SPRAYED 01

iTrader: (22)

Ok so I watched the Banish DVD and decided to do everything in lambda and not afr. Gas around here is e10, I spray 100% meth so figured lambda would be easier. Have some questions.

So when I was tuning with afr I would aim for 10.9ish afr on meth.
Now that I log lambda should I should for the lambda equivalent of 10.9 or the lambda equivalent of say 11.5afr?

Is there anyway in hptuners to set the stoich in lambda? It's factory at 14.68xxx afr. If it can't be changed to lambda should I change it to e10 which is 14.1afr?

Thanks
Alex

vinceI

iTrader: (5)

Lambda will always be 1 volt at stoich for any given fuel so when your reading 1 volt with an e10 fuel your afr is 14.1 to 1. If you were getting your best power before at 10.9 afr using e10 fuel the lambda equivalent would be figured by dividing the target afr by the lamda afr for the given fuel. In your situation that would be 10.9 divided by 14.1 giving you around .77 lambda to be at the same as your 10.9 afr. The only problem with your setup is your adding two types of fuel into the mix and you have no real idea what the actual stoich is with the mix of the meth and e10 is. That being said you didn't know it before either, you were just using the 10.9 afr I assume because that's where the car was making the best power.

subeone

iTrader: (5)

doesn't matter what the stoich of the mix is, lambda is lambda for any hydrocarbon. if you have 65 percent meth and 35 percent ethanol, the wideband gauge will read 14.68 (give or take the setup on the gauge) if the fueling is at 1.00 lambda which in reality should be somewhere near the 8 AFRs or so if the gauge read in AFR units. The gauge reads in lambda units and uses a simple calculation to spit out an AFR number based on isooctane,e10. Whenever you are on e85 for example, if your wideband gauge reads 11.5 AFR at WOT the sensor/gauge is reading .79 lambda units. The OXYGEN sensor reads OXYGEN content not hydrocarbon content, you can put in any hydrocarbon you want and the units will forever be 1.00 lambda=ideal for fuel consumption efficiency and,depending on the setup, .79 being ideal for medium boost and .87 for NA.....

Thats what makes using lambda so awesome, it is always the same thing

SPRAYED 01

iTrader: (22)

Ok so I run a max of 20 psi on a 370 ci t4 88mm turbo with dual 15gph meth nozzles. I'm going to go for .77-.79 check plugs and let it rip.

Now second part is setting stoich in the factory pcm. Can you set it with hptuners to lambda? If not should it be set to 14.1 or so?

vinceI

iTrader: (5)

1 volt Lambda will only read 14.7 afr assuming your wideband is only set up for gasoline, some widebands controllers can be configured for the fuel being used.
The other nice thing about tuning with lambda is that its very easy to tune with it because lambda at stoich is always 1 volt so that means that any portion of lambda is a percentage. If your target is .77 lambda and your logs are at .75 you can take out 2% fuel and be at your target.

vinceI

iTrader: (5)

No matter what fuel you are running stoich is always going to be 1 volt so you wont change anything in the pcm to set stoich to and actual afr. Some a/f gauges or loggers you can change the fuel being used but that will just correct the displayed afr on the gauge to the fuel being used. Example being if your running gasoline stoich is 1 volt and af gauge will show 14.7 but if you were running e10 and the controller allowed you to input e10 as the fuel you would still see 1 volt at stoich but the af gauge would read 14.1 afr. Lambda is just a percentage of the afr for any give fuel at stoich this is what makes it easy to tune with. Saves you from dividing actual afr versus target afr to come up with a percentage of change needed to meet you target afr. Not sure if this is helping or confusing you more, I will look tonight to see if I can find a link to a site that may explain it better.

SPRAYED 01

iTrader: (22)

When I refer to changing the stoich setting Im not talking about the gauge or even loging. Im refering to the editor part, in the tune the factory sets stoich at 14.6xxx. It can be changed to whatever. Are most entering in a different number for lets say e10? Does changing that have any effect?

1970camaroRS

iTrader: (8)

Yeah, as long as you divide by the same stoich number in your PID for commanded lambda that is in your tune, and you have a WB that will report in true Lambda, you're good-to-go.

1970camaroRS

iTrader: (8)

If you change you stoich in the tune to say 14.2222, you need to setup your commanded lambda to be [PID.6001]/14.2222 in the scanner. There's other ways to do it, but if you do it that way it will work. That said, if you are tuning in Lambda the only thing that matters is that the stoich number, whatever it is, matches everywhere you input it. The actual true AFR number is meaningless at this point.

LilJayV10

iTrader: (39)

I need to get on board with this. AFR is the only thing I've ever known but apparently this "lambda" thing is ****.

eaglegoat

I use 14.12 for all pump gas cars I tune. You cannot change the editor to command lambda, it uses that afr setting so it knows how much fuel to spray relative to the amount of air it has measured/calculated.

Are you logging directly in lambda or are you converting to lambda from afr? You should be logging directly.

eaglegoat

Oh and lambda has nothing to do with volts. So please stop saying it.

SPRAYED 01

iTrader: (22)

I believe I would be logging direct. My wideband has a dial on the gauge to switch to to display lambda. I found online the proper setup in the hptuners for logging lambda. It reads lambda on my logs. My command lambda is afr high res/stoich of 14.1 for e10. So thats converted.

Is that what you mean?

eaglegoat

Yes. But commanded lambda should be 1/commanded eq.

SPRAYED 01

iTrader: (22)

Hmm, I set it up with the banish dvd and its working well. Let me ask you this, what exactly is afr high res? What is that reading?

eaglegoat

http://www.hptuners.com/forum/showth...Resolution-AFR

SPRAYED 01

iTrader: (22)

Ok so its just a calculation right? Of what stoich is set to and then any adders?

eaglegoat

It's AFR*commanded lambda. All the adders and multipliers are rolled into it already.