may sound stupid, but...
 

i have run a water/methanol injection system for years (mixed at 50/50) on my turbo buick that uses a washer bottle w/integrated pump from a nissan, a hobbs pressure switch and discharge jet in front of the T/B. the switch turns pump motor on at 2 psi, so the system is primed and pumping when i get to full boost - it works great.
Why spend $500 on an alky kit when water inj has been successful in turbo applications since WW2?

is the goal to kill detonation, or add fuel, or both?

Doing what your doing, your not adding any fuel. And I doubt you can get any really "real" gain due to the pressure output of the pump you run. The $500 dollar alky kits pump will make over 200 PSI pressure vs the 20-30 PSI pressure a WW pump will make if that.

As the boost increases the output of your pump decreases due to pressure in the intake pipe. So forget trying to run 30 PSI boost on 91 octane as your doing it. This may not be your goal. Thats fine.

Does a little liquid being injected into the intake tract work.. sure does. Guess it depends on your goals. If your trying to kill detonation at 30 PSI boost on marginal gasoline octane, your setup will never support that.

The first alky kits from BG Customs used a little tank with a WW pump. The Edelbrock VariJection used a similar setup.. this was 10+ years ago and the items worked. So did 286 computers. Technology has advanced and so have the "kits". Today we see 200+ PSI pumps, teflon braided hoses, electronics, dedicated systems per vehicle, custom proms, etc.. So as time progresses there have been advancements to the WWII scheme of things.

So yes.. we use todays systems to suppress detonation, as a fuel system, and as both. And increase the performance/drivability through better design of a simple concept.

so do you shoot 200 psi down the TB, or is it regulated down? are these systems intended to take over when the intercooler can't drop the intake charge air temp enough? how do you know when you need one?

Yes and no. See the pump is capable of 200 PSI. Meaning if you set the system becuase you needed 200 PSI then that capability would be there.

Yes its regulated down, most operate at approx 30 PSI when they activate at 6 PSI boost and pressure up to 125 PSI at 23-25 PSI boost. Electronics change the ramp rates allowing for a smooth curve.

Yes they are intended to take over when the IC is not big enough. Yesterday did a system on a twin turbo SBC with a large FM IC and he was seeing 170 degree's intake temp at 16 PSI boost.. with the methanol the numbers came down to 80 which is below ambient here through the traps.

When is more needed.. typically when you want more from the tuneup. Meaning you want to run more aggressive timing, higher boost, leaner AF ratio's, etc.. all those things that create power.

On a Buick application.. I have used straight water, mix(50/50,60/40,70/30,etc) and straight methanol. All three yield positive results. The difference basically is which of the three yielded the highest detonation resistance and most power. That was straight methanol. Each one had its own tuning strategy.

Hope this helps

Yes, that helps a bunch. You have been very informative, thank you very much!