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Turbo selection, and stuff.

Wheel House Motorsports

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With the season winding down, I am beginning to look to the land of boost. im riding the sled in my sig. I have been plagued with the urge for more power. I see people running the garret GT27RS on quite a few boosted sleds, but I am looking to try one of their GT20 series turbo, they arent huge, but i dont want huge power either, im looking for something that spools super fast, hence the smaller turbo, and solid power at elevation. only want like 180-190 HP.

What kind of boost would i have to run to make these kind of numbers, as i dont wanna go to high, i need to keep it a mix fuel sled.

does a stock fuel pump have enough pressure to run a 5 PSI system?

another question, with the oil cooled turbos, is it possible to just run the oil injector pump as an oil pump for it? and then just run premix? this seems semi-simple and would allow for less underhood clutter, maybe use the factory oil resivoir as the oil tank.
 
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Boyko

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A gt20 would not be a good Idea, you will have a hard time keeping your EGT down and be burning up pistons regardless of the amount of boost. There is a lot of info on this form and the old one. If you are really serious about building a kit the best thing to do is just spend the time and research it. You will end up with a lot of info you never thought of. It is pretty clear cut what has to be done to make a boosted 2-stroke live a long happy life.

Good luck with it and please post some pics when you start fabbing stuff up.
 
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Wheel House Motorsports

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Didnt even think about the smaller turbo being way to toasty, but it makes good sense.

I have been looking around, its just hard so many people are running aftermarket setups, its hard to find good custom information.
 
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It could be done with a small tubo, you would just have to rig up some sort of external wastegate abortion to keep the drive pressure at a resonable level.

You will have to run an electric pump with a boost referenced regulator, you want to keep fuel pressure at least 5psi above boost (so at 5psi boost you need 10psi fuel)

An injection pump will not move enough oil to feed the turbo, you will have to run a 12v pump or someone on here sells a mechanical one to replace the injection pump but its not cheap!

What kind of sled are we talking about here? a 2056 wont push much air, probably end up just blowing hot air...

A rotax 800 will do 210hp @ 8psi @ 8000ft with low comp head and avgas.
 
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Wheel House Motorsports

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I have a rotax 600 thats a re-sleeved to a 755, it is totally rebuilt, like every moving part rebuilt or replaced, like my whole crank. I dont wanna run to much boost, as this motor is already pumping plenty more power than it used to be.

I found a pretty good deal on a GT2871RS with the 63 trim in it, what is the CPI turbo kit have in it? these ones have the built in wastegate set at 7 PSI which is exactly what i want. i will get really low comp domes so i can run this down to 3000ft with 50/50 91 and avgas or racefuel.
 
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Boyko

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I have a rotax 600 thats a re-sleeved to a 755, it is totally rebuilt, like every moving part rebuilt or replaced, like my whole crank. I dont wanna run to much boost, as this motor is already pumping plenty more power than it used to be.

I found a pretty good deal on a GT2871RS with the 63 trim in it, what is the CPI turbo kit have in it? these ones have the built in wastegate set at 7 PSI which is exactly what i want. i will get really low comp domes so i can run this down to 3000ft with 50/50 91 and avgas or racefuel.


The .64 A/R (63 trim?) on the exhaust would be to tight. The norm for the GT28 series turbo on a 2-stroke 600-800cc is the bigger .86 turbine housing. Personally I would not run a turbo on a modified 2-stroke unless I was confident that the blow down & port timing was not overly extended and parts were always readily available.

Most of the kits I have build have ended up costing quite a bit of time and money. (I do have a whole wack of extra parts though). Chances are after you are done you will want to redo the whole system.

It is getting to be the end of the season and might consider looking for a used turbo sled, It could end up being cheaper by the time you get every thing together.
 
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The CPI kit uses a mitsubishi TD05H (12g i think... cant remember for sure now...)

Like said above, watch the turbine housing size. You dont want a housing too small or you will end up with high drive pressures (bad for the turbo) and even worse, you will be putting more heat into the pipe and motor. In the end = walking home!!
 
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