Custom Turbo Setup - 14 RMK 800

I’ve had the sled for two season now and have been collecting parts the last two years.

So far I have:

Bosch Motorsports 1000cc Injectors drop right into factory harness, and location.
Power Commander PTI - Installed
Power Commander Autotune
V Force Reeds - Installed
K04 Turbo Charger - Looking at turbine and compressor maps it should provide lightning fast spool, and be able to support about 295-325hp depending on efficiency of the intercooler with the turbo running full tilt. Wastegate hat is currently set at 8psi.
Boondocker Oil Tank, and pump.
All the exhaust flanges needed to mate the turbo up.
Adjustable Clutch Weights.
Blue/Pink Primary spring
Larger Pump for the Oil supply line

Brand new top end with:
BMP case spacer
Arctic Cat Wiseco pistons.
All new bearings and seals

Brand new bottom end
New crank and rods, water pump, bearings seals etc.

Things I still need buy:

Some stainless steel tubing for exhaust fab.
Aluminum tubing for intake fab.
Aluminum plate for airbox fab.
Misc. nuts and bolts - Hardware store is a block away.
Fitting for the oil feed line.
A/W or A2A Intercooler and fittings.

Questions:

1) I notice a lot of the kits have some method of securing the charge piping or airbox to the throttle bodies with something other than a silicone couple and t-bolt clamps.

I’ve seen some companies that use a bar that bolts to the jugs, and then to the airbox and others that use a screw on type connector to the throttle body itself.

Is there a reason for this I am not seeing?

2) Blow off valve. From listening to a lot of the kits run, it sounds like they are running a very VERY light spring on the valve itself. I assume this is due to the small amount of vacuum that these sleds pull at idle.

Any idea on what this spring setting is? I’d like to use a blow off valve that I have on hand, and am assuming I’m going to need to order a lighter spring for the valve as it’s coming off a high vacuum 4 stroke setup.

3) Air fuel ratio vs. EGT for engine monitoring purposes.

If you were to run one or the other, what do you guys prefer and why?

4) Air fuel ratios at WOT and 2 strokes.

What target air fuel ratios are you guys using when establishing a safe test tube? I understand there will be a bit more unburned Air fuel mixture coming into the down pipe, and the air fuels I use to tune 4 strokes may be too lean or too rich for a 2 stroke.

5) Timing.

The PTI has full control over ignition timing. As I understand 2 strokes their ignition timing curves are very different than 4 strokes.

Are any of you guys messing around with boost based ignition control, and if so what kind of results are you seeing, and what does a safe timing curve look like on these sleds?

6) Compression.

I have a BMP head at the house, and was kicking around the idea of picking up a set of the low compression turbo domes.

Would you recommend doing so? What are your arguments for or against this?

7) Injector relocation.

I was kicking around the idea of installing the injectors pre-throttle body.

Worth the time and effort?

8) Intercooler

I’m planning on running wastegate spring pressure of 8 psi initially. Which should put the sled around 190-200hp.

Is an intercooler necessary at these boost levels?

Would you recommend running an Air to water or Air to Air setup? Weighing the pros and cons of increased weight vs cooler charge air coming from tunnel cooled water.

9) Voltage Demands

How are you guys running all these additional 12v systems?
Is this putting a significant increase in demand on the stator?
Is it capable of reliably supporting the increased amp draw?

Are any of you supplementing with a small battery? If so where are you mounting it? What size are you you using?

10) Plugs.

What heat range plugs are you running and at what power levels?

11) Cooling

Are any of you adding supplemental cooling systems to keep these sleds alive, or to increase performance?

12) Adding an external wastegate in conjunction with the internal gate.

I have been kicking around the idea of installing an additional external wastegate. Reason being, I have one in the garage collecting dust. I would like to get the sled up and running on a very low boost setup. Think near atmosphereic pressure. Maybe 2-3psi, and start working out the kinks in the system before I start pushing for more power. Thoughts?

13) Limits of the engine.

Once everything is dialed. I’ll have enough injector, and turbo to push some significant power.

Has anyone reached the upper limit of these engines yet? I’m talking about jugs splitting, or crank case halves coming apart.

Where are the weak links?

14) Using the power Commander to power a secondary set of injectors.

Obviously the power Commander has its own injector drivers, and uses the signal from the factory computer, modifies it, and powers the injector driver within the power Commander to power the injectors in the sled.

Is it possible to still have the sled power it’s original injectors, Tap the wires send the signal to the power Commander and have the power Commander drive a set of secondary injectors pre throttle body for boost purposes only?

That way I get stock ridablity with supplemental fuel only when the engine needs it.

Pros and Cons?

15) Axys Pistons.

Getting did of the aftermarket pistons and spaced for a set of Axys pistons. The Axys pistons look like a great design.

Pros and Cons?

Thanks for the read.

I sized the injectors to flow enough fuel to run 300hp at 80% duty cycle without a secondary set of injectors. I was planning on running them in place of the factory injectors.

I selected this specific turbo for quick spool. It’s capable of flowing enough air to produce about 300-330 crank horsepower at 8500 RPM.

However will flow 200-225hp at 8500 RPM at peak efficiency of the turbine and compressor wheels.

The turbo was designed for a 1.8l engine producing 225hp at 6000RPM.

The 800cc 2 stroke has an effective displacement of 1.6l. I ran the air flow calculations for my desired power level, compared compressor maps, and turbine maps, and for my targeted power level of 200hp, the turbo will flow more than adequately, and provide a very quick spool.

Have you spent much time tuning the PCV?

xpturbo600 said:

Two things...

1. Not knowing more about your turbo, it is likely that your turbo is too small since it has small turbine. A 2 stroke is like a rotary motor...they flow a lot of air and they only take a sample of the air flowing through them. A typical 800 flows around 225 cfm on displacment only. That doesnt include air flow wasted into the pipe. Two strokes need low back pressure, so run an external gate.

2. The pcv can be wired to run secondary injectors and that is a great way to go with an autotune. Finally, why do you have 1000cc injectors? You're better of with multiple stages of smaller injectors. There is a science to injector selection i cannot get into here, but large injectors are not always a better option.

Click to expand...

The turbo i selected will flow 321 CFM at 9 PSI.

This is the biggest K series turbo they made.