Are you kidding me? It makes a very big and real difference. Beside the fact that lambda is lambda regardless of fueling. 1 will always be stoich. Tuning to the wrong stoich by assuming fuel and AFR leads to many drive-ability problems and hunting for the correct AFR all the time for best power, best lean cruise, etc. It gets worse if you are street tuning only and don't have access to a dyno. Lambda honestly just makes everything easier and more accurate.

 

Either you have a fundamental lack of understanding as to what the stoich scalar does in the PCM or you really think that a 2-3% difference in fueling will make the car run discernibly different than before.

 

Why would you think I don't know how the stoich scaler works based on what I've said? Also, 2-3% fueling can make a huge difference, not sure why you think it wouldn't. If you're fueling is wrong, it's wrong.

 

you can put your stoich where ever you want and scale the maf and ve to fuel accordingly... yes its a good practice to have your stoich correct for the fuel youre using, but that's mainly to keep your airflow numbers from being either astronomically high or low which in turn can greatly skew calculated tq numbers (auto trans concerns).... it sounds like you have a real lack of tuning knowledge, and should really stop before you look even more incompetent.

 

No ****.

Also, no ****. BUT, what happens if you tune to 14.68 AFR and your fuel is actually 14.12, like a lot of pump-gas these days? You're going to be wrong. And wrong is wrong. That's all I'm saying.

This is one of many reasons I was saying what I was saying! It's especially important to get it correct when you're doing an open-loop SD tune, for other reasons. But, of course you know that but want to belittle me.

This was uncalled for.

 

and what happens if your stoich is 14.12 and the gas is e0 which is a stoich of 14.68?? the point is all you can do is tune for the fuel on hand ... the fuel can be e10, and be tuned just fine on stoich set at 14.68... my point is you're making a huge deal over 3-4% of a fueling difference. unless the car is has a ethanol content sensor, it does not know the current ethanol content.

 

Yeah, most E10 gasohol blends are more like 6-8% but I'd air on the conservative side and use the Stoich at E10 as the baseline.

Remember, all gas, even ethanol, makes best power around .9 lambda or ~1.11 equivalence. So if you set your EQ ratio in your PE table to less than that ~ 1.14-1.17 or so, you'll give yourself a little bit of cushion and with E10 vs E0 the difference is barely anything. But all gas has some ethanol in it now, so the safer practice is to treat it all as E10. This is why tuning in lambda/EQ is preferable to AFR. You don't have to worry about the type of fuel. Set the stoich and go from there. Is the difference worth it? Not for E10. Moving to E85 is a different story of course. As a compromise you could split the difference in stoich and input 14.3, which I know a lot of folks do.

Either way, I'm making a suggestion based on best practice. Whether or not pros do it is on them and based on their experience for what works. As someone who does a lot of process for my job, there are things you can sort of fudge and it doesn't have any detrimental affect on the overall process. Over time, you learn where those things are and what short cuts you can take while still maximizing the end product/service - whatever is quickest with acceptable levels of quality for you to turn a profit is understandable.

But, if the OP wants to buy tuning software and do some tweaks down the line, why not expose him to preferred practices? The other way to is adjust the VE table the same amount ~3% from what the AFR % error is. At the end of the day, you're doing the same thing to eliminate the fueling error (that is if you even do it). I'm very meticulous. I prefer not to have any errors if I can help it. And the time spent isn't much to make a difference. Does it matter? Probably not, but I would recommend degreeing a cam vs installing dot-to-dot. Doesn't mean dot-to-dot is wrong or that suggesting degreeing is the blind leading the blind because 99% of the time it's a waste of time - and again time is money when you own a shop. Just one is a more accurate and meticulous method and for the shadetree mechanic who only sees a handful of these motors, it gives him peace of mind.

Tuning is a learning experience. This site is geared toward shadetree mechanics who are looking for advice on how to do projects in their garage or driveway. Maybe you roll your eyes at some of the advice. Provide constructive criticism or elaborate on why it's a bad practice if you have something to add. Otherwise, being arrogant and condescending is not appreciated nor a good reflection of your business practices.

 

Thanks for your input Jake. I agree with everything you said.

 

You will be safely rich instead of dangerously lean at WOT. I mean, if you're ok with risking your customers' engines, that's fine I guess. I still maintain, and likely forever will, that tuning VE and MAF to 14.68 using AFR instead of Lambda is a mistake. One that amateurs would make, even if it's "good enough".

In all honesty, if you're tuning lambda, it doesn't even matter what you chose your stoich to be in the tuner, just as long as if matches your wideband output as you setup VE. Stoich of e10 is 14.12 and lambda is 1. Stoich of e0 is 14.68 and lambda is 1. Stoich of E85 is 9.765 and lambda is 1. Unless you have a programmable wideband and guess on what fuel you're getting out of the pump which as Jake pointed out can vary greatly between 0 to 10%. Tuning to "fuel on hand" doesn't matter when dealing in terms of Lambda. It will always be 1. Of course, best EQ will change as fuel changes, but that's not what we're talking about here.

Why do some people simply reject the idea of tuning in Lambda? It's what the tools you're using work in natively anyway!

 

At least Ryne gets it.

The point is changing the stoich AFR ratio for E10 in the computer makes a ~3% difference in fueling, it's a essentially a global fuel multiplier. Every O2 sensor reads lambda and it's value is converted to AFR based on the stoich value set for the fuel you are using so talking about how lambda is the only way to tune is hilarious because it's all the same. This is the fundamental lack of understanding that is killing me and acting like a 3% difference in fueling will be felt or noticed or whatever is just as funny. Fuel trims swing that much on a daily basis from weather conditions, sensor drift, minute changes in fuel, etc.

 

Except for throwing it on the dyno (which I will in the spring) just to double check things, the car is now is now fully tuned as of last nite. We spent several hours last nite (plus the 3 days that my guy kept the car) fine tuning everything and getting it exactly where we wanted it. Bottom line...the car is simply just better! One thing that surprised me is at how much timing this setup likes. At WOT we are now at 29 (27 before) and as high as 31 at some points in the the mid - high end. Even at 33 degrees it showed no knock but actually felt less crisp and responsive. After several runs we found the best compromise of max power and safety. Idle is now at 800 rpm (was 950 before) and has no fluctuations, no dips or hanging idle, and actually feels smoother and just plain better. In a nutshell the car is actually running a tad richer but with more timing. So pretty much everything is improved on every level....what more could I ask for The only thing i might have a problem with is my LNC-2000....according to his software it may not be pulling timing for the nitrous even though we have a good a/f. I need to verify this. All in all I'm extremely happy with the new tune, and may never again take my car to some high end/volume speed shop just because they are well known. Great lesson learned for me

 

You can't check the LNC-2000 with any software because it is hooked directly to the coils. The PCM is advancing the time based in the timing tables, that's what you see in the datalogs. The LNC is retarding the timing after the PCM send the pulses to the coils.
To check if the LNC is pulling timing you need a light gun and a damper with degree marks and a timing pointer. That's the only accurate way to check.

If you only want to know if it pulls timing, set it to max retard and deactivate the nitrous system. Do a WOT pull and activate the LNC, with the 15* of retard the car will bog or lose a lot of power. Be careful to disable both solenoids.

 

Funny you just posted this, as I just found this all out like 15 mins ago....literally lol! I appreciate the feedback though.

 

Double post

 

Bumping this back up because we've run into a issue and am curious too see if others have experienced the same thing. Car runs awesome with the new tune but one little problem....car has trouble starting when cold. My tuner believes it's because of the IAC being closed when I had my throttle body ported. Since we dropped the idle to 800 rpm from 950 it now has become an issue. Raising the idle back up (which I'd prefer not to do if at all possible) may solve the issue and/or going back to a stock throttle body as well. So I guess my question is are there any other possible solutions to this problem other than what I've already mentioned? Thanks

 

I'm having this exact same problem! I have to give the car gas now on cold weather start ups. Once the car warms up everything is good. This never happen with the stock TB and I noticed a .156 hole on the stock TB blade. I've considered drilling my new one... All and all I think my tune may need adjusting.

 

Pain in the *** isn't lol! What's wrong with your tune?

 

I have no clue. One thing I do know is my tuner hates the FAST TB that I have and said he's had nothing but problems with them. I haven't driven the car much since the intake and TB swap so it's been hard to get it back to him. Keep us posted!

 

And that's the thing...you see dozens of others that have a Fast throttle body and have no issues, so it makes you wonder lol. Hoping for some more feedback, but I'll be sure to keep everyone posted as well

 

lol 27* on that compression ratio, i sure hope you have a big cam to bleed off most of it. Then you have cnc'd heads, which should be more efficient than factory, which generally require less timing.

24* is a very good timing number imo. 15 ramping up to 22-24 is good.