Actually it makes Villers engines and vintage racing look interesting.

Here is a bit about the transfers much like the unmasking you encouraged me to look at earlier.

“The vast majority of the gas to be pumped up the transfer ports comes not from the crankcase but from under the piston as it descends, and the gas has to do a 180 turn to go up the transfers …………………… From this it can be seen that any tuning effort would be wisely directed to the underside of the piston, smoothing out any sharp edges on the gudgeon pin boss and particularly the transfer cutaway, which should accurately match the cylinder cutaways at BDC.”

http://www.lortim.demon.co.uk/vsih/pistons.htm

I couldn’t find a date but it looks to be written in the mid 90’s, what do you think?

I will download the whole book I think.

From what I have read so far, it seems pretty good, just because it's about Villiers doesn't mean it isn't any good!

The new piston designs that come out still concentrate on just the unmasking ideas we have discussed (some are really expensive), and rather than simply rely on the boost port supplying more fuel via the reeds (in the case of reed induction, which is where the majority of work is happening nowadays), they put alot of effort into ensuring as complete scavenging of under the piston as possible with-out sacrificing reliability .

It seems too that with the higher crankcase volumes benefit more from work in this area (logically).

To dredge up another concept that has been discussed, I just have to agree with sonicV that a new pipe is in order (if anything I would change the baffle cone angles and
lengths , putting up with a "hole" in the midrange to enable you to get a longer peak power curve in the upper RPM.

I have still never seen a 125cc engine with a 24mm carb that puts out more than 22 PS, did you manage to find some power curves for these Kart engines that claim 30PS?

I'm really interested in how this experiment progresses, because if it works I would certainly use your data to start my own experiments.

It's winter now, and I am starting to have some spare time on my hands again!

[F5 Dave]

...… “The vast majority of the gas to be pumped up the transfer ports comes not from the crankcase but from under the piston as it descends, and the gas has to do a 180 turn to go up the transfers ………

So logically it would make sense to reduce the crankcase volume to approach zero & fit as tall piston as possible,

which is largely what those engines did.