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XP big bores - lets compare

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D
Nov 26, 2007
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Innisfail, Alberta
ps... are you a pirate? Looks like you have a peg leg in that pic " Arrrrggg where's me snobunge... again"?

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LOL
 
T
May 25, 2008
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Oroville Washington
That might work well...really well!! John, can you post something in regards with how the port timing and configuration has changed through the years from the old 800 to the 800 ho to the 800r?? Transfer and Exhaust port heights??

I am interested to see how these compare. Wondering about an alteration for boost with the 800r.

Thanks!!
 
D
Oct 19, 2003
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Rapid City, South Dakota
John and I have talked and it looks like there will be some 860 turbo options available. Talk to John about the big bore and I'll sell the turbo. The turbo kit willl be the same with the change being in the big bore configuration.

Dave

That might work well...really well!! John, can you post something in regards with how the port timing and configuration has changed through the years from the old 800 to the 800 ho to the 800r?? Transfer and Exhaust port heights??

I am interested to see how these compare. Wondering about an alteration for boost with the 800r.

Thanks!!
 

BIG JOHN

Well-known member
Premium Member
Nov 26, 2007
1,953
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Minnesoooota
That might work well...really well!! John, can you post something in regards with how the port timing and configuration has changed through the years from the old 800 to the 800 ho to the 800r?? Transfer and Exhaust port heights??

I am interested to see how these compare. Wondering about an alteration for boost with the 800r.

Thanks!!

in a nut shell...

800...ex port @ 198-199 transfers @ 129-130
800HO...ex port @ 201-203 transfers @ 131-132
800HO PT...same port timing as HO but better ports
800R...ex port @ 205 transfers @ 132 (HUGE intake/transfer/ex port area vs HO motor) I cant port a 800HO to stock 800R configurations..

On average the sub exhaust ports have been 8 degrees less than main port...

There is some variables from cylinder to cylinder but this is the basic differences over the years...

Twin pipe porting is diff than single pipe and turbo porting is (educated guess) stock port timing but enhanced volume/flow..BJ
 
T
May 25, 2008
1,213
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Oroville Washington
Thanks very much! Exactly what I needed. So, I think that probably answers the questions about the power differences you saw Dave. Interesting what may be gained with the 800r.

John, we were thinkin similar for the turbo port. Im probably not going big bore for next season but I did just tear my xp down and I have a trashed cylinder. If warranty doesnt cover it I guess 860 turbo it is. Do you think there would be an effective gain to lower the exhaust port on the turbo setups??

Thanks for the info

Jake
 
D
Oct 19, 2003
1,247
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Rapid City, South Dakota
Jake, I understand all the questions and enjoy the input, but maybe I am at fault by giving turbo/big bore info on this thread. I would like this thread to stay focused on the big bores. Any turbo/big bore talk please take it back to one of my original threads or lets start a new one. I hope I don't come off as an a$$ about this comment:)

Dave Halverson

Thanks very much! Exactly what I needed. So, I think that probably answers the questions about the power differences you saw Dave. Interesting what may be gained with the 800r.

John, we were thinkin similar for the turbo port. Im probably not going big bore for next season but I did just tear my xp down and I have a trashed cylinder. If warranty doesnt cover it I guess 860 turbo it is. Do you think there would be an effective gain to lower the exhaust port on the turbo setups??

Thanks for the info

Jake
 

BIG JOHN

Well-known member
Premium Member
Nov 26, 2007
1,953
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Minnesoooota
Jake, I understand all the questions and enjoy the input, but maybe I am at fault by giving turbo/big bore info on this thread. I would like this thread to stay focused on the big bores. Any turbo/big bore talk please take it back to one of my original threads or lets start a new one. I hope I don't come off as an a$$ about this comment:)

Dave Halverson

LOL- dont worry Dave... BB turbo would be the only logical step!!! ..:D-BJ
 

joshkoltes

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Dec 16, 2007
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ranchester, wy - nashua, mn
set up

does anybody have an idea of a baseline set up for say 8- 10000 ft?
i tried 540 mains like jaws said and couldnt get 8200 so now i tried 500s and the r's seem to be the same but noticeably less power?
860 with twins, advanced timing, air box mod, 500 mains 17.5 pilots, took all the set screws out of the pins, softer spring.
any more info apreciated.
 
O
Nov 27, 2007
1,058
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Western Wyoming
Dave, heres some advice fur you...stay away from from the BB/turbo kit idea your just going to open up a can of worms....Let those that want to do it do it at there own risk.....Imo there is nothing logical about a shkidoo BB/turbo other than it sounds cool.

You ever here of the KISS method ?

OT
 

BIG JOHN

Well-known member
Premium Member
Nov 26, 2007
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Minnesoooota
Just a thought here...:p

stock 800R = high exhaust port, 1 ring piston, wide squish band head...

SHR 860R "turbo ported" (lower exhuast port height, similar to twin pipe porting), bigger 2 ring cast piston and a narrow squish band head (hemi)...

Yup...NO reason to try that...a BB/turbo DOO would WAAAY off the mark:rolleyes:BJ
 
O
Nov 27, 2007
1,058
101
63
67
Western Wyoming
Just a thought here...:p

stock 800R = high exhaust port, 1 ring piston, wide squish band head...

SHR 860R "turbo ported" (lower exhuast port height, similar to twin pipe porting), bigger 2 ring cast piston and a narrow squish band head (hemi)...

Yup...NO reason to try that...a BB/turbo DOO would WAAAY off the mark:rolleyes:BJ


BJ, in theory perhaps YES...In reality NO. from a consumer standpoint many sledders are cost driven. Just read Daves thread all most folks want to know about is cost...Furthermore the turbo community has done R&D and resiults/gains are minimal at best while the headache's in the field still persist. The BB community has there issues to deal with and so does the turbo community. And to date reality says they don't mix very well with the consumer market out in the field.

Do yo honestly believe there will be performance/reliabilty to be gained in BB/Turbo kit ? Or just addional expense to the consumer ?


K
eep It Simple Stupid :D

OT
 
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F

Fack

Member
Nov 28, 2007
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I would think an 860 with turbo friendly porting would be sweet. I'm no expert on the subject but the 800R port timing is not as friendly as some of the other stuff (turbo wise). If a person could develop a larger bore (860) to match the bigger case volume of the R motor along with lower exhaust ports and a better head design you've got a better situation all the way around that will no doubt make more power. It's not like you are dealing with some wild race porting where you are trying to flow as much as possible. I think Big John and Dave are just the perfect guys to do it too...

-Fack
 
Last edited:
S
Nov 26, 2007
1,664
166
63
Helena, MT
does anybody have an idea of a baseline set up for say 8- 10000 ft?
i tried 540 mains like jaws said and couldnt get 8200 so now i tried 500s and the r's seem to be the same but noticeably less power?
860 with twins, advanced timing, air box mod, 500 mains 17.5 pilots, took all the set screws out of the pins, softer spring.
any more info apreciated.

You need to go with a stiffer finish to get your R's up.
Taking weight out and putting in a softer finishing spring cancels each other out.
 
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