I've been spending some time over at Turbobuick.com and have seen how big water/alky or even propane injection is. Why is it that you dont see much about it over here. Is it because those guys routinely run 25+ #'s of boost and NEED a supplement to the intercooler to bring combustion temps down?. Just seems like a very cost effective AND efficient way to "intercool" (DIY for ~$200) compared to buying or building an intercooler set up.

 

I use it and find IAT's of ~130-150 degrees with 80-90 ambient after a quarter mile run with 14lbs of boost from an S-trim. Not as effective as a good intercooler/aftercooler. But much easier to install and cheaper. OTOH I don't see how you could do a good system for $200, even DIY. A good pump (you want ~100psi) will set you back nearly that much.

Rich Krause

 

I have an ATI 8# P1-SC with twin intercoolers and I plan on putting in a water/alky system. IMO I think it's cool just to have plus it gives you a little more HP.

I'm getting some knock right now and I'm not sure if it's false or what, so I just bought TTS datamaster and LT1_edit to do some tuning. I figure if it's real knock, then the water/alky system can only help.

 

Rich:
The $200 set up I was refering to used a single stage pump at 60psi. At any rate, its a cheap alternative to an actual intercooler.

http://home.att.net/~stevemon/AlcoholInjMod.html

 

The SMC kit seems to be the one that the guys use. From my talking with alot of the turbo buick guys and some of the faster ones though it is just a crutch though. I personally like the idea of injecting some alcohol but from talking to the faster guys over there they say it is really unneeded. I have a freind who daily drives his GN and he runs 30+ psi at the track had a stock motor and went 9's turn the boost down for the street to roughly 20's and never ever ran alchy or water. The whole deal is to get the tune right though.

Just my .02 but if you have enough for your combo then it is not needed.
Steven

 

I had read a post quite some time back about a guy from our site wondering why propane injection was not considered an option for us supercharged guys. It was being widely discussed in the turbo forums but not on our site, did I miss the response? Or is it still uncharted? I personally am thinking about running a propane injector post MAS. Good or Bad?

 

Anyone want to comment on how effictive alky injection is when used in conjuction with an intercooler?

 

I was always under the impression that the propane was used to supplement fuel delivery. I've seen a Viper using a propane/nitrous mix. There's a company that sells it, but I don't remember who it was. It just seemed wierd to have a crack bottle and part of a BBQ grille in the trunk.

 

I'm getting ready to try it on my setup. I've still got the stock bottom-end with 77K on it. Against everyone's objections, I'm bolting on a D-1SC with the stock 12# pulley. Here's the plan to keep the damn thing together until next winter...

1. New CNC heads with 64cc chambers to achieve 9.5:1 CR.
2. I'm at 5800FT altitude and the thinner air lets us run more boost safely.
3. I'm going to give alky/water injection a try.
4. I've got a really good tuner and almost a day on the dyno to dial everything in.

I'm going to do absolutely everything I can to keep it away from detonation. I've got my fingers crossed.

 

It will not last with 12psi, sorry. I tried 10psi with water and it go boom (stock bottom end). There's just no way to keep it from detonating at 12psi on pump gas, and the pistons are just too fragile.

Welcome to the "rebuild club" (if you try it).

Rich Krause

 

That's what everyone says and I respect your opinion. I'm going to try it anyway.

 

I have a Buick GN driveline transplanted into my 2700lb Mazda
RX-7. I run a nice 1080cfm Spearco intercooler up front and use an SMC alchy injection kit on the street.

On standard crappy California 91 octane gas I can run 18* timing and only 15psi of boost without knock.... 16psi if it is cold out. On 91 octane and alchy injection (turn on point 13psi) I can run 21* timing and 22psi on a stock GN turbo. The car has about 80hp+ more than running on just 91 octane alone and can annihilate the tires at anything under 40mph even with stock turbo.

Alcohol injection works really as a knock suppressant from the cooling of the intake charge. Propane cools it down even more and adds some fuel at the same time. I run 100% denatured alcohol with no water. That is how my car runs best. I've tried the 50/50 water/alchy mix, 30/70 mix and 10/90 mix. My car likes 100% denatured and that is what is recommend in the SMC kit.

The stock GN turbo blows hot air past 22psi and actually slows down if turned beyond that.

I am soon stepping up to a built shortblock with T-70BB turbo, 72lb/hr injectors, LS1 MAF, Trans+, PTE ported iron heads, and ported lower intake with 218 duration .520"+ lift flat tappet cam. I am hoping to run low low 10's on 91 and alchy injection with this setup. I expect to be able to run 24psi+ on the street like this.

On the street alchy injection is awesome.... propane injection is better as it is injected at -40 degrees (I think) and lasts a long time ( a few months). I refil my alchy tank about 1x per week (1/2 gallon). A downside to propane IMO is that if it were ever punctured... it could explode. My car has no sealed trunk area like a stock Camaro... so that wouldn't be good for any occupants.

Alcohol injection is great for the street as it is like running 100 octane all the time..... but only is like that under boost conditions (where you really only need it obviously).

However your best et's will be run with 116 leaded race gas and an efficient intercooler system.

You guys are aware of the 100 octane homebrew fuel mix:
7 gallons 92 octane
3 gallons Xylene (117 octane)
2 ounces Marvel Mystery Oil
yields 100 octane......

100 octane with alchy injection would yield 107 octane+.... but the cooling results from propane injection would be much better.
-GNX7

 

Wow... pretty scary Mazda.

What I don't understand is that everyone says you can't control detonation on the stock bottom-end and that's why it'll grenade. So... are they saying that with a forged bottom-end they are getting detonation and it's just not killing the pistons? What keeps the head gaskets from blowing, etc?

Am I correct that detonation is the culprit that needs to be dealt with? If I can avoid detonation will the pistons hold up?

 

I will be running a ati p600b on my stock bottom end z28. I will be running ~9#pulley and a 2 core front mount intercooler with a smc alky injection system with dual nozzles. Im hoping it will last a couple of months as this will allow me to purchase some forged pistons to lower my compression to 9:1 and then stepping up to the 12# pulley. See, as you have now found out, alot of us here are or will be using some sort of injection to help out detonation.

 

Cast pistons are weak, period. After you start making a certain amount of power, and putting a certain amount of pressure on them, I think they will often break whether detonation is present or not . Especially with forced induction. Compared to forged pistons, they in a way are like glass.


Of course they will last in some guys engines longer, while another guy breaks them with less boost, but I don't think you neccessarily need detonation to break a cast piston.(Especially with nitrous or boost)