ESE's works engine tuner

[Rudex]

Thanks Wobbly and Vortex,

Yes, You are right. I checked in R1 case and cylincer is closed. I read the whole thread and see your spigot sometime ago, great idea.
But , my question if the spigot input and the output are connected with ineer conduit, I cant see in picture. Do you have better pictures of case?.

Best Regards.

The factory deleted the water entry up under the Exhaust duct completely with the R1 , as this means the duct heats all the cold water before it runs over the transfer tops.
The 10B and 10C they added a side water hose to push cold water over the duct top only.
The best solution is to use an extended spigot over the top of the duct with holes pointing back over the transfers , and have 2 x3mm holes up from the case to keep some flow
travelling up to the head.
Thr R2 has my spigot extension within the casting , it just needs the 3mm holes to move water around the duct from the case.
This can also be done to a Vortex , as it has a threaded hole in the cylinder - the CIK have confirmed to me in writing this is legal.

[wobbly]

Yes , there has to be a slot in the casting between the crankcase and the gearbox as water enters at the bottom , travels up to keep gearbox heat away from the crank , then exits out the side
up into the cylinder via the external hose.
I tried to get the factory to change the water flow in the R2 by having the cold water entering as normal at the bottom , then up between the crankcase and gearbox , but then to flow forward
in passages over the main bearings . This cold water would then enter the cylinder up each side of the boost port.
Thus cold water cools the transfers immediately . I proved this worked by boring a hole above the boost port , behind the carb , and putting the water hose around into that.
It looked ugly as fuck , and is of course illegal to race , but added 1 Hp instantly.
This was a step to far for TM to do this homologation as I was still struggling with the R2 update to the ports and pipe designs.
I have not split open an R2 case , as no one has done enough Km for a rebuild yet.

[diesel pig]

Yes , there has to be a slot in the casting between the crankcase and the gearbox as water enters at the bottom , travels up to keep gearbox heat away from the crank , then exits out the side
up into the cylinder via the external hose.
I tried to get the factory to change the water flow in the R2 by having the cold water entering as normal at the bottom , then up between the crankcase and gearbox , but then to flow forward
in passages over the main bearings . This cold water would then enter the cylinder up each side of the boost port.
Thus cold water cools the transfers immediately . I proved this worked by boring a hole above the boost port , behind the carb , and putting the water hose around into that.
It looked ugly as fuck , and is of course illegal to race , but added 1 Hp instantly.
This was a step to far for TM to do this homologation as I was still struggling with the R2 update to the ports and pipe designs.
I have not split open an R2 case , as no one has done enough Km for a rebuild yet.

very interesting, I have a picture with flow lines ( the blue lines ) where I think the water flows based on my understanding of your description the other (brown)lines are where I think based on your other descriptions where barriers to flow would have to be place for the water to follow what I think you had said. If I have not done this right please let me know.

[Rudex]

Yes, I remembered when you tested the idea to put the hose in the front of transfers and You got more power.

Yes, the little slot is there, my question is If under this slot will be another bigger conduit for more flow travelling from bottom to the upper part before to exit in the hose to cylinder.
Checking the homologation files, It seems Modena KK3 and Vortex VTZ are similar.
Modena seems a copy of TM case, very similar. And Vortex with water cooled too is near to TM.
Vortex doesn't has the slot but the conduit is under for sure, and the water flow from the upper space to cylinder with the holes only. Modena has the holes under cylinder and use the hose output to lateral flow to cylinder.

BTW, Rexon motors applies similar concept you exposed, only lack the holes between boost port.

Regards

Yes , there has to be a slot in the casting between the crankcase and the gearbox as water enters at the bottom , travels up to keep gearbox heat away from the crank , then exits out the side
up into the cylinder via the external hose.
I tried to get the factory to change the water flow in the R2 by having the cold water entering as normal at the bottom , then up between the crankcase and gearbox , but then to flow forward
in passages over the main bearings . This cold water would then enter the cylinder up each side of the boost port.
Thus cold water cools the transfers immediately . I proved this worked by boring a hole above the boost port , behind the carb , and putting the water hose around into that.
It looked ugly as fuck , and is of course illegal to race , but added 1 Hp instantly.
This was a step to far for TM to do this homologation as I was still struggling with the R2 update to the ports and pipe designs.
I have not split open an R2 case , as no one has done enough Km for a rebuild yet.

[wobbly]

The best scenario would be to have the cold water going over the main bearings , then up each side of the boost port - but the small trick is to have small 3mm holes under the main Exhaust duct
This works with the extra spigot tube in an R1 as well as the R2 that has the tube cast in .
It is important to keep the Ex duct cool , but not use that heated water on the transfer tops - see the small red arrow I added to the R1 flow diagram..
Even better is having cold water between the bore and the inside transfer radius , that is worth 1 Hp in the RSA , and was done on the BSL500 and the KR3.
The Rexon looks good , but the water cannot " flow " anywhere ",so will simply heat up , not cool the alloy .
Unless they are very clever and have the water entry from the case , each side of the boost port.

[Rudex]

Check the pdf, interesting. Look at spigot entry water cooled and the gasked cylinder base and the exhaust port output.

https://www.rexon-motors.com/wp-cont...on-2019-V1.pdf

https://www.facebook.com/rexonmotors...s?locale=es_LA

The best scenario would be to have the cold water going over the main bearings , then up each side of the boost port - but the small trick is to have small 3mm holes under the main Exhaust duct
This works with the extra spigot tube in an R1 as well as the R2 that has the tube cast in .
It is important to keep the Ex duct cool , but not use that heated water on the transfer tops - see the small red arrow I added to the R1 flow diagram..
Even better is having cold water between the bore and the inside transfer radius , that is worth 1 Hp in the RSA , and was done on the BSL500 and the KR3.
The Rexon looks good , but the water cannot " flow " anywhere ",so will simply heat up , not cool the alloy .
Unless they are very clever and have the water entry from the case , each side of the boost port.

[katinas]

Kawasaki used a similar cooling circulation scheme for KR 500, that envelopes the boost port first . Same with Suzuki RG/XR 500.

[Flettner]

Just feed it E85 and cool everything from the inside.

[Flettner]

Not this one because its air cooled.
By having two smaller exhaust ports, with extensive water cooling atound the ports and a heavily cooled bridge area, has to be better at keeping 'exhaust charge' cooler?

How much work has been done on twin port exhaust with water cooling, modern transfer layout and up to date exhaust design?

If we are in fact after maximim blowdown time / area.

[SwePatrick]

So,,,
Sorry to disturb your discussion, but i had a big success today and want to share it =)



Ok,, back to your discussion =)

[Pursang]

So,,,
Sorry to disturb your discussion, but i had a big success today and want to share it =)

No need to be sorry..thanks for sharing!

[Flettner]

So, the limiting factor for the twostroke ( loop scavenge) is blowdown time / area, ultimately? Run out of time / area to let the gas pressure out.
So if we could magic up some more area, would it give us more time, i.e. hold max BMEP to a higher rpm?
Would we leave ports at 195 and 130 respectively?

[Frits Overmars]

So, the limiting factor for the twostroke ( loop scavenge) is blowdown time / area, ultimately? Run out of time / area to let the gas pressure out. So if we could magic up some more area, would it give us more time, i.e. hold max BMEP to a higher rpm?
Would we leave ports at 195 and 130 respectively?

I came to the same conclusion some time (40 years) ago which resulted in my FOS symmetric scavenging system.
Here is a picture that you may have seen in another forum a while ago Neil.

[Javier Ruda]

Hi wobbly, can I have your advice about EGT?

I added an EGT probe but now I realise that it is not that easy to understand what to do with that information, even after reading all your good writings on the subject.

The engine is a Rotax 122 (Aprilia RS125 motorbike) and EGT topped 600 ºC (1112 ºF) and remained constant after >1km pull.

Would it be correct to downjet 1 size and check if the EGT goes ~55 ºF (~30 ºC) higher?

Technical data:
• Unleaded fuel pump 98 octane
• Compression ratio 13.5:1
• Squish gap 0.9 mm on toroidal head
• Ignition timing 15º at 11000 rpm, 6º at 12000 rpm then flat line

[wobbly]

Your method is on the money , but the devil is in the details.
Temp rise from a jet change depends on the area delta , and history tells us you simply cannot rely on factory quality control for mass produced jet sizes.
If you are prepared to bet your motors health on a stamped number - you have to pin size all the orifices.
There are several flow/time based checking systems on the net , but I have only checked Dellorto sizes against pins and a Diesel injector rig , and confirmed the same results.
In that case a normal Dellorto change , say 142 down to 140 would give around 20*C , but I have all the measured intermediate odd sizes as well and 142 down to 141 is close to 10*C.

Next pitfall to be aware of is the timing curve.
15* at 11,000 is perfect if peak power is at that rpm , but if you are holding close to 12,000 with 6* of timing the egt will continue to rise faster and faster.
This is a self sustaining loop , in that the extra pipe heat makes more power , that creates more heat , that creates more power Ad Infinium.
You then have to add more fuel , not to make power , but simply to prevent egt runaway in the overev region.
This then negatively affects the fueling at 11,000 and you may never see the egt drop - that's why its good practice to flat line the ignition with as much timing as you can,
as soon after peak as you can , commensurate with how much overev you actually use for every gearchange point.

Most racebikes I have tuned will drop to 10* about 1000 rpm past peak then flatline , trying to balance the fine line between overev bandwidth and egt at peak.
Of course a solenoid powerjet changes all that , and can run a longer pipe - then using the switched lean off to extend the rpm.