2005 5.3 - More Power For Towing?

Drunken Sailor · September 9, 2007

Hey guys,

I've got a 2005 GMC 1500 CCSB with the 5.3 and 4.10 gears. This truck is a little lazy driving around unloaded but not bad for a 4X4 truck and it still gets 20 MPG on the highway towing our Seadoo.

However... for any more serious towing this thing is useless. My girlfriend and I are thinking about buying a small 15-18" 5th wheel camping trailer, and I've got the truck all set up with a brake controller, hitch, rear add-a-leaf (since when did fullsize trucks start coming with 2 leafs in the back? Pathetic!) etc. This weekend I was helping a friend move and got a very rude awakening that's throwing a wrench into our camping plans. I was pulling my friend's big 18' enclosed trailer and it got ugly. This trailer was our moving truck. It's wider than my truck and has a big wood box, 7' high. We're guessing that it weighs around 3000 lbs empty. And even empty, my truck is WORKING to pull it. On the highway, 4 gear was totally useless. I had to drive in 3rd to stop the constant gear hunting. To maintain 70 MPH in 4th you've got to keep the truck floored and even then you can't climb any hills. So I went the whole way in 3rd doing 3000 RPM and getting.... wait for it... 7 MPG! But even in 3rd I had to back way off on the hills, and I can't pass. I got behind an old man going 50 and I simply couldn't pass him. My truck just was screaming but just couldn't get past 75 MPH with that trailer. Remember, it's still empty at this point. So it was 70 MPH in the slow lane the whole way, burning a disgusting amount of gas. To add insult to injury, my other friend's 93 GMC LD 2500 with a TBI 350 was getting 18 MPG the whole time towing a 20' 3000 lb car hauler like it wasn't even behind him.

On the way back, with the trailer full, I actually saw no difference in power or fuel economy. I joked to my friend that my truck probably couldn't get any worse, and I guess this was true. We crossed the weigh scales just for s**ts and giggles and the trailer was now over 7000 lbs. Still getting 7 MPG on the highway, still can't pass, still can't maintain speed on hills. The only difference I noticed with the weight was the truck was even slower taking off from a stop. My buddies 93 350 now had a 5000 lb 1963 Pontiac on the trailer and he was still just cruising along in overdrive, doing 1800 RPM like there was nothing behind him. We switched trucks for a bit and the 93 towed the car amazing, it hardly had to gear down out of 4th gear. It was barely touching the throttle. Behind me, my truck is still screaming at 3500 RPM trying to keep up.

Anyway, we're done now, and I'm a little disappointed with my truck. I really do like this truck, though, and I want to keep it. I don't believe (this is just my personal taste) that there is a nicer looking truck than a 99-06 GMC, and this truck is perfect for me is almost every way. Anything bigger won't fit in my garage, it's got a great interior with tons of room, it's been super reliable, I just really like the truck. I dont' want to spend the megabucks getting a big diesel. But I want to give it some more power, for around town and especially for towing. I have been looking at these supercharger kits (especially the Whipple) as a means of making more power so my truck doesn't have to work so hard with a load and not burn so much gas doing it. What do you guys think? What can I do to my truck? Any suggestions, even not about the superchargers? I want my truck to be able to tow small trailers easier (in particular the 3600 lb small 5th wheel we are looking at) with less fuel consumption.

Keep in mind when making suggestions that my truck is low mileage and very well maintained. It's in good tune with new plugs, wires, fuel pump (includes filter) etc. Everything is kept in like-new condition. I go overboard on maintenance.

Thanks guys for reading my long blurb. I appreciate your advice/insight?

asilverblazer · September 9, 2007

This is a very typical towing environment for your truck. The weight is not so much an issue as the aerodynamics are. Which is why you did not notice any difference with the trailer loaded. Also a 7,000 lb trailer is pretty close to max for your truck with out looking it up. Fuel consumption will always be a problem for your truck. Try slowing down to 65 or less, any faster is obviously pushing the truck too hard and not nearly as safe as a slower speed. Adding a supercharger will deliver more power, but for what purpose? I really don't think the benefits will out weigh any detriments, but then again I don't see any need to tow that kind of weight at those kind of speeds. If you must get to yuor destination a few hours sooner the only real solution is going to be a diesel. Anything else is a lost cause.

Your truck is more than capable to tow what you would like, but something has gotta give. You are wanting more power (it takes more fuel to make more power), higher speed, and better miles per gallon. The first two are totally counter productive to the latter.

Another thing to keep in mind, you should not be towing in overdrive to begin with, the heat will kill the transmission, second the engine in your truck is not designed to produce the low end grunt of the 350 c.i. engine (I wish it were though.) The engine in your truck is designed to rev much higher, it developes power much higher in the rpm band. So running a higher rpm than your buddy is nothing to worry about.

Mark_in_Tulsa · September 10, 2007

A super charger would help out a little. But you would first have to beef up the tranny.

But towing that much weight either way at 70 is not smart with a 1500 truck.

BigJayDogg3 · September 10, 2007

You wouldn't necessarily need a diesel for that amount of weight, but you will need more truck than you have. My 1500HD with the 6.0 pulls more weight than yours does(about 6-8 thousand), and not very often(maybe 10 times a year), but it will get around 12 MPG when towing, and 16 when unloaded.

Drunken Sailor · September 10, 2007

I should make it clear that I never intend to regularly tow 7000+ lbs with this truck. If I did I would have bought a 3/4 ton. I just so happened to be pulling that much this weekend and mentioned it because I think it's completely unrealistic for GM to say you can tow 9900 lbs with this truck. I mean, you could... but....

I want to tow the 3600 lb 18' 5th wheel and sometimes the Seadoo behind that (allowed 2 trailers in Alberta if the first one is a 5th wheel). I was asking about the supercharger and whether or not it would be a means of making the truck pull this easier and possible with lower fuel consumption. Of course I wouldn't mind waking up this lazy truck a bit when it's unloaded a bit too. If you guys had any other mods you think would help me, please post them too. I hear alot of you talking about this wait4me tune... maybe that would help? Of course I would have to decide not to do the supercharger if I did that because there's no point in paying for reprogramming the PCM twice...

Paul58 · September 10, 2007

I should make it clear that I never intend to regularly tow 7000+ lbs with this truck. If I did I would have bought a 3/4 ton. I just so happened to be pulling that much this weekend and mentioned it because I think it's completely unrealistic for GM to say you can tow 9900 lbs with this truck. I mean, you could... but....

I want to tow the 3600 lb 18' 5th wheel and sometimes the Seadoo behind that (allowed 2 trailers in Alberta if the first one is a 5th wheel). I was asking about the supercharger and whether or not it would be a means of making the truck pull this easier and possible with lower fuel consumption. Of course I wouldn't mind waking up this lazy truck a bit when it's unloaded a bit too. If you guys had any other mods you think would help me, please post them too. I hear alot of you talking about this wait4me tune... maybe that would help? Of course I would have to decide not to do the supercharger if I did that because there's no point in paying for reprogramming the PCM twice...

A couple of things to point out... 1st, the 9900 lbs claim is for a specific set-up, not necessarily yours! Probably with the 5.7L or 6.0L engine with 4.10 gears in a standard bed, regular cab 2WD! Becareful of the claims, the actual towing capacity is different for each truck configuration! Adding taller tires also effects your towing capacity, as it effectively reduces your final drive ratio.

2nd, the weight you quote for the 5th wheel is probably the manufacture's claimed dry weight (if you got it from their brochure). This does not include appliances or other options! When you shop, the actual dry weight is normally listed on a sticker inside one of the kitchen cabinets. Also, dry weight does not include your stuff! I've been told to add 600 lbs to the brochure's dry weight to get a decent estimate of the actual dry weight and then add about 400 lbs per person for your gear.

Still, adding another 1400 lbs to the weight you quoted is still well below the capability of your truck (which in the configuration with the least capacity, should still be around 6500 lbs), so you should be fine.

Remember also that the surface area of the trailer acts like a parachute going down the highway, and the drag increases in proportion to your speed. Slowing down will decrease the effect of this drag! Also realize that a 5th wheel rides higher than a normal Travel Trailer, so you'll have that much more resistance to overcome!

Having said all that, I would recommend a good tuner with a strong Tow tune (I have the new Edge Evolution), a decent CAI, and possibly a freer flowing exhaust. All these components combined will cost way less than a S/C and not put undue strain on the rest of the driveline. Remember, the driveline is only as strong as it's weakest link, and you have a transmission, drive shaft, U joints, and rear differential added to that mix as well. If you go with the Wait4Me tune, get the tunes loaded in the SCT Hand Held so you can switch to an economy tune or Performance tune when not towing, if not, you'r stuck with a Tow Tune all the time, or your swapping your PCM back and forth and are back to your stock tune when not towing! I've just started running 92 Octane all the time, and use the Performance Tune when not towing and get close to 19 mpg on my 50/50 City/Hwy Commute.

I tow a 6700 lbs Travel Trailer with my 07 GMC Ext Cab, 2WD, 5.3L, with 3.73 gears. I've swapped the stock 245/70-17 tires for taller 255/75/17 tires, which effectively reduced my rear axle ratio from 3.73 to 3.55, which in-turn has reduced my max towing capacity from 7700 lbs to about 7300 lbs. Adding the Edge Evolution made a world of difference in both towing power and fuel economy! Stock, running 87 octane fuel at 65 mph, I get about 8 mpg, with the Edge Tow tune, running 92 octane at 65 mph, I get 12 mpg! On ramps and passing are no longer a nightmare either! I have the GMPP CAI on order and hopefully it will arrive this week. I'm hoping this will help as well. I'm also considering adding SuperSprings to the rear leafs. This should increase my load capability without affecting my unloaded ride quality. Looking at the stock exhaust, GM did a decent job, and there aren't any major bottlenecks in the system, so I'm going to leave it for now because I've heard too many horror stories about hearing the engine switch from V8 to V4 and back, and with the stock exhaust there is no difference in sound at all.

One last thing... Be sure to get a sliding 5th wheel hitch so you don't have issue with clearance while backing!

Sorry about the long post, but hopefully some of this will help you with your decisions! Good luck and happy camping!

Bowler807 · September 10, 2007

I have to believe there is something not quite right with your truck. With the 4:10 gears you should be able to pull that weight significantly better than you state. How many mles are on your truck? When was the last time it was tuned up? Is your air filter clogged? These will affect your towing performance.

I have an 06 Sierra CCSB with the 5.3 and 3:42 gears. 3 or 4 times a year I pull a 30 foot travel trailer that weighs loaded about 6700 pounds. I have no trouble maintaining highway speeds. With the gearing, it takes a while to get there, but I have had numerous vehicles that didn't pull nearly as well. I normally get around 12 mpg towing this weight.

I do have one modification to the truck. I installed a Wait4me 89 octane tune with 50% of the torque management removed. The difference in towing ability was amazing.

One other thought. I always tow using the tow/haul mode. You didn't state if you do or not.

NeverRest · September 10, 2007

I have to believe there is something not quite right with your truck. With the 4:10 gears you should be able to pull that weight significantly better than you state. How many mles are on your truck? When was the last time it was tuned up? Is your air filter clogged? These will affect your towing performance.

I have an 06 Sierra CCSB with the 5.3 and 3:42 gears. 3 or 4 times a year I pull a 30 foot travel trailer that weighs loaded about 6700 pounds. I have no trouble maintaining highway speeds. With the gearing, it takes a while to get there, but I have had numerous vehicles that didn't pull nearly as well. I normally get around 12 mpg towing this weight.

I do have one modification to the truck. I installed a Wait4me 89 octane tune with 50% of the torque management removed. The difference in towing ability was amazing.

One other thought. I always tow using the tow/haul mode. You didn't state if you do or not.

I agree. The 5.3 is no slug, and the 4:10 gears on top of that should make it fairly easy I have a 01' 1500HD. 6.0/4:10 This thing pulls EASY. The 6.0 wasn't rated much more than the 5.3 either when I bought. 300/300 were the specs on my truck. Torque/Hp wise.

The only way your going to see significant gains is to get a diesel.

cmoore74 · September 10, 2007

A 5.3L w/ 4.10 gears should pull that trailer unloaded at 3k lbs with ease. Sounds like there's something wrong with your truck if it's struggling that much. I pull a 4k lb boat and mine has the whimpy 3.42 gears in 3rd with ease and I get about 12 MPG when towing (my only regret with this truck is that I did not get the 3.73 gears, oh well live and learn).

A supercharged 5.3L will eat up that 4L60E tranny in no time especially if you're towing heavy loads. Also IMO with the amount of $ you're going to spend on a supercharger ($4-5k+installation) plus having a tranny which will now be borderline you'd be better off trading in for a 3/4 ton or at least a 1/2 ton with the max trailering package.

If you want to keep that truck and use it for towing those loads I would suggest making sure there isn't something wrong with it first and then a tune might help.

dcovell · September 10, 2007

From my understanding of superchargers they are not designed for towing applications, more for speed. They are only good at higher RPMs. The best thing that I would suggest is a catback, maybe a more open air filter and then run 91 in it with a custom program. That will get the most out of your engine for the money. Also as mentioned above, check aero dynamics on the load and keep your speed down. Find the sweet spot in the RPMs.

Here is a HP Dyno chart of the 5.3 from the K&N site http://www.kandn.com/dynocharts/77-3058.pdf

It shows the peak horsepower at around 5200/5400 RPMs. Now the peak toque on this motor is at around 4200 RPMs. So if you keep your gearing and speed between those RPMs (play around) you will get the most power. Outside of that band it will fall on its butt.

04z71steve · September 10, 2007

I'm pretty sure danny's correct on the higher rpms, the superchargers that I've owned haven't kicked in until wide open throttle, which won't really help too much if your driving around town from stoplight to stoplight, but i also agree with him in the sense that you should just play around with it and see whats really good for ya before you strap on that supercharger (which would be sweet as hell... bye the way)

^^ there right on with the fuel economy/aerodynamics, i got a 25' flatbed utility trailer made of steel tandem axle trailer and nothing but 2x12's for the platform somewhere around 2400lbs, then thrown a 4200 lb scissor lift on the back and my truck hauled it like a dream, no strain off of the line, no hard time breaking, no nothing the truck was simply brought to life bye all that weight, so in your case it was probably just the crappy aerodynamics of that box trailer...

good luck...

steve

Bish · September 10, 2007

From my understanding of superchargers they are not designed for towing applications, more for speed. They are only good at higher RPMs. The best thing that I would suggest is a catback, maybe a more open air filter and then run 91 in it with a custom program. That will get the most out of your engine for the money. Also as mentioned above, check aero dynamics on the load and keep your speed down. Find the sweet spot in the RPMs.

Here is a HP Dyno chart of the 5.3 from the K&N site http://www.kandn.com/dynocharts/77-3058.pdf

It shows the peak horsepower at around 5200/5400 RPMs. Now the peak toque on this motor is at around 4200 RPMs. So if you keep your gearing and speed between those RPMs (play around) you will get the most power. Outside of that band it will fall on its butt.

The centrifugal type superchargers are the ones that like higher rpms. The Roots type like the magnuson supercharger have their power right off the bottom and are very good for towing.

I would agree with the comments that your trans may have issues with the blower given it is a 4L60E or 4L65E. 4L80 in the HD would be much better but you could also beef up your 4L60e too.

Lastly, I also agree that you are about at the limit for a 1500 and if you are going to tow regularly, your best bet would be an 1500HD or 2500HD.

Mark_in_Tulsa · September 10, 2007

I have to believe there is something not quite right with your truck. With the 4:10 gears you should be able to pull that weight significantly better than you state. How many mles are on your truck? When was the last time it was tuned up? Is your air filter clogged? These will affect your towing performance.

I have an 06 Sierra CCSB with the 5.3 and 3:42 gears. 3 or 4 times a year I pull a 30 foot travel trailer that weighs loaded about 6700 pounds. I have no trouble maintaining highway speeds. With the gearing, it takes a while to get there, but I have had numerous vehicles that didn't pull nearly as well. I normally get around 12 mpg towing this weight.

I do have one modification to the truck. I installed a Wait4me 89 octane tune with 50% of the torque management removed. The difference in towing ability was amazing.

One other thought. I always tow using the tow/haul mode. You didn't state if you do or not.

I agree. The 5.3 is no slug, and the 4:10 gears on top of that should make it fairly easy I have a 01' 1500HD. 6.0/4:10 This thing pulls EASY. The 6.0 wasn't rated much more than the 5.3 either when I bought. 300/300 were the specs on my truck. Torque/Hp wise.

The only way your going to see significant gains is to get a diesel.

Well the motor in it doesn't so much change how much you can tow. The tow rating is based not on the engine but on how much the truck can stop a load, or haul it with out breaking.

C & A s Dad · September 10, 2007

Chris, I will have to agree with a few of the other replies, there has to be something wrong with your truck. My 02 Yuk XL is a 5.3 with 4.10s and I am pulling a 29' camper that weighs approx 6500lbs loaded. I do have a Trueflow CAI and run 93 octane only with no tune and it does great. I run in 3rd only with Tow Haul mode engaged and drive no more than 55 on 2 lane roads and no more than 60 to 65 on the Interstate. I get about 10 to 12 MPG while doing so depending on the head winds.

As you have already heard, towing anything at the speeds you were speaking of is not safe by any means. I know you do not want to hear this, but it is absolutely true. This past Saturday, I saw what was a really nice brand new 30 ft camper that had rolled. It was not a piece left that was useable. An older guy on a towing forum told me this and I live by it everytime I am towing. "You are not going to win any races when towing a camper, so why even try". I have also heard the argument that I know what I am doing and can drive at these speeds while towing. You likely do know what you are doing but there are thousands of other drivers all around you and you can never know what they are going to do. A pick up of any size with a trailer behind it is an entirely different animal and has to be driven as such.

asilverblazer · September 10, 2007

I also agree that 4.10's and 5.3 liter should be pulling what he described quite a bit easier. My 99 would have done that good, which a lot less power, torgue and gearing. (3.73's)