Getting a custom tune on my 04 Silverado Z71 5.3L V8

[joutlaw]

In late May early June, I picked up a 2004 Chevy Silverado Z71 regular cab short bed with the 5.3L V8. The truck has tons of power, but has always felt limited off the line and soft when downshifting to pass.

After researching it seems that torque management was the cause of my problem. Basically the ECU retards timing and won't give the motor 100% WOT with drive by wire throttle bodies when you floor it off the line or WOT downshifts.

Link with info on torque management

With EFILive there are a lot of tuners out there that can modify your ECU to give you more power and adjust the torque management. I found a tuner, Justin at Blackbearperformance.com, that you can do a datalog tune. To me it's the closest thing to dyno tuning.

Basically he sent me EFILive's FlashScan datalog got me to drive around cruising, stop and go, idleing, and a few WOT pulls. I then sent him the log file and he looked at the data to see how my truck was running. I then send him my ECU and modifies it based what he saw in the logs.

He is also chaning my Tow/Haul button to a different more agressive set of tables for the transmission when I really need firmer quicker shifts.

Anyways I thought it was pretty neat, b/c from everything I've read is a custom tune is much better than those handheld tuners. Most people even pick up 1-2mpg if they can keep their foot out of it.

 

[aleckz]

Would this affect the transmission any? That would be my main worry.

 

[joutlaw]

I asked the same question. Justin told me as long as I don't keep it at WOT all the time I will be fine.

I imagine most GM cars and probably other mfg's are implementing similar programming as the ECUs get more powerful. I believe some turbo vehicles limit boost in the 1st gear... etc. I'm all about new technology, but I want my vehicle to perform to it's maximum potential. I think GM implemented torque management for warranty reasons which is understandable.

My brother-in-law has a 94 Silverado with the 5.7 V8 and the same transmission as my truck... the 4l60-E. In 94 these trucks didn't have torque management and he has over 200K on his. He's been driving the truck since he was 15 so I'm sure it has seen it's fair share of WOT pulls... etc.

I am leaving the abuse mode enabled. This won't let you do neutral drops and other things the ECU deems as abuse.

 

[RU482]

cheaper to program in limits to the ECU than to beef up the weaker components in the drivetrain

 

[joutlaw]

I agree RU482.

To me it's neat that there are products such as EFILive that can adjust the necessary parameters. As a software developer I give them a lot of respect b/c I'm sure GM didn't give them a nice API to go by.

Some of the other things I changed were shift points. I could have changed information in the event I added electric fans, different thermostat, or different gear ratios. I left the speed limiter stock. I couldn't imagine doing over 80 in this beast. I'm used to my mazda millenia which has a much lower center of gravity.

This will be it for performance mods. The truck currently has a K&N drop-in and a magnaflow catback. I'm hoping after the tune I will be in the neighborhood of 275+ RWHP / 300+ RWft/lbs of torque.

 

[iamwiz82]

That 94 you are comparing to had significantly less power than your 5.3. GM specs out the 4L60E at 360 lb-ft of torque at the flywheel. You will be coming very close to that.

 

[joutlaw]

Yep most people who know GM know the 4L60E sucks. It is in a lot of GM vehicles ... S10s, Blazers, Camaro's etc...

It was behind the LS1 in the camaro which isn't as torquey, but plenty of people are running more than the rating. There is a 4L65E that is put behind some 6.0 liters which addresses some of the 4L60E's weak points. The 4L80E is the stoutest and comes behind some of most of the 3/4 ton and up trucks.

My understanding is the 4L60E dates back to the TH350 and the 4L80E dates back to the TH400.

Although the GenI 5.7 in the 94 is weak compared to the 5.3 GenIII... the older 350s were low-end torque monsters where you have to spin the 5.3 relatively more to get power.

 

[joutlaw]

Got the new PCM with the tune in Saturday. I had to do a Security Relearn in order for the truck to start. Basically it was a series of putting the key in the on position for 10 minutes then remove the key for 45 seconds... repeat 3x then the truck started.

I then had my laptop with me with EFILive's FlashScan unit hooked up. I had to do a Crank Relearn as well. The way I understand it is the PCM needs to learn the crank position angle. Basically I went into EFILive's software ... hit the crank relearn button revved the truck to 4K RPMs and it cut fuel letting me know all was well.

Then the fun began. Off the line at 1/4 throttle the truck felt the same. It seems to hold onto to gears longer, similar to the way the transmission functioned in Tow/Haul mode. I let it get warmed up and hit the interstate. At 60MPH I gave it full throttle... the difference is night and day how the truck pins you back in the seat. I then tried at 75MPH... it pulled just as hard as at 60MPH... I then hit some empty roads to try some launches from a stand still. Before the truck bogged off the line then was pretty strong until the 1-2 shift. The truck launched off the line this time... I felt the auto-locking differential kick in with a brief amount of wheelspin from my 265/75/16s... basically a 31" tire with AT tread. The truck now redlines at 5700-5800 RPM in every gear. 2nd is the most noticeable b/c it pulls like crazy on the highway.

Tow/haul mode was also modified, but I didn't get to play with it much. I only made one run from a stand still with it, but I had traffic around me and didn't want to give it 100%. It felt different than the regular mode, but I need to play with it more. I'm going to try again today at lunch.

Did I gain horspepower with the tune... maybe some... but the most difference is in the 80% removal of torque management and shift firmess. I didn't lose any driveability, but the truck feels completely different when you are beating on it. I'm hoping to gain some MPG and I'll give that a test the weekend before Christmas. I could get around 19MPG as is and I hoping to be at least 20MPG after the tune. Not bad for a full size truck with a V8 and 4x4.

 

[JJ650]

There is also www.pcmforless.com

These guys specialize in the Chevy engines. They do a lot of the same things you mentioned as well as "tune" for specific fuel (87, 89, 93 octane, etc..).

When I had my S-dime, I had it tuned specifically to 89 octane, removal of torque management, remapping of the fuel/spark, shift points adjusted, shift firmness adjusted. It did go from 15mpg to 17mpg, which wasn't bad at all for that 4.3 which was known for drinking the juice down. The butt dyno definitely said there was a performance gain. How much, I couldn't tell you. All I know is that it pulled way harder than it had ever pulled before.
I was very pleased with them. I paid less with PCMforless than what I did for the Hypertech tuner.

 

[joutlaw]

I ended up getting this tune for $200. His prices went up on November 1 and its now $200 for a mail order tune and $300 for a data-logged tune. I went with the data-logged tune.

I play around at lunch and the 1-2 shift in tow haul mode is amazing. I did a non-scientific 0-60 time of around 7 seconds. I'll be able to tell for sure once I get the data-logger hooked back up. Justin wants to see some logs before I send my old PCM to him and the data-logging equipment.

No joke on the 4.3... I had a 94 regular cab short bed non-Vortec with the 5 speed when I was in highschool. No torque management on that one for sure b/c I went through at least 6 sets of back tires when I had it. It was a fun little truck... probably not that fast because it could never get traction.

 

[joutlaw]

Thought I'd give an update 4 months later.

The truck is still running great. No transmission issues.

Good thing with blackbearperformance is that the re-tunes are free other than shipping. I've thought about going 93 octane and maybe converting to a lower thermostat and electric fans. I hate the clutch fan especially in the summer.

The truck with the new tune still amazes me. I was getting onto the interstate of a clover-type onramp. Right as I was approaching the interstate I punched it and it hit first and broke the rear end free. Needless to say my buddy with the 99 Z71 ECSB was impressed.

I've been driving the truck a lot more while gas has been low. I'm getting around 16-17 with my work commute which is pretty good to me.

 

[fbrdphreak]

Your 04 Silverado doesn't have electric fans???

IIRC, a lower thermostat really doesn't help. I want to say it can result in the engine never fully warming up properly and causing it to run rich, which actually loses power. Or maybe that's only on some cars. I dunno.

 

[JJ650]

Originally posted by: joutlaw
Thought I'd give an update 4 months later.

The truck is still running great. No transmission issues.

Good thing with blackbearperformance is that the re-tunes are free other than shipping. I've thought about going 93 octane and maybe converting to a lower thermostat and electric fans. I hate the clutch fan especially in the summer.

The truck with the new tune still amazes me. I was getting onto the interstate of a clover-type onramp. Right as I was approaching the interstate I punched it and it hit first and broke the rear end free. Needless to say my buddy with the 99 Z71 ECSB was impressed.

I've been driving the truck a lot more while gas has been low. I'm getting around 16-17 with my work commute which is pretty good to me.

:thumbsup: Electric fans!

I did the Taurus e-fan swap on the s-dime after I had the tune done. It was a surprisingly beneficial mod that made a difference in power across the board and in mileage. It was relatively simple to do as well.

The T-stat change will see more benefits with a tune so that shouldn't be an issue. It's not a good idea in the winter time, but in the summer you should see no issues at all with warm ups. Custom tunes normally have adjustments to fuel curves for the different thermostats. I wouldn't get anything lower than a 160 t-stat.

 

[franksta]

Originally posted by: JJ650


:thumbsup: Electric fans!

I did the Taurus e-fan swap on the s-dime after I had the tune done. It was a surprisingly beneficial mod that made a difference in power across the board and in mileage. It was relatively simple to do as well.

Seconded.

I ditched the mechanical fan on my F-150 for the Flex-A-Lite duals. It doesn't feel any quicker but I'm getting an additional 2 miles per gallon.

 

[crab]

Originally posted by: franksta

Originally posted by: JJ650


:thumbsup: Electric fans!

I did the Taurus e-fan swap on the s-dime after I had the tune done. It was a surprisingly beneficial mod that made a difference in power across the board and in mileage. It was relatively simple to do as well.

Seconded.

I ditched the mechanical fan on my F-150 for the Flex-A-Lite duals. It doesn't feel any quicker but I'm getting an additional 2 miles per gallon.

Did the same on my E150 in my sig...my biggest change was that my A/C works drastically better when stopped. On a hot July day, that thing would blow warm air when parked after just a few minutes. I evacuated, vacuumed and refilled the system three times, and even replaced the orfice valve to no avail. I still got rising pressures and eventual cut-out when parked....not anymore

 

[franksta]

Originally posted by: crab

Originally posted by: franksta

Originally posted by: JJ650


:thumbsup: Electric fans!

I did the Taurus e-fan swap on the s-dime after I had the tune done. It was a surprisingly beneficial mod that made a difference in power across the board and in mileage. It was relatively simple to do as well.

Seconded.

I ditched the mechanical fan on my F-150 for the Flex-A-Lite duals. It doesn't feel any quicker but I'm getting an additional 2 miles per gallon.

Did the same on my E150 in my sig...my biggest change was that my A/C works drastically better when stopped. On a hot July day, that thing would blow warm air when parked after just a few minutes. I evacuated, vacuumed and refilled the system three times, and even replaced the orfice valve to no avail. I still got rising pressures and eventual cut-out when parked....not anymore

I forgot about that. Mine blows slightly colder air but the difference wasn't drastic. It was already pretty cold to begin with.

It's also much quieter at idle...until the fans start up. That's a fun feature stopped in traffic on a hot day. The other drivers --> :shocked:

 

[TheSlamma]

Trans will be fine, after 2002 they fixed the slipping TC and the 4L65 is already much more beefy then the 4L60's on the 98's and older.

EFILive is cool.. far better then LS1Edit was.. if you ever want to tune on your own though I think VCM suite is the best option for non-pro tuners.