MTNTK Performance 2019 Turbo Launch

You guys reprogram the ECU or use a piggyback

chinese turbo i assume? for a $3k kit

Sounds like a pvc

Can’t wait to get mine on the snow! Great work guys!


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That turbo is too small for an 800 class engine to run well. At least offer an upgrade. That turbo was selected for price. The turbine mass flow rate capacity does not match to the mass flow rate potential of the motor.

Way to screw up a thread by adding a retarded large photo.

Making claims without evidence is boondickers game. Hope your not follow suit.

Now can you please edit that pic so this thread is actually useful

Can everyone else feel the turbo love on Snowest?

Snowest Turbo thread history:
- "Turbos are too much!" They get cheaper. "They are junk."
- "No piggyback controllers!" Done. "Can't tune, this sucks."
- "Release them sooner." Done. "Shouldn't have released so soon...bugs in the tune."
- "Too many parts." Kits get simplified (minus intercooler and minus controller). "Need more parts so I can tune everyday and go from 4 PSI on pump gas to 12PSI race gas."
- "Pump gas turbos will never work." They work. "They don't make enough power."
- "These turbo companies don't respond and suck." They respond to a thread. "You are lying."

$3k for a pretty clean looking turbo system with a Garrett. VERY COOL!

I wouldn’t buy another MTNTK.... they can’t pull stink off a fart!!

jim said:

Can everyone else feel the turbo love on Snowest?

Snowest Turbo thread history:
- "Turbos are too much!" They get cheaper. "They are junk."
- "No piggyback controllers!" Done. "Can't tune, this sucks."
- "Release them sooner." Done. "Shouldn't have released so soon...bugs in the tune."
- "Too many parts." Kits get simplified (minus intercooler and minus controller). "Need more parts so I can tune everyday and go from 4 PSI on pump gas to 12PSI race gas."
- "Pump gas turbos will never work." They work. "They don't make enough power."
- "These turbo companies don't respond and suck." They respond to a thread. "You are lying."

$3k for a pretty clean looking turbo system with a Garrett. VERY COOL!

Click to expand...

I agree.

But your still adding weight

xpturbo600 said:

That turbo is too small for an 800 class engine to run well. At least offer an upgrade. That turbo was selected for price. The turbine mass flow rate capacity does not match to the mass flow rate potential of the motor.

Click to expand...

Im not gonna disagree with you but i think they have done testing on it. if it doesnt run they wouldnt release it.

I appreciate your position. May I clarify. I did not say it would not run. I said it would not run well. It will be limited by back pressure and the extra heat will directly into the piston, decreasing longevity. This was a problem in the 90s. Guys melted a lot of piston until sleds were fitted with larger turbos. Ask brad story, bryce kendrick, or steve packer (some of the original turbo sled pioneers...there are more).

2 strokes are like rotary motors. They generate a lot of air flow. For example, my 1049 (4 stroke) viper motor generates the same flow volume as my 600. They both generate ~170 cfm at max rpm. The difference is my 2 stroke takes only a sample of the air mass passing through the motor and my viper captures ~95%. 2 strokes waste air into the pipe, but the volume of flow is still there. So what happens?

Most people think I need a 250 hp turbo to meet my goal. That is false. You need a turbo that flows significantly more because of the volume and mass of air passing through a 2 stroke engine. Therefore, using a smaller turbo does 2 things: 1 increases back pressure and piston temp per pound of boost, and 2. It demands a lot more shaft speed to meet the air demand of the motor heating the charge per pound of boost.

This hurts performance because it significantly reduces the pressure differential across the motor. What does that mean? Think about the weather... wind happens between a high pressure front to a point of low pressure. This is why fluid dynamics law states that flow can ONLY happen between two points of differing pressure. If you take away the differential, flow stops.

What does this mean for your motor? An increase in the flow of air mass increases hp. A decrease, decreases hp. Assuming nothing changes but an increase in backpressure (smaller turbo and manifold absolute pressure remains constant), hp decreases because the pressure differential decreases. This impacts 4 strokes by a significant portion, 2 strokes are even worse since they rely on air velocity coming out of the port to run efficiently. As a result, you require more boost to increase the differential more.

Next, you can make an engine run on a turbo that is too small. But, you will get worse mileage and performance because you will be expending more fuel to cool your pistons, the turbo will be way out of the efficiency range, and you may end up knock limited from heat, requiring more race fuel if you like more power. Otherwise, your option is to limit boost. But, why spend that kind of money if your only looking for a big bore kit increase in power.

Sorry if this is too much, but I am an engineer; and, I see this mistake made quite often. If you want better spool, there are other ways to get it. Finally, I sincerely posted this to help educate unsuspecting people who do not have the expertise. Please do not assume I am trying to be rude or argumentative. Happy sledding!

Interesting points XP. Yes, will be curious to see how these systems perform. I'd expect they will be super responsive and quick spooling with monster mid and would expect they fall a bit flat on top compared to bigger turbos. I was curious regarding what you talked about so looked up the turbo flow specs on Garrett site. I compared this 2554 to the historically more typical 2860 Garrett you see on PG set-ups. The 2554 hits max flow at a pressure ratio of 2.00 and flows about 13 lbs/min past that (flattens). The 2860, as you are stating, flows more and ranges from 14-19 lbs/min at a pressure ratio of 2.50 (curve flattens). One can assume for the 2554 that anything past the 2.0 ratio is basically building heat...because it's not building more flow. The 2860 flattens out at 2.5...so it can stand more pressure differential before the curve flattens, which is, in my mind, building heat.

So, to me, the key will be for this turbo to be tuned and optimized to run at a 2.0 pressure ratio and stay there. As above, this to me would mean a lower flowing turbo running less boost. But this may very well work great for the pump gas situation where you only want 5 PSI and the peak power is made at something like 7900 rpms (this is a guess). Could be a really cool boondocking set-up. The throttle response should be instant and the mid power huge. Should be an arm jerker turbo set-up. Will it out-pull a 2860 on a big pull? Shouldn't. Will it make more HP? Nope. But the on/off throttle situations that most like to ride all day should be pretty dang fun...should shift the power curve left pretty good. Will be curious to see how it does.

As for fueling and detonation aspects and comparing to early gen turbo sleds. No comparison. I'm sure they can work around the detonation and/or hot piston stuff of earlier days. The ability to fuel these new gen turbos can't be compared to the early days. Interesting stuff. Fun to watch.

jim said:

Interesting points XP. Yes, will be curious to see how these systems perform. I'd expect they will be super responsive and quick spooling with monster mid and would expect they fall a bit flat on top compared to bigger turbos. I was curious regarding what you talked about so looked up the turbo flow specs on Garrett site. I compared this 2554 to the historically more typical 2860 Garrett you see on PG set-ups. The 2554 hits max flow at a pressure ratio of 2.00 and flows about 13 lbs/min past that (flattens). The 2860, as you are stating, flows more and ranges from 14-19 lbs/min at a pressure ratio of 2.50 (curve flattens). One can assume for the 2554 that anything past the 2.0 ratio is basically building heat...because it's not building more flow. The 2860 flattens out at 2.5...so it can stand more pressure differential before the curve flattens, which is, in my mind, building heat.



So, to me, the key will be for this turbo to be tuned and optimized to run at a 2.0 pressure ratio and stay there. As above, this to me would mean a lower flowing turbo running less boost. But this may very well work great for the pump gas situation where you only want 5 PSI and the peak power is made at something like 7900 rpms (this is a guess). Could be a really cool boondocking set-up. The throttle response should be instant and the mid power huge. Should be an arm jerker turbo set-up. Will it out-pull a 2860 on a big pull? Shouldn't. Will it make more HP? Nope. But the on/off throttle situations that most like to ride all day should be pretty dang fun...should shift the power curve left pretty good. Will be curious to see how it does.



As for fueling and detonation aspects and comparing to early gen turbo sleds. No comparison. I'm sure they can work around the detonation and/or hot piston stuff of earlier days. The ability to fuel these new gen turbos can't be compared to the early days. Interesting stuff. Fun to watch.

Click to expand...

This is my hope that it will be the ultimate boondocking weapon


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Thanks for the post jim you raise a good point on the compressor map. However, that is not the area of concern. For an 800 class motor, the 2554r can overspin to supply the air in most cases. Plotting the mass flow points, they all fall on the far right past the efficiency island on the graph from 1.5 up to 2.0 (roughly 6 to 12 psi using Pisa =12).

But that is not the issue as I stated before. The turbine cannot flow what is commanded by the motor. The turbine is rated for 13 lbs/min at 65% efficiency. At 5 psi, the motor will make 17lbs/min with no restriction. To meet the max efficient capacity, the motor is choked to 75% volumetric efficiency. So for sake of argument, let's say you push boost up so the efficiency falls off a a slightly higher flow rate 14 maybe 16 lbs/min at the high end (highly unlikely). At that point your riding a 145 to 166 hp turbo 800 from roughly 6 to 9 psi at elevation. This may feel good compared to an NA motor at elevation, but it is weak compared to what the motor is capable of.

A good back of the napkin on a proper setup at elevation would yield 162 to 191 hp using the same 6 psi and 9 psi boost levels. Just eliminating the back pressure will net 17 to 25 hp across the boost range just because the turbo does not choke flow. I can tell you, I would rather run 2 to 3 psi less boost to make similar hp.

Finally, I did not say the 2860 is my turbo of choice. To me that turbine wheel is smaller than I would like for an 800 motor as well, but it works. The issue is not the compressor wheel. It is the turbine. The efr turbo was a much better turbo for the 800, very nice. However, it costs 2 to 2.5x what a 2554 costs. The simple test is to take an efr mtntk pro and run it against a new 2554 pro at 2 psi less boost. I bet the efr sled performs on par or better in all situations with minimal change in spool. I hope this clarifies what I intended to say in my last post. Unfortunately, I had to get tedious to explain.

I didnt mean that it would run at all. I mean they probably did the testing and it ran fine and didnt burn the piston up. i get the back pressure idea and yes a two stroke flows alot more air. what boost pressure are they running i havent done any research on it? i just have never seen a mtn tek kit that didnt run. i havent seen very many but they all seem to run flawless. i was just surprised when people said they suck.

I am sorry for the distraction in the discussion. I will stop posting. It has not been stated that this kit sucks. I would say the turbo sizing is suboptimal or limiting, hence my turbo upgrade recommendation for those who want more for their money; that is all. Will the sled run, yes, not as well as the prior product. Finally, this is a lot of cost and hassle for this amount of hp unless you ride at really high elevations and another option cannot fit the bill for less money.

MTNTK, I hope you chime in here and answer some questions. I'm considering one of these kits for my '18 Mtn Cat.

It's my understanding this is about a 6lb kit. Should be great for the sidehill boondocking, in-and-out of throttle all day.

A friend has a MTNTK high pressure kit on his '18 Axys and it flat pulls it apart! Well running turbo. ( I understand its apples to oranges) Just seems to me these guys have done their homework as well in a very competitive turbo market.

Well bummer they never responded to any of you.. Guess I have no need to call them for a turbo.