Octane requirements with head shim and boost

[nos]

I have a supercharged sled with a head shim. How much boost is safe to run on pump fuel? I'm currently running 6lbs with 87 octane and have not experienced any detonation at all. If I were to bump the boost to 10 could I still run safely with 91 octane? If I were to do an ECU reflash as well would that take too much of the HP away to be worth it? Between the timing and the shim could I get away with lower octane requirements?

 

[mpi xtx]

I wouldn't even be running 87 with you current setup.
I ran 13psi with low comp pistons on 91 pump gas without issues

 

[PowderFalcon]

You can run 91 with shim and studs (may as well do studs while head is off) on 10 lbs of boost. That is what I run in my sled.
I would be running 91 with your current setup if i were you, not worth the chance of a $5000 motor.
Also, please add your location on your profile! Cheers!

 

[rat4020]

I put the ARP studs and head shim on my Apex and its suposed to be good for 10-12lbs with 92 oct. But I dont trust pump 92 so I mix it 3.5 gal 92 to 1.5 gal of 110 Then even if I get 87 my octaine is still around 102 and safe & smellin great

 

[nytrozula]

I suppose you guys that are mixing fuel never really ride far from home. I can get away with that at the beginning of the day but my second fill up is generally 100 miles from where I'm staying so its simply not an option.

 

[rat4020]

Filling up at a gas station is not an option for me LOL there aint no fuel stops where I ride. Just lots of sand ,my fuel comes from a 50 gal tank in the inclosed trailer

 

[Yamadog]

When I turn up the boost I ride with 5 gal of race fuel which gets me 2 additional fill ups if I am getting 92 pump gas so 3 tanks a day or about 250 miles. After that I head home and do it all over again

 

[kinger]

Where do you put 5 extra gallons?

 

[Yamadog]

In the large rear tunnel bag
a 2.5 gal plastic tank and then 6 large fuel cell bottles depending on how far I am planning on riding or I can always flip the switch to reduce boost and lower my octane requirements.