ESE's works engine tuner

[jfn2]

"That HEAD-program should behave now. It was not initially meant to stand-alone; it was part of a bunch of programs that I am planning to make available to you guys, but that will still take some testing."

Now that is GREAT news!

[wobbly]

If the geometry is calculated correctly there is no need to produce a radiused squish to follow the piston at all.
Here is a 50% squish on a 66 piston with only a tiny amount of divergence using a simple straight cut.

Also a pic of the special CPI cylinders I had cast for Charletts new 400 Superlight, brought them home in my bag from Vegas.
The first oval ports they have done.

[WilDun]

If the geometry is calculated correctly there is no need to produce a radiused squish to follow the piston at all.
Here is a 50% squish on a 66 piston with only a tiny amount of divergence using a simple straight cut.

Is there a reason for the piston crown (squish area) to have a curve at all?

[wobbly]

No reason at all.
Most all the Italian 125 race engines have a conical dome shape ( 4* or 7* ) , so the squish could match perfectly.
VHM make a flat top with a radius on the timing edge that makes more power,but I believe the perfect setup would be the radius combined
with a conical the same width as the squish, then a flat top.
This may not in fact be the best for a KZ engine , as I found that a flat top is only superior when combined with a proper toroidal chamber, and this cant be done
in this class due to the way the compression cc is checked,simply filling to the top plug surface.

But in any other engine I would bet a few dollars that the radius/conical/flat top/toroidal hybrid would show the best result overall.
The SwissAuto/Pulse engine had sort of this setup using a stock radiused RS125 dome, but the non squish area of the piston was machined flat, as did the BSL500
that had a straight conic squish and a flat top with a toroidal.

Flat top pistons are technically strictly speaking not as strong under the compression UDL, but if the tune is wrong and the dome collapses a little, then that piston immediately traps the ring.
A flat top will collapse a little, but then doesnt trap the ring,causing a DNF.

[Haufen]

Wobbly, what do you say about the "bimotion type" squish band, taking the area the gases have to pass through into consideration?

point 3 lower column red and blue line
further explanation in 3.1

in this link here

Sounds reasonable to me from a theory point of view.

[wobbly]

I totally disagree with a diverging squish gap.
There are three considerations.

1st. Is the trapped end gas volume.This is minimized with a parallel squish gap.
A diverging angle has greater volume so contradicts that rules requirement.

2nd. The gap at the chamber edge sets the squish velocity number, not that at the bore face.So a diverging squish angle has less effective velocity.
This effect is only useful if having a low MSV is what is needed to reduce chamber turbulence ( as is the case with a straight line ignition, and we threw those in the rubbish a century ago ).

3rd. One of the main reasons for having a minimal squish height ( determined by the mechanical limit of the piston contacting the head ) is to keep the piston cooled as much as possible
by the heads boundary layer close to the water cooled squish band.
A tapered squish doesn't conform to this rule either.

I have no way of confirming the theory, but I know of a couple of very clever 2T engineers that have access to all the equipment and CFD software, and they are
adamant the squish rotation is in the opposite direction to that shown.
But aside from that the theory of a thick boundary layer in the corner of a " bathtub " chamber coincides with the dyno work of Jan Thiel at Aprilia using a domed piston.

It could also be one reason a proper toroidal chamber works so well, as it too would have an area of high boundary layer thickness in its chamber roof.
Despite technically having greater surface area over a bathtub or a simple spherical chamber shape.

One last point now that I have seen the old dumb - arse idea brought up again, is that having " slots " in the squish-band, straight, radial or whatever, contradicts all of the above rules.
This CAUSES detonation, and where has ANYONE published a back to back dyno comparison to show ANY positive effect from this idea that may seem clever, but simply is not.

[Muciek]

Wobbly what kind of gains do You expect to get from those cylinders compared to the last 400 cc bike You build (96hp aprilia chassis)?

[peewee]

If the geometry is calculated correctly there is no need to produce a radiused squish to follow the piston at all.
Here is a 50% squish on a 66 piston with only a tiny amount of divergence using a simple straight cut.

Also a pic of the special CPI cylinders I had cast for Charletts new 400 Superlight, brought them home in my bag from Vegas.
The first oval ports they have done.

the gap may be a bit excessive right now but once I cut the width down to 13mm (50%) then ill have nearly a parallel gap or close enough I guess anyways. outer 1.35mm/ middle 1.33mm / inner 1.47mm. rather than fooling with a radius band maybe it would be better if I just try to get the band down to 50% and get the comp ratio alittle lower and try it

the cylinders look nice. I hope its just a small batch for yourself and close friends. other wise every tom dick and harry banshee tuner will likely end up with a set and surely claim the idea as their own . hek I would even be becareful posting photos. its one thing to copy a idea for personal use but a lot of them guys have shops and use copied ideas to make money.

hey while I think of it, did you do anything different at the front of A , so you could get more of a rsa type of aux shape ? I always wondered if the square A and square aux were something that could be improved or not. either way good luck and let us know how they go. if my frankerstien yami twin cylinders turn out like piss I may need to try some of yours

[wobbly]

Maybe the new Superlight 400 will crack 100RWHp but I am not looking for ( or need ) more peak power, but just wanting to add to the front side
for acceleration.
The cylinders were cast off special cores made for me from my CAD files, so no one else has access to the changes, and for example the bottom of the Aux port cores were hand scraped
enabling enlarging to the ideal teardrop shape by hand grinding before plating.
This was also extended to enlarging the water jacket sides so I can grind the Aux ducts right up to the flange like an Aprilia.
Lastly the curved powervalve slots will be CNC cut here, so even CPI cant simple copy this technology for others.

[Grumph]

Also a pic of the special CPI cylinders I had cast for Charletts new 400 Superlight, brought them home in my bag from Vegas.
The first oval ports they have done.

No welding to leak on those ones ? Lucky Dennis.....

[F5 Dave]

Still have to be sound after machining. So CPI are still going sans Calvin?

Just restarting my 496. Found the pvs weren't playing to the same tune the servo pulley was.

[wobbly]

Yep, CPI is now being run by Calvins wife.
I had endless arguments with Calvin over 2T theory, so things were a bit strained sometimes, but he was an absolute casting maestro.
His wife and her new tech/shop team are more than amenable to making my changes, and I was
real lucky to be able to piggyback onto an order of 20 stock Cheetah cylinders for another big USA customer.
These new castings are porosity free, the machined bore looks like its chromed already, plus the area in the Ex port that was prone to leaks is now 5mm thicker - so I dont see any issues there.

I have subsequently " fixed " the weld leaking problem with the pre 82 TZ400, but that doesnt reduce the piss off from the Sheene meeting.
Dennis smoked them ( and pre 89 ) in practice and easily won the first heat, so he was super gutted about the reliability issue,but I am even more pissed
as my bikes have easily won that title 4 years in a row.

[Sketchy_Racer]

Maybe the new Superlight 400 will crack 100RWHp but I am not looking for ( or need ) more peak power, but just wanting add to the front side
for acceleration.
The cylinders were cast off special cores made for me from my CAD files, so no one else has access to the changes, and for example the bottom of the Aux port cores were hand scraped
enabling enlarging to the ideal teardrop shape by hand grinding before plating.
This was also extended to enlarging the water jacket sides so I can grind the Aux ducts right up to the flange like an Aprilia.
Lastly the curved powervalve slots will be CNC cut here, so even CPI cant simple copy this technology for others.

100whp in a 130 something kg bike that is setup well will smash not only F3 lap records, but also threaten F2 lap records. I know for a fact that a 1:08.5 is possible around Manfeild with 100hp in a 165kg bike and a 1:07.5 with 115hp and 160kg

Keeping in mind that the current lap record is 1:12.0 for F3 at manfeild it's going to be fuckin awesome to watch!!

[EssexNick]

Sorry to drag this thread back to earlier posts (342 on), but it looks to me like an oil cooler for the gearbox. Would the reduction of transmission losses justify the added complexity/weight/increased load on the engine?
I'm thinking of buckets at this point.

[husaberg]

Sorry to drag this thread back to earlier posts (342 on), but it looks to me like an oil cooler for the gearbox. Would the reduction of transmission losses justify the added complexity/weight/increased load on the engine?
I'm thinking of buckets at this point.

http://www.kiwibiker.co.nz/forums/sh...post1130173462
It could be but it only appeared on that model?
All the others have some plain alloy electronic looking box (not the PGM though)
Also the lines appeared to lead to it as well as the text.
Further pics and test o one here
http://www.kiwibiker.co.nz/forums/al...id=4837&page=7
Regardless it was a dead end as it was to slow in responding and getting back up to temp.