858 rkt dyno hp

[polarisblue]

Has anyone ever put a 858 rkt on a dyno to get some real hp numbers? I have a 858 rkt in my 14 swb assault and it doesn't seem as strong as my 11 swb assault with par head, porting,slp pipe, and longrod kit, that made 170 hp on D&Ds dyno.We are only at 1800 ft .We do lake racing and are always clutching and tuning.Just wanted some input from you guys out west because you guys are more familiar with these big bores and really put these motors to the test.

 

[Merlin]

Has anyone ever put a 858 rkt on a dyno to get some real hp numbers? I have a 858 rkt in my 14 swb assault and it doesn't seem as strong as my 11 swb assault with par head, porting,slp pipe, and longrod kit, that made 170 hp on D&Ds dyno.We are only at 1800 ft .We do lake racing and are always clutching and tuning.Just wanted some input from you guys out west because you guys are more familiar with these big bores and really put these motors to the test.

Interesting.......

Not sure whether you did the porting on the L/R engine yourself but it looks like you would have about the same amount of money invested into into each package. Is that accurate?

How are you controlling the fuel on both set-ups?


FYI, forum member Jkinzer has been running the RK Tek 858 this season with success(see below). You may want to contact him for details.


http://www.snowest.com/forum/showthread.php?t=366034

http://www.snowest.com/forum/showthread.php?t=364186

 

[mountainhorse]

Polarisblue... can you post up some photos of your RKT 858 installation?

Sounds like you had a strong running 2011... nice.

When did you install the kit?

Have you been working with RKT on this?

Kinzer and VOHK has been having good results with the kits... maybe something is "off" in your sled or your install.

Where are you riding (lake racing?)... how much time have you spent refining your fuel map? What gas are you running? What compression? What does the piston wash look like?
LOTs of variables that will affect how she runs.








.

 

[rydningen]

I ran a long rod slp single with PAR head and a pcv before my 858. It ran very good, and so far I have not been able to get it setup correctly so I can not say anything about a comparison.

But a shop here in Norway has done some changes to the setup, both intakewise and to the exhaust to make it work(will not elaborate on this) and they got right under 170hp on tjeyre dyno. I am waiting for some components to match the setup they ran, will have nore to report then

 

[tinkerjohnson]

858

There are two different rkt 858s out there one is a rev 1 and the other is a rev 2 if it's a prior to 14 season kit it's probably a rev 1 if it's new this season probably a rev 2 I believe there is some power difference between the two

 

[rydningen]

You are right, this was the rev2 kit with the shim.

 

[polarisblue]

Thanks for getting back to me. Im really having a hard time getting the right map. I have tried 6 or 7 different maps and all it wants to do is det or take timing away. I have tried to add fuel on top (8000-8150) but no luck. Im wondering if anyone has a pcv map for a 858 at low elevation. Bikeman map doesn't work at all nor does anything from slp. I know its supposed to rev 8300-8500 , but it pulls timing and dets around 8100. Its a 2014 swb assault, I think it will go if I can get the fuel right so I can tune the rest of the sled.

858 rkt
pcv
13.1 head
91 octane gas
non ethanol mode
stock pipe

 

[diamonddave]

Need more octane...

 

[4Z]

Need more octane...

X2

Plus, TPS calibration is key as well. Have heard of some pretty goofy things happening with some of them. I would calibrate and re-calibrate (check often) to make sure it is solid.

$.02

 

[turbo pro]

i have never dyno a 858.but I have another pro that made 182 on the dyno and the 858 that I have is dead evan with it and maybe alittle faster and I have gone from both back and forth

 

[tinkerjohnson]

Thanks for getting back to me. Im really having a hard time getting the right map. I have tried 6 or 7 different maps and all it wants to do is det or take timing away. I have tried to add fuel on top (8000-8150) but no luck. Im wondering if anyone has a pcv map for a 858 at low elevation. Bikeman map doesn't work at all nor does anything from slp. I know its supposed to rev 8300-8500 , but it pulls timing and dets around 8100. Its a 2014 swb assault, I think it will go if I can get the fuel right so I can tune the rest of the sled.

858 rkt
pcv
13.1 head
91 octane gas
non ethanol mode
stock pipe

I would get a boonie box instead of the PVC then you can tune it right there on the mtn plus he has good starting numbers for this already

 

[polarisblue]

I would like to think someone out there would have a pcv map that would get me close.Again im at 2000ft in northern NY. Im sure there isnt many rkt 858 around here...but if I dont have any luck finding a pcv map I will have to spend another 400$ on a boondocker.Thanks again for responding to my post you guys!!!

 

[2XM3]

You are not going to run 13-1 compression at that elevation on 91 pump garbage fuel, period. Even our slp stage 4 at 7500 feet requires a mix to not pull timing and det light. I would really try 50% race gas and start again on the fuel map. Then wean it off the race fuel until it just barely pulls timing, then give it a few % more

You can never get the fuel map correct if you are "over the line" into mild detonation, the sled is just trying to save itself by pulling timing.

 

[jeepin270]

I would like to think someone out there would have a pcv map that would get me close.Again im at 2000ft in northern NY. Im sure there isnt many rkt 858 around here...but if I dont have any luck finding a pcv map I will have to spend another 400$ on a boondocker.Thanks again for responding to my post you guys!!!

You could buy the wideband with lcd then you can make fuel changes without having laptop. Plus datalog to fine tune a map. Or since you already live in N.Y. why dont you take your sled down to dynotechresearch and tune it on dynojet?

 

[polarisblue]

858 rkt

The sled ran a little better today , I added some more fuel from 8000 to 8300 it ran 111 mph on the gun but it still has det issues. Yesterday it ran 108 mph its still a work in progress though. The bad thing is a Etec 800 (mod) ran 116 mph so I still have lots of work to do. I have noticed engine temp. is very touchy with this kit more so than others I have had.

 

[mrquick68]

They are right. You are too low in elevation to run that motor and head on 91.

 

[3beans]

I run a par 12-1 head and I have det at 1000ft with 91oct so if you listen to what others have allready mentioned and run some race gas or atleast a good booster I'm sure you will see better results!!!!!!!!!!!!!

 

[2XM3]

Its running hot because your adding fuel and its pulling timing in a vain attempt to bandaid the detonation, you cannot "tune" the detonation out of this

 

[sledhead Ed]

2xm3 Is right. I never been able to run any of my polaris big bores or my customers with more than 12.1-12.5 compression ratio depending on pipe combo on 91 oct. without adding race gas. Just letting you what I have run into. I run 1000-3500ft.

 

[mountainhorse]

Have you talked to RK on the phone about this??

Best to talk to the supplier most of the time.





.