Low-end improvement suggestions?

[Shdwdrgn]

Most of my driving is in-town, and I do some occasional very heavy towing. Unfortunately I have 3.42 gears, and 30.6" tires, which is just going in the wrong direction for low-end power. Right now I have a pcm4less tune and a custom intake that could be modified if it would help. My engine is at about 86,000, and I have full synthetic everywhere but the tranny and transfer case. I've cleaned the TB before, and am planning on checking it again tomorrow. Like most, I don't have the money to drop into a new set of gears, and I know basic tune-up techniques aren't going to give me much, but I'm just looking for any suggestions that might help the low-end performance for my day-to-day driving?

Mind you, the truck seems to be running normal. The only thing I could consider an issue is there seems to be a slight hesitation when I take off from a stoplight. I'm just wondering if there are low-budget mods, some tips&tricks that anyone is aware of, that would help get a little more power or gas mileage (the two are not always mutually exclusive) out of the low end?

 

[Pittdawg]

Most of my driving is in-town, and I do some occasional very heavy towing. Unfortunately I have 3.42 gears, and 30.6" tires, which is just going in the wrong direction for low-end power. Right now I have a pcm4less tune and a custom intake that could be modified if it would help. My engine is at about 86,000, and I have full synthetic everywhere but the tranny and transfer case. I've cleaned the TB before, and am planning on checking it again tomorrow. Like most, I don't have the money to drop into a new set of gears, and I know basic tune-up techniques aren't going to give me much, but I'm just looking for any suggestions that might help the low-end performance for my day-to-day driving?

Mind you, the truck seems to be running normal. The only thing I could consider an issue is there seems to be a slight hesitation when I take off from a stoplight. I'm just wondering if there are low-budget mods, some tips&tricks that anyone is aware of, that would help get a little more power or gas mileage (the two are not always mutually exclusive) out of the low end?

4.11 gears would make the most difference but labor on installing them is not cheap. My ported throttle body seemed to add a decent amount of low end so if you do the labor yourself it should be relatively "low-budget".

 

[Shdwdrgn]

4.11 gears would make the most difference but labor on installing them is not cheap. My ported throttle body seemed to add a decent amount of low end so if you do the labor yourself it should be relatively "low-budget".

Ported throttle body??? You have me intrigued, I have not heard of this mod. I've read a lot about porting the head, and on my old '74 Pontiac this was something I had done by hand. I'll have to look around, but can you point me to any threads that give a good "how-to"?

[EDIT] After some hectic thread-scanning and google-searching, the information I've found suggests that while TB porting has minimal gains (conservatively around 5hp), it adds those HP to the first 1000 rpm, which is exactly where I need them. I think while I'm cleaning my TB today, I'll take a good look and see if there is any obvious work I could do to polish out casting marks.

 

[limequat]

I have a hard time believing that the throttle body is a restriction at 1000 RPM.

 

[ScarabEpic22]

I have a hard time believing that the throttle body is a restriction at 1000 RPM.

Ported tbs arent cutting it for me, until someone sticks a truck on a dyno, does 3-5 runs (with cooldown period) back to back, then swaps to a ported tb and does the exact same test (with no tune changes). Im betting its worth maybe 5hp TOPS.

If you want low end, get one of the new Kooks I6 headers. Buy an 06+ head, have it ported n polished, buy cam blanks and have Comp Cams cut them. Drop all this on, should be good for ~+30-50rwhp (header, new style head + p'n'p, cam, retune).

 

[Hypnotoad]

I would think that the ported TB would give power up top, not on the low end. I'll be the first to admit I'm no expert though.

 

[Pittdawg]

I had a ported throttle body on my 4.7 liter Magnum V8 Dodge Dakota and now on my Voy. In both instances, throttle response was greatly improved. I did not dyno either tb but I equate better throttle response with "low end".

 

[Shdwdrgn]

From what I've read on polished heads, most of the gains are in the upper RPMs. I'm not racing, I just need better low-end performance. Unfortunately I think a new set of gears is really going to be the only option that gains me a noticeable amount of power, everything else is just fluff.

On the matter of the TB, I got mine cleaned up today. Significant reduction in off-the-line hesitation, which is sad, because its been less than 10k miles since the last time I cleaned it. Also of note, in stock condition (unless someone made changes before I bought the truck) there are absolutely NO casting marks or flashing of any kind through the bore. My TB is highly polished all the way through, and appears to match up decently to the intake plastic, so I saw no reason to take a dremel to it and mess with it.

I would love to get that extra HP from swapping in an '06 ported head, but I think new gears are going to be first on my major upgrades list. I've always assumed I would just go with 373s, but now I think I need to do some gear and wheel comparisons, and see exactly what a set of 410s would do for me. Mileage-wise, I put on as many highway miles as I do city miles, because when I do get out on the highway, it's usually a couple hours or more of driving on the interstate, so retaining a comfortable 75-85mph range is essential. However I definitely spend more time overall driving around town, and when I tow a trailer, its over 5000 pounds going up a mountain. It's tough to find that sweet spot in the middle.

 

[seanpooh]

I have the ported TB, I feel a very slight improvement in response of the throttle but nothing more. It's not something to spend money on.

As for tune ups to increase the low end... nothing that will give a night and day improvement. Maybe changing spark plugs?

Oh, there is a difference in exhaust I think. Right now I have a straight glass packed muffler. Before that I had the offset one but the exhaust guys didn't weld it right and it rattled against the frame. Anyways, when I had the offset exhaust, my low end from a stoplight to WOT was much more better, more peppy if you get what I'm saying.

 

[Pittdawg]

From what I've read on polished heads, most of the gains are in the upper RPMs. I'm not racing, I just need better low-end performance. Unfortunately I think a new set of gears is really going to be the only option that gains me a noticeable amount of power, everything else is just fluff.

On the matter of the TB, I got mine cleaned up today. Significant reduction in off-the-line hesitation, which is sad, because its been less than 10k miles since the last time I cleaned it. Also of note, in stock condition (unless someone made changes before I bought the truck) there are absolutely NO casting marks or flashing of any kind through the bore. My TB is highly polished all the way through, and appears to match up decently to the intake plastic, so I saw no reason to take a dremel to it and mess with it.

I would love to get that extra HP from swapping in an '06 ported head, but I think new gears are going to be first on my major upgrades list. I've always assumed I would just go with 373s, but now I think I need to do some gear and wheel comparisons, and see exactly what a set of 410s would do for me. Mileage-wise, I put on as many highway miles as I do city miles, because when I do get out on the highway, it's usually a couple hours or more of driving on the interstate, so retaining a comfortable 75-85mph range is essential. However I definitely spend more time overall driving around town, and when I tow a trailer, its over 5000 pounds going up a mountain. It's tough to find that sweet spot in the middle.

I will have an 08 head to sell to you soon.

 

[limequat]

From what I've read on polished heads, most of the gains are in the upper RPMs. I'm not racing, I just need better low-end performance. Unfortunately I think a new set of gears is really going to be the only option that gains me a noticeable amount of power, everything else is just fluff.

On the matter of the TB, I got mine cleaned up today. Significant reduction in off-the-line hesitation, which is sad, because its been less than 10k miles since the last time I cleaned it. Also of note, in stock condition (unless someone made changes before I bought the truck) there are absolutely NO casting marks or flashing of any kind through the bore. My TB is highly polished all the way through, and appears to match up decently to the intake plastic, so I saw no reason to take a dremel to it and mess with it.

I would love to get that extra HP from swapping in an '06 ported head, but I think new gears are going to be first on my major upgrades list. I've always assumed I would just go with 373s, but now I think I need to do some gear and wheel comparisons, and see exactly what a set of 410s would do for me. Mileage-wise, I put on as many highway miles as I do city miles, because when I do get out on the highway, it's usually a couple hours or more of driving on the interstate, so retaining a comfortable 75-85mph range is essential. However I definitely spend more time overall driving around town, and when I tow a trailer, its over 5000 pounds going up a mountain. It's tough to find that sweet spot in the middle.

The 06+ head will actually cost you low end torque. The valves are larger and cams bigger. Slower airflow = less torque. You get some torque back with the higher compression, but I think that's accomplished with different pistons.

I agree that the most practical route to more torque is gears. You'll spend a fortune getting new a new ring and pinion and paying for setup. Instead, go to car-part.com and find a complete rear axle with the 4.10s. Swapping an axle is something you can do in your driveway on a Saturday. Should be able to find one for < $200.

 

[Shdwdrgn]

I have 4WD... Unfortunately changing gears isn't going to be quite that easy for me...

 

[Mypetropig]

I noticed in your other thread that your custom intake does not have the resonator at the throttle body. I have read either here or the OS that deleting that resonator could result in the loss of low end torque. Not sure how much though. I always thought resonators were just for noise but I guess I could be wrong.

 

[Shdwdrgn]

Hmm I think my butt-dyno would have to disagree with that statement. After changing to the new intake (and now having changed back to stock again), I did not notice any difference off the line. What I did notice was that above 35-40mph there is a definite difference when I punch the gas to pass someone. Now that I'm back on the stock intake again, I'm noticing that lack of punch. It still has power, its just not the same.

 

[oh05ext]

could you try to source the axles from a trailblazer with 3.73's?im not sure how involved the swap is on the front but the rear shoundnt be that bad right?