EFI Sled engine

[minibajaman]

So if I were to get a four stroke EFI sled engine like from a Phazer or the Weber from Polaris, does the EFI need to be remapped to run optimally in warm weather or will it just automatically adjust everything to run fine? *It seems to me that the computer would be programmed for winter conditions, and that while it will change the settings enough to run in warm weather it might not be ideal. *Or does it not matter with EFI, since after all road cars run in both really warm and cold conditions with no changes needed. *Maybe I'm just overthinking this.

Also I'm trying to get a list of all the 4 stroke sled engines available. *So far I have:

Yamaha - everything newer - Phazer, Apex, Nytro, RS Vector, etc
Polaris - sleds using Weber 750
Arctic Cat - sleds with Suzuki 660 engine

any others?

[nutnbolt2002]

Rotax has a 4 stroke sled engine

http://www.rotax.com/en/Engine/2004/Sno ... Models.htm

[absorka]

Not really sure on your questions regarding re-mapping of the ECU's, but I thought I would pass along that the Pol 750 FST (4 stroke turbo) did have some issues in the 05 or 06 years. *If you search for Polaris forums on Google, you should find a few.

I thought they were really cool sleds and have seen a few tuned up that run like a rapped ape, but there was quite abit of negative press on them for *while.

The Yammi's are pretty bomb proof and I ride with a few guys that have turbo'ed them, the RX-1 and 3cyl Vector and they flat scream and are still pretty reliable. *The early RX-1's are pretty cheap and carbed if thats what your are looking for. *I have seen whole sleds for around $4k with really low miles. *As well, there is a ton of aftermarket goodies for these as compared to the others.

Good luck.

[K-fab]

The Apex engine that Jay had in one of his Coyotes was pretty much dropped into the chassis and run. * I drove it in Feb - mid 80's - in the Dunes and it didn't miss a beat. *He'd not done anything other than a different exhaust system (I believe it's a copy of the stocker, to a point - redone to fit in the car). *I can't recall what he did for the airbox.

It didn't appear to need any sort of re-mapping.

I'll let you know about the Phazer fairly soon.

[Bugpac]

do they have a onboard mapping system, like o2 sensors etc? cars are designed to map themselves, seems like 90% of the bike motors do not...Doubtfull a snow engine will...

[PilotHawK]

I got to ride in that car...wicked fast, and soaked up most everything amazing well.

[Bugpac]

a snow engine would generally run leaner in the winter than summer correct? modify exhaust and open the airbox and a rich motor gets leaner, maybe he just lucked out and got it pretty close? kfab, does you rx1 fuely conversion have an o2 sensor or any sort of mapping capabilitys?

[PilotHawK]

Any engine with run leaner in the winter than the summer if there is no compensation for the changes in air temperature. This is related to a phenomenon known as air density. There are gauges you can buy to measure it. Most EFI systems have some way of measuring that air density and then compensate by increasing or decreasing the amount of fuel required for optimal combustion.

[Bugpac]

Only for air density then correct? as the gixxer 600 if you were to do an air box mod and exhaust would run lean, it has to be remapped manually...

[K-fab]

No O2 sensor, but it has ambient air temp, both inside and outside the airbox and it also has air density sensors both in and outside the box. *The system is off of an R1 bike, so I would believe it to be quite similar to the Gixxer setup. *I'm still learning about EFI - it's my first time to mess with the stuff.

The mapping in the old Dez is off right now - I have a Power Commander attached to it - can make changes on the fly (pretty amazing how much it can be modified with the push of a few buttons). *I do have a K&N fuel/air ratio meter that will get installed when I get back to working on the old Dez - will make mapping the system much easier.

I don't know about the Apex that Jay's using or the new Phazer engines - many sensors, but I've not really sat down and started going through the leads and how they're marked yet. *Spent the day working on one of the new Lites, but not messing w/the engine yet.