My KTM 500 EXC turbo project
- Thread starter swedenturbo
- Start date
This gonna work pretty well. My big concern is detonation. Running 103 RON with stock compression. With 10 PSI I'm on the limit, I think. Reliability is my big concern. Crank and cluch will hold up. I'm in to unknown teritory. Gonna look on my sparkplug and with a boroscope on my piston to check for detonation. The MCX gen II EFI box and TCV valve will have the benefit of two boost levels. One with pump gas and the other on race gas.
Looking at the dyno graph, power was still climbing significantly when you let out, torque was still flat too. Did you hit a rev limit?
This gonna work pretty well. My big concern is detonation. Running 103 RON with stock compression. With 10 PSI I'm on the limit, I think. Reliability is my big concern. Crank and cluch will hold up. I'm in to unknown teritory. Gonna look on my sparkplug and with a boroscope on my piston to check for detonation. The MCX gen II EFI box and TCV valve will have the benefit of two boost levels. One with pump gas and the other on race gas.
You'll need to retard the ignition with that gas and compression ratio or there'll be a hole in the piston soon enough. For a few hundred dollars why don't you get a custom forged piston made up about 9-1 CR and also a metal head gasket. Its the proper thing to do.
Lots of free turbo and EFI info here on my brothers site http://www.sdsefi.com/
Yes we did.
The RPM axle is maybe showing wrong numbers on the dyno chart.
We had some problem with signals from the OEM fuel injector.
Made a heat chield of 1 mm aluminum
Hopefully I will have a test ride before christmas.
There are a lot of work to do. Most of the mounts, fittings and tubing was temporary for dyno testing
Air intake for snorkle.
Powder coated plenum and intercooler. Flat black.
Plenum mounted
MCX piggyback fuel controller
There are a lot of work to do. Most of the mounts, fittings and tubing was temporary for dyno testing
Air intake for snorkle.
Powder coated plenum and intercooler. Flat black.
Plenum mounted
MCX piggyback fuel controller
First testride!
Have enlarged the wastgate and now I have only 7,3 pounds of boost.
Thats a good starting point and will raise boost after some real testing.
Doesn't matter what gear I have, pulls really good. Hitting the rev limiter all the time
Little video of my first run
Have enlarged the wastgate and now I have only 7,3 pounds of boost.
Thats a good starting point and will raise boost after some real testing.
Doesn't matter what gear I have, pulls really good. Hitting the rev limiter all the time
Little video of my first run
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Second test ride.
Not much snow for some boondocking.
Very pleased by the power an tourqe.
Not much snow for some boondocking.
Very pleased by the power an tourqe.
My KTM turbo works really well. Currently boosting only 7 pounds.
Power seems to be enough and the only problem is that I'm hitting the rev limiter all the time, no matter what gear. Changing sprockets to a higher gear ratio will probably help but I think a bigger track would be the trick .
Running 121" Challenger Trail with 1,75" lugs.
Should I go for a longer track like the 136"x 2,323"?
Will it be front heavy and less nimble and manuverable?
Or keep length 121" and bigger lugs like 2"?
Power seems to be enough and the only problem is that I'm hitting the rev limiter all the time, no matter what gear. Changing sprockets to a higher gear ratio will probably help but I think a bigger track would be the trick .
Running 121" Challenger Trail with 1,75" lugs.
Should I go for a longer track like the 136"x 2,323"?
Will it be front heavy and less nimble and manuverable?
Or keep length 121" and bigger lugs like 2"?
You should switch the gears inside the mountain horse chain case for sure takes a couple min. to swap around the 2 outside sprockets they are a 17 tooth and a 20 tooth here is a spreadsheet of all the different gearing combinations. I did not do this so I am not taking any credit for it but it is pretty helpful. I am running 13-16-17-20 now but I might switch out the engine sprocket for a 14 to get a bit more top end. I think you should start out with the 13-17-20-17.
Your project looks awesome very nice work I should do that to my 500 exc also.
Your project looks awesome very nice work I should do that to my 500 exc also.
Thanks Ryan for the gear ratio calculation spreadsheet .
I see the point in changing the sprockets but I wonder if a longer track is better thing to do, especially in big bore or turbo bikes .
The KTM EXC has a good gearbox ratio on all gears so this will only make my bike go faster on all gears.
Have looked in threads on this forum regarding ST vs LT.
Not many seems to have done some real comparison test.
What are the drawbacks with LT?
I see the point in changing the sprockets but I wonder if a longer track is better thing to do, especially in big bore or turbo bikes .
The KTM EXC has a good gearbox ratio on all gears so this will only make my bike go faster on all gears.
Have looked in threads on this forum regarding ST vs LT.
Not many seems to have done some real comparison test.
What are the drawbacks with LT?
Having owned both a long track and standard track, the only disadantage of the long track is helping your buddies who didn't upgrade this year. The long track is easier on the motor, as you don't have to rev it nearly as much.. It floats obviously better, but also makes the front less likely to plunge, so you get more confidence when jumping it.
The longer version doesn't really have any negative handling aspects which I was surprised by. The turned up rails might be the reason, or just the fact that it's really only a few inches longer doesn't seem to affect handling in a bad way.
I'd say this as well, the new long tracks are easier to push on the ground than the standard kit from last year. The rolling resistance is quite a bit less for some reason.
Jon
The longer version doesn't really have any negative handling aspects which I was surprised by. The turned up rails might be the reason, or just the fact that it's really only a few inches longer doesn't seem to affect handling in a bad way.
I'd say this as well, the new long tracks are easier to push on the ground than the standard kit from last year. The rolling resistance is quite a bit less for some reason.
Jon
Nice photo from last weekend 
B
B-Line Snow Bikes
Banned
More YouTube please?
Small update in this thread about my turbo conversion:
So far, one can summarize that it works beyond expectations and look forward to the coming winter season!
Among the final rounds last spring began pushing coolant. Realised pretty quickly that I had blown the head gasket. In pic below you can clearly see where it failed. A fairly simple error to fix. Need stronger head studs.
While I still had the head off I wanted to take the opportunity to examine the comp reduction was possible.
Original gasket is more than 1 mm. Washers in the photo is 2 mm, and then the timing chain max tensioned without chain tensioner fitted. This gives the comp ratio 10,05:1. The limitation to raise the head is the timing chain length.
Mounted the head. There were two gaskets. Cylinder head gaskets are comprised of three layers. Had to remove one. Otherwise it would have been too thick and the chain is too short. The chain is stretched with the tensioner in the end position.
This fall I disasembled head, piston and cylinder. Sent them to MotoSpeed in Sweden for correct measurement of volume of the combustion chamber. They work with JE pistons who hopefully make a custom made low comp piston. There are at least 8 weeks delivery time so I'm a little late ...
Stock comp ration is 11,8:1 and I will run 10:1. This will also require race fuel but do not want to lose too much bottom end. My goal is to safely boost 10-11,5 psi with race gas or 7-8 psi with pump gas.
Measuring squish
to be continued.....
So far, one can summarize that it works beyond expectations and look forward to the coming winter season!
Among the final rounds last spring began pushing coolant. Realised pretty quickly that I had blown the head gasket. In pic below you can clearly see where it failed. A fairly simple error to fix. Need stronger head studs.
While I still had the head off I wanted to take the opportunity to examine the comp reduction was possible.
Original gasket is more than 1 mm. Washers in the photo is 2 mm, and then the timing chain max tensioned without chain tensioner fitted. This gives the comp ratio 10,05:1. The limitation to raise the head is the timing chain length.
Mounted the head. There were two gaskets. Cylinder head gaskets are comprised of three layers. Had to remove one. Otherwise it would have been too thick and the chain is too short. The chain is stretched with the tensioner in the end position.
This fall I disasembled head, piston and cylinder. Sent them to MotoSpeed in Sweden for correct measurement of volume of the combustion chamber. They work with JE pistons who hopefully make a custom made low comp piston. There are at least 8 weeks delivery time so I'm a little late ...
Stock comp ration is 11,8:1 and I will run 10:1. This will also require race fuel but do not want to lose too much bottom end. My goal is to safely boost 10-11,5 psi with race gas or 7-8 psi with pump gas.
Measuring squish
to be continued.....
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