2 stroke tripple

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RP66
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Joined: Fri Mar 15, 2019 12:44 am

2 stroke tripple

Post by RP66 »

Here we go.
Let me start buy saying I am willing to go down the rabbit hole, but I am going to need some help.

My father and I race high performance snowmobiles, but they require a carb. This keeps us from using a turbo. So the first step is figure out an EFI system.

I'd like to buy a test snowmobile to start with.
My questions on that are as follows.

-a lot of snowmobiles use an CDI based off of RPM from the crank. Can I throw this CDI in the trash and start new.

-coils crank puts out an AC voltage used to run the existing coils which get timing from the existing cdi. Can I use existing coils?


-I was going to use a newer throttle body with injectors and tps to match up with the RUSefi what are the parameters.

I know there is a lot more that I need to think about along these lines but anything will help.
I may be a little behind in EFI but with a little help I can find my way.
RP66
Posts: 4
Joined: Fri Mar 15, 2019 12:44 am

Tripple 2-stroke

Post by RP66 »

Let me start by saying I tried to post this already but I think it didn't work.

My name is Michael and my dad and I race high performance snowmobiles. We use nitrous and are running into a wall because 2-strokes with carbs dont play well with turbos. The ultimate goal is to do a turbo, but I'd like to start with the basics.

My preference would be to buy an old tripple Polaris Storm and go from there.
My questions are as follows.
-can I throw the CDI in the trash and primarily use the EFI.
-what parameters are needed for a crank sensor.
-what parameters are needed for a tps & injectors.
-if I can make what I have work how does the EFI map work do I need to purchase anything for this.

A couple of thoughts.
Newer Polaris Snowmobiles utilize throttle bodies that come with an injector and a tps, that interfaces with a EFI. Will I be able to purchase and utilize this items. If so what are the parameters I need to be concerned with?

Disclaimer: my EFI knowledge is low but my electrical knowledge is high. I think I can do this but I think I need some help.

I am at the purchasing stage.
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AndreyB
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Re: 2 stroke tripple

Post by AndreyB »

Please start at https://github.com/rusefi/rusefi_documentation/blob/master/FAQ/how_to_convert_from_carburetor_to_EFI.md

How comfortable are you with fabrication? If we point you at a shaft position sensor would you be able to mount it somewhere close to something moving? I am oversimplifying but what are your fabrication skills really?

How are you wiring skills - are you comfortable soldering or crimping two wires together?

Where are you located by the way?

EFI is relatively easy as long as all the mechanical parts are in place. rusEfi is flexible enough.

One of the issues with rusEfi - Frankenso assembled board in case is about 7 by 7 inches, is that not too big?

Potentially one of the risks - are these injectors "low-Z" or "high-Z", meaning low or high impedance, meaning do you know what year did OEM use them? To the best of my knowledge you are probably fine since probably modern stuff.

Obviously no guaranties of anything, please have a fire extinguisher but hopefully we have a somewhat positive track record here.
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

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RP66
Posts: 4
Joined: Fri Mar 15, 2019 12:44 am

Re: 2 stroke tripple

Post by RP66 »

I am comfortable with doing fab work, if their is something I struggle with my father can help me he is motor builder (porting, boring, compression,...etc). Between the two of us not much we cant do in that field.

I am an electrical engineer so i am okay with electrical but, my career is mainly HV. I did a lot of micro controllers in college. If I dont know it I'll figure it out.

I am in Idaho my dad is in washington.
On FB we go under ruthpower.

The motor already has a crank position sensor but my impression is that it sends a pulse once a revolution (not complicated)
RP66
Posts: 4
Joined: Fri Mar 15, 2019 12:44 am

Re: 2 stroke tripple

Post by RP66 »

Sorry not good at answering all of your questions.
We can work around size of the unit.
Injectors are most likely 04 or newer.
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AndreyB
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Re: 2 stroke tripple

Post by AndreyB »

It sounds like it's worth trying. Please be aware that rusEfi documentation is the weakest point of rusEfi - while the board is documented more nicely https://rusefi.com/wiki/index.php?title=Manual:Hardware_Frankenso_board - the firmware could be a steep learning curve in the beginning. But it sounds like all the code for your setup is already there you would only need to adjust settings accordingly to your setup.
Very limited telepathic abilities - please post logs & tunes where appropriate - http://rusefi.com/s/questions

Always looking for C/C++/Java/PHP developers! Please help us see https://rusefi.com/s/howtocontribute
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