crf450R, crf450X, or WR450F

[mscwu]

our engine guy now has problems regarding which engine to choose. r version of crf has efi without electric start which is against the rule i assume? x version of crf has e start but we have to put efi system on it . with regard to wr450, no efi except the new 2012 version? i have seen teams running CRFs or WRs. any advice? we can't judge if adding an efi system is easier than adding a electric starter or it's actually another way around.

any comments?

[Ben K]

Don't forget the LTR450!

Ben

[AxelRipper]

Also don't leave out the TRX 450er. Its pretty close to the CRF with a bigger starter.

Being on our 3rd of the 5 engines mentioned in this thread I can say there are benefits and problems with each one. Depends on what your budget and tuning skill is.

[Mbirt]

I'm the engine guy that's dealt with 3 of the 5 above. I wouldn't even consider trying to add electric start to a kicker motor. Spend your time designing a good intake and calibrating the EFI instead of designing custom components for an e-start retrofit. Those custom parts, by the way, could cost you an endurance restart and finish. The same goes for the stock starters and starter clutches, which have proven to lack reliability in the FSAE realm (GFR FSUK 2011 endurance restart failure is among many other examples).

The LT-R450, YFZ450R/X, and 2012 WR450f are great choices because they have factory EFI. If your ECU supports the trigger pattern (Yamaha is 12-1), you shouldn't have to crack open the engine until it needs servicing. You would be the envy of many teams in that case.

Of the choices discussed so far, the LT-R will make the most power without ever opening the motor: http://ltr450.theatvchannel.co...x.php?showtopic=7079 (http://ltr450.theatvchannel.com/invision/index.php?showtopic=7079). The Yamahas and Hondas need cam changes to equal the output of the uncorked LT-R.

Can anyone give input on the various KTM offerings? I find their naming conventions confusing, but the motors seem to hold their own.

[Drew Price]

Cal State Northridge switched to one of the big bore KTM's this year, a 570 or 580 - I haven't heard positive things.

I own a KTM motorcross bike, and parts are generally quite expensive (usually around double what my buddies pay for comparable parts for their Japanese bikes) and usually have to be special ordered. Seems like not much stock stays in the US, a lot of my stuff has had to come from Austria, but I have kind of a weird model.

Can't comment on reliability, but I know there have been other teams recently using the big KTM 4-strokes.

Definitely agree it's not worth the effort to adapt electric start to a kick-only engine.

BUT - the rules don't say the car has to have electric start - they say that the driver must be able to start the car while seated and wearing all safety equipment.

[B Lewis @ PE Engine Management]

I am partial to the Yamaha YFZ450R motors. They are factory fuel injected, have a starter, light and very durable. We have a bunch of GNCC riders on that quad with stock wiring and sensors using our ECU. We even worked on a bored, alcohol injected one for Pike's Peak. That bike is in the May issue of Dirt Wheels magazine. I would also second the concern of trying to add a reliable starting system to a motor that doesn't have one. That little experiment will add hours and hours of unnecessary time to the project.

[Carrington]

The same goes for the stock starters and starter clutches, which have proven to lack reliability in the FSAE realm (GFR FSUK 2011 endurance restart failure is among many other examples).

While the stock CRF starting system can be temperamental at time, the FSUK restart failure was not due to starting components, but rather a battery issue.

[mscwu]

Originally posted by Mbirt:
I'm the engine guy that's dealt with 3 of the 5 above. I wouldn't even consider trying to add electric start to a kicker motor. Spend your time designing a good intake and calibrating the EFI instead of designing custom components for an e-start retrofit. Those custom parts, by the way, could cost you an endurance restart and finish. The same goes for the stock starters and starter clutches, which have proven to lack reliability in the FSAE realm (GFR FSUK 2011 endurance restart failure is among many other examples).

The LT-R450, YFZ450R/X, and 2012 WR450f are great choices because they have factory EFI. If your ECU supports the trigger pattern (Yamaha is 12-1), you shouldn't have to crack open the engine until it needs servicing. You would be the envy of many teams in that case.

Of the choices discussed so far, the LT-R will make the most power without ever opening the motor: http://ltr450.theatvchannel.co...x.php?showtopic=7079 (http://ltr450.theatvchannel.com/invision/index.php?showtopic=7079). The Yamahas and Hondas need cam changes to equal the output of the uncorked LT-R.

Can anyone give input on the various KTM offerings? I find their naming conventions confusing, but the motors seem to hold their own.

so you guys custom built the EFI system? how long does it take you to design and calibrate it?

[Mbirt]

Originally posted by mscwu:
so you guys custom built the EFI system? how long does it take you to design and calibrate it? We had to do the same things as any team would when implementing a stanadalone ECU on an FSAE car. Starting with a new engine (CRF450X) and a new ECU (Megasquirt 2) in 2008 for 2009 was a big challenge for our small team. We competed in 2009 and 2010 with a carburetor on the car because the EFI setup had not proven itself better in drivability or startability. The Honda thumper/MS3X setup was finally good enough to go to comp in 2011 and was the 4th fastest single after ETS, GFR, and Wisconsin in accel and auto-x at California. The best of "the other half", you could say. In my opinion, it took us 3 years to get the problems ironed out with the engine and ECU combination.

If you make the right decisions early on, the same does not have to be true for your team. The PE-3 (EDGE) and YFZ450R combination is a sure bet for something that will work out of the box (with good intake design). We switched to a MotoTron-based controller from Megasquirt this year in addition to switching from the Honda single to the WR450f. What took 2 years to acheive previously has taken only a few months with the new engine and ECU. I attribute half of the short development time to the ECU and the other half to already having been through this before. The Northwestern guys in this thread might be able to give some input about their switch from Megasquirt to Motec.

[mscwu]

Originally posted by Ben Kolodner:
Don't forget the LTR450!

Ben

is the LTR450 EFI and electric started? Will the 2009 or 2010 model work?

[B Lewis @ PE Engine Management]

Yes, the Suzuki LTR450 (quad) is fuel injected and electric start. As far as I know they were electronic controlled all the way back to 2006. They have a less standard crank tooth pattern (18+1) but we can handle that one as well.

[Drew Price]

Originally posted by mscwu:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Ben Kolodner:
Don't forget the LTR450!

Ben

is the LTR450 EFI and electric started? Will the 2009 or 2010 model work? </div></BLOCKQUOTE>



Keep in mind that when you add the intake restrictor the stock EFI calibration goes out the window.

Probably greater than 90% of teams design and calibrate custom standalone fuel injection systems, or at the very least extensively modify the system as it comes equipped. You may be able to use things like the Power Commander, but I have not heard of any teams who actually had success doing it that way.

[Spetsnazos]

Retrofitting your own electric starter sounds easy on paper until you actually see what is involved. Ask me how I know(no not my great idea)...

From my experience(short), the best single is the one that you can get parts for relatively cheap and doesn't have a common fail part(WR450 starter). Also being able to find one at a decent price is key(preferably 2).

[AxelRipper]

Originally posted by Spetsnazos:
Retrofitting your own electric starter sounds easy on paper until you actually see what is involved. Ask me how I know(no not my great idea)...

From my experience(short), the best single is the one that you can get parts for relatively cheap and doesn't have a common fail part(WR450 starter). Also being able to find one at a decent price is key(preferably 2).

I think they likely all have a common part that fails, especially using them for something they aren't really designed for. You mention WR450 starters. From experience: CRF 450 starters and both CRF and TRX starter clutches. I've heard bad things about the Ape starters. Poor starting calibrations will eat through those things real quick, and they aren't parts that dealerships stock up on. I've also heard horror stories from some alumni "back in the day" about starting systems.

Really, on dirtbikes the weakest system seems to be the starting system. They seem like they're designed as an afterthought, and most riders kick their bikes over rather than using it.

[kcapitano]

BUT - the rules don't say the car has to have electric start - they say that the driver must be able to start the car while seated and wearing all safety equipment.
I don't mean to hijack this thread, but since we're talking about starters does anyone know of a team that has used an engine without electric start? If there was a reliable way to start the car without a starter motor I think that would open up a lot of design choices and possibly higher performance. I've ridden both a YZ250F (kick start) and a CRF250X (electric start) and the difference in engine behaviour is night and day (both bikes were carburated though so EFI could change things quite a bit).

[Mbirt]

Originally posted by kcapitano:
I don't mean to hijack this thread, but since we're talking about starters does anyone know of a team that has used an engine without electric start? If there was a reliable way to start the car without a starter motor I think that would open up a lot of design choices and possibly higher performance. I've ridden both a YZ250F (kick start) and a CRF250X (electric start) and the difference in engine behaviour is night and day (both bikes were carburated though so EFI could change things quite a bit). Michael Royce mentioned Tokyo Denki's first CRF450R-powered car in another thread that I couldn't find after a quick search. They push-started it at the FSAE-A competition because the CRF450X had not yet been released and they had not developed a custom e-start. This is now against the rules.

To compare 250's, you would have to compare the YZ250f to the CRF250R and the WR250f to the CRF250X. It is to be expected that you noticed a gap in performance between the motocross and enduro bikes. The e-start enduro bikes can be modified to meet or exceed the power of the motocross bikes, however. A local builder has his CRF250R making 39 hp at the rear wheel on a build that is not what I would call aggressive. Competitive power can be produced with less weight, less plenum volume, and less fuel consumption than the 450's.

[Francis Gagné]

Originally posted by kcapitano:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> BUT - the rules don't say the car has to have electric start - they say that the driver must be able to start the car while seated and wearing all safety equipment.
I don't mean to hijack this thread, but since we're talking about starters does anyone know of a team that has used an engine without electric start? If there was a reliable way to start the car without a starter motor I think that would open up a lot of design choices and possibly higher performance. I've ridden both a YZ250F (kick start) and a CRF250X (electric start) and the difference in engine behaviour is night and day (both bikes were carburated though so EFI could change things quite a bit). </div></BLOCKQUOTE>

The hybrid team here uses a CRF250R that they retrofitted with a powerdrill engine and custom gear reduction for electric starter. They struggle a bit to get the degearing reliable at first but with small redesign they seem to have it covered and working well. So it is definitely doable if you think the added design team is worth the shot.

[Drew Price]

Hmm. Does it drive off the kick-start shaft, or is one of the cases modified to accommodate the reduction gears?