JZ28Max

well, after disassembling the motor for a new set of pistons the crowns had pretty bad scarring that my engine builder said most likely was from too much alky washing away the oil in the cylinders. i had the pressure turned all the way up since i had removed the intercoolers but now i am thinking too much can be a bad thing. so when it goes back together i will have a new front mount and turning the injection way down. my question is what is the best way to set the meth inj. up? i am thinking turn it up until you eliminate all knock and no more than that? also does the meth read on a wideband or does it throw the reading off? in other words should i tune for my target a/f ratio with the meth off and then inj. it on top of that? thanks
Josh

engineermike

The Methanol is not what caused the scarring. Some turbo Buick and DSM guys run up to 50% Methanol. Others run straight Methanol. It's an engine builder's trick to use Methanol on break-in to help seat the rings because it doesn't lubricate like gasoline. However, they also build 1600 hp supercharged big blocks that run on 100% Methanol with no piston scarring.

A common number is to run 85% 93 octane and 15% Methanol. This is good for over 20 psi boost.

With a Wideband, you want to tune it for ~11.5/1. This has been discussed in-depth and that's the bottom line.

Mike

markinkc69z

Josh, Methanol won't change your wideband reading. (it will just show the addition of methanol on the overall afr) The WB 02 sensor natively measures lambda and the software converts to an afr number for whatever fuel its programmed for. If you found best performance at a particular afr in the past you may still tune for that number if you wish. There is no absolute universal best afr, and afr requirements often change with rpm. Each setup is unique and it up to you to find what it wants.

rskrause

The effect of alcohol on the WB reading depends on what you are doing with the alcohol and how the meter is calibrated. If it's calibrated for gas, you want to see a very rich AFR. I agree with Mark that a typical ratio seen with alky injection is ~11.5:1. I wouldn't want to see anythining leaner than 12:1 in any case.

As far as how much alky, the best way to find out is on the dyno. Start with a small amount, and keeping upping it until you see a drop in hp or other problems (running rough, etc.) Keep an eye on the AFR and adjust the fuel as needed.

Rich

Kevin Blown 95 TA

If you are looking at AFR you might seem to go lean when the ALky comes in, but it's really not - just the Stoich point is changed messing up the calculation which is based on the fuel type. If you tune by Lambda, this isn't an issue because it just looks at oxygen content. Either way, it's just a number - just don't be fooled when you inject the Alky and it goes to 12.8 or something when it's really going more rich. IMHO, its just easier to tune with Lambda when mixing fuels - besides you might even be using gasahol where you live. For a better understanding of this, go to the Wideband forums or the Alky/water injection forums of the manufacturers of these products - DIY Wideband, Innovate, Snow, etc. for advanced discussions by some very knowledgable people on these very subjects.

JZ28Max

thanks for the replies. glad to here it isnt a meth problem because i didnt want to take the kit off. seems to work really well. i will def. spend a lot more time on the wideband this time around and be a lot more careful.

engineermike

Here we go confusing people again. . .

All A/F meters (whether lambda or A/F ratio readout) measure lambda. Some correlate this lambda to an A/F ratio for gasoline. So, if you run 100% Methanol and lambda is 1.0, then the meter will display 14.5 even though the real A/F ratio is 6. Therefore, you tune for 11 - 12 / 1 A/F ratio no matter what fuel or fuel mixture you use. Aim for 11.5/1 and you'll be fine. Aim for 12.8/1 and you'll blow a motor (been there, done that).

Mike

David @ Thunder

Mike, what did I tell you about confusing people again!!! When are you going to get that thing to crack 700rwhp???

SMOKNZ

Thanks for the explanation again

Kevin Blown 95 TA

Well, when the methanol was fully on, the mixture switched from 11.5 to what looked like 12.8:1 on AFR (And scared the crap out of me), but it dropped down to .7 Lambda when I changed how it was displayed. This is extra fuel on top of the already rich condition I was running on straight gasoline.

engineermike

I promise you that something else changed when you switched over the display. All the meter does is correlate the lambda it measured to an A/F ratio.

If your gauge is calibrated for gasoline, it will read as follows:

.7 lambda = 10.2 A/F ratio
.85 lambda = 12.3
1.0 lambda = 14.5

Remember, it measures lambda, then scales it to A/F ratio.

Mike

Kevin Blown 95 TA

SMOKINZ - sorry if I misled you - i don't mean to post bad information. Mike, I know what you are saying, and I know that the alcohol has a lot of oxygen in it - the water too, but are you saying that adding the alcohol/water makes it leaner so that you have to add fuel to bring the AFR back down to 11.5 or whatever? This is originally what I tried to do for a few days, but was having trouble getting the AFR number to come down even with a lot of fuel added to the PE tables. So then I changed over to the Lambda reading in the software and it looked very rich from all the fuel I added - Maybe I got bad data somehow or it's a possibility my blowby was queering everything up. In closed loop, it always seemed calibrated, but I guess I could go in there and verify the AFR tables are correct. Also, can't understand why the Alky injection sites tell you you will need to pull fuel when you add the methanol/water if you are really leaning it out in the first place?
Can you take a few minutes to read this post over at the LM1 forum and see what you think? I'm afraid I misunderstood it and was confused by what I saw on my wideband. The discussion answers by the LM1 guy is confusing, and not direct. Some parts of the post seem to agree with you as well.

http://www.innovatemotorsports.com/f...ead.php?t=1860

markinkc69z

See, I have been through all of this before as I am the "andereck" in that thread. I have been using an LM1 for a couple years now and have learned a lot more than I would have ever thought from a wideband.

Kevin Blown 95 TA

Well, I read everything over a couple times and I finally had a moment of clarity which made it seem obvious that whatever lambda you have, the AFR will just be calculated off it so tuning for either makes the same amount of sense.

But, i am not the only guy to have seen the AFR go lean when the alky came in and I would like to know what everybody has to say about that. According to some experts, you are cooling the mix down enough that you should be able to advance the timing and pull even more fuel out to get optimum power. I guess this is the part that I still don't get. Should injecting the water/alky make you go richer or leaner?

The other thing is that I wonder what the distribution is like in the manifold, since it is a dry manifold not suited for fuel and the fuel is basically being shot in the front towards the back with a certain amount of inertia.I'm sure the fineness of the mist helps, but to what extent is the misture uneven?

Kevin Blown 95 TA

Small world, huh? That post really just confused the crap out of me. I think it was the way the LM1 guy tried to explain the answers without giving straight answers.