My KTM 500 EXC turbo project
- Thread starter swedenturbo
- Start date
That is an awesome set up!! What gearing are you running? I was only able to get a 12t to work on my '12 xc-w so that meant 48 mph top speed at 8500ft! Did you get a 13 and a chain combo? I could not get enough tension.... Grrrrr you will need to with that.
An many know, each bike has its specific internal gear ratio. Dont know if xc-w has the same as EXC?
Currenly running 13-16-17-20. My drive wheels is 8 tooth 2,86".
That geraring works fine for me but others maybe prefer other. 6 th gear is very high on the EXC and is only used when crusing to the playgrounds...
I´m in the process of building a new snowbike kit.
It will look similar as the MH but with EZ-ryde style suspension, movable secondary chaft and many new features. Will post some pics of the build when I'm done.
That will have 136" with 59 mm lugs.
I going to run 7 tooth 2,86" drive wheels.
This kit will probably have different gearing.
Here´s my overview blueprint of the kit
Some parts have arrived
Currenly running 13-16-17-20. My drive wheels is 8 tooth 2,86".
That geraring works fine for me but others maybe prefer other. 6 th gear is very high on the EXC and is only used when crusing to the playgrounds...
I´m in the process of building a new snowbike kit.
It will look similar as the MH but with EZ-ryde style suspension, movable secondary chaft and many new features. Will post some pics of the build when I'm done.
That will have 136" with 59 mm lugs.
I going to run 7 tooth 2,86" drive wheels.
This kit will probably have different gearing.
Here´s my overview blueprint of the kit
Some parts have arrived
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Nice. Have you considered doing a head shim instead of 2 gaskets, 30 or 40 thou with ARP studs should cure that problem, whenever you stack gaskets its just too many layers IMO. MCX should be able to whip that out for you, I'm not sure how thick you can get with the timing chain issue but its another option to look at anyways. Travis at Thumper Racing could do the piston for you, I'm almost positive.
M5
M5
Thanks for all input.
Sorry, my swenglish wasn't clear. My point is when you want to run comp ratio 10:1 and below, head chim is not an option, no matter what kind of gasket or chim you choose. Timing chain is simply too short for that aplication. The only thing to do is to have a custom low comp piston made.
ARP studs is a thing to consider...
Sorry, my swenglish wasn't clear. My point is when you want to run comp ratio 10:1 and below, head chim is not an option, no matter what kind of gasket or chim you choose. Timing chain is simply too short for that aplication. The only thing to do is to have a custom low comp piston made.
ARP studs is a thing to consider...
Not exactly handy but if you are having any trouble sourcing a piston Thumper Racing makes a lot of the big bore kit parts for these bikes, so I'm pretty certain Travis could set you up with a custom piston. Maybe I misread the thread but I was just under the impression you had 2 head gaskets in there so I thought you might be able to do a really thin shim is all. For sure piston is the best option. Keep posting its very interesting.
M5
M5
Have been waiting almost 4 months for delivery of the new custom made 10:1 low kompession pistons.
I was about to give up hope but now they're finally here!
Ordered 3 sets, one for my buddy who also building a turbokit and the final one just for spare.
More parts.
APE heavy duty studs.
Didn't find stronger bols with allen keys as the original bots were.
I will use nuts instead.
TCV valve to electronically raise boost pressure from 0.5 to 0.7 bar.
That will give the options to run on two boost levels.
Could be useful if i run out of race gas. Just flick a switch an run on pump gas.
Installation of the stronger studs
The nuts base were a little too big. Machined them down to 19 mm-
Its a close fit but it seems to work.
Here's a pic from my buddys build.
This kit is made with my templates and some minor improvements
I was about to give up hope but now they're finally here!
Ordered 3 sets, one for my buddy who also building a turbokit and the final one just for spare.
More parts.
APE heavy duty studs.
Didn't find stronger bols with allen keys as the original bots were.
I will use nuts instead.
TCV valve to electronically raise boost pressure from 0.5 to 0.7 bar.
That will give the options to run on two boost levels.
Could be useful if i run out of race gas. Just flick a switch an run on pump gas.
Installation of the stronger studs
The nuts base were a little too big. Machined them down to 19 mm-
Its a close fit but it seems to work.
Here's a pic from my buddys build.
This kit is made with my templates and some minor improvements
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I did'nt order the pistons directly from JE but through a Swedish JE-retailer.
They sent the OEM piston to JE to make some measurements on it before the new pistons were manufactured.
For those of you who are planning to run with lowcomp pistons, prepare that it takes a long time until delivery. At least thats my experience so far.
Jonas has made a hole punch to make an extra hole in the oil filter to get the oil pressure through the lid. Punches from the inside out to minimize the risk of steel chips inside the filter. The option is to drill but then it's almost impossible to know if you got it out all shavings.
Maybe not the best looking man made creation but its faily simple and works well.
They sent the OEM piston to JE to make some measurements on it before the new pistons were manufactured.
For those of you who are planning to run with lowcomp pistons, prepare that it takes a long time until delivery. At least thats my experience so far.
Jonas has made a hole punch to make an extra hole in the oil filter to get the oil pressure through the lid. Punches from the inside out to minimize the risk of steel chips inside the filter. The option is to drill but then it's almost impossible to know if you got it out all shavings.
Maybe not the best looking man made creation but its faily simple and works well.
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Will test a new connection of the oil return from the turbo. Previous design was an adapter to the oil filler cap.
Adapter solution has in itself worked well, but as always you want to refine the details ....
New connection is with a banjo connection in the oil drain hole under the engine sprocket.
A neater solution that at the same time provides a greater height difference between outlet of the turbocharger and the inlet to the engine.
Reduces the risk of oil build-up in the return hose if the bike will stand in sharp uphill.
Here's the final solution. Looks like it's gonna work. Welded to a short tube with a bend on the banjo.
I will make a protection shield so that no back spray from the track will damage the connection. A break here leads guaranteed to engine failure because you hardly have time to detect damage or oil leakage.
Adapter solution has in itself worked well, but as always you want to refine the details ....
New connection is with a banjo connection in the oil drain hole under the engine sprocket.
A neater solution that at the same time provides a greater height difference between outlet of the turbocharger and the inlet to the engine.
Reduces the risk of oil build-up in the return hose if the bike will stand in sharp uphill.
Here's the final solution. Looks like it's gonna work. Welded to a short tube with a bend on the banjo.
I will make a protection shield so that no back spray from the track will damage the connection. A break here leads guaranteed to engine failure because you hardly have time to detect damage or oil leakage.
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Fitted the TCV valve under the right side cover. There it's protected from snow and ice. The valve makes it possible to electronically raise the boost pressure from the mechanical setting of 0.5 bar to the desired pressure. Have preset the EFI box so that the valve opens by 30%, which hopefully will raise the a boost pressure to 0.7 bar.
The electronically controlled boost pressure adjusts to different altitudes.
This means that when the atmospheric pressure decreases, it will compensate for this, increasing the boost pressure and maintain the same horsepower at sea level as well as at high altitude.
Connected an on/off switch or to the TCV, a High / lows witch. Low = about 84 hp, high = approx 96 hp.
Low can be useful if I run out of race gas and have to run on pump gas.
The hoses from the TCV valve are connected to the compressor housing and wastegate actuator.
The electronically controlled boost pressure adjusts to different altitudes.
This means that when the atmospheric pressure decreases, it will compensate for this, increasing the boost pressure and maintain the same horsepower at sea level as well as at high altitude.
Connected an on/off switch or to the TCV, a High / lows witch. Low = about 84 hp, high = approx 96 hp.
Low can be useful if I run out of race gas and have to run on pump gas.
The hoses from the TCV valve are connected to the compressor housing and wastegate actuator.
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Great thread, keeping it coming. It is making me wish I was riding instead of working.
Here you see how the low compression piston crown differs from a OEM piston.
It's pretty impressive that you can remove material from such a thin piston to increase the volume of the combustion chamber.
It's pretty impressive that you can remove material from such a thin piston to increase the volume of the combustion chamber.
See that many are discussing about the turbo placement. Front or rear?
I'm not saying that front mounted is bad but to claim that rear mounted turbo leads to turbo lag is completely wrong. I dont feel any lag!
To describe this in text is of course difficult.
Have made a simple video that shows only the turbo pressure gauge.
The black tape tab is pointing towards 0 atmospheric pressure.
As soon as the needle passes 0 motor delivers more power than stock.
Run deliberately on a high gear and low revs to better show how early the pressure comes.
Unfortunately, very little snow, so there were not very long pulls before it started going too fast.
I'm not saying that front mounted is bad but to claim that rear mounted turbo leads to turbo lag is completely wrong. I dont feel any lag!
To describe this in text is of course difficult.
Have made a simple video that shows only the turbo pressure gauge.
The black tape tab is pointing towards 0 atmospheric pressure.
As soon as the needle passes 0 motor delivers more power than stock.
Run deliberately on a high gear and low revs to better show how early the pressure comes.
Unfortunately, very little snow, so there were not very long pulls before it started going too fast.
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Have had problems with the head gasket that not seals on the turbo build.
The problem is still not solved, despite stronger studs.
You would think that it boils but in fact, pressure of combustion leaks to the cooling system when the gasket doesn't seal between the bore and the cooling channels.
It seems to hold up for a whole winter season. The last trip in mid-May, it began again evacuate water.
Will take everything apart and install a new head gasket. Then run a thorough warmup and tighten, something I didn't do the last time I put it together. Perhaps the lack of re-tightening is part of the problem?
Not quite sure if the problem is due to the studs. Could also simply be due to lack of cooling, maybe both ...
With 70% more power, equal amount of cooling seems to be required.
Volume of coolant system and radiator area is small on dirt bikes. On a turbo system it's perhaps undersized?
The fan on the radiator works but it seems to start too late.
Have found a KTM accessorie with an adjustable thermostatic switch.
With it, you can freely adjust the fan engagement in the range of 65-95C. Simply, you can get the fan to kick in earlier.
Would be nice if you can connect this thermostat to the second cooling fan and run dual fans.
Tunnelcoolers similar to sleds is of course a solution, but to get better cooling with air coolers is easier. Will test this before I take the next step ...
http://www.eurotekktm.com/shop/powerparts/cooling/fans/602-detail
The problem is still not solved, despite stronger studs.
You would think that it boils but in fact, pressure of combustion leaks to the cooling system when the gasket doesn't seal between the bore and the cooling channels.
It seems to hold up for a whole winter season. The last trip in mid-May, it began again evacuate water.
Will take everything apart and install a new head gasket. Then run a thorough warmup and tighten, something I didn't do the last time I put it together. Perhaps the lack of re-tightening is part of the problem?
Not quite sure if the problem is due to the studs. Could also simply be due to lack of cooling, maybe both ...
With 70% more power, equal amount of cooling seems to be required.
Volume of coolant system and radiator area is small on dirt bikes. On a turbo system it's perhaps undersized?
The fan on the radiator works but it seems to start too late.
Have found a KTM accessorie with an adjustable thermostatic switch.
With it, you can freely adjust the fan engagement in the range of 65-95C. Simply, you can get the fan to kick in earlier.
Would be nice if you can connect this thermostat to the second cooling fan and run dual fans.
Tunnelcoolers similar to sleds is of course a solution, but to get better cooling with air coolers is easier. Will test this before I take the next step ...
http://www.eurotekktm.com/shop/powerparts/cooling/fans/602-detail
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Not sure about your auto parts stores but napa stores have a different coolant sensor that turns on at a colder temp. Maybe bring in the stock sensor to an auto parts store and see if they can help.http://m.napaonline.com/parts/PartsDetail.aspx?k=ATM1435033_0317963826
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As the turbocharger requires pressure lubrication, I used previously an oil filter cap from a KTM 690. In the cap the oil out through an angled banjo connection.
Have never been happy with this solution.
It's so badly angeled that the front engine bolt is in the way.
A simple fix was using recessed bolt instead.
This was never an optimal solution.
Have now ridden whith this for two years with this bad solution and finally took the bull by the horns and machined a new better cap.
Now a proper connection!
The intercooler is now mounted with rubber pads to reduce vibration.
(the damaged meshfilter fabric will be replaced)
Have never been happy with this solution.
It's so badly angeled that the front engine bolt is in the way.
A simple fix was using recessed bolt instead.
This was never an optimal solution.
Have now ridden whith this for two years with this bad solution and finally took the bull by the horns and machined a new better cap.
Now a proper connection!
The intercooler is now mounted with rubber pads to reduce vibration.
(the damaged meshfilter fabric will be replaced)
