OK so I have been doing some thinking about tuning in general. And my question is this, when tuning our fueling parameters we always base it off a Stoich AFR of 14.7:1. But if you look at HPT it lists the stoich afr as 14.69971:1. Now that is NOT 14.7. So would changing the stoich in HPT to 14.7 adversely effect anything. Im thinking not, since all my fueling, ie: PE, Command AFR, and so on, has been based off of 14.7. Also would changing the stoich to 14.7 help in everyday mpg? Again I would think it would, since it is being leaned out a tad at cruising.
Just asking, and I in no way want to start a debate. Thanks

 

Ok so I guess no one knows the answer.

 

I don't think any one smart enough to help you is awake.

 

There is no difference between 14.7 and 14.699. So, no it won't do anything. I believe it changes it back to 14.699 any way if you change it to 14.7.

 

Hmmm? Interesting. I dont see how it would revert back to 14.6997xxxx. If I manualy type in 14.7 in the Stoich AFR section on HPT it should stay. And your right its such a minimal amount that it probably wouldnt effect a thing fueling wise. I was just wondering is all.

 

like you said, it wouldnt affect anyhting, since theres only a .00029 difference in the numbers. Your AFR wouldnt be at 14.7:1 anyway, since its always moving around.

 

Thanks all. Kinda thought the same thing, just thought Id ask.

 

i was considering throwing in like 14.9 or 15.0 in there for ***** n giggles. just to see what it would do. probly not a great idea though

 

What's funny is the guys on the LS1/2 forums are doing something like that as far as leaning out there cruising afr's to increase there mgp. Been doing it for quite a while. I know you can deff do it with let's say a LS1 04 GTO. Had it on mine. I was pushing 16.0 cruising and still had my wot fueling dial in.

 

All calculations for fueling go off that number. If you change it from 14.6xxxxx to say 16 then all fueling tables go off the number 16. Which means your AFR at Wot will be off by two points (roughly probably some more may be less just depends on factors) so thats what will happen.

 

I'm very much aware of that and wasn't planing on making that kind of a change. I was just commenting about Bika's post. My original question was would changing the Stoich afr from 14.67xxx to 14.7 hurt anything since when we do any adjustments to our fueling tables we are always basing off of 14.7 and not 14.67xxx. The only reason I did that to my GTO was to help with the mpg last year when gas (prem) was 5 bucks a gal. And yes I had to change all my fueling tables for wot.

 

no it wont change anything, nor will it stay like that. 14.699xx is just the way hptuners rounds its decimals. it wont do a whole number, in any fueling table.

 

I tried that. Set it to 15.2 and the wideband still read 14.7 even though I was commanding 15.2. Not sure why that is but my theory is that it has something to do with the O2 sensor feedback. Afterall its a narrowband anyway and moving stoich by .5 AFR probably isn't enough of a voltage change for the computer to adjust the LTFT and STFT. Just look at the voltage chart for the O2 sensor



just my theory I haven't been able to prove or disprove it yet. Well more like I didn't want to waste the time trying to...

 

Didnt know that thanks Bika, oh did you get my other email with my config file to see MAF and Inj dc?

I have a simular chart on my computer, but good info.

 

yeah i got the log files. You look like you are running better now.

IMO, set your PE to 11.5 (1.278), put your timing back to stage 2, and make a log and send it to me.

 

Why put the timing back to S2? The only KR I saw was a bit of burst knock on the low end for a split second, the rest of the runs had no KR at all and this is with the timing settings you set up.