"Double down or fold" - Part 2 ...

Ducky's Dad

Explorer
FYI, my old K1500 with the 5.7 Vortec is running a stock exhaust and a K&N Filtercharger (big filter, open air box, fat plastic air tube to the intake) and my seat-of-pants dyno says it does improve performance. Not a heck of a lot, but enough to notice. But beware, it is LOUD under full throttle. I went with an Injen CAI for the Power Wagon and it is much quieter.
 
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ExplorerTom

Explorer
Well the my axle guy said he won’t touch a GM IFS axle. He says it’s a clam shell style where for every adjustment, the axle needs to be split in half to make the adjustment. It’s a tedious process that he doesn’t want any part of. He turns down GM IFS work all the time because of it.
 

Buddha.

Lurker
I’ve looked at upgrading my 6.0 but it seems like even if you spend a couple grand you only gain 20-40hp.
If you are gonna spend that kinda money I’d think a gear swap would be better. 4.10’s at least, maybe 4.56 since it’s basically a dedicated tow rig.
 

Jnich77

Expedition Leader
I’ve looked at upgrading my 6.0 but it seems like even if you spend a couple grand you only gain 20-40hp.
If you are gonna spend that kinda money I’d think a gear swap would be better. 4.10’s at least, maybe 4.56 since it’s basically a dedicated tow rig.

Define "upgrading" are you just going with bolt on mods, or were you looking at swapping the cam and tuning the ECM to take advantage of it?
 

Buddha.

Lurker
I don’t personally think intake or exhaust mods do much of anything. Also the stock manifolds pretty much are shorty headers to start with if you look at what manifolds used to look like pre ls engines.
I was looking at a cam swap and tune which would cost ~ $1000 if I did the work myself. The power increase is in the range of 4,000 rpm and above which isn’t where I want more power for towing anyway.
With my six speed I always have power if I downshift but I don’t want to deal 4,000+ rpm at 55mph towing into a headwind for eight hours. I’ve been there and it’s loud and oddly stressful.
 

Ducky's Dad

Explorer
I don’t personally think intake or exhaust mods do much of anything.

I gotta disagree, at least as it applies to my 5.7 Hemi. I did a CAI and cat-back exhaust, and those helped a little. Adding the Edge Insight tuner (one of the few that was CARB-approved for CA st the time) made a huge improvement in driveability and power. I am using the 87-octane tune, not even the max power tune, and the truck definitely has more power. How do I know? I drive the same mountain roads several times each year, and now I can easily pull grades at speeds that I struggled with in the past. The tuner reprogrammed trans shift points, but that just means that I don't have to play as much with the tow/haul mode and the shift lever. Just leave it in drive and go. These mountains are from about 4200' to 9200' and I tend to drive fast.
 

XJLI

Adventurer
BTR truck cam or the Texas Speed 212/218 are good for like 50HP at the crank and no other internal mods. Add headers, exhaust, and a tune and you're good to go. A cam is on my 'long term' list for this truck if family planning lets me keep it longer than a couple more years.
 

Buddha.

Lurker
BTR truck cam or the Texas Speed 212/218 are good for like 50HP at the crank and no other internal mods. Add headers, exhaust, and a tune and you're good to go. A cam is on my 'long term' list for this truck if family planning lets me keep it longer than a couple more years.
If the OP tows at five or six thousand rpm's it's probably a great way to go.



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XJLI

Adventurer
If the OP tows at five or six thousand rpm's it's probably a great way to go.
Still makes more power. OP needs gears.. 4.56s. Find a different shop that will gear the IFS front, seems like they just didn't want to do for whatever reason.. plenty of trucks get that front axle regeared.

It's all about compromise. Nothing is going to make all it's power off idle unless you want a diesel, ecoboost, or an old straight six truck motor.. which won't help anyway.
 
I think doing engine and gear mods on a 1/2 ton Suburban to tow that trailer is overkill personally. But, if that's what the OP wants to spend their money on, have at it.
 

rayra

Expedition Leader
Buddha those charts do show some gains but they only realyl show around 3-4k rpms. Doesn't seem like a lot of gain for the money (either).

It sorta is Todd, but the other options cost a lot more, finding a 6.0 2500 GMT800, or buying a new quad cab, A couple grand on a cam change (and might as well freshen hydraulic lifters while you're in there anyway, as most of these engines are developing #1/#3 lifter ticks by now anyway) is on the lower end of the cost/benefit range.

eta this topic sort of outlines the problem and meshes with my own understanding of needing a good bit of hp and torque bump in the lower RPM ranges for towing. Lots of top-end performance building going on for these motors, but that's not what Martin needs
http://forums.superchevy.com/gm-high-tech-performance/70/1014970/lsx/squeezing-performance-out-of-the-53l/

seems like the best bang for the buck and least modification would be the taller gearing and getting a 'pro' tuning / programming. Better yet a switchable tune that can let him alter his settings for the grades. A super 'tow mode' sort of thing. Need to target lower RPM range performance improvements. I'd do that before opening the money pit of engine internal mods / cam / valvetrain "upgrades". martin's trying to find a workable solution for towing in the Rockies, not looking to turn a Sub into a race truck.
 
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It sorta is Todd, but the other options cost a lot more, finding a 6.0 2500 GMT800, or buying a new quad cab, A couple grand on a cam change (and might as well freshen hydraulic lifters while you're in there anyway, as most of these engines are developing #1/#3 lifter ticks by now anyway) is on the lower end of the cost/benefit range.

internal mods / cam / valvetrain "upgrades". martin's trying to find a workable solution for towing in the Rockies, not looking to turn a Sub into a race truck.
For sure. Sorry, I meant doing any mods to tow that trailer. Not mods vs new truck. I would think that Suburban would'nt even feel that trailer behind it. I guess it depends on the terrain. But, even driving my old 2000 through the Canadian Rockies I never felt the power was lacking.
 

zoomad75

Observer
Let me throw some apples to oranges comparison with my truck. On the surface it's completely different, but drivetrain wise it's closer to the OP's Suburban. I'm running a 5.3 with a 700r4 (call it an analog 4L60 if you want) but the gearing is identical internally. I am running 4.10 gears, but here's where I differ, I'm running 315/75r16 tires which measure out to 34" and change. Take my barn door aerodynamics out of the equation and only look at the weight and it's pushing over 6,000 pounds for a trip. The 5.3 is otherwise stock internally with true 2.25" dual exhaust with no cats and a H-pipe.

In my case climbing any grades out here like Monarch, LaVeta and Wolf Creek passes is a frustrating experience. I learned pretty quickly that RPM is needed in order to tackle these passes without bogging down and getting stuck doing 30mph in 2nd because I lost all momentum. The sweet spot for mine is 2500 and up. With the 4.10's and tires at 65mph I'm turning 1,800 rpm which is well below my target zone for torque. 75 MPH has me still only turning 2,100. If I'm in 3rd at 65, the engine is right at 2500 rpm and climbs to almost 3,000 at 75. I've learned if I keep it there I don't loose the momentum and can generally keep up with traffic and not be "that guy" holding everybody up. The point I'm getting to is 4.56's would keep the 5.3 wound tighter, but with my tire size negating some of the gain. It only brings my rpm up a couple hundred at any given speed. Shorter tires would get the engine spinning closer to my target speed. However I'm not going to go down in tire size, so it's not an option.

LS engines are great, but in stock form just don't make gobs of torque down low. Gearing with moderate tire sizing brings back in some mechanical advantage to get more out of the engine in stock form. The LS design is one to rev in the first place. Roller lifters, roller rockers are standard equipment when you have to pay through the nose to upgrade an original gen 1 small block. That valvetrain and free flowing heads is what allows the high rpm running happen. Let it spin and keep it wound up.

The solution to my 5.3's need for more power? Remove and replace with an 8.1 and dropping the slushbox for a nv4500 5 speed. I already have the engine waiting. No replacement for displacement right?
 
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