Supercharging a WR250x - Build thread

[proz07]

Hall sensor (all the info you need is there/on the manufacturers page): http://www.digikey.com/product-detail/en/GS100701/CH398-ND/280932

 

For MAP sensing, no you do not need a cam sensor as long as you are using a missing tooth crank sensor.

 

 

 

Awesome thanks for the hall info.   so i understand using a missing tooth crank sensor you can pull your reading at a certain degree of crank rotation but how does it know which 360 rotation to pull from or does it just take 2 readings during the 720 degree cycle and use the lowest?  I ask because that's also a reason  sequential fuel may not work as it it doesnt know which stroke is the intake stroke. 

 

Z

[aw113sgte]

Awesome thanks for the hall info.   so i understand using a missing tooth crank sensor you can pull your reading at a certain degree of crank rotation but how does it know which 360 rotation to pull from or does it just take 2 readings during the 720 degree cycle and use the lowest?  I ask because that's also a reason  sequential fuel may not work as it it doesnt know which stroke is the intake stroke. 

 

Z

Bingo. Here you can see the map signal in red, then the sample window in white. You can see it hits the lowest MAP point, as well as a fairly high point. This is how it detects the particular rotation for sequential.

[BushPig]

Thanks for the read.... ?     A little "blown" (bad pun, I know) away at this project and your skills to make it happen. 

[Dirtymutt9]

this is really impressive. great build!

[eerk]

Awesome build man, keep us posted

[aw113sgte]

I'm waiting on a new 1:1 ratio pulley to come in so I can play with the varying boost. I'll be using the bypass valve as a pressure regulator or sorts (basically I'll limit it's fully closed position so some boost pressure will be bleeding off at full throttle).

 

I did take some time to weld up a coolant overflow tank as the original one doesn't fit. The new air filter/intake is in the way.

 

 

 

My time is also being taken up with my new toy, 690 KTM Duke. This thing is a riot, love it so far!

[aw113sgte]

Put the coolant catch tank on and reinstalled all the plastics. Afterwards, took the bike out to go relax and do some fishing.

 

 

[aw113sgte]

I finally got the 1:1 ratio pulley in (26 teeth on both engine and supercharger). While it muted the peaks a little, it still follows the same general profile of the other pulley. Also interesting, in the black scatter plot, you can see 3 different groupings. This is from upping the boost for 3 different runs. The MAP profiles follow the same curve. I was also changing the phasing of the supercharger to the engine and noticed no variation in MAP values. 

I'm not sure where I'll go from here. I'm thinking I will just up the peak boost to the 6-8 PSI range and call it good. I am only seeing fluctuation on the sensor but can't feel it on the bike and the PW stays consistent. Basically it's an anomaly, but not one that seems to make a difference in how the bike rides.

 

 

[dfurr2fiddy]

So does it pull pretty hard? Probably ain't got nothing on that 690 though haha

[LazyWaffleman]

Very cool project, not sure it would be possible, but Ive read in car applications having the throttle body pre inlet of the supercharger helps with throttle response and to not blow open the throttle. 

Are you running a IAT sensor or just using the wide band senor to tune? Methanol would cool the intake temperature but cars use it in their trunk, but I can see the room restrictions. 

Impressive project you have. 

[aw113sgte]

So does it pull pretty hard? Probably ain't got nothing on that 690 though haha

Well it will power wheelie first gear and it didn't before. I haven't dynoed it and there isn't a bike dyno nearby either. Yeah it can't compare to that 690 at 70hp and tons more torque, at least not with it's low boost level.

 

Very cool project, not sure it would be possible, but Ive read in car applications having the throttle body pre inlet of the supercharger helps with throttle response and to not blow open the throttle. 

Are you running a IAT sensor or just using the wide band senor to tune? Methanol would cool the intake temperature but cars use it in their trunk, but I can see the room restrictions. 

Impressive project you have. 

For best throttle response you want the TB close to the engine. Mine is in the stock position to keep good throttle response. I am also running a bypass valve so the TB doesn't see boost when off throttle. The dual TB setup is common on Miatas to keep good throttle response with a TB in the stock location but one before the supercharger to lessen the need for a bypass valve, and also keep the noise level down.

[aw113sgte]

Finally had a little time to work on the bike again. Since the power pulse of the engine was being a bit rough on the belt drive, I moved to a larger pitch(5mm to 8mm) belt with way more strength. I still didn't like the shock loads so I made a cush drive to mount on the supercharger. I haven't gotten a chance to try it out yet as I'm waiting on a special nut to affix it. Here is a SolidWorks print of it:

 

Edited July 4, 2015 by aw113sgte

[EnglertRacing]

do we get to see a full throttle pull video??

[aw113sgte]

do we get to see a full throttle pull video??

I'm try to get one tomorrow! I hope I can get the dash in view with the Contour. Not a videographer, not sure how to make it that enjoyable of a video.

 

So the shore 40A urethane didn't work out, wasn't strong enough. I have some shore 60 and 80 as well so next is the 60 and if that fails I'll go the the 80 (that is getting pretty hard though). I've been surprised just how severe the shock load from the crank is.

 

Shore 40A urethane failure is below. I also added a tensioner bracket so the belt is held in tension much more reliably. Before it was just held with a rotation arm, so if the bolt loosened, tension would be lost. Now there is an adjusting bar that prevents this.

 

 

I also lost the nut holding the assembly on, thankfully the pulley stayed on. I added some flats (carefully as to not upset the balance of the cush drive) so I could tighten the nut without having to use a crappy strap wrench. I will do safety wiring the new one as well.

 

 

The pulley with set screws installed. I'll be reversing the set screws so if one ever shears off I will still have the hex drive to aid removal.

 

The nut was originally a lug nut for offroad wheels. Only thing I could find that had 14x1.5 threads in a decent length. I really didn't want to try to tap threads that large in high strength steel so I wanted off the shelf. It's still modified with a hole for safety wire, cut off excess hex length, and faced the end.

 

Edited July 18, 2015 by aw113sgte

[aw113sgte]

Took a decent ride today with lots of throttle variation. Basically I wanted to stress test the system. So here are some "fun" results:

 

Temp outside: 82 deg F

Max air intake temp: 144 deg F (after a long 6th gear pull)

Max Coolant temp: 208 deg F

Max speed: 88.9 mph GPS verified.

Max boost: 152.3kPa (7.58 PSI) at 5986 RPM 

Average boost from 3600 RPM to 11000 RPM: 5.3PSI

Max RPM: 11587 RPM

Max timing: 39.3 deg BTDC, about 31BTDC when at max boost

Max injector dutycycle: 85.0%

 

Very happy with all those results. Intake temp isn't too high for a roots so the intercooler seems to be working well. The duty cycle is right where you want it. Boost pressure I'm going to say is good, I don't want to push the engine. Timing is conservative. AFRs all look great. Basically I think I'm done working on the bike now!

 

Videos (finally!)

Idling and some revs (still warming up). If you look close you can see it builds boost in neutral ?

 

This one is of a longer ride. Unfortunately I haven't used this camera on this helmet before and the video isn't wide angle enough to capture both the road and the dash.

 

To avoid the boring stuff:

Full throttle through the gears: 6:40

Full throttle through the gears: 7:50

Some twisties: 17:10

Full throttle through the gears: 20:20

Lame stoppie 21:28

Take off from stop 21:45

 

A couple final photos:

 

Edited July 18, 2015 by aw113sgte

[aw113sgte]

I might consider selling it now that's it's complete. Maybe a trade for something else cool. I hardly have time to ride anymore with a kid and another in the wife's oven. The KTM690 takes my free time now.

[coryf89]

thats insane, thats some serious skills there.

 

just curious... what do you normally do for work?

 

and what would you ask for that bike if you were to sell it?

[EnglertRacing]

I might consider selling it now that's it's complete. Maybe a trade for something else cool. I hardly have time to ride anymore with a kid and another in the wife's oven. The KTM690 takes my free time now.

 

 

so does the 690 get a turbocharger?  ?

[jjktmrider]

Where here in Wisconsin are you ? Some of your pics appear to be scrub oak trees from south western area like LaCrosse.There was a black turbo'ed WR250 for sale in Marshfield last summer that looked pretty nice and tempting. I might need some info on setting up the Microsquirt and injectors. I'm putting dual WR t-bodies on a XT600 and using the Microsquirt to trigger both of them at the same time. Will use oem cdi for ignition though. Hard to find specs on what injector flow rates and which ones fit in which t-bodies ect... Might have to buy yours as an example ???? Was wanting to turbo one of my XT's , never considered a supercharger.

Edited July 19, 2015 by jjktmrider

[aw113sgte]

thats insane, thats some serious skills there.

 

just curious... what do you normally do for work?

 

and what would you ask for that bike if you were to sell it?

Well before I became a stay at home dad, I worked as a R&D design engineer. I'd probably sell the bike for around $4k, depending on extras. I have the dirt setup and studded ice tires. I wouldn't mind having a dirtbike either.

 

so does the 690 get a turbocharger?  ?

Haha, nope. It's already in a highly tuned state, it's also on a fly by wire throttle which makes turboing with a standalone difficult. I love it's instant throttle response too and I'd loose some with a turbo.

 

Where here in Wisconsin are you ? Some of your pics appear to be scrub oak trees from south western area like LaCrosse.There was a black turbo'ed WR250 for sale in Marshfield last summer that looked pretty nice and tempting. I might need some info on setting up the Microsquirt and injectors. I'm putting dual WR t-bodies on a XT600 and using the Microsquirt to trigger both of them at the same time. Will use oem cdi for ignition though. Hard to find specs on what injector flow rates and which ones fit in which t-bodies ect... Might have to buy yours as an example ???? Was wanting to turbo one of my XT's , never considered a supercharger.

 

If you really guessed my location from the foliage I'm damn impressed. Yes, in La Crosse ? I'd be happy to help with any questions you have on setting up the Microsquirt. It took a lot of looking to find a long nose high flow injector. Most guys replace the long nose injectors with short ones but I thought that was a terrible way of doing it as the spray would hit the wall where the injector sits. 

 

Using the stock CDI will make things way easier. Fuel is pretty simple in comparison.

 

Mine is definitely a project bike. With how many things have been changed and the complexity it's a bike for a tinkerer ?