Tuning And Towing

music · August 16, 2010

I asked this in another thread, but no replies... so I'll try again. Considering the option of a custom tune and am curious about towing performance. I don't see how it will improve towing performance much, but I'm open to hear experiences to the contrary. It's obviously not a good idea to remove torque management when towing (heavy), so what other real benefits are there when towing? The best that can be hoped for out of a stock 5.3 is probably ~10 to 15 hp at the wheels. That's about the same as turning off the A/C. Very interested to hear from those of you with a tune and who tow a good bit of weight (preferably w/ a 5.3, but 6.0 opinions are welcome too).

For daily driving: I can see where there's some obvious changes to be had. I'm guessing that the primary change is quicker power delivery during shifts and from a dead stop? My old S15 (2.8 V6) (long gone) was a 5-spd straight shift with zero electronics, no cat and dual exhaust. That thing seemed to put more power to the wheels at a dead stop than my 5.3, but I also couldn't get traction on a wet road uphill. Honestly, it could be frustrating, as I had to feather the throttle to get up the hill where I live. I don't race, and really didn't like that it responded so promptly to my foot. Is that what a tune is going to do, put more power to the wheels (over a shorter time period) at the get-go and give it that more powerful "feeling"?

66nova · August 16, 2010

I obviously have the 6.0 so this is not a direct comparison, but I have driven and been passenger in a few 5.3 (one while towing).

First off, this is one of the beauties of going with a custom tune (especially if you get the Autocal) the tune can be adjusted for your needs. Yes, daily driving is much better, but you can most certainly tell a difference while towing. Yes the additional power does help some, but like you said it is not a huge difference. The main difference is...

1. The power you paid for is on tap. So while you may only gain and additional 15-20, it will feel like much more.

2. Shift points - Up and down shift points can be adjusted. You can make it hold a gear longer or down shift quicker what ever your preference.

3. Shift firmness/quickness- The shifts are not as sloppy and they are much firmer (from mild to knocking stuff off the dash if you want).

4. Torque Converter lock/unlock

5. Throttle response is improved, you don't have to get on the throttle as much.

6. I'm sure there are things I am missing

My experience. I tow my car on a regular basis, and no my Vmax was not a slouch before the tune, but I was not super impressed with it either. It down shifted more then I thought it should and it would lose more MPH on hills then I thought it should.

Now, it doesn't really matter where I am towing. I can pretty much set the cruise and go. It gets to speed much better and holds it. I could be making this up, but I swear my tranny temps are cooler now too since it doesn't shift as much and shifts firmer/quicker.

Is it going to turn your 5.3 into a Duramax, NO. But, I can certainly run with my Dads tuned 2005 Dmax while towing now.

[email protected] · August 16, 2010

I like your avatar.

cerbomark · August 16, 2010

66nova put it very well. One more thing is you may gain 1 or 2 MPG on the same regular fuel.

terzmo · August 16, 2010

I've towed for thousands of miles on gas and diesel engines. I have towed over 1000 miles with My 2010 silverado with the 5.3...6 speed.....308 gears. I like to run at 72 on a 65 speed limit as it works well for the engine and police are never an issue. The truck has a tow mode and that automatically adjusts the shift point on the tranny. IF...I feel that is not working well, I can use the manual shift but haven't so far when towing.

I don't see the profit in running the nads off a vehicle to get up a hill. On steep hills the truck has downshifted to 4th and that gave way too much power as I usually let off the gas well before the top of the hill or I'd be doing well over 80.(towing 1 car trailer,loaded with mid 60's plymouth) I don't see the profit in "tuning" to get a few more ponies or a chubby when accellerating off the line. (I leave that to My 498 mopar motor) Basicly a truck is for work or doing things a car cannot do and that doesn't include drag racing.(and I know there ARE truck drag racers out there but they are a minority) These things are well over 5000 pounds, dry curb weight, and are a truck; not a muscle car.

Driven sensibly, the vehicle will pull well, not fantastic. It will also get decent mileage with a sensible driver. I would prefer a standard transmission like My 97 silverado had,350/5 speed. It was a much better tow vehicle.

96chevy7.4L · August 16, 2010

This is just my take on it but tuning a vehicle is only helping it. The torque management and sloppy shift points are only helping you get back to the dealer as soon as the warranty is out.Torque management is only retarding ignition timing to help the transmission get thru its sloppy shifts. It is a way of making a TRUCK shift like a cadillac. There are people out there that don't want firm shifts they want there truck to ride and drive like a cadillac or a mercedes. And there truck will never see any work or towing in its life. Sloppy shifts only generate heat in the clutches and transmissions don't like heat. If the factory made the trans shift quick and firm they would NEVER sell transmissions. Also optimizing the the factory tune is basically just improving what the factory started to. Lets face it NO 2 engines are the same. Some like more timing fuel etc. And the factory doesn't have time to optimize every vehicle they sell. But by tuning and optimizing you are tailoring the program to what your engine wants. Thus making the engine more efficient and gaining fuel mileage.

Back to what was previously mentioned about it pulling okay but not fantastic. The tuning makes it run as optimal as possible. But instead of turning screws on a carb your simply editing a computer program. Trucks are made to work no doubt. But why not make it work not as hard to do the same task. Less throttle to achieve the same task and less heat in the transmission is only helping. Just my opinion.

terzmo · August 17, 2010

I've towed for thousands of miles on gas and diesel engines. I have towed over 1000 miles with My 2010 silverado with the 5.3...6 speed.....308 gears. I like to run at 72 on a 65 speed limit as it works well for the engine and police are never an issue. The truck has a tow mode and that automatically adjusts the shift point on the tranny. IF...I feel that is not working well, I can use the manual shift but haven't so far when towing.

I don't see the profit in running the nads off a vehicle to get up a hill. On steep hills the truck has downshifted to 4th and that gave way too much power as I usually let off the gas well before the top of the hill or I'd be doing well over 80.(towing 1 car trailer,loaded with mid 60's plymouth) I don't see the profit in "tuning" to get a few more ponies or a chubby when accellerating off the line. (I leave that to My 498 mopar motor) Basicly a truck is for work or doing things a car cannot do and that doesn't include drag racing.(and I know there ARE truck drag racers out there but they are a minority) These things are well over 5000 pounds, dry curb weight, and are a truck; not a muscle car.

Driven sensibly, the vehicle will pull well, not fantastic. It will also get decent mileage with a sensible driver. I would prefer a standard transmission like My 97 silverado had,350/5 speed. It was a much better tow vehicle.

so what is too high of tranny heat when towing...down the road My fluid temp rarely gets over 155 degrees....not the same in traffic where slow speeds and stop and go repitition has driven the temp over 180...and the truck has the extra cooler...cooling package. And by what I'm getting out of the "tuning" issue is that gm has purposely mis tuned the vehicles to get repair busines....are ther any groups out there pursueing this ilegal action ?, Truck has a 100k warranty....gets lose to that and any issues will prompt a different vehicle. Now it sounds like I am sticking up for the stock configuration and this new GM truck but in all actuallity, I'm very disappointed in it and most likely will dump it for a competitor vehicle in less tha 2 years

brainpause · August 17, 2010

I have the Wait4me performance towing tune. I had Jesse remove80% of the TM. I like the quicker shifts when trying to accelerate into traffic or just climbing a hill. I am not using it to drag, as a previous poster implied. The tune simply gets power to the ground more responsively.

I want to get a BB tune. I'll have to wait however. Is love to compare the two. Been using w4m tune for 3 years now.

Larry

music · August 17, 2010

Thanks for the input, much appreciated.

Robert, if I understand correctly, you found that your truck pulls noticeably "stronger" when towing w/ the custom tuning than stock, and that it doesn't "need" to downshift as easily. Did you request anything special for towing? I find 4th all but useless towing the camper, but it could probably pull a load in moderate terrain (in 4th) if the TC didn't lock so quickly. I can also see where downshifting from 4th to 3rd quicker and staying there until very light throttle may help make 4th usable. Running w/ the TC unlocked may require more cooling capacity to compensate... not sure. This may be where a custom tune could shine w/ regard to towing, as parameters could be "tuned" to match throttle/transmission response to a specific load... whereas GM engineers optimize parameters to a nominal set of assumptions, and also have to protect against the folks who want to hammer a 6k lb truck around town every day.

I've just about beaten the "towing a 7k lb camper w/ a 5.3" topic to death, partly for the fun of it and partly for learning more about how these things tick. It's really not a matter of whether I "need" more power, it's really more a question of whether I can noticeably improve the feel/experience, and whether it's worth the cost. It sounds like (good) custom tuning improves the "feel" by a fair margin. Again, appreciate the input.

jimlem · August 19, 2010

Robert,

My truck has a 6.0L & 4L80E A/T but I have a great real life comparison for you to look at. I haven't driven the 5.3L but I think you can get a good before and after pic from this that you can still apply to your truck. Thirteen months ago, I went on a 2K mile camping trip pulling my 24' trailer which is about 5800 lbs. wet & loaded. It's supposed to be a "Lite Trailer" but I'm not so sure on that anymore. This was just about 6 weeks before I got the Blackbear custom tune. When I made that trip, the computer parts of my truck were stock. I already had headers and a 3" dual exhaust plus a K&N CAI on the truck. I had a pretty miserable time on that trip when negotiating any real grades. The biggest problem was the A/T shifting. When I really needed power to to get over the last half mile or so of a grade, I always got to the point where trying to hold any speed over 40-45mph became a nightmare. It was like playing chicken. Seeing how long and how high I'd hold the RPMs in 2nd gear before finally backing off. These were the only times I ever saw my temp and trans temp gauges get anywhere near the red. For some reason, even in Tow/Haul mode the A/T would not down shift no matter how far you pushed the pedal, until you actually floored it. Then the damn thing would d/s from 3rd to 1st for a few seconds then up to 2nd but not long enough before slipping back into 3rd and starting it all over again. PITA! I just started manually shifting the gears on any real hills encountered.

Fast forward to a month ago. My kids had so much fun we did the same trip again in the end of July. Same truck & trailer, same people, same routes & destinations. All very consistent with last year. The big difference was last Sep. I had Justin at BB Perf tune my truck. Last Nov. I switched over to electric fans with BB's custom wiring harness and the changes Justin made in the tune to support the new fans. I did a very detailed review back then on my tune. (It should still be in the Reviews Forum).

I'm not sure the elec fans make a huge power difference but you likely already have them on your truck. During my tune, Justin found that right away my K&N CAI was indeed flowing much higher air into the engine but that the stock PCM was failing to add enough fuel to cover about the last 8% of increased air flow. He fixed that before we even drove out of the parking lot. He set me up with -75% of torque control mgmt. and left the shifting tables stock in the tow/haul mode. This was based on many questions he asked about my towing needs and he said he might have done it differently had my answers been different. This is the best part of that tune right there, having it setup for my needs. I won't go into all the details here except for 2 more. All the engine mods of the tune are in effect 100% of the time. Going into tow/haul mode only changes A/T shift details not the things done to increase engine performance. The best single function he changed in the mod was the full throttle / open loop delay. Stock, the truck stays in closed loop on those difficult uphills where I was playing chicken with the RPMs versus temperatures. If you hold it at full throttle for 60 seconds, it will go into open loop and it knows it's because of the steep-assed hill you're trying to crest, so it will just dump in as much fuel as possible to meet your air intake and adjust timing for max power just short of detonation. The problem is I never got to 60 seconds before too high of RPMs or temps caused me to back off a bit (which starts that clock all over). During the tune, he set it so anytime I go full throttle the PCM immediately goes into open loop. That right there saved my ass numerous times last month and was worth the cost of the tune by itself.

I have a Scan Gauge II engine/ PCM monitor installed. It tracks mileage/ MPG and many PCM functions in real time. I was able to watch my temps in real time as well as my throttle position and when the "LOOP" setting changed from closed to open and back again. Great feeling to monitor all that and see (how) safe you are. I noticed that open loop kicked in anywhere from 3/4 to full throttle depending on the grade and engine load and it would remain in open loop until I started down the hill's back side (even if I backed off the throttle a little bit) A side benefit is you can get that open loop power anytime you stomp on it, not just on a hill. I still found my best driving and smoothest ride on big hills, was done working the gears manually because of the stock shifting in tow/haul mode. I just had much better power to do it with. On level road and mild grades, tow/haul mode was no problem at all. For that matter, on normal roads with just the occasional small hill, my A/T's non tow/haul mode worked best. I only have 4 gears, not 6 like you so it's a pain when the A/T won't downshift with just a small increase in throttle when you really need it to. That all changed with the custom tune. In regular mode if you just need it to drop out of OD or out of TC lockup or from 4th to 3rd, it does it with just a touch of throttle. No more having to slam the pedal down and have the thing d/s 2-3 gears at once, is a great feeling and makes the truck so much nicer to drive.

I know we have different trucks and engines and A/Ts and yours is no doubt light years ahead of my '02 in power, and smooth shifting, but I really doubt you'd get this tune and then think your truck was better before it. It makes weak, jerky trucks smoother & stronger and I'm sure better trucks just feel even nicer with it. Especially when towing. Well there you go all the details of my apples to apples towing experiences with and w/o a custom tune. Sorry for the length but I wanted to give you as much useful info as I could. Good luck.

Jim

music · August 19, 2010

Thanks for the input Jim. Just to clarify, I have the 4L60 4-spd w/ 3.73, as they didn't start putting the 6-spds into trucks like mine until 2009. Even so, the 4L80 isn't geared as steep in 1-2 as the 4L60, so we probably have similar overall (stock) pulling power in 2nd (accounting for the newer motor specs plus the differences in rear axles, etc.). I found your original post summarizing how you felt about the BB experience. It's very clear that you're a happy customer. Your input above definitely helps with the specific application that I've been questioning (i.e., towing), and I'm sure it will help others too. I had no idea about the open loop delay @WOT, and wonder if the same is true for the 5.3 (?).

jimlem · August 20, 2010

Thanks for the input Jim. Just to clarify, I have the 4L60 4-spd w/ 3.73, as they didn't start putting the 6-spds into trucks like mine until 2009. Even so, the 4L80 isn't geared as steep in 1-2 as the 4L60, so we probably have similar overall (stock) pulling power in 2nd (accounting for the newer motor specs plus the differences in rear axles, etc.). I found your original post summarizing how you felt about the BB experience. It's very clear that you're a happy customer. Your input above definitely helps with the specific application that I've been questioning (i.e., towing), and I'm sure it will help others too. I had no idea about the open loop delay @WOT, and wonder if the same is true for the 5.3 (?).

Sorry about the mix up on A/Ts. I must have confused someone else's post w/ yours. I think your right on it being a fair comparison because I believe in the years in between our trucks, all the engines gained in factory rated HP & TQ numbers (mine was rated 300 BHP & 350 +/- Torque in 2002). I believe the newer 5.3L is a little higher or real close to that in BHP. As I understood Justin during my tune the open loop delay setting was the same for all the gas V8s. If it is different on yours, it is likely a product of updates to newer models and not related to the engine's size. Another big factor in towing power gained from the tune was what octane gas I wanted to run. In CA, 91 octane is the highest "pump gas" I can get. It costs more, but the HP difference between the 87 octane tune and the 91 tune was substantial. You should feel free to email Justin at BB Perf with your questions and concerns. I probably set a record for "just one more question please" and I'm probably in his Pain in the Butt Email Folder, but he always answered everything honestly and quickly (and very patiently too).

I have one more figure for you on towing with & w/o the custom tune. I was adding up all my gas receipts for our trip and I found my notes from last year's trip too. All in all I spent about 15% more money on gas this year than last, but this year my trip was almost a week longer, I only used 91 octane, and after dropping the trailer, we drove to a different place almost every day of our trip to see the local sites. Last year, we mostly hung around camp. Last year, my mileage for the entire almost 2K mile trip averaged about 7.6 to 7.8 MPG. The local driving I did w/o the trailer averaged about 8.8 MPG but there wasn't much of it and that one tank of gas probably had some trailer miles figured in too. This year, my average for the total 2K trip was 9.4 MPG and my local driving w/o the trailer was approx. 12.6 MPG. This year though I had at least 2 full tanks that never saw a trailer hooked up so I'm sure it bumped up the average. FWIW on both trips, I never sat in the far right lane and did 35-40 MPH up hills with the big rigs and logging trucks. I did my best to stay at the posted limit (55MPH) on uphills and about 63+ MPH on normal terrain (the truck just sort of naturally falls into a comfortable strong pace at about that speed).

The only mechanical differences between the 2 years is the BB tune and some new shocks all around, this year. Everything else (oil, tires, air filter etc) were all the same as last year. This year, I also had a Scan Gauge II engine / PCM monitor installed. One of its big attractions is how it lets you see your fuel use from about 10 different points of view, all in real time. I imagine the newer trucks have something similar already on them. Watching the MPG figure in real time, I was amazed to see my truck getting 12 to 14 MPG with the trailer on flat terrain and even 15 to 18 MPG w/o the trailer on the same roads. This would go on sometimes for 20-30 min at those avg MPG figures. Then we'd come to a series of small, mild hills and next time I looked those averages went down by 4-6 MPG overall. Oh well I know now how Chevy came up with those optimistic EPA mileage ratings. They must have done something similar on favorable roads.

One other item the Scan Gauge II has is the "ability" to estimate BHP and torque in real time as you drive. They don't publish how they compute these numbers and I know it's a bit controversial, but it is there and it's interesting to watch. I asked Justin about it and he told me he does not know exactly what they use to get the figures but he gave me one formula that they use and said it was a fairly accurate test for my engine (the multiplier in the formula changes somewhat for different engines and I'm not sure if it goes by displacement or what) For my engine, I had to monitor max air flow past the MAF sensor and convert the SG2's "grams per second" reading into "pounds per minute." Then multiply that number by 10 to get a fairly accurate BHP # for my 6.0L engine. I found his formula was pretty close to the built-in SG2 BHP reading. Keeping in mind, I already said this is an estimate and no substitute for a real dyno run, I have been able to repeatedly measure 400 BHP (with one run hitting 420 BHP and several others coming in at 410 BHP) Using industry standard math to determine torque from HP at a given RPM, I have measured 500+ in TQ many times (unfortunately always at way too high an RPM to be really useful for trailer towing- can't turn it into a Dura-Max Diesel that easyily). I consider these numbers to be for fun but It also gives me a sense that I did well picking the parts and upgrades that I installed on my truck. Hey at least the BHP #s didn't go down. Hope some this helps with your research into custom tunes. And, as always your mileage may vary.

Jim

Ryan00TJ · August 23, 2010

I asked this in another thread, but no replies... so I'll try again. Considering the option of a custom tune and am curious about towing performance. I don't see how it will improve towing performance much, but I'm open to hear experiences to the contrary. It's obviously not a good idea to remove torque management when towing (heavy), so what other real benefits are there when towing? The best that can be hoped for out of a stock 5.3 is probably ~10 to 15 hp at the wheels. That's about the same as turning off the A/C. Very interested to hear from those of you with a tune and who tow a good bit of weight (preferably w/ a 5.3, but 6.0 opinions are welcome too).

For daily driving: I can see where there's some obvious changes to be had. I'm guessing that the primary change is quicker power delivery during shifts and from a dead stop? My old S15 (2.8 V6) (long gone) was a 5-spd straight shift with zero electronics, no cat and dual exhaust. That thing seemed to put more power to the wheels at a dead stop than my 5.3, but I also couldn't get traction on a wet road uphill. Honestly, it could be frustrating, as I had to feather the throttle to get up the hill where I live. I don't race, and really didn't like that it responded so promptly to my foot. Is that what a tune is going to do, put more power to the wheels (over a shorter time period) at the get-go and give it that more powerful "feeling"?

I had Justin remove 75% of TM along with tuning the engine and raising the rev limiter with an 87 octane tune. Justin said the truck was running really good on 87 with just the GM CAI. It's a night and day difference from stock. Drive it for a few months then throw back in the stock modules. It makes you sick in the stomach the difference. Justin recommended to leave T/H mode alone if you tow and we did. GM's T/H mode shifting setup is really good and combined with a tuned top running engine it's much much better than stock and worth every penny for the tune.

I tow my 21' Challenger boat around 4500-5Klbs and my Father felt the before and after difference without telling him. I pulled 6-6500lbs trailer and Kubota tractor this past friday and I was impressed with the performance with a few steep grade pulls.