Thread: Tranny Upgrade Results: HP Tuners, Torque Management, MPG

Like the title says, no GP for the whole week. Dave (of TEP fame) has my car to build the tranny up for me. I'm stuck in my wife's Buick Century until next Saturday when I pick it up again. It's been a great car for us, but that 3100 just doesn't get it done for me. I wish I could get my trans like the 3800 guys, mail order swap, but the only local cores I've found were either $800 or had a damaged case (the case is the reason I can't get my trans like everyone else). I couldn't handle dropping the trans, shipping it, waiting, waiting, and then getting it back. Too long and too much uncertainty.

I'm going to 3.29's, so I'll let everyone know how that turns out when I get it back. I already could roast the tires in 1st gear at will, but I think 2nd and 3rd will like the extra gear.

The first thing I'm gonna do when I get it back is just enjoy the 3.29s for a bit, but the very next thing I'm gonna do is use HP tuners to remove the torque management. I'm really interested to see how much the engine was choked off to save that tranny. I plan to leave the differential protection in place because I have the stock diff still.

Still.... a whole week without my car. I just got done adding an MP3 jack too, now I'm back to the radio. I might need anti-depressants.

Got the car back yesterday, and wow is it better. The 3.29s really woke the car up, and it shifts like an automatic should. I'm gonna start tuning it today, so I'll post more later.

The big thing that I was worried about was fuel economy, but I'm not anymore. Cruising along at 75-80, I still get about 24-25 like I did before, maybe as much as 0.5mpg less. I spent more time in V4 mode because I needed less throttle to cruise, so that offset the higher RPMs a lot. The big thing is I now get into 4th, Locked Converter, V4 mode at 45mph instead of 50mph, which is great because most city streets are 45 around here. It's too early to call, but I may end up getting better fuel economy on average with more gear.

BTW - Does anyone know if I can change the title of the thread, or add to it? I survived it and it was worth every second, and now I want to talk about the result.

I turned off the torque management, and wow, what a difference again. Looking at the scan tool, you could see that it was pulling a lot of spark and closing the throttle a little bit when shifting. Then I set the "Torque Reduction" to 0, but I left the differential score protection and abuse mode protection on. When I took the car out, and the first WOT 1-2 shift chirped the tires. Old school. I've got a lot of tuning to do yet, but this car is starting to really be fast, not just feel fast. With the torque management off, it didn't feel as fast because there wasn't as much of a surge after the shift, but I don't doubt that it is faster.

Sounds like another satisfied TEP customer...I tell ya Dave's transmissions are the shiz

On another note...GET SOME VIDS!!

I'll keep posting for sure. Right now, I'm a little overwhelmed by all the flexibility in HP tuners. Right off the bat, I can tell this thing is running as rich as a pig. The commanded A/F ratio at WOT is like 9:1, so I'm sure there is a lot of power to be found by leaning things out. I've been reading the HP tuners forums for advice before I mess with the fueling, though. I'm still playing with the shift pressure too. When I'm happy, I'll post the curves I used.

I don't have a video camera, but when I visit family over thanksgiving I'll have access to a camera and a safe stretch of road. I spent most of today mocking up an LS6 intake, so hopefully I'll have that mounted by then too.

LS6 intake on the LS4? Didn't think it was possible as I thought someone already tried it...

Yeah, fitting the LS6 takes, time, money and a rubber mallet. The fuel rail is the big problem, cause the LS4 rail doesn't fit without extensive massaging and the LS6 fuel rail uses taller injectors and doesn't clear the alternator bracket. And it's not close. Anyway, I finished mocking it up last night and once I make sure there are no particles in my manifold I'll bolt it up tonight.

After a week of driving the car around and tuning the shift pressures, I have a couple thoughts. First, I for sure get better mileage in the 45-65 range (mid 30s instead of low 30s), about the same at 70, and a lot worse above 75. The left lane to work typically cruises at 80 or so, and I get about 19mpg on average at that speed compared to about 22 before. Going 65-70, I'm in the high 20s low 30s, and I can hold that mileage at 75 if I'm following somebody. So, as long as I don't speed, I get the same or better mileage. Not a bad deal considering how much more get up and go I picked up (12.3% more torque at the wheels in every gear, by the numbers).

I'm having a lot of fun with HP tuners. I turned some torque management back on in normal mode to save the tranny, and left it all off in performance mode (tap shift). I also put a shift RPM in performance mode (6100RPM) so I can drop it into tap shift and safely rip off a max acceleration. I've seen guys say you can safely go to 6200RPM with the stock valvetrain, but I don't want to push it to the limits. I also used higher shift pressures in performance mode. I'll probably wear out the half-shafts, but they're much cheaper than transmissions. Maybe some of the 3800 guys can comment, but I'd imagine that there are aftermarket half-shafts when the time comes.

For the 05-06 guys, you should really look at the 07-08 spark tables in DOD mode. I pulled a stock 05 cal from HP tuners, and it had less advance than V8 mode. My car has significantly more advance in DOD than V8 mode, and way more than the spark curves of the few tuned cals I found out there. Stock V8 mode advance looked the same for all years. I need to find someone with a wideband O2 sensor before I do too much with the engine cal, but once I bolt up the LS6 I'll pretty have to tune it too.

So, my idea about shifting based on RPM doesn't seem to work. I've tried the trick of setting the WOT shift speed to 0 and it still ignores the shift RPM table and looks at the normal throttle shift curves. So, I had to run a scan and use tap shift to find my WOT shift speeds, then play with them a bit.

Another thing that is interesting is the interaction between DOD and the TCC lockup points. When I set my TCC lockup points at a lower speed, I actually lost a bit of mileage when in DOD. DOD likes a little more RPM in 3rd, and by upping my TCC lockup point a bit I get better mileage. Since I made my TCC lockup more aggresive, you can feel the TCC lock and unlock when going in and out of DOD. This doesn't bother me, because when getting out of DOD I usually want to accelerate a couple MPH and letting the TCC slip a bit helps.

By the way, don't disable COT (Cat Overtemperature Protection) if you keep DOD. You have to tune sometimes cause it will dump a lot of fuel when the CAT gets hot and mess up your readings, but don't forget to turn it back on! Once the cat gets warm, it won't go into DOD. I forgot to turn it on before going to visit some family (3.5 hour drive), and I was wondering why I was burning so much fuel. On the way there, I burned between about 5/8ths of a tank. I reflashed, and on the way back I burned less than 1/2 a tank, close to 3/8ths. There wasn't a big change in elevation.

Finally, I think I picked some mileage back up from the LS6 intake swap. It seems to help a lot when DOD is active. I got maybe 1/2 mpg from the swap once I dialed in the MAF curve. When it was running really rich I lost quite a bit (1-2 mpg).

Sorry, no 0-60 times or anything yet. I'll run in the spring for sure. After giving in and springing for those group buy headers, I definately don't have any more hot rodding money for a while either.

i refuse to use my tap shift. everytime i drive the car hard in tap shift the tranie starts to slip when i put it back into drive. im sure the valve body takes a beating.

i gained mpg when i uped my tcc lock up. i think some of it has to go with your theary of getting better mpg with the 3.29's because it does not take as much gas to maintain a speed. 3rd and 4th used to lock up really early and well if i was on a flat strait away, it did help but if i was on any kind of incline, with the lower rpms i had to push the gas harder to keep the same speed. you gotta kinda find the median.

do you have a shift kit in it?? firming up the shifts alot with line pressure and shorting the shift time and shifting hard like that really starts to take a toll on the trans after a while.

all of this is with my 04 3.8 so yes there is some diffrence but thats just a few things i have run across. happy tuning to you. sounds like you gotta a nice set up going on.

Yeah, Trannyman95 put a Transgo shift kit in my tranny, along with every other trick in his book. The major weak point left is the chain, but I went with a stocker because this is my daily driver. I asked him about how the shifts felt with the stock tune, and he liked the 1-2 but not the 2-3. I set the 2-3 to shift like the 1-2, and up'd the 3-4 shift pressure a little bit just for low torques. I also still use torque management when in standard mode, but not tapshift. I've heard tapshift isn't good too, but I still use it from time to time because I have it set so the TCC never locks up and I usually can't get to WOT in 1st without a lot of wheel spin, so if I want to hold 1st to 48mph I have to do it manually. Since the rebuild the car downshifts without messing around, so leaving it in D gives me good enough performance.

Thanks for the advice. I'll have to try even higher TCC lockups and see if they help. I may also lower the throttle point at which the TCC locks up.

sounds like you got it going on!

cant wait till i get a built tranie. all of my adjustments are mainly to prolong the life of my 100k trans. ive heard nothing but good things about his transmissions.

how are the heads on the ls4?? are they as good flowing as the other lsx blocks?? i bet a nice cam would really open it up but no more DOD :/

saw they also got some headers for those things also. the aftermarket is starting to grow.

Thanks everyone for your interest!

The heads are the same 243 casting that come on the LS6 in the 01+ Z06 vettes, but the intake valve is a little smaller. But they are great heads. The LS6 also has a little more compression (10.5:1 vs 10:1 for us) and a much bigger cam.

There are two DOD cams out there that I'm looking at: the stock L92 cam (from the DOD G8 GT) has a little more duration and about the same lift, but it should be really cheap. There is also the New Era Performance DOD cams for the G8 GT, but they would be pretty radical in my smaller displacement engine. I think a cam would be fun, but I'm starting to lean towards a 100HP wet shot. It would be a lot cheaper and easier to install. I mean, I still have to do a CAI and some exhaust mods, and at the moment my hot rodding budget has $0 in it because I got on the waiting list for those headers.

By the way, to everyone looking at those headers, they are talking about a one time production run of 60, and I think about 40 are spoken for. That's why I pulled the trigger even if it means less fun doing small mods like the CAI and the mufflers.

i think you made a good decision with the headers. one of the best mods for most vehicles. looking at the dyno numbers looked like they picked up some nice mid range but droped a little off on the top end. maybe the ls6 manifold will help out with that.

243 heads, hell yea!! and yea you probably could pick up the gt cam for a decent price. and a 100 shot cheap, simple install, easy maintinece. cant go wrong there. i think the spray would really like the longer duration of the gt cam too if you were to go that route.

man im really liking your build you gotta post videos some time.