RK Tech Drop in Piston Kit compared to PMS Polaris Fix Kit

[tdorval]

I just wanted to see what everyone's' thoughts are now that we have a few more options for potentially better and more reliable top ends for our Pros. I'm not saying the sleds need these, just trying to start a little discussion for people like myself that will be rebuilding for preventative reasons and are considering something other than oem.

I plan on putting a new top end in my 2011 T-Pro for next season and am just starting to weigh the options available. The two big contenders I'm interested in are the RK Tech Drop ins and the PMS polaris Fix kit.

Are there any pros or cons to these kits that should sway my decision. Will one of these work better in a Turbo application? I don't mind that the RK kit has a full head as I can't claim to be stock with a Turbo anyway so that's not a concern. Price is close enough to not worry me if one will be better suited either.

Lets get some discussion rolling and see what everyone thinks.

 

[hostile1]

I think If you have a turbo you might want to call the shops and make sure there pistons don't change port timing to much. I know rkt drop in for zoos change port timing.

 

[tdorval]

I'll look into it. If I remember correctly RK Tek mentioned they offered a turbo head that should work well, and when I last spoke with PMS they said their kit would work great in a turbo but I'm not positive.

Any other thoughts out there?

 

[milehighassassin]

I think the head only changes compression (lowers), the pistons claim to change port timing, although I'm not sure how they do that without changing the base gasket.

 

[RKT]

Comparing these 2 kits is comparing an apple to an orange.. They are VERY different in their objective, approaches, and how they function..

 

[milehighassassin]

Kelsey care to explain how port timing changes with your pistons?



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[TurboMatt]

Comparing these 2 kits is comparing an apple to an orange.. They are VERY different in their objective, approaches, and how they function..

Kelsey care to explain how port timing changes with your pistons?

Kelsey can you please explain why this is such an apples to oranges comparison?

 

[RKT]

Apples to oranges because, OUR kit adds a substantial amount of power and fixes an internal piston issue. Cooling in also increased via the patented head design and the engine is set to run at a different RPM..

I will not get into the other kit because it is not my place.. All I can do is tell you what our kit brings to the table and how it performs. The 2 kits are completely different.

Kelsey

 

[MN_SUMMIT]

Kelsey, I know you already have a lot of questions to answer, but how is R&D going on the 858 kit. I know I will be one of the first in line when this becomes available...

 

[xc6rider]

What RPM does this kit intended to run at now, or where has it been running the best at?

 

[RKT]

858 is doing well.. Thanks for askin.....still dialing in the clutching and fine tuning it.. Very fun engine and making good power.. Just making sure all is as it should be before releasing it..

 

[RKT]

What RPM does this kit intended to run at now, or where has it been running the best at?

Drop in kit runs 8300-8500 rpms.

 

[chunkysoup]

Not a pro question but didnt want to start a whole new thread for this question. Do you have any of your kits in the cfi4 motors yet and what were the results? I know the "fix kit" with PA head has a great track record so far. Just checking other possibilities with new heads. Interested with the increased rpm design but at 0-3000ft. Reliability and longevity are a real concern for any cfi4 owner. Thanks

 

[RKT]

Not a pro question but didnt want to start a whole new thread for this question. Do you have any of your kits in the cfi4 motors yet and what were the results? I know the "fix kit" with PA head has a great track record so far. Just checking other possibilities with new heads. Interested with the increased rpm design but at 0-3000ft. Reliability and longevity are a real concern for any cfi4 owner. Thanks

We have not installed this kit on any CFI-4 engines.. While I am sureit would work fine on that engine as well, We have no plans on buying a Dragon to test it on.

 

[skippy]

Drop in kit runs 8300-8500 rpms.

Kelsey, Isn't 8500 RPM getting very close to tripping the DET light? and if so, clutching will have to be extremely spot on. Do you agree or am I missing something here? Thanks

 

[RKT]

Kelsey, Isn't 8500 RPM getting very close to tripping the DET light? and if so, clutching will have to be extremely spot on. Do you agree or am I missing something here? Thanks

DET light is not related to RPMS.. So, "no"

this kit runs stronger than stock at ALL RPMS!! Much stronger..

But optimum rpms with stock pipe is at 8300-8500 and has no problem getting there and holding it

 

[skippy]

OUR kit adds a substantial amount of power and fixes an internal piston issue. Cooling in also increased via the patented head design ..

Kelsey

How are you determining your substantial Horsepower results? Is it racing/climbing against a stock sled for comparison, and if so is there any video showing the results so we can get an idea of how much better your kit is to justify voiding a pretty good factory warranty for the additional cost of the kit. Serious question. Thanks

 

[skippy]

DET light is not related to RPMS.. So, "no"

Can you explain this a little better? If I have to light of weights in my sled and my RPM hit a certain number(8500 or so) it will throw a Det code on the screen and when I go and add the right weight it won't throw the code. Its a very common problem on the PRO. Mostly in the mid range. Thanks

 

[RKT]

Can you explain this a little better? If I have to light of weights in my sled and my RPM hit a certain number(8500 or so) it will throw a Det code on the screen and when I go and add the right weight it won't throw the code. Its a very common problem on the PRO. Mostly in the mid range. Thanks

Not sure how to have 8500 rpms at midrange.. So, I am a little confused with the question.. Midrange is 6500-7500 rpms.. If you have deto there it is not because you are running 8500 rpms.. We have actually ran this kit at 8600 with success.

 

[chunkysoup]

Where is the rev limiter set? you have to be getting pretty close to it... lol