08 xp, trying to get it set up right

[sewell386]

i have a 08 xp that i have just put a terra alps intake and head on,rage cage reeds dyno port pipe and Y pipe on and 30 miles later i had a piston failure, none of the mods fault but i am just trying to get everything set right when i put in my new piston kit and need some ideas on what i should do. When it went down i had my mains at 480

 

[drop the hammer]

Bet you had detonation issues. A buddy had his set up similarily and couldn't just stop the detonating at 50% VP111 in fresh premium, we unload at Golden/Revy around 2000 feet. Once in the alpine it was fine. His was 14:1 head though, not sure on yours. The 14:1 head by itself is not too bad with mild temps we usually see and with fresh premium, but add the Ypipe/pipe combo and she detonates like crazy. That's why I didn't go further than the head on mine.

 

[sewell386]

yeah my head is a 13:1 and your right it does detonate like crazy i am not sure what would be best to get rid of that?

 

[DownhillBill]

We put the billet head (14:1) on my 08 xp and it was detonating like crazy. Tried changing out to a cooler thermo, flashing it, and nothing seemed to fix it. Searched and searched and finally found out that it was due to the head making the compression too high! Went down to 13.5 in the domes and hasnt went off once since! Hopefully this helps!:d

 

[BIG HEAD]

put a thicker base gasket in?

 

[pistonbroke800]

yeah my head is a 13:1 and your right it does detonate like crazy i am not sure what would be best to get rid of that?

What fuel and elevation are you running your 13-1 at? Shouldn't have deto problems with that running good premium. I run 94 octane with my 13-1 and have never had trouble.

 

[Sun Sport]

I am running RK drop in kit 14:1 head with rage cages ,modded air box,slp intake mod,450 mains needle shimed .20 and 12 liters of vp 111 per tank and runs great from 2300-8700ft @ 8200rpm.