ESE's works engine tuner

[F5 Dave]

Yeah there's a whole industry based around reducing diesil engine braking; slipper clutches, blipper electronics.

Engines aren't brakes!

[bucketracer]

Yeah there's a whole industry based around reducing diesil engine braking; slipper clutches, blipper electronics.

Engines aren't brakes!

Because of the poor gear ratios on the GP's I know TeeZee clutches it on the down changes and slips the clutch going into the corner if the engine has buzzed up and the back is skipping around from the induced engine braking, poor mans slipper clutch I guess.

[Frits Overmars]

i wish my fourstrokes had less engine braking, i hate having to brake, gear down and have the hold the throttle open a touch to stop the rear skipping/locking.

Set the idle rpm above 3,000 rpm.

[F5 Dave]

So just a rambling question while I was out walking & while Frits is online or perhaps I missed him, but why is it that the RSA ex port is canted downward at 30 deg? I can see that it makes p/v packaging easier and perhaps the key is the water cooling of that area is clearer, - so without a powervalve one might have a straighter passage?

Or is it something to do with the opening & closing port when piston near top of port, although I can't see quite how that helps.

Further if I may, I wonder how effective the PV is at racing speeds, ie: is it still tracking after 10,000 and if so does it keep up in the lower gears?, or is it just full open by then, & if so - why bother?

thank you.

[Frits Overmars]

why is it that the RSA ex port is canted downward at 30 deg? I can see that it makes p/v packaging easier and perhaps the key is the water cooling of that area is clearer, - so without a powervalve one might have a straighter passage? Or is it something to do with the opening & closing port when piston near top of port, although I can't see quite how that helps.

The exhaust port isn't canted downward 30°. The flange mounting face is canted downward 30° but the roof of the exhaust duct exits the cylinder at 25°.
The reason is that this angle gives the best flow.

I wonder how effective the PV is at racing speeds, ie: is it still tracking after 10,000 and if so does it keep up in the lower gears?

The power valve starts opening at 10,000 rpm and it is fully open at 12,000 rpm. It can keep up with acceleration in any gear. And when you blip the throttle in neutral, the power valve servomotor moves almost as quickly as the revcounter needle.

[F5 Dave]

Ah, yes I casually glanced at the drawing but I see that the roof is a bit off. 25 deg gives best flow; I can accept that but I'll still have to ponder why that is.

ok PV action quick-as & effective at race revs. Nice. I'm too used to road & dirt stuff.

Thanks for the reply.

[wobbly]

As a side point to what Frits was saying re 25* down angle giving the best flow.This also reduces the duct area by the cosine of the exit angle,thus reducing the duct
volume.
And this then also allows steps and transitions in the flange to promote the flow exiting the Aux Ex ports,helping blowdown efficiency.
The main handbrake at the limits of power production.
The flow exiting into the duct, just as the piston cracks open the port,is dropping over a cliff - the piston face.
This is why the down angle helps flow,it is " pointing " the exiting gases toward the duct centre,not keeping it attached, normal to the piston dome.

[F5 Dave]

ok now I'm getting brain damage, but I was looking at the port floor shape.

[edit] Ahh see what you are saying about the piston & what I was pondering in original post.

I think I need to go on another walk.

[husaberg]

Yeah there's a whole industry based around reducing diesil engine braking; slipper clutches, blipper electronics.

Engines aren't brakes!

Yeah but i am not after full on compression braking just the character.
Although as i doubt it will be that much of a problem as the 2 stroke has no where near as much reciprocating mass friction and a shorter pause between the compression strokes so i kind of sincerely doubt it will behave exactly as a four stroke does anyway.

I Mentioned the VP of HRC and the NR500
The NR500 had something i believe was the first use of something that all the Moto gp bikes, i think now have, Virtual choc fish for anyone who can guess what it was?
ps it is not carbon or USD forks or Valves cams etc either
Hint it is to do with the fact it had virtually no flywheel effect.
It failed, but a least they tried to do it as an even match 500cc vs 500cc

The first use of a slipper clutch i am aware of is the Honda NR500.
Allegedly if you were to shut the throttle it would just lock up. After a while the riders got kind gf sick of falling off it.
So they persuaded the engineers to sort out a solution or have a go at riding it themselves. This was the question no one got right a while back, or not bothered to answer if they knew.


splitters

It is interesting look what he says the effect is i guess what you are looking for in a round about sort of way?
I have also looked at these with a bit of suspicion esp as the Mikuni and Keihin aren't exactly rushing to fit them.
so are they just another bolt on goodie.

The carb spltter allows the air flow to be smooth, drawing into the carburettor without turbulence and with a much higher pressure accross the fuel nozzle.
The splitter mainly improves Throttle response and off idle to midrange power, but you can run out farther on top after leaning out the main jet.
Re-jetting will be required to maximize performance but often the main jet can be dropped as the fuel atomization is greatly increased..

Heck check out his price i hope it is four all four of them!!!!

http://www.suzuki-rg500.com/carb.htm

It would be pretty easy to test and make a spiltter and a factory squad with the unlimited resources such as Team ESE should be able to whip one up over smoko?
Other two are out of interest one is a needle jet rg500 and other is how to do a air bleed mod to a TMX.


http://homepage.mac.com/rg500delta/d...bleed_mod.html

http://www.bdkraceeng.co.uk/RGV500 Conversions.html

Below is a nice little air box made for RG500 very Aprilia looking

[TZ350]

Those are some pretty interesting ideas Husaburg has posted, in due course I will try them.



I think I may have made a mistake in my previous post, the realy good 150mj low end drive (blue line) may have been when the Ex opened 80deg ATDC and now its 78.5 (red line) so not quite apples with apples and the later 80 deg opening probably accounts for some of the good low end and 78.5 the loss. Anyway I tried a 150 main again with a bigger air correction drilling and it was hopless but things got going when I went to a 135.



135 main jet and air correction drilled out to 1.45, nice consistant results.



the 135mj improved the bottom end but I could not get the bigger main jet with air correction (blue line) to give as much top end as the old 112mj did.

The graph does have a little better bottom end so it looks like playing with the main jet and air correction can pay off, maybe if I fiddle with the air correction to lean out the top a little more.

If you are generous and take the very extremes of the torqe curve it looks like its a good 4,000rpm power spread, 30+ hp and 4k power spread, now that has to be good.

[Ocean1]

i wish my fourstrokes had less engine braking, i hate having to brake, gear down and have the hold the throttle open a touch to stop the rear skipping/locking.

Yeah there's a whole industry based around reducing diesil engine braking; slipper clutches, blipper electronics.

Engines aren't brakes!

I like engine braking. The 1125 has a very clever vacuum-actuated arangement controling the main clutch, progressively slipping it. Very cute. I hate it, it's one of the features I miss from the XB12. You could just roll off the throttle, tip it in and the back would step out a tad. It was very predictable, reasonably self correcting and seemed to keep the bike stable.

But then, I wasn't stomping it down 3 gears for corners...

[quallman1234]

Rotary Valve 4 strokes...

http://www.coatesengine.com/csrv-system.html

[husaberg]

The progress of jet engine development overtook that of the Crecy and replaced the need for this engine. As a result the project was cancelled in December 1945 at which point only six complete examples had been built, however an additional eight V-twins were built during the project. Crecy s/n 10 achieved 1,798 horsepower (1,341 kW) on 21 December 1944 which after adjustment for the inclusion of an exhaust turbine would have equated to 2,500 horsepower (1,900 kW).^[11] Subsequent single-cylinder tests^[12] achieved the equivalent of 5,000 brake horsepower (3,700 kW) for the complete engine. By June 1945 a total of 1,060 hours had been run on the V12 engines with a further 8,600 hours of testing on the V-twins.^[13] The fate of the six Crecy engines remains unknown.

Seen this i was actually looking for the areo engine that ran a rotary sleeve valve kind of like a cup shaped spinning disk it was a ww2 engine and came across this.
better than a Crecy?. Certainly less moving parts.

Oh yeah it mentioned the planes that had in in WW2 not the design i was looking for though.

Little history of the Sleeve Valve Engine The basic design of the sliding or sleeve valve engine has been around since 1909 when English Daimler used it in their 1909 automobile models. Other companies like Voisin, Stearns-Knight and Willys-Knight also incorporated this engine technology. The Bristol Engine Company's Centaurus, sleeve valve, 18-cylinder two-row design radial aircraft engine delivered over 3,000 hp! This engine was used in some of the Blackburn Firebrand, Hawker Tempest, Hawker Sea Fury, Vickers Wellington, Supermarine and Vickers Warwick RAF fighter aircraft in WWII. The Napier Sabre 24-cylinder sleeve valve aircraft engine used in some of the Hawker Typhoon and Tempest during WWII developed over 3,500 horsepower!

http://www.rcgroups.com/forums/showthread.php?t=567998

Rotary Valve 4 strokes...

http://www.coatesengine.com/csrv-system.html

I remember reading about a guy who though he had solved the problems of the overheating or top end seizing ,or if they are lubricated adequatly to stop those both. Oil burning.
The guy was an Aussie he had one running on a i think Honda 125 and a old Pommy banger.
As it was never seen again i guess not. He had a lot of piston rings arranged around the sphere i think.

It was however able to run a much higher comp ratio than a poppet valve motor. 15;1 on pump fuel or so. It was also ment to be ecomical and quiet.So with modern ceramics and so forth who Knows
the first time i saw the pic on the link you posted was about 93 in a car mag.So i guess devolpment has been slow.

[dinamik2t]

Guys, just want to add a way of measuring axial port angles.

What is needed is a pair of these (angle measuring-protractor):
http://cgi.ebay.com/ws/eBayISAPI.dll...ht_1665wt_1270
Unfortunately one must be modified..


The long ruler must be shortened to about 5-6mm from one side and 10-11mm from the other. In this particular one, I cut the semi-circular angle plate base too, because it was too wide to fit into my 54mm bore.



The straight side of the semi-circular plate -if cut- must remain parallel to the original straight line, because it will be used as the vertical plane for measurements. Like this:



Finally, after you determine which side (short or long) to use in the port roof/floor and you tighten the screw, you can measure the angle like this:



As a tip, you can tighten the screw frow the start and carefully apply pressure to the protractor until it is aligned with the duct.

In this measurements most attention has to be paid when aligning the ruler side to the port roof. If that's done perfectly right the instrument can provide easily one degree accuracy.

That's it!



ps Ah, excuse the logo, I used the photos in our local forum too..

[Frits Overmars]

No need to buy two angle protractors and mess up one of them. One protractor, two metal strips and a bolt with a spring washer work just as well.