how much alky/water is optimal

[quick-ls1]

I'm an ls1 guy, but I came here to learn more about alky/water injection because I know you guys have the most knowledge and experience around.

I'm trying to figure out what the ideal amount of water alky is. I've heard many different #s and mixes and I want to see what you guys have found to be optimal.

I'm currently running a 50/50 mix of water and denatured alky. I'm pushing in about 18% of my fuel volume at full boost/redline with a single m15 nozzle (I have the SMC kit). I've found this to be very helpful in fighting KR, but I still get a few blips of KR right about the time the alky/water % drops below 20% of my fuel volume. My timing is very conservative right now and I want to get a little more aggressive. I'm about to add in a second nozzle as an experiment, but I wanted to hear what % of fuel you guys are pushing in first.

I tired to follow the "turn it up until it falls on its face and then back a notch technique", but I can not get it to bog under boost with my current nozzle and pump. I also figured a more scientific approach would save me some trial and error.

I talked to one guy with a non intercooled ls1 that is pushing in 40% of his fuel volume and having great success (I have a pretty good intercooler and I’m not running as much boost as he is, so I don't think I need this much). A friend told me that 10% H2o is the ideal ratio. I found it interesting that I started to see knock just as my % of H20 to fuel dipped below 10%...based on 50% water 50% alky.

I did a test tonight and it looks like dual m15 nozzles will put me right around 25% of my fuel at redline (this does not include the impact of boost backpressure so it could be a bit lower).

I’m also interested to hear what you guys do when you put in race gas. Are you able to turn off the system completely? Do you keep it on and get more aggressive with the tune? Do you back down the pump speed? If so, how much?

Sorry if these questions are repeats. I tired search, but could not find the answers I was looking for.

Any advice or info would be greatly appreciated.

 

[zam70]

HavHmmmm I'd search more...There's alot of discussion on this in the past.

....some like straight alc, others prefer a 50/50 or 60/40...jury's still out.

The other questions, some run alcohol on race gas, others don't...so far seems we can't agree on anything.

 

[Razor]

Have you tried running straight denatured with zero water and see how it responds. Some of us have great results with zero water..

Let us know how it responds.

 

[quick-ls1]

I understand some trial and error is required, but I was hoping to get some #s to base my new nozzle configuration on.

Is there a generally accepted ratio target in terms of fuel vs alky/water?

 

[Razor]

Ok..non Buick guy..its like this...

The FAST Buicks run straight.. with zero water to "blow" the flame out.

Comprende..zero water works better for some of us . Eveytime this discussion comes up..someone chimes in my car gets 2 extra PSI on water..water is sooo good..when I see a 10 sec 231 run a water mix..i'll jump in.

I run 100 percent Methanol..no water..and make close to 500 RWHP

Does that help

I get slack from non-Buick guys bout add water..the paper says..its suppossed to...this says this and that..Oops the Mustang guys believe in the water fairy too.

Phouey

Dont believe me..try for yourself..its amazing..really..

And actually the way my understanding is..run straight alcohol..then add water..and continue mixing down till the same results disappear..and it needs more.

Consensus has been to drop FP and replace with a higher percentage of alcohol. Currently rule of thumb is 2 lbs less fuel pressure to take the additional alcohol..becuase alcohol does burn and cool the intake charge big time.

I dunno..I have 500 passes in two years 90 percent on alcohol..zero engine failures. Thats my resume. Motor has never been apart.

Ok I'll lie.. run 10 percent alcohol and blow it up.

 

[quick-ls1]

OK, I'll try anything.

But I do have on question. What's the max volume of alky that you run? What % of alky vs fuel. I would also be interested to hear what nozzle at what PSI and what injectors at what PSI.

I'm just trying to figure out the optimal nozzle and pump configuration. I'm going to turn the 2nd nozzle on after a certain PSI is hit. I just don't think a single nozzle is going to cut it with a 60-70psi pump. I ordered a Sureflow to play with and I may end up taking it in that direction.

One more thing, where do you buy Methanol.

 

[Razor]

Volume as much as possible..

I run twin M10 jets and about 100 PSI. Your car has a bigger motor and may require more. If I run 125 PSI its too much .. I adjust mine by simply turning the knob on the dash..

See alcohol by itself is high octane..so replacing your 93 with high octane fuel is a benefit, let alone the cooling properties..how can you go wrong injecting a cool liquid thats 108+ octane?

Methanol I get at the racetrack. Most raceshops will also carry it..Its what race cars on alcohol use..its not recommended to use with the SMC pump, since its real dry..my buddy uses a lot of klotz and has had zero issues last 5 months on his SMC kit.

2.50 a gallon. Look under automobile race cars in the yellow pages and call around...

 

[zam70]

what Razor is trying to tell you is EVERY car is different. There are fundamentals you can follow but, you have to experiment to find YOUR answer.

Start at one end of the spectrum and work to the other (add/subtract). Don't change anything else so any performance changes (good or bad) can be attributed to NOTHING except the alcohol-water mix/volume. You might find yours likes something completely different than others.

As far as volume, that's another variable. Typically, go big (within reason) and dial back. This is the one nice feature of the adjustable in car controller (Razors and SMC).

It takes time but, in the end you'll know what your engine wants (not what someone elses wants)

 

[quick-ls1]

Thanks for the info. This actually helps. I'll go as big as I can (two m15s) and then dial back with the pump speed if it is too much.

Here is one more stupid question. Has anyone tried freezing the alky and then insulating the tank, so it will already be real cold as it exits the nozzle? I was thinking about insulating the tank while I had it out of the car.

 

[Razor]

Wonder if anyone has frozen and made some alky ice cubes..drop those in the tank...yummmm

No not the Bacardi ones..

 

[1badTTA]

Use some dry ice in the tank, just make sure the tank is vented. We use dry ice and alcohol to freeze bushungs/bearings before installing. Works great and would be worth trying at the track, just don't freeze the pump