slp head compression for xp?

[badass1000]

I have ben looking at getting a slp head. I mainly ride 6,000-8,000' so I have ben looking at getting that head.
The head for the xp is only shown to gain 2.5hp peak and 6-11hp midrange. the 07 800r is shown as 7hp peak and 6-14 mid. that is alot more. I called and asked a tech at slp why the difference in hp. He said they changed some thing in the way a coolant passage was ran on the xp. I said I had heard of people useing the 07 800r head on a xp and why I couldn't do that. He said I could use the 07 800r head, but the compression would be too high.
I was just looking at the instructions for the heads and it shows the xp 6-8,000' head as 13.1 compression ratio. It shows the 07 800r 6-8,000' head as 13.7. I talked to guys who used the 07 800r head on the xp with 13.7 compresion and they said it worke fine. I believe I heard of useing the 14.3 rkt head with no problems on the xp. How come they lowered the compresion from 13.7 to 13.1 on the xp? the 8,000'+ head from slp for the xp is listed as 13.7. Should I just order the 8,000'+ head?
How much more hp/tq would I gain going from 13.1 comp to 13.7 comp?
Just trying to figure out. 2.5hp peak gain isn't really worth doing a head. I would definatly get a head if it was 7hp peak like claimed on the 07 800r's.

 

[Mr. Redrock]

I ran the 13.7 to 1 head for the 07 on my 08. Was a nice midrange improvment. But my deto sensor went off alot if I was under 7500'.
But some clamied it was just the sensor.
Not sure witch way I will go this year, may try some one else's head.

 

[PJ-Hunter]

If you are gonna run the 8000' and up head you must mix some race fuel with your pump gas. I have an RKT head for my XP (Kelsey says that the ratio is 14:8) I am also going to try the SLP high altitude head with their pipe combo and see how that works out.

I ride 9500 and up mostly. Very rarely do I start at 8000'.

 

[Thundy]

I have the 14.8 head from RKT and kelsey said I can run it at 6000-10000 ft with 91 octane

ill mostly be using it at around 8-9000 ft but the trails down low will sometimes get close to 6000

 

[badass1000]

how do you know if your detonation sensor went off?
isn't their a way to deactivate it or desensatise it? Like putting it on a different bolt or where does it mount?

If the detonation sensor goes off doesn't it pull timing?

thank you
jeremy

 

[madmax]

Definitely do not disconnect your deto sensor, especially if you are doing mods. It could save you a motor.
I ran my 14.8:1 RKT head last year on my XP on pump premium for about 600 trouble free miles at over 7500ft elevation. Never had a deto problem.
Just curious, does SLP recommend jetting down or up with thier head?

 

[Long Gone]

I am curious as to the answer to the original question by BA1K as well.

Will there be much difference if you run a RTK head with a SLP Pipe? I do not want to settle for 2.5HP if you can get more HP for the same $ elsewhere. If not, I will buy the 07 head and make the bracket so that it works on the XP.

 

[badass1000]

14.8 rkt for 6-8,000 and 13.1 for slp 6-8,000' is a HUGE!!!! difference.

jetting specs for the 08 xp head are not released yet. called slp and they said they would be released after a few days riding when we get snow.

on the 07 800r slp head it is recomended to go up two jet sizes by slp.

I will see if I can call slp tomarrow and ask a few more questions.

 

[bungeeguy]

Hey looser don't forget that we start our rides as low as 4500 ft. Don't blow your heap up before I get to humiliate you all day!

 

[badass1000]

I know, but we just ride on the trail or across the lake to get to the mountain.
Most of the riding we do is 6,000 and up. Lowest we go is your cabin wich cascade lake is listed as 4,800'.
Hopefully my sled will be leaving your xp like I did your rev last year.
Hopefully not too far though so you can give me a tow back.
Two of us on xp's this year sounds scarry. We need to get looper or some one else with a cat or yamaha to ride with us so we got a reliable sled to tow us back. LOL..

 

[Union Pass DOO]

hey badass 1000 on the sensor for the head on the x models it will show up on your gauge i think its a hot light ,what we did was make our own gasket to put under the sensor . the stock is to thin and sets off the idiot light. we used the waxed candy bar piece under the bar, dont laugh it works .it is about the right thickness. we ride at 8000 feet. the guy we bought the heads from said it will cure the problem .give it a try cant hurt any thing!

 

[badass1000]

it is funny. , but sounds like it should work. thank you for the info.

I talked to dustin at slp today. He said a xp with their pipe will detonate at 6,000' with a 13.7 head. He said a xp with a stock pipe will not detonate with a 13.7 head at 6,000'.
I forgot what his reasoning why was.

I am not sure if I want to just order a 13.1 and play it safe or if I want to try a 13.7 head and see what happens.

 

[HPJUNKIE]

it is funny. , but sounds like it should work. thank you for the info.

I talked to dustin at slp today. He said a xp with their pipe will detonate at 6,000' with a 13.7 head. He said a xp with a stock pipe will not detonate with a 13.7 head at 6,000'.
I forgot what his reasoning why was.

I am not sure if I want to just order a 13.1 and play it safe or if I want to try a 13.7 head and see what happens.

A more efficent pipe design traditionally raises the "running compression" of an engine. So if wanting to keep the stk pipe, then a '07 spec head should work for your desired elevation. If going with the SLP pipe which is more efficent, a lower compression ratio would be required.

 

[madmax]

the main reason in replacing the stock doo head is because it is poorly designed for maximum combustion effeciency, how much of the air fuel mixture is burned before its thrown out the exhaust. imo if you are buying a head that requires more fuel to be dumped in for it to work youre not doing your motor any favors. there is a reason why the rkt head is 14.8:1 vs the slp is 13.6:1 for the same altitude and running pump gas premium.

 

[justadude]

hahahahaa!!

Hey looser don't forget that we start our rides as low as 4500 ft. Don't blow your heap up before I get to humiliate you all day!