Need some set up suggestions. Looking at Devilsown progressive 2bar kit properly sized for my displacement, boost lvl. 03 2500hd CC 8.1L twin T62-1's CR is 9.3:1 intercooled has 2bar tune. I run 8lbs boost and high setting 12lbs. Currently max timing is ~17*. Will run 50/50mix
? is at what level should I set the start and at what level for max flow? What timing increase might b possible?

 

With that compression, you could have the meth come on at maybe 5-6psi. Your max flow is going to be determined by what AFR you hit with the meth thrown into the mixture. You wouldn't want the meth to come on full if its just going to richen the mixture to the point of diminishing returns. I set mine so that it just barely creeps in on the MAP trigger, and gains almost linearly with boost. Target AFR on my setup is 10.5:1 with meth on. Timing increases are dependent on a lot of factors...it isn't realistic to be able to say x-amount of meth added to the mixture will let you add y-degrees of timing. Some people add timing until they see KR, and then back it down to be safe. Personally, I run only a couple extra degrees of timing...I don't push until KR. The meth is only really there as a knock suppressor, in case something actually does go wrong. Its personal preference, really.

 

Speaking from my personal experience, and my personal preferences:

I never even had to retune for a 50/50 mix, running hard. Not much benefit there IMO. 100% meth is where the magic happens. Meth adds fuel, and explosive power to the mix if it isn't counter acted by the uncompressable water...

I would not even turn the kit on for 8 psi. You would need to turn it on at 2-3psi to the get the timing right IMO. That means its going to spray anytime you touch boost at all (e.g. almost all the time except cruise, idle, and being careful, etc.).

Even at 12psi, I'm not sure how much benefit you will see. With 100% meth and the intercooler, you can run more boost and timing easily at that CR. I would run 15psi (unless the motor is bone stock, in which case I wouldn't spend money on the meth kit), turn it on at 7 psi for high boost only, and redo your boost table at 7 - 15psi to accomodate for the meth.

with 100% meth and forged internals, your timing will depend on your ambient temps and the efficiency of the IC. I would rather run more psi than more timing. More bang for the buck.

 

I have played around with different mixtures and settings with my devilsown kit. Personally, I don't think it is worthwhile to even have it if you don't run at least 80% meth, and tune for it. If you think about it, when you add meth, you will only gain power from the added knock resistance, and its slight cooling effects. If you don't lean out your BE table to keep you at say 11.5:1, or whatever you prefer, you are pissing in the wind. Some people just add it, and run rich because they worry about it failing and going lean. If it fails, its going to go lean, and or pre detonate because you now have too much timing for just pump fuel. So my opinion on it, if you are going to use it, buy a very good quality kit, and NO afro-engineering on the wiring, solder all connections, use heat shrink, good grounds, etc... and you should be ok. I would turn it on around 7psi, full by 10.

 

Thanks for the suggestions...another reason besides the (hp) power with added timing is mileage. Because the same max timing number is used thoughout meaning that even with moderate throttle still in vac range max timing is ~17* and of course affects the mileage; if was not boosted tune timing would be say upper 20's*. Maybe asking too much to have stock mileage and still surprize Mustangs and the like with 7000lbs of iron...

 

What are you using for tuning?? If your using a stock PCM with HPT or EFILive, then you can most certainly run more then 17* of timing at cruise. The timing table is MAP based so if your not in boost, then you can run normal NA type timing in the cruise areas of the tune.

 

Yep Cruise and light throttle timing is normal 30*+ just when throttle ~30% or so with a little load 7000lbs of truck going up mild incline not in boost mayb 5Hg vac timing down ~17* and AFR 10.5-11

 

My Tuner is using HPT software...will b going in for a touch up since I changed exhaust to 5 inch will be adding the Meth kit stage2. also have issues that i want looked at Burst Knock, Rolling Idle, Throttle delay etc...