Updated the guide with some new info :)
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Updated the guide with some new info :)
Curious as to why you adjusted the MAL table the way you did? Are you trying to keep the throttle from being too "touchy" with the DAL's you're commanding?
I gave it a shot just to see how I'd like it with the GMPP setup and I lost 2lbs of boost and 20ish % load (220, down from 240+).
When I had the MAL set at 100% from 27 or 3K up the car would spike hard, then dip down, then pick back up. It never held 22psi for me, it would be a 23-24 spike, then the dip then hold 20.5-21 for a little bit.
Switching to the MAL table I posted now the boost comes on smooth, holds more, and is flatter holding more boost longer. I also tried making the DAL table 270 down to 3K then ramp them up to 350 by 6k.
Even with the modified WG Duty cycle?
I'm just wondering if mine has to do with the fact that my DAL's are extremely conservative and I've never really needed to exceed 260 in order to achieve the boost I was after.
I'll give this MAL table some 60-100 runs and see how it performs.
Thanks again BYT.
I can tell you why that happened with the stage 1 tune. One time I wanted to do an experiment. I set the MALT to 75% straight across but I cranked the DALs in the 100% column to 400% or so. When I used to do this with the normal GM tune and 2.5 bar sensors the car would spike 25psi then hold 22 psi or so like normal. When I did this with the GMPP file the car was boosting only 16-17 psi.:bigshock: I thought I had something broken on my car LOL. It appears that on the GMPP tune the MALT controls the boost level to a much greater degree than the DALs. I find with the GMPP tunes it is always best to leave the MALT at 100% all the way across as it gives better boost response in the midrange but that is my own personal preference. With the normal non GMPP tunes I normally ramp it up smoothly starting from 75% on the first cell and up to 100% by 3K.
Thanks for the heads up Term. I had a hunch that the MAL table was much more of a factor with the S1 but I had no evidence to back that up.
I'm going to do 3 60-100 runs on both tunes and report back later on, when it's cooled off a bit... ONLY 110 degrees right now, nothing serious :shrug:
Thanks for this again.
I just wrapped up an 09 Cobalt SS today but unfortunately I just saw this thread tonight! Here are some random thoughts...
This was the first of the platform that I have tuned. I enjoyed it so much that I spent a lot of time working with the car. I have an update session with the owner on my dime just because I want to spend a little more time on a few smaller points with it.
I spent some time playing with cam timing... more than I should have and all roads led back to OEM. This car had a Hahn (sp?) intercooler and cold side, an aftermarket downpipe and a replacement turbo that looked the same as the OEM unit to my eye (?). The cam timing will be more important later with a larger turbo and the need for more camshaft.
At WOT from about .87 all the way down to 0.75, the car made the same tq except up top. North of about 5500 there was a small (2-4 ft/lb) drop being that rich. I was somewhat surprised to see zero impact on tq in this area. It just didn't mind being fat. Also, the car didn't do as much with timing as expected. I ended up with the car being up to 14 deg up top. You guys can lean on your own cars and have more time to push on things; I'm not game for testing the limits on something that I don't own. :) Also as I said, I hope to have an update session with the car in a week or so.
The correction moves fast... with LTFT-ing disabled correction can move more than 10% in a half second even applying no learned value. As nice as this is, this is going to get people into trouble for relying on it! Having an on-board wideband, short term trimming literally becomes an expression of AFR error when filtered down. Once you get things like IAT normalized on a short cruise, 2-3 passes through the MAF table get's it within a percent. I actually set timing lower than stock and went over the MAF first thing after the base setup before doing any other tuning. The correction is nice but it should not be used as a crutch. If the underlying MAF is off, correction may work fast, but all of your transitional fueling will be off in the direction the MAF curve is off in that particular spot. It's good to get the underlying airflow model done BEFORE fine tuning spark at all. Any lean spots covered up by correction in the MAF curve have the potential to create tip in or transitional knock. It's important to realize the root of the issue rather than hacking up a sprak table right off. It's also comfort to know that you will hit target AFR at WOT regardless of correction so that you have the confidence needed to begin to manipulate timing at WOT.
Unlike mentioned by some in this thread, this car really had little-to-no false knock anywhere. A side note... you guys should expand the resolution of your timing tables. The screen shots on the front page show whole numbers. The factory carries it out a good bit farther. You can click the error with the 0's in the table's tool bar to get at least one decimal place on your timing values. The extra res is nice for fine tuning. The same is true for the MAF correction table; you might go 3 decimals on it if you take that approach.
Best of luck guys; I have to get back into my email.
This is a basic guide to show examples of how to work with the software on our cars. It is not intended to be an in depth hand holding guide. If you are tuning the car, you should have a general idea of how a motor works and what effects fueling, boost and timing have on it. Reading some guide quickly on HPT isn't going to teach anyone that stuff lol
I didn't read this to learn how to tune a car (or maybe you didn't fully read my post); I read it after tuning one and was just sharing some thoughts and what I observed. I don't normally do it and I can certainly take the post down if you are having a hard time with it..
Your post is fine, Im just explaining that there's a LOT still not covered and this is just a very basic how to for the software.
Why are you running that poor car so rich? 0.75 lambda is way too rich for this car. I am shocked you did not loose a ton of power up top running it so rich. When I dyno tuned my last LNF (I normally street tune) going from 0.84-0.88 PE lambda made a 26 whp difference in the car.
I didn't say I LEFT it there, just that running that range had no impact and that I was surprised (as you were as well). It was the first one that I had for tuning (typically all F-bodies and Vettes, trucks, etc) so I spent some extra time playing with everything to make sure that the owner was getting a good return on his dollar. I ran the range of AFR testing timing along the way. Also worth noting, you would expect running that rich would allow for at least SOME gain in timing vs. the leaner setting but that didn't pan out either.
Last weekend went to dyno and played with lambda on the 5500-6500rpm range.
Initially I had 0.78 on that range, based on my reading especially around here I thought I loose power because of that.
I have bumped it little by little up to 0.86 on that range, no difference in the power.
The only thing which made me to gain something on that rpm range was Advance changes, initially had 11-12 degrees and bumped to 14 degrees (13.5 read) made to gain 2-4 KW ( 2 - 6 whp)
Used a mustang dyno.
I am a big time street tuning fan, but this underscores the importance of having BOTH sides of the coin. Why would you leave a car at .86 to .88 if it made no power leaning it out past .78 right? I left the car I tuned at .8. Going to .86 or .88 would just mean higher cyl temps and less resistance to knock. .88 is for N/A cars :)