Twisted Turbo pro Rmk

[product tester]

Our kit is now ready we have 3 complete sleds done and running great.
Only issue that we are dealing with is it keeps breaking the motor mount bolts.
We are working on a fix for that.
we are putting one together tomarrow and will post pics as we go as to show all the quality parts that are offered in our kit.
This will be the sled to out run the cats.

 

[aebsledder]

motor mount bolts

How many have you gone through? I have a STOCK Pro-RMK and broke my motor mount bolt after only 100 miles. Are they backing out or shearing off? Mine were sheared off. I am really worried there is a bad batch of bolts or some sort of manufacturer defect. I was hoping mine was an isolated incident, but apparently not so. I understand that there are different conditions when applied in a turbo application, but it still worries me.

 

[RMK-King]

Could you just replace yours with a higher grade bolt? What grade do they come with factory?

 

[brycter]

glad you got her working.

 

[4Z]

Fix for the motor mount issue

FTX saw this coming I guess. Put one on our Pro.....

FTX motor plate

The all new Pro chassis needed a little help in the motor mounting department when the power levels go beyond stock so we've stepped up and developed the ultimate system for this chassis-introducing the Pro billet motor plate. With 6 total mounts and extremely rigid CNC billet aluminum construction, this baby will hold all the power a CFI twin can make and more!

 

[mountainhorse]

I have a feeling that these motor mount/plate combos from FTX/Power-Addiction will be popular among the boosted crowd!!

 

[Arcteryx]

Could you just replace yours with a higher grade bolt? What grade do they come with factory?

X2^^^^????

I like the motor mount plate from FTX but the price is way to high especially if I can get away with a better quality bolt.

 

[4Z]

X2^^^^????

I like the motor mount plate from FTX but the price is way to high especially if I can get away with a better quality bolt.

A guy spends how much on the whole package? Sled, boost, and the plate is too expensive? Anyway, a stronger bolt isn't the answer, It has to be a system type solution.

 

[Dunatic]

We will soon find out if a stronger bolt isn't the answer...

Is a Titanium bolt stronger than a grade 8 bolt?

 

[mountainhorse]

"Stronger" is a relative term that can apply to many different aspects of a fastener design.
Hardeness or toughness may be better terms here.

Grade 8 bolts would be more similar to a Class 10.9 fastener.

From what I can tell... The Socket Head Cap screws that Polaris is using are a very high grade Metric, Class 12.9 Alloy Steel (self locking)... they have a tensile strength in excess of 170,000 psi with a Rockwell hardness of 35 - 45.... It is a pretty high quality bolt.

The titanium high strength Race fasteners that I have seen used are made from Ti6Al-4VA... it's most attractive property however is its lightweight... it IS strong... but has similar yield and tensile strength to the Class 12.9 Alloy steel. IMO, a Ti replacement fastener of the same dimensions will fail as well.

In my opinion…. to make the stock mounting system stronger... it would be better to use a cap screw with a longer unthreaded section that would insert further into the motor mount strap… or all the way through and Install a Stainless “TIME-SERT” into the far end.

The clamping aspects of this fastener, IMO, are much less important than the locating aspects of this fastener. The bolts do NOT seem to be failing in tension, but in shear.

From what I can tell from others photos (I don’t have a motor mount/strap/cap-screw in my hands) the bolts are failing from impact shear … in the treaded section of the bolt, which is exposed to the shear loads the engine as it tries to rotate, as a unit around the axis of the crank, in the mounts. The treaded section of the bolt starts inside the mount rather than inside the strap. The failures seem to be happening along the grain boundary of the threads at the shear plane… ie the bolt is shearing in the weaker threaded section rather than a stronger unthreaded shoulder section of the bolt.

ARP makes some very high grade Cap Screws with reduced wrenching 12 point heads... their "ARP 300" stainless bolts are very tough, very high quality fasteners with rolled threads and consistent metallurgy. They are rated at 170,000 psi and have a Rockwell hardness of around 45.

Rather than finding a custom fastener, a longer ARP bolt with a longer unthreaded section could be used and the threads could be trimmed at the end. I've used these same type of bolts from ARP to fix the problematic front PTO mount bolt on the turbo 2008-2010 800cfi Dragons. The strap would have have the threaded section bored (partial depth) to accommodate, snugly, the larger diameter of the unthreaded section.

Here is a crude cross-section of what I'm talking about.

Again, this is just my Opinion.

Under the extreme loads of turbos… stronger bolts will not keep the motor from twisting in the sled… that is where the additional mounts in the FTX arrangement will come in handy with the huge twisting loads that a turbo engine can put on the mounting system. Twisting moves the clutches out of alignment… Clutches that are not aligned make more heat, shift poorly and waste power.

Also, under the extreme forces produced by a turbo engine, the plate will help to isolate & stabilize the crankcase from the twisting forces that are not isolated by the two, separate, mounting straps.

I don't think this will be a problem on the non-turbo sleds... but time will tell.

 

[product tester]

Does really good silicone make any sence? as the rubber on these mounts have alot of room (air space in them) I have filled them with silicone and got grade 8 bolts. The mounts feel alot more stable filled with silicone. also going to look at some way of doing some extra mounts.

 

[Arcteryx]

A guy spends how much on the whole package? Sled, boost, and the plate is too expensive? Anyway, a stronger bolt isn't the answer, It has to be a system type solution.

Wasn't trying to disrespect your product, I do want one. But you hit the nail right on the head. New sled, bumper, vents, turbo, hand guards, skid plate, tether, race fuel, Zbroz front end etc etc etc. In my situation I would LOVE one of your mounts. But at this point ponying up for another $650 seems to expensive if I can fix the problem with better bolts. I'm guessing the labor to intall one in runs kinda high. Won't the motor need to come out??
Like I said. I would love one. I think it's a great product and for the guy that can afford them I say do it.

 

[4Z]

Wasn't trying to disrespect your product, I do want one. But you hit the nail right on the head. New sled, bumper, vents, turbo, hand guards, skid plate, tether, race fuel, Zbroz front end etc etc etc. In my situation I would LOVE one of your mounts. But at this point ponying up for another $650 seems to expensive if I can fix the problem with better bolts. I'm guessing the labor to intall one in runs kinda high. Won't the motor need to come out??
Like I said. I would love one. I think it's a great product and for the guy that can afford them I say do it.

Not my plate, just a loyal customer. I feel ya.

 

[FTXMOTORSPORTS]

So I don't get to get on here much and chat in season guys and I apologize-the joys of running a busy sled shop I guess...

the issue here IMO is movement-why do bolts shear? do you honestly think we are applying enough direct shear load even with a turbo to do it? No. BUT, what we are doing is applying a big shear load and letting it amplify through all the movement/elasticity of the OEM mounting arrangement. So instead of diectly whacking the head of the bolt with a 3# hammer, we are whacking it with a 2# hammer while swinging the hammer at the end of a bunje rope!

MH , the buried shoulder idea is very sound and will help-especially if the machining is done so the shoulder and counterbore fit is very snug-it may even be enough for lower power levels to survive in this arrangement.(meaning 20 hp over stock)

Polaris engineers told us straight up that the OEM arrangement is designed for stock power levels only-and we are already seeing the results of that.

We prefer to focus on one longterm permanent fix rather than "stages"-mostly because of the fact that we play this game with 4 brands of sleds which really limits R&D time for several stages of repair on the same problem.

You also still have the issues of clutch misalignment under torque and case flex along with accelerated motor mount degredation from all the excessive/un needed motor mount movement.

Aaaaah, the beauty of a new production model! It will be interesting to dissect one of these after 1500 miles!

Great problem solving guys-seriously, thats the beauty of a forum that is working for its members! Let us know how the bolt upgrades work-we'll do the same.

Curt

 

[product tester]

rode today with just grade 8 bolt in the 1 that broke held up all day ,
theses sleds are wicked and at 8#s it seems to be enough for me but it needs more clutching to go higher boost turned it to 10 and just hit the rev limiter instantly.

 

[whittaker727]

We need some Vid of that thing making boost Shain.

 

[product tester]

Derick got some yesterday on his phone maybe we can get him to post it.

 

[product tester]

Owning one of these sleds is all I can think about. I had grown board with the m series. Not that it is a bad sled just that it hasnt changed and I have been riding it for 6 years. this sled is what I have been looking for in next level riding for me. I am still amazed at how well our turbo has been working on this sled with a total 4 days on the snow. it out performs the cat in every way. its funner to drive it drives smoother and responds cleaner than 80% of the turbos on the market. the coolest thing is that it drives and runs better the harder you drive it. you will get tired long before this turbo does.

 

[Anthony Oberti]

How is the stock rear skid working with the turbo? Weight transfer a problem?

 

[guidoxpress]

Owning one of these sleds is all I can think about. I had grown board with the m series. Not that it is a bad sled just that it hasnt changed and I have been riding it for 6 years. this sled is what I have been looking for in next level riding for me. I am still amazed at how well our turbo has been working on this sled with a total 4 days on the snow. it out performs the cat in every way. its funner to drive it drives smoother and responds cleaner than 80% of the turbos on the market. the coolest thing is that it drives and runs better the harder you drive it. you will get tired long before this turbo does.

WOW, that is a HUGE statement coming from a Turbo guru, and a Cat genius!!

wish i had one