target AFRs on WB with meth?

[Flyin Ryan]

I know gasoline has a stoich of 14.7:1 and methanol is 6.4:1 and even ethanol is 9.0:1 but when we use alky injection we're actually using two types of fuel, so which should we go off of or shoot for on a wide band o2?

 

[TYTILIDIE]

Re: target AFRs on WB with meth?

Im told 11.9-12.0. But I did a search the other day and there are TONS of variations and different opinions.

 

[Maverick87]

Re: target AFRs on WB with meth?

Nolan shoots for 10.5 I have mine a 10.7-11.0

 

[Raist103]

Re: target AFRs on WB with meth?

12.0-12.5 is a safe tune

 

[Flyin Ryan]

Re: target AFRs on WB with meth?

cool thanks fellas

 

[fivetodrive]

Re: target AFRs on WB with meth?

A wideband oxygen sensor only reads LAMBDA.

With the PLX I have it will read the same no matter what fuel because they just read the amount of oxygen. To get what the AFR ratio is you need to multiply the Lambda number displayed on the wideband by the ratio of the fuel.

Does that make sense to you?

 

[JSM]

Re: target AFRs on WB with meth?

Mrburntsy is correct, the WB reads lamba then converts it to AFR and assumes your using gas to get 14.7 as 1 lamba.

When people say what target AFR to shoot for there are a LOT of variable. Cruising you want 14.7, under acceleration you want to go richer. More boost typically the richer you go. I would never want to run say 11:1 at 2 psi boost. But I might consider 11:1 at 20psi boost. But it will depend on what the truck wants, the rest of the parts, cam, lots of things.

Don't just go to X # because Mr. so and so does. Maybe start there then see what your truck likes.

On jeremy's syclone at 25psi boost we are at 10.8-11 AFR. At 10psi boost it is probably 13:1 maybe a bit leaner. My personal typhoon anything more than 10.2 it will spit out the exhaust and backfire like no tomorrow. Still not sure what AFR it will like yet. Everything truck is slightly different.

 

[nallj92]

Re: target AFRs on WB with meth?

i tend to go for about 11.2-11.5 for about 25psi on 93/92 pump depending on weather/ humidty, quality of methanol etc

 

[fivetodrive]

Re: target AFRs on WB with meth?

Mrburntsy is correct.

I may have to change my username to that! :tup:

 

[Flyin Ryan]

Re: target AFRs on WB with meth?

man nothing's ever simple is it hahah

thanks for the explanation guys really appreciate the help and examples

 

[autoaddictions]

Re: target AFRs on WB with meth?

I cracked my head running 12.5 AFRS with 100 meth in my alky tank. I think if your running 100 meth you need to be closer to 9.99 or 10.0.

 

[Tooky]

Re: target AFRs on WB with meth?

I ran the shit out of my stock turbo setup on 93 octane and meth at 12.5-13.0 with no problems! NOT that I would recommend it necessarily (every truck and every wideband is a little different). Nowadays I like to run 11.9-12.1 when everything is said and done (11.0-11.5 when I'm still dialing it in.)

I have heard that it's ported large-valve Vortecs that are most likely to crack due to the thin wall between the two valves, that could have been your problem Frank??

 

[autoaddictions]

Re: target AFRs on WB with meth?

Im sure the thin wall in the ported vortechs didnt help any. However, I made over 200 runs at the track at 30 psi and had no problems. I ran 50/50 water and meth no problem! As soon as i switched to 100% meth BOOM! My advice would be to start at 10.0 and watch your knock count if you can run leaner than go for it. Small detonation at 375 hp and small detonation at 650hp are 2 different things! Thats another topic in its self..

 

[sharkbait]

Re: target AFRs on WB with meth?

so really the knock sensor/gauge is also gonna be a big consideration? no knock and you can possibly run leaner? like 11 or 10 AFR?

 

[TYTILIDIE]

Re: target AFRs on WB with meth?

Its like Jeff and Dig always say, its not the #/AFR, its what your truck likes. No sense in shooting for a particular AFR, this will take you for an annoying ride. When I first started tuning I tried and tried to get my truck run a lot of boost on a certain AFR, it was a total waste of time. Once I started listening, and giving it what the truck wanted, that was when things started to come around.

 

[turbodig]

Re: target AFRs on WB with meth?

I have heard that it's ported large-valve Vortecs that are most likely to crack due to the thin wall between the two valves, that could have been your problem Frank??

Big valve stockers and L35s have the same issue... the less space between the valves, the more likely a crack will happen.

 

[TYTILIDIE]

Re: target AFRs on WB with meth?

Big valve stockers and L35s have the same issue... the less space between the valves, the more likely a crack will happen.

Great, and I was super excited to put mine on that I just bought.

 

[turbodig]

Re: target AFRs on WB with meth?

Its like Jeff and Dig always say, its not the #/AFR, its what your truck likes. No sense in shooting for a particular AFR, this will take you for an annoying ride. When I first started tuning I tried and tried to get my truck run a lot of boost on a certain AFR, it was a total waste of time. Once I started listening, and giving it what the truck wanted, that was when things started to come around.

Yup. Once you get over the "X is fast, and he runs 11.5:1" mentality, things really start to come together.

Bruce used to preach this to people years ago (like 10 years), I guess we're all finally starting to come around.

I've been working for quite a while now on exactly *why* this is true, given a motor with the same specs. There's lots of good theories, but I haven't found any that work in a repeatable fashion.

 

[turbodig]

Re: target AFRs on WB with meth?

Great, and I was super excited to put mine on that I just bought.

You're ahead of the game, as your tune is gonna be more stable. A truck that pings a lot will bust 'em a lot quicker.

Has a bit to do, also, with who did them and how, too.

 

[Flyin Ryan]

Re: target AFRs on WB with meth?

wow great info guys... I understand that each truck is completely different tune-wise and was really looking for a natural ground so to speak on where to start from AFR wise.

Something to start out with then work my way richer/leaner from there until I see my truck's happy knock wise with the AFR