ESE's works engine tuner

[Condyn]

Thank you for the explanation. It matches what I am seeing. My customer sent me his datalog Which seemed strange to me because there was random downward spikes in the rpm logs which mostly occurred late in the races, or at the end of a long straightaway. His wash was non existent but the transfer windows/ducts looked somewhat wet. The plugs look like they have flecks of aluminum on them, but it must be microscopic damage because the pistons look undamaged, unless the flecks are coming from the ring grove ( which I have not asked for a photo of ) where it is getting pounded by the ring.

[wobbly]

A normal ring has a bright shiny bottom surface from being pressed down and moved back and forth into the Exhaust port.
That ring has serious deto, the bottom ring groove face will be torn up.
The EGT dropping at the end of the straights is a sure and obvious sign deto is occurring.
Kart datalog gauges have warning lights to show just under the max achievable EGT value and prevent damage.

[porttiming124]

Question for Wayne. You already said that on a 2-cylinder engine with a Y-pipe, you cut the piston skirt on the exhaust side so that the exhaust port remains slightly open when the piston is at top dead center. Is this a fragile area? If I run tests on the dyno, can I go to 1mm per step? How many millimeters did you leave the port open when you were finished? Do you remember, to give me an idea please?
Thank you .

[wobbly]

The initial engine was a " stock " SeaDoo 951, this had the skirt 3mm above the port floor.
This created havoc with the tuning of the pumpers, that were already severely reverse jetted at about 2 1/2 B - 1/4 T.
That wasnt possible with the cut skirts, and the needles ended up near closer together.
It was near on 4 boat lengths faster to the first buoy, and won a title at Havasu.

Another cheat on that engine was a clear ceramic coating on the piston crown and combustion chamber, inboard of the squish area.
The tech officer commented that it was no wonder we had won so easily, as the squish was shinny metal, and inside that was real burnt black - and no one else had that clearly defined pattern.
I said " yea I tuned it near death ", which was close to the truth.

Later we did a stroked/big bore open class SeaDoo at 1140cc with twin pipes and fuel injection - the cut skirts did not work in that scenario.

[lodgernz]

A normal ring has a bright shiny bottom surface from being pressed down and moved back and forth

That's what Epstein said

[wobbly]

That's what Epstein said

.

Reminds me of a visit to the doctor where I told him my anus was painful - he said where exactly, my reply was around the entrance.
He said as long as you keep calling it an entrance , it will keep on being painful.

[lodgernz]

.

Reminds me of a visit to the doctor where I told him my anus was painful - he said where exactly, my reply was around the entrance.
He said as long as you keep calling it an entrance , it will keep on being painful.

Almost wet myself larfing!

[wobbly]

For more information there is this unwanted but apparently thoughtful Xmas gift. Free to anyone wanting to bone up on the subject. Very in depth.

[porttiming124]

The initial engine was a " stock " SeaDoo 951, this had the skirt 3mm above the port floor.
This created havoc with the tuning of the pumpers, that were already severely reverse jetted at about 2 1/2 B - 1/4 T.
That wasnt possible with the cut skirts, and the needles ended up near closer together.
It was near on 4 boat lengths faster to the first buoy, and won a title at Havasu.

Another cheat on that engine was a clear ceramic coating on the piston crown and combustion chamber, inboard of the squish area.
The tech officer commented that it was no wonder we had won so easily, as the squish was shinny metal, and inside that was real burnt black - and no one else had that clearly defined pattern.
I said " yea I tuned it near death ", which was close to the truth.

Later we did a stroked/big bore open class SeaDoo at 1140cc with twin pipes and fuel injection - the cut skirts did not work in that scenario.

It couldn't be clearer, thank you Wayne.