oakley6575

iTrader: (5)

I launched it 5-6 times yesterday on the 2 step at 3200rpm. I had the tires at 19psi and they held on the street no problem. There is a lot of tire to grip the road now. The tires weren't even warm. So with a burnout at the track, I don't see traction ever being a problem anymore. I have a tricky set up with such a small engine and such a big turbo. Obviously a transbrake would be ideal for my situation but I'm going to see how far I can get on the footbrake first. I really need to get the 2 step up to around 3500-3600 to spool this turbo. So a converter change is necessary to get that out of this truck. I have already been talking to Chris @ Circle D. He says he can do some special tweaks to his 258mm 3B converter to get this little 4.8L to foot brake that high and still be efficient at 800rwhp through the traps.


Yesterday I could make 6psi @ 3200rpm. How do most of you guys tune while on the 2 step. I am running around 30* of timing and commanding .87 lambda.

Atomic

iTrader: (42)

No different than normal. 18 degrees and .76 lambda

oakley6575

iTrader: (5)

From what I've gathered, most of the race cars either run rich and retarded on the 2 step (like -10*) or super advanced (30-40*) and lean to spool the turbo.

I miss the window for my set up so 7psi is about all I am able to spool too. Must be nice having all those cubes

Vortec350ss

iTrader: (20)

I get that... but if hes showing an AFR of 8.xxx when lambda is set to show as 14.7 on his gauge then he is far too rich regardless of what fuel he is running. That's all I was trying to clarify.

When I refer to scale, i am referring purely to what the output on his gauge is... nothing more.

To put it in terms you will understand... what does the 8.xx AFR mean in lambda. Does that make you happy?

oakley6575

iTrader: (5)

This is what I'm trying to clear up for you. That above statement makes zero sense. Either you just keep wording your questions wrong or you don't understand what lambda is... Not being a dick or rude in any way, just trying to help you understand why that doesn't make sense. Lambda can not be set to show anything. Lambda is lambda and AFR is AFR. Two seperate things. His gauge can show AFR in the gas scale, AFR in E85 scale, lambda, ect. Which ever one he choses, is going to be shown on the gauge no matter what fuel he is using.


He said he was around 8.4 AFR and his gauge output was reading in terms of E85. So the stoich value of E85 is 9.765. (8.40/9.765) = 0.86 lambda.

The gauge only knows lambda. So the sensor reads lambda and then converts that number to what ever AFR scale you want to read it in. Since we know his truck was running 0.86 lambda during that run, you can calulate what he was running on the gasoline scale if you wanted to.

0.86 lambda = (x/14.68) ..... So he was running 12.62 AFR if you wanted to look at it in the gasoline scale.

Atomic

iTrader: (42)

2steps work by retarding timing to limit the rpm. No need to do it in the tune, thats what the 2step does.

oakley6575

iTrader: (5)

Sure it cuts spark in individual cylinders. There are still the rest of the cylinders that are controlled by the tune.

Most of the high horsepower auto cars use the high timing lean AFR method to get up on the converter. I was watching dedicated drag cars one night with gauge overlays in the vids that showed how they had it tuned for spool up and launch. It was pretty interesting to watch. I'll see if I can find some vids

Vortec350ss

iTrader: (20)

Thanks. Exactly why I was asking if he was showing on the Gasoline Scale. I must have missed that he was showing in the ethanol scale in his post. All he stated was that it was equivalent to a 12.5 in gas... Sure, that's true if he is reading lambda or reading on the ethanol scale, but if he is going off simply what his gauge is telling him then he could be reading 8.5 on a gasoline scale... or a lambda of about .58. I know it seems like a silly question and he is smarter than that... but I had to ask. People make silly mistakes sometimes. he never said it was reading .86 lambda, only the AFR. That's all I was trying to clarify.

We are using the same words here... I don't know why my post is so confusing. I was simply trying to ask if his gauge was showing him lambda (1) or Lambda on a scale of 9.76 for ethanol. If he was not, then his AFR would have been really far off. Again, kind of a silly question... but **** happens and people overlook things. I think the confusion here is that you assume I have no idea what lambda is or means...

This kind of feels like we are arguing over who makes more boost when I claim 14.7 PSI and you claim 200 kPa on your scans...

I GET THAT LAMBDA IS LAMBDA REGARDLESS OF FUEL USED!! LOL

I'm not trying to be a dick either... I hope i made myself a little more clear.

Atomic

iTrader: (42)

I am pretty sure it alternates which cylinders it cuts and can retard them all if needed. You are overthinking this. Set the rpm you want and let it do its job. If you arent building enough boost, set it higher or make sure your gate is staying closed.

GMCtrk

iTrader: (27)

I have the NGK AFX wideband and their display only shows in the gasoline scale. So, when my gauge shows 14.6 I know that my true AFR is 9.8, given that I was running E85.

Now, only my EFI live scan tool, I have a PID set up to display the AFR in the E85 scale, so on there is does display the correct AFR. Regardless though, the AFR is not that important to me. Lambda is what I'm after. It would be nice if the gauge had the option to show in lambda, but either way its fine.