The LNF Tuning Guide

[BackyardTurbo_FTW]

^byah!

[sUiCiDe]

Very good writeup

[IFRYRCE]

I gotta say, I disagree with some of this. Do NOT set your Max Airload Torque table to 90+ everywhere. That is what causes the twitchiness that you experience, and then you turn to the max torque vs gear tables to eliminate. The Max Airload Torque table and the desired airload work in concert, one table modifies the other.

The GM stage 1 tune has a lot of hints to be found in it if you examine it closely. I'm looking at mine right now and comparing it to the tune I did following these instructions. The driving experience (and boost) was IDENTICAL, however the GM tune was much less twitchy. They obviously modified a lot of tables we don't have access to, however I have learned a lot from what they did to the ones we can access.

GM, for their Max Airload Torque table, adds 2 at 1650, ramping it up to adding 13 at 4k rpm, and finally back down to adding 3.75 at 6500. If I were you guys, I would modify my max airload torque like that, and work the DAL table to achieve what I want from there. I found it makes for a much smoother driving, better performing car.

To clarify my point, the Max Airload Torque table is described in this guide as "Across the top is the RPM obviously and the value below each RPM is the Max Airload in % the VCM will be looking for." However, HPTuners describes the table as "Torque used to calculate the maximum allowed airload." Granted, HPtuners description makes ZERO sense, because torque is a function of airflow not the other way around, HOWEVER if you think that Max Airload Torque is simply a table that modifies your DAL table it is simpler to understand. But until someone proves me wrong, I refuse to believe the description included in this guide. The Max Airload Torque table is not a torque limiting table, it is simply a torque-that-exists-for-the-purposes-of-our-calculations table.

If anyone disagrees with that, I'd love to hear your reasons why so I can learn from them.

[Gimpster]

There are a few things that cause twichyness (however you spell it) from my experience. The biggest offender in my opinion is grossly jacking up the DAL's. You can "out DAL" all of your gear based max's and such.

Go to the drag strip or whatever some time and jack your 80+ DAL to like 400 and set your gear based to like 20 1/2 and my car totally ignores that and goes max effort.

Also everyone likes to drive their car differently, so adjust to your feel.

Shrug

[T-Man]

I'll play

I gotta say, I disagree with some of this. Do NOT set your Max Airload Torque table to 90+ everywhere. That is what causes the twitchiness that you experience, and then you turn to the max torque vs gear tables to eliminate. The Max Airload Torque table and the desired airload work in concert, one table modifies the other.

The only places you should be setting the MAL to 100 is past 2700, IMO. Since you're using the GMS1 as an example, GM also starts to ramp up the MAL at 2700 but only to levels they needed to achieve the airload/power they were after (as well as modifying the WG duty cycle). We're after more, obviously.

Max torque vs gear table will only limit the ETC. It has nothing to do with the MAL or DAL.

The GM stage 1 tune has a lot of hints to be found in it if you examine it closely. I'm looking at mine right now and comparing it to the tune I did following these instructions. The driving experience (and boost) was IDENTICAL, however the GM tune was much less twitchy. They obviously modified a lot of tables we don't have access to, however I have learned a lot from what they did to the ones we can access.

The "twitchyness" is easily taken care of by reducing the DAL from 400RPM down to 2500 (more if you prefer) and all the way across to 60 or 70 ETC%. This way, instead of allowing the MAL to be the nanny torque management, you use the DAL. Best of both worlds. Also helps to keep 1st gear from being annoying.

GM, for their Max Airload Torque table, adds 2 at 1650, ramping it up to adding 13 at 4k rpm, and finally back down to adding 3.75 at 6500. If I were you guys, I would modify my max airload torque like that, and work the DAL table to achieve what I want from there. I found it makes for a much smoother driving, better performing car.

GM made small enough changes to the MAL, DAL and modified the WG duty to allow for more boost and to achieve a specific airload/hp limit. They also wanted to protect the turbo from being "overspun", which is why a GMS1 car will fall off to near stock HP levels past 5-5500 RPM. HPT cars do not, thanks to the MAL table being maxed. You may have a "smoother" driving car (This is only relative to the person behind the wheel as we all enjoy different driving styles and the ETC is slow as balls, which causes a lot of people to try to over compensate and give it more pedal. By the time things have "caught up" the car is "twitchy" etc.) but it definitely will not be better performing.

To clarify my point, the Max Airload Torque table is described in this guide as "Across the top is the RPM obviously and the value below each RPM is the Max Airload in % the VCM will be looking for." However, HPTuners describes the table as "Torque used to calculate the maximum allowed airload." Granted, HPtuners description makes ZERO sense, because torque is a function of airflow not the other way around, HOWEVER if you think that Max Airload Torque is simply a table that modifies your DAL table it is simpler to understand. But until someone proves me wrong, I refuse to believe the description included in this guide. The Max Airload Torque table is not a torque limiting table, it is simply a torque-that-exists-for-the-purposes-of-our-calculations table.

If anyone disagrees with that, I'd love to hear your reasons why so I can learn from them.

The MAL table is one of, if not the main torque management table...

Read this thread as it will help you to better understand how this Bosch ECU works. It will also illustrate as to why you want to use the DAL as the "limiter" instead of the MAL table as MAL is calculated via the DAL and the ETC position (and more I'd assume): http://www.hptuners.com/forum/showth...ight=LNF+bosch

[mkriebs]

Don't drive my car, you would die. That 'twitchyness' is called RESPONSE in my book. I have my DAL's jacked from 60% up. 25 psi of boost at 50% tps, yes plz.

[BlackBaltSw]

Don't drive my car, you would die. That 'twitchyness' is called RESPONSE in my book. I have my DAL's jacked from 60% up. 25 psi of boost at 50% tps, yes plz.

[Terminator2]

Don't drive my car, you would die. That 'twitchyness' is called RESPONSE in my book. I have my DAL's jacked from 60% up. 25 psi of boost at 50% tps, yes plz.

I have tried this on my car as well but I have since smoothed it out because doing unintended rolling burnouts gets old after a while. Still hits hard when I want it to and has great drivability.

[mkriebs]

I have tried this on my car as well but I have since smoothed it out because doing unintended rolling burnouts gets old after a while. Still hits hard when I want it to and has great drivability.

Mine doesn't really do an unintended burnout. I have my tq management dialed down in the lower gears, I just want it to hit super hard when i come out of the curves. Its not really a DD map, its more of a tearing the curves map.

[Iam Broke]

It's all personal preference. I ramp my DAL's up hard 80% and higher so I don't burnout rolling around people in traffic. No torque management except first gear and MAL table at 100% by 2500rpm, steeper than stock or GMPP.

[IFRYRCE]

Man I like you guys quick responses...

Twitchiness in my book is defined as response beyond what is expected... Such as having the car lunge forward when I move the throttle less than 1/8 an inch. I hate ETC, I can't wait until HPtuners releases whatever table Vince is getting 1:1 throttle control from. I just don't want to be trying to pull away slowly from a stoplight and start doing a burnout, or have my girlfriend slamming my head in the headrest accidentally while she drives my car. While we're on the ETC subject, I also hate how I can leave it at 25% and the car accelerates to 100 mph if I just hold it there... I am supposed to have to open the throttle more, the car isn't supposed to do it for me. Stupid smart cars.

After studying the GDI guide I see what you guys are talking about, I was totally incorrect & got no problem admitting it. Anyone have an idea what the max torque table does (the one next to MAL)? I have mine doubled in all the cells that weren't 100%, but I am hesitant to set it all to 100%. I've also changed my MAL tables back to 100% from 4k up.

Finally, does anybody know how I stop this stupid computer from closing the throttle when I shift? I don't care if you call it no lift shifting or powershifting (NLS is a cop out in my book, I've been powershifting cars that didn't have fancy electronic nannies since before I got my license) but the throttle is NOT supposed to close at all when you do it, and I can both feel it closing and see it closing in the logs, especially on the 1-2 shift.

[Iam Broke]

No way to stop the nanny from closing the throttle until you can turn her off completely. If I get wheelspin in third with ESC off she still shuts me down.

1:1 throttle like while the key is on, engine not running (try it while logging sometime) would be very nice but might cost a transmission or two.

[IFRYRCE]

1:1 throttle like while the key is on, engine not running (try it while logging sometime) would be very nice but might cost a transmission or two.

I don't care, as soon as this F35 trans blows up I'm going to the F40. Six speeds ought to fix the shit gas mileage this car gets. My LS1/T56 RX7 averages 20, I only get 18.5 in the cobalt. Although, that is comparing the DIC mileage to the calculated mileage.

[Jaxon]

Your getting HORRIBLE mileage in your cobalt. I beat the hell out of my HHR thats been tuned for over 30k now and am just getting my worst mileage, 20mpg at worst running 1:1 e85 to 93 and a/c on all the time. Also, the f40 isnt easily swapped in and doesnt have a double overdrive like the t56. Your t56 should be getting better than 20mpg on the highway...

[mkriebs]

Wow, tune your MAF tables. I get 28 in mine, when I am ripping it.

[Iam Broke]

25 mpg on 50% ethanol beating on it.

[Gimpster]

I did the ratio comparison of the F40 not too long ago, and it would IMO be a really awful choice of transmission for this car. Also I doubt the F40 is much stronger than the F35 from the specifications I've seen.

[IFRYRCE]

My T56 gets way better than 20 mpg on the highway, I am not talking highway MPG, I am talking average per tank. The T56 in the RX7 gets 34 mpg on the highway with the cruise control at 70.

If you guys are talking average per tank mpg, I am way behind... I'll get on tuning those MAF tables since it makes such a difference and then I'll get back to you guys. I mean I picked up the car off the lot last friday I haven't had it long either.

Gimp, I don't see what about those ratios is bad-- Closer 1-4, farther 5-6. Better acceleration and MPG. Trans is plenty strong V8 guys use them in Fieros, and I am looking into the new parts available with the 2011 Regals that come with F40s and LNF-variant motors to see if I can acquire some of the parts for the swap. Gimp, you also got a PM about that E85.

[Gimpster]

We have the torque to pull the longer gears, I'm just thinking all the extra shifting in the end is going to be a wash. Kinda like all the turbo K series cars I've ridden in, they end up shifting all the time and get almost always seem to get pulled.

Hey, the stock T5 in my old SBF RX7 held up well too hooking 1.5-1.6's... but I also had about 1200lbs less than a Mustang all a matter of perspective. Try that in a Mustang and usually you'll have a bucket full of T5 parts.

Not trying to be a jerk or anything man, I love to be proven wrong.... just don't think its a good transmission for the Cobalt.

[T-Man]

Ask the MS3 guys if they enjoy shifting as much as they do...