Z-type's Tune Thread

That makes sense. I guess that's why I made several columns to get an average, rather than just inserting one value. I probably did the same thing and forgot about it.

Just curious, did you alter your lambda A/F ratio to 14.2 instead of 14.7? You should do this before you get too deep into your tune if you get E10 at the pump. 14.7 is for "pure" gasoline, which most of us can't buy anymore. It's one reason LTFTs are really high on most of our cars - they are already compensating for the E10 pump gas. It made a big difference for me.

No i did not, although I remember you mentioning that in another thread I read. I wont be home for a good while today, are you able to point me in the direction of that table/cell? Is it hanging out in the fueling section i imagine?

Z-type wrote:

No i did not, although I remember you mentioning that in another thread I read. I wont be home for a good while today, are you able to point me in the direction of that table/cell? Is it hanging out in the fueling section i imagine?

Fuel/Base Fueling/Closed_Loop_Desired_A/F

Beat ya to it deek

deekster_caddy wrote:

Just curious, did you alter your lambda A/F ratio to 14.2 instead of 14.7? You should do this before you get too deep into your tune if you get E10 at the pump. 14.7 is for "pure" gasoline, which most of us can't buy anymore. It's one reason LTFTs are really high on most of our cars - they are already compensating for the E10 pump gas. It made a big difference for me.

I'm just now getting my fuel trims in check with it set at 14.7. Would dropping it to 14.3 mess them up to much?

I'm also assuming you need to reset the fuel trims after doing this?

You would need to reset fuel trims after this, and it will mess things up a little bit. Your original MAF table will be a lot closer.

My MAF tune is so close now too. I wonder if i should just change it slightly, to maybe 14.4 or so, just to see what it does.

I think it's worth changing. It will not take you long to get back to where things belong.

I'm not gonna say change it if it's working for you this way but I know at least two of the tuning smart asses told me it's better to scale IFR for fuel type in a nutshell because it works with the rest of the existing afr related tuning. The stoic number in the tune is not really meant to be a fuel density definition as much as just a afr home for the tune. This is a subtle change so I doubt you're gonna be hurting either way but just to mention it

I thank you both again for the information. I think since my tune is so darn close now I'm just going to stick with MAF tuning and see how it serves me for a couple months. If it turns out it's not working out quite right for some reason, I'll change that ratio to a lower number.

I'm changing the MAF table right now as I type, but I probably won't get to upload it until Saturday. Too many things going on, and my tune ain't too shabby right now!

Once again, this is fun as hell.

Quick question about your spreadsheet AA. I've been entering LTFTs scanned only within +/-5Hz of the given MAF (for example: Given MAF is 3875Hz, I enter any LTFTs between 3870-3880Hz). Is this similar to what you did, or...?

That's all I did Matt...just go to whatever frequency is closest, no biggie.

Small report. Did another flash the other day and the LTFT's are never above 3 in any case now, which is huge to me. Just a little more tweaking...

Still having a blast doing this.

EDIT: Still getting a little knock, but once again, only at extreme throttle, or sudden downshifts, and make some small blips between high-load 1-2 shift. Seems normal, all things considered?

It's perfectly normal. You might find that your car might be pretty particular. For example, if my fuel trims are at -2 I'll knock pretty bad, but -1.9 to 0 I'm pretty much knock free. It's pretty hard to be completely knock free, especially with changing temperatures and what not.

That is pretty specific, but hey. If it works it works. I don't expect to be knock free but I'd like to be worry free .

Quote :

Quick question about your spreadsheet AA. I've been entering LTFTs scanned only within +/-5Hz of the given MAF (for example: Given MAF is 3875Hz, I enter any LTFTs between 3870-3880Hz). Is this similar to what you did, or...?

I would plug it in the field that's closest to the recorded value. So logged scans between 3812.5-3937.5Hz would be entered as 3875Hz; value between 3937.5-4062.5Hz would be entered as 4000Hz, etc.

Ha! Finally some decent results. Any time I'm on the throttle over 20% my LTFT's are 0, or 0.7 . I'd say that's pretty good.

Question though - pretty much between 3000hz and 4300hz is my cruising frequency for the MAF, and anything lower than 3000 is off-throttle. I know off throttle it will have a tendency to be rich, but that part throttle area is sitting at about -7.8 for the LTFT most of the time. Should I back off the fuel in that range?

That's about where my idle sits now. It used to sit ~-20 and it would cause the idle to surge, but now that it's ~-8 it idles fine.

Okeedoke, cool. I figured since it was dumping fuel more than stock it might get overloaded and be rich.

Also, i was a little discouraged today. Went to dinner a ways away and up any hill around 50mph i couldnt go over 15% throttle without 2 degrees or more of knock. 3 people in the car, engine was already heatsoaked from coming home from work. Seems a little sensitive to me, but i guess it was overloaded. Anything i should look into?

Im going to check for vacuum leaks again when i get home.

You can have the fuel curves perfect, and the knock can still come from a variety of factors: heat, timing, boost, and in the case of your uphill experience: load.

Load is one of the biggest bears of 3800 tuning, imo, because the engine makes so much torque, and we love tapping into it. The feeling of pulling up a steep grade in 4th gear, with TCC locked - because the engine will gladly do it! We are proud of this car with its locomotive-like torque levels.

One of my professors once told me: "just because you can, doesn't mean ya should."

In the same situation, with TCC released, you would likely have less knock, and in 3rd gear probably zero KR. This is why I ran an aggressive TCC release curve (when I had a working TCC). Also my trans drops into 3rd pretty willingly when the load increases. I can just hear the engine thanking me when the revs go up and it finally breaths. More power with less knock.

And there are other negatives to high load, like transmission strain and bearing wear. Is using big torque at ultra-low RPM really worth it?

Another thing to consider is a trans cooler. Back before I got one, on warm days I used to notice the trans heating up to 220º after 30 miles or so of driving. The engine would stay around 185-190º, but for some reason I saw increased KR after the trans was at full temp. Since adding the trans cooler, I notice this less. Since the radiator cools both the engine and the trans, a trans cooler is like an extra radiator that takes over some of the duty of the OEM radiator. Every little bit helps.

Thanks for the info Aaron. One thing i didnt do is force it into 3rd gear. It was only in 4th with no TCC up the hills.

I actually do have a good trans cooler. It's 11x7" and keeps the temps around 160-170. I dont have a thermostat on the systme like yours though. I have a blockoff plate i use in the winter.

Anyway, i havent changed any downshift settings. ill need to poke through your settings and Scott's settings again.

Alright, sort of a mini update/question.

Besides the fuel pump issue, the fuel trims have been extremely consistent, but slightly rich since I mainly tuned in the Winter with cooler air and crappier gas. Between 40% and WOT my trims are just about 0.0 or 0.7. At cruise it stays around -3.4ish. Should I adjust that? I didn't know if it was worth fussing with to get it closr to 0.0 at cruise or not. Gas mileage doesn't seem to be a problem.

Also, I think it's about time I adjusted the shift firmness at lower throttle. It's a little firmer than it probably should be at the low range. Easy though.

Another question, where in DHP can I adjust the temperature at which the knock sensors start reading? I can't find it. I don't have an actual problem I just wanted to turn the triggered temperature down to be more safe than sorry if I have to jam on it when the car is cooler.

I would get your idle/cruise trims as close to 0 as possible. Sometimes the car will hesitate or stutter if they aren't close.

if you are + or - 5. that is amazing. i think + or - 10 is acceptable. anything outside of the range should be tightened up. better to be in the negatives tho

charlieRobinson wrote:

if you are + or - 5. that is amazing. i think + or - 10 is acceptable. anything outside of the range should be tightened up. better to be in the negatives tho

What do I get for being -3 to 0 all the time...?