Teach your old Chevy new tricks?

[MikeK5117]

Booster, any follow up remarks regarding your tranny programming project?

My C190P runs right at 170F when on the road, with outside temps in the 90F range. However, as soon as I slow down or get into traffic, it shoots up toward 200F pretty fast.

Knowing if doing the lock-up reprogramming will help this would be a great help.

Thanks, Mike.

[booster]

We just got back for 6K miles of testing on the changes, including lots of mountains and also quite a bit of slow and go.


The testing is muddied a bit because I had done two other changes since the last tests before I discovered the reprogramming could be done. I installed a two core radiator that was the core size they used in the previous generation vans for the 8.1 and diesel (there is a writeup on the forum of how to do it), and I moved the oil cooling back into the new radiator and used the oil cooler for more trans cooling by paralleling it with the standalone trans cooler. No trans cooling in the radiator used, and do have a thermostat in the trans cooler lines.


The most critical, and probably most accurate, test of the reprogramming was the repeat of our last test up from Estes in RMNP to 12K feet. Pretty much all second gear, now locked up compared to before when it wasn't. On our last test we got to 230* on the trans with the two big Spal auxiliary fans on. Water was at 220*. This time we barely saw 200* on either of them, and never even turned the extra fans on. Huge improvement, I think. We had the AC running both times.



The only time we saw the trans temp climb was on some very, very, steep hills that either required the trans to be in low gear or the in second gear in an area where it can't have the converter locked due to not enough power to climb with it locked at that low an rpm. Those climbs were short, so never got over 200* either, but would have for sure if they were longer.


Since we took the trans cooling out of the radiator, we have not had any real issues with heating up in traffic for either the water or trans. Before the last changes we would need to run the auxiliary fans if it was very hot out (100*), but with the current changes we didn't see any temp issues under any of the slow and go we were in even though it was very hot outside.


I do think you could probably get some benefit from reprogramming on stop and go temps, but a lot would depend on just how "stop and go" it is. It is not possible to lock the converter in low gear, so if you never get out of low you would have no change. The same is true for the low speeds in second gear, maybe under 20 mph where you need the power to move the van from being unlocked. If you get a little faster, even once in a while, so the converter locks, the trans temps drop very quickly (unless the water is also hot and you still have the trans cooling in the radiator). Water temps drop also, but lag some.


With the varied ways everyone uses their vans, it is kind of hard to predict what changes would help folks the most.


I would say that the programming changes to the trans is a huge factor for long climbs at speeds where the stock program does not lock the converter. The changing of shiftpoints helps some on temp also, but the biggest benefit we saw was getting rid of the super annoying auto downshifts on rolling hills.


The other changes, big radiator, auxiliary fans, standalone trans cooler, all seem to work together to cover the rest of the remaining weakness, although the fans are more for slower speed stuff.

[MikeK5117]

Thanks Booster for the great detailed reply.

Right now I just have the factory transmission cooler setup with the secondary external cooler but I am sure it runs through the radiator as well. I am not in a situation to undertake a radiator/cooler swap at the present time but could be a project for a few months from now. I will check the posts to read up on your radiator swap. Thanks again. Mike.

[User1213]

Do you think that the new radiator or the tune contributed more to the lower temps?

Was the larger radiator a simple swap or more involved?

[booster]

Originally Posted by Hondo

Do you think that the new radiator or the tune contributed more to the lower temps?

Was the larger radiator a simple swap or more involved?

As I mentioned above, the different changes most likely have an affect under different conditions.



The programming changes really did the trick on the long climbs in second and third gear where the speed is such that the torque converter clutch wasn't locked before. The radiator would not have had any affect on that, for us, because we don't have the trans cooling in the radiator any more. If the cooling was still in the radiator, my guess is that the radiator would have helped, but hard to guess how much. Likely not enough though.


The radiator did do a very good job at keeping the water and oil temps in line. We never needed to use the auxiliary fans to keep the water cool on any of the conditions we saw, which were very hot. Rarely even got close to 200*


Radiator install details are here,


http://www.classbforum.com/forums/f8...vies-7131.html


Pretty much a drop in with the exception of the lower radiator hose and connection which has to be modified and an adapter used and the radiator to block bleed line hose which has to be adapted to the different hose connection size on the radiator. I had trouble finding off the shelf hose size adapters of the right size and style, so I just made my own out of aluminum tubing.


The new radiator is truly massive, with double the core thickness of the original. It also seems to have larger trans and oil coolers in it, as it was for the 454CID, 8.1L, and diesels.

[Stevemo]

Has anybody tried to put Hill Descent Control into one of the 4 speed transmissions using this software? I assume it just requires proper torque converter lockup relative to closed throttle conditions. Being able to mess with the BCM would also be nice.

[booster]

Originally Posted by Stevemo

Has anybody tried to put Hill Descent Control into one of the 4 speed transmissions using this software? I assume it just requires proper torque converter lockup relative to closed throttle conditions. Being able to mess with the BCM would also be nice.

You certainly could so some things with that by messing with the unlock speeds for torque converter in various gears, except for low gear which can never be locked. The problem would come, I think, in that the unlock speed is the unlock speed so it wouldn't know if you were trying to do the downhill control or not so if you could get too low a speed to have any power available to reaccellerate. You might be able to program the manual gear selecting gears individually, but I would have to look and see if that would be accepted.


There may also be minimum speeds allowed in the various modes. I need to check to see is TPS at zero, or pedal at zero with drive by wire, in the various modes. I know the Chevy does not unlock the converter when you step on the brakes, so it may leave it locked in pure coast conditions sometimes as you do get engine breaking with them but it may just be from the unlocked converter. Locking a converter in decel might also shorten the clutch life as that can be quite high load.

[booster]

It does look like there is a way to keep it from unlocking at closed throttle by changing settings in what appear to be a safety type thing in the program that sets a fixed vehicle speed sensor reading (but they didn't say what the units are so I could see the speed that was) to enable unlocking at a settable TPS reading. The problem is that it not settable by gear or mode, so it would be the same all the time so no unlock mode to improve mileage, it appears.


I also think there is a coast mode, but couldn't find any real information on it except a note the stated "except when in coast mode" the above settings areas. I think coast is a timed thing that unlocks the converter when you get to low TPS but puts it back on only after a delay to prevent hunting like it could do if based on speed.


When they talk about downhill speed control, are you sure they are leaving the converter locked or is it more of an auto gear selection based on closed throttle and cruise speed? Even unlocked, you get pretty good braking in lower gears.


Personally, I would not want to give up the mileage to stay locked when coasting, but we also don't really ever have downhill speed issues even on really steep stuff.

[Stevemo]

I suppose I don't know how exactly hill descent works but I know the newer models of vans have it along with the additional gears. If you had access to one to suck the programming out of that would be interesting. To be frank, my 1991 Dodge Roadtrek with the 318 handled down hill grades better than our 2004 Chevy.

[booster]

It appears that the downhill/descent features in newer vehicles uses the antilock brakes to handle slippery downhills without needing to actually put on the brakes, so nothing to do with trans lockups, as far as I was able to find.

[tlillard23]

@Booster did you do any more fine tuning with HP tuners tables? I overheated the trans, then started looking at hp tuners, then found your post(s). Specifically, the 2nd gear TCC lock up tables engage/disengage

edit: did you post your tune file somewhere?

[booster]

Originally Posted by tlillard23

@Booster did you do any more fine tuning with HP tuners tables? I overheated the trans, then started looking at hp tuners, then found your post(s). Specifically, the 2nd gear TCC lock up tables engage/disengage

edit: did you post your tune file somewhere?

I don't recall if I have done anything in the trans since these tables were posted. but if I did it would not be large changes. It is a fine balance between driveability and generating heat and I think most people have their own ideas on driveablility. Another member who has done this change also used my program file and then changed some things to his liking. I did concentrate quite a bit on heat, but also with keeping the converter locked longer and limiting the number of irritating downshifts we got on minor hills.


I haven't posted the file anywhere, but if you want a it I can email it to you. PM me and we can get that done. I am not at home this week, so it would be after that, as I don't I have that file on this laptop currently.

[dicktill]

Originally Posted by booster

I don't recall if I have done anything in the trans since these tables were posted. but if I did it would not be large changes. It is a fine balance between driveability and generating heat and I think most people have their own ideas on driveablility. Another member who has done this change also used my program file and then changed some things to his liking. I did concentrate quite a bit on heat, but also with keeping the converter locked longer and limiting the number of irritating downshifts we got on minor hills.


I haven't posted the file anywhere, but if you want a it I can email it to you. PM me and we can get that done. I am not at home this week, so it would be after that, as I don't I have that file on this laptop currently.

I'm the "other member" that Booster referred to. I think the changes I made to his maps were primarily because my 2009 Chevy Express had a different set of maps to work with than his 2006 or 2007 chassis, that is, I couldn't physically plug his numbers directly into my maps. Depending on what year your chassis is, you may want to use his or mine ... I can also send you mine if you choose. I think the ECM & TCM (and therefore the maps) changed after 2007. The issue that bothered me most before this re-tuning was those same annoying downshifts (sometimes 4th to 2nd!) on hills, and this has fixed all that.

[tlillard23]

@Dicktill I have a 2007, but if you wanna share your tune I'd like to see it! I'll send a dm. judging from Booster's tune, I am a little bit more race car than he is, but I'm towing a race car behind the van. Stepping on the gas is what i do.
The tune in these vans isn't that bad, had a 2002 Ford V10 with what I like to call the Vegas automatic transmission. every time you stepped on the gas it would DOUBLE DOWN!!!! lol

[booster]

Originally Posted by tlillard23

@Dicktill I have a 2007, but if you wanna share your tune I'd like to see it! I'll send a dm. judging from Booster's tune, I am a little bit more race car than he is, but I'm towing a race car behind the van. Stepping on the gas is what i do.
The tune in these vans isn't that bad, had a 2002 Ford V10 with what I like to call the Vegas automatic transmission. every time you stepped on the gas it would DOUBLE DOWN!!!! lol

You are probably towing near GCWR with a race car and trailer, so you will need to be more "racey" in shiftpoint selections or the unit won't make enough hp to move it. I found that locking up instead of not cost nearly one full gear in pulling power due to the rpm loss in the lower, under 3500rpm ranges. With that much weight you will be running much higher.


Time to do a 6 speed transplant? They will drag big weight and not overheat from all we have heard. They keep the converter locked nearly all the time ( I have a copy of a stock read program from one to look at) but can get away with it better because of all the gear choices.

[tlillard23]

A 6 speed (or 10!!) is on the list of desired mods, 4X4, and swapping out the steel block 6.0 for the LS2 in the GTO, buuuuuuut that's a looong ways off! (likely never, but its fun to dream)

I updated the D1/L1 gear hold, I didn't even realize it would shift out of first until I tried it today - stooooopid design in a heavy vehicle. I understand in a rental car and passenger car, but we're trying to slow the vehicle down, give me the gear!! Also upped the MPH that will allow D1/L1 to engage - good mods!

I noticed your tune has short shifts and doesn't tach out the engine, I guess you did that for MPG?? I've kind of done the opposite, enabled PE at 70% throttle and no RPM delay to get full HP, knocked a couple seconds off of the TurdWrek's 0-60 times.
trying to decide how I want to attack the 2nd gear no-lock-up and still run up to redline as needed *only for accelerating, normally stay below ~3700rpm for pulls up hill.

@Booster & DickTill what section of the shift tables is "the annoying rolling hill downshift" that you are talking about. because I'd also like to get rid of the cruise control rev-limit-double-down-shift. I think it's the high MPH @100% TPS in downshifts for 2nd and 3rd?

Also, I see you upped the TCC shift PWM, what's that for? quicker/firm shifts?

Thanks

[booster]

Originally Posted by tlillard23

A 6 speed (or 10!!) is on the list of desired mods, 4X4, and swapping out the steel block 6.0 for the LS2 in the GTO, buuuuuuut that's a looong ways off! (likely never, but its fun to dream)

I updated the D1/L1 gear hold, I didn't even realize it would shift out of first until I tried it today - stooooopid design in a heavy vehicle. I understand in a rental car and passenger car, but we're trying to slow the vehicle down, give me the gear!! Also upped the MPH that will allow D1/L1 to engage - good mods!

I noticed your tune has short shifts and doesn't tach out the engine, I guess you did that for MPG?? I've kind of done the opposite, enabled PE at 70% throttle and no RPM delay to get full HP, knocked a couple seconds off of the TurdWrek's 0-60 times.
trying to decide how I want to attack the 2nd gear no-lock-up and still run up to redline as needed *only for accelerating, normally stay below ~3700rpm for pulls up hill.

@Booster & DickTill what section of the shift tables is "the annoying rolling hill downshift" that you are talking about. because I'd also like to get rid of the cruise control rev-limit-double-down-shift. I think it's the high MPH @100% TPS in downshifts for 2nd and 3rd?

Also, I see you upped the TCC shift PWM, what's that for? quicker/firm shifts?

Thanks

I short shift at the lower speed ranges so I can get it to lock in second or third gear in traffic to keep the trans cooler. At higher throttle/higher MAP I move the shifts back up a bunch where needed.


The hill thing is taken care of in the downshift table where you can set the maximum speed a downshift will happen. I moved the high gear one to 50 mph instead of something like 70 mph. To prevent a double, you make sure the 3-2 downshift max is even lower. With it set at 50mph I need to loose speed to 50 before it will downshift even at high load, so on long hills I may need to manually put it down to prevent too much lugging time on the engine.


I will have to look at the tables again to see if there is a way to get full rpm with no lockup but early lock up below that. I think there is a way, but not certain.


AFAIK, I did not intentionally change the shift PWM, so it may be a year to year thing and maybe tied to the change in 2007 to drive by wire. I will look at my stock read and see if it matches my current read.

[booster]

trying to decide how I want to attack the 2nd gear no-lock-up and still run up to redline as needed *only for accelerating, normally stay below ~3700rpm for pulls up hill

I really don't see a way to do that without losing the ability to go to full throttle at lower rpms with the converter locked since the lockup table is based on TPS.


You would be able to run it manual by using the tow/haul button, I think. Just program no lockup in second all the way to 100% TPS and then once you get to speed push or unpush the button to revert to 2nd gear locups you have programmed.

[tlillard23]

I loaded booster's tow haul/performance tables today and drove around a bit. It's very nice, it's a short shifting torque converter locked smooth operating program. It never downshifts so it's sort of like a manual valve body for downshifting, My only complaint is if you leave it in D it doesn't run up to redline. since I have power enrichment coming on at 75% throttle there seem to be plenty of torque to pull a trailer, would like the additional RPMs though.... going to tinker with it a little but see if I can get it where I want it.

basically you push the tow haul button and boot the gas, torque converter locks (after 1st gear take off) and the engine pulls. if you're cruising along and then step on the gas it won't downshift, so you need to either grab the gear lever or shut off tow haul. if you come to a stop or are going slow it will downshift according to miles per hour, it never bogged.

Hptuners- I could do it for a ~$100, or you can buy HP tuners for about 300 bucks now with enough credits to do two vehicles.

overall though, absolutely no heat generated because the torque converter is locked up. trans temperature stayed right at 165 in stop and go, full throttle application for about 30 minutes.

[booster]

Originally Posted by tlillard23

I loaded booster's tow haul/performance tables today and drove around a bit. It's very nice, it's a short shifting torque converter locked smooth operating program. It never downshifts so it's sort of like a manual valve body for downshifting, My only complaint is if you leave it in D it doesn't run up to redline. since I have power enrichment coming on at 75% throttle there seem to be plenty of torque to pull a trailer, would like the additional RPMs though.... going to tinker with it a little but see if I can get it where I want it.

basically you push the tow haul button and boot the gas, torque converter locks (after 1st gear take off) and the engine pulls. if you're cruising along and then step on the gas it won't downshift, so you need to either grab the gear lever or shut off tow haul. if you come to a stop or are going slow it will downshift according to miles per hour, it never bogged.

Hptuners- I could do it for a ~$100, or you can buy HP tuners for about 300 bucks now with enough credits to do two vehicles.

overall though, absolutely no heat generated because the torque converter is locked up. trans temperature stayed right at 165 in stop and go, full throttle application for about 30 minutes.

Glad it is working for you to this point. Just getting close so you do your own personalizing saves a whole bunch of work.


It will downshift if the speed gets low enough, like 50 mph in fourth gear, but if you need a quicker pull you need to do it yourself as you say.



It is somewhat amazing just how much heat the converter generates in these heavy vans and how minimizing non lockup time will really take the temps down.


I am sure you will get it just where you want it to be over time. For us it took a few real trips, like to the Rockies to get it to where it felt right. I carried the tuner with on those trips.


Have you converted yours to Dex VI ?