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Upgrades for Tow Rig

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fixmy59bug

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Riverside, Ca
I finally have my 89 'Burban hooked up how I like it looks wise, so now I am looking for more stump pulling power. I mainly use my suburban for towing and hauling stuff around. Fuel economy is not the biggest concern (my modifications (completed and planned) are proof of that, but I am not looking to get into the single digits either. So here's the skinny:

89 GMC R1500 Suburban (Yes, it is 2wd unfortunately)
350 TBI, Completely bone stock
Stock 700R4 trans with torque convertor lock up switch (installed by previous owner. Not too sure on the hack job, but it works.)
3/4 ton suspension swapped in from a 73 C20 suburban. Bolted right in with no problems.
Hummer H2 wheels
3" Performance Accessories body lift

Now that I got it sittin pretty, I am looking for more towing power. This truck only gets driven when something needs towed or hauled. I already know the Hummer H2 wheels do not help my torque, but I want form and function. LOL. A few items I have been considering are a Throttle body spacer, maybe an RV cam (unless someone has another suggestion), and headers. But I don't know what brands or specs to go with. But here's the catch. I would like it to be able to pass smog (I live in Ca, so I have strict smog laws). If anyone has any advice, Please give it. Thanks.

Edit: I almost forgot. I am also planning on running an electric fan to eliminate some drag on the motor. But should I run a single (possibly 16") or should I run dual fans (something like 12"). I know my car runs dual fans. One kicks in when the temperature gets up there, and the second fan is primarily used when the A/C is on. Should I look at running a setup like that or something else. All help provided is really truely appreciated.

P.S. On a side note, These sealed beams suck something fierce. I have the 4 beam side by side system. I have found only 1 place that sells upgrade lamps (LMC finally has "Euro Lamp" replacements at $30 per headlight. That's $120 for all 4). I also saw mention of someone using Chevy Celebrity headlights. Is this a direct swap? Most importantly, it is better output than the sealed beam lights? And finally, Does anyone have pics of this Chevy Celebrity setup? Thanks again.

Edit 2: Cancel the pic request. It's amazing what can be found if you use the search button up top. I am thinking those "euro Lamps" may be the best upgrade, Unless someone has any better advice.
 
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fixmy59bug said:
I finally have my 89 'Burban hooked up how I like it looks wise, so now I am looking for more stump pulling power. I mainly use my suburban for towing and hauling stuff around. Fuel economy is not the biggest concern (my modifications (completed and planned) are proof of that, but I am not looking to get into the single digits either. So here's the skinny:

89 GMC R1500 Suburban (Yes, it is 2wd unfortunately)
350 TBI, Completely bone stock
Stock 700R4 trans with torque convertor lock up switch (installed by previous owner. Not too sure on the hack job, but it works.)
3/4 ton suspension swapped in from a 73 C20 suburban. Bolted right in with no problems.
Hummer H2 wheels
3" Performance Accessories body lift

Now that I got it sittin pretty, I am looking for more towing power. This truck only gets driven when something needs towed or hauled. I already know the Hummer H2 wheels do not help my torque, but I want form and function. LOL. A few items I have been considering are a Throttle body spacer, maybe an RV cam (unless someone has another suggestion), and headers. But I don't know what brands or specs to go with. But here's the catch. I would like it to be able to pass smog (I live in Ca, so I have strict smog laws). If anyone has any advice, Please give it. Thanks.

Edit: I almost forgot. I am also planning on running an electric fan to eliminate some drag on the motor. But should I run a single (possibly 16") or should I run dual fans (something like 12"). I know my car runs dual fans. One kicks in when the temperature gets up there, and the second fan is primarily used when the A/C is on. Should I look at running a setup like that or something else. All help provided is really truely appreciated.

P.S. On a side note, These sealed beams suck something fierce. I have the 4 beam side by side system. I have found only 1 place that sells upgrade lamps (LMC finally has "Euro Lamp" replacements at $30 per headlight. That's $120 for all 4). I also saw mention of someone using Chevy Celebrity headlights. Is this a direct swap? Most importantly, it is better output than the sealed beam lights? And finally, Does anyone have pics of this Chevy Celebrity setup? Thanks again.

Edit 2: Cancel the pic request. It's amazing what can be found if you use the search button up top. I am thinking those "euro Lamps" may be the best upgrade, Unless someone has any better advice.
Click to expand...

Yes he's found the light, Search light that is, it's a very powerfull tool, use it wisely.
:D
One question, did you match the tire size you have with proper gearing?
That will make the difference in you power and mileage.
 
I have no clue on how to match tire sizes to gearing. The 14BFF that I pulled out of the '73 has 4.11 gears. And my speedo reads about 10% slower than actual speed. Acceleration is about the same as it was before with the 10 bolt and stock tires. So I figured there was no problem. Am I mistaken?
 
What size of tire did you go with on the H2 wheels?

To match the tire size and gearing you need to keep the ratio of tire diameter to gear ratio somewhat the same. So, as you increase the tire size the gear ratio needs to go lower (numerically higher) to compensate. Your 1/2 ton Sub probably had about a 235/85-R15 stock so that's about a 31" diameter. Let's assume you had 3.73 in the rear pre-swap. With the 4.10s you can now run a 34" diameter, which is about the true diameter of a 35" tire, (31/3.73 = 34/4.10) to keep things equivalent.

That being said a 33" tire is probably a pretty good size for usability with the 4.10s; they aren't so big to put a lot of stress on the engine and, especially, the transmission while towing and should allow for decent cruising in OD while not towing.

I'd also add a extra transmission cooler to your list to keep the 700R4 a little happier.
 
I think your on the right track, electric fans may free up a few ponies and help with mpg at the same time. Defintely add a cooler to that 700.

As far as the headlight thing, there is a thread on here for a headlight wiring upgrade that suppossed to make a huge difference.

If you do decide to do some sort of motor upgrade you certainly can think about chip, intake, headers, and EFI friendly cam. Dont put in a "RV" unless it has been specifically designed for the TBI system. Talk to any major cam manufacturer about what would be right for your application. Edelbrock makes a nice aluminum intake thats 50 state legal, although to be honest I dont know if there would be a huge improvement as compared to the stocker. The stock piece is aluminum too and may flow almost as well as an aftermarket, but this is unfounded by my part and should probably be researched further. And lastly you can get 50 state legal headers and I do believe it would be a worhtwhile upgrade along with a cam, headers, chip, intake?, and maybe slightly more powerful fuel pump with a regulator.
 
Forget the electric fan. You trade draw from the waterpump to a draw on the alternator. Electric fans are cool for the control they provide (water crossings, variable on/off temps) and space savings. Other than that, they are just eye candy if you've got a properly operating clutch fan.
 
my 1 ton 2x4 crew cab has 4.10 and 245/75/16 tires. i had 265/75/16 on it and it droped my rpms a bit to much for the 10k trailer. when i swaped back the power was back. its a good combo.

and dont forget that 700 will die quick if you tow in over drive.
 
Ok, I will try to address all questions and points that stuck out in my mind:

GMCJason - The tire size on the H2 wheels is 315/70-r17. They are the stock tires on the wheels. They equate to 35x12.50x17. You are correct on the 3.73 gears pre swap, but I am unsure of the stock tire size as I am still at work right now. When I get home I will double check on that.

K5er4Life - Where can I find this headlight wiring upgrade you spoke of? I tried searching for it and I couldn't find it. Is it just a matter of relaying the system? If so, that is a cake walk for me and I may as well do the low's on with high's mod. That should be simple enough.

Dyeager535 - Would you happen to know where I can find info pointing out that the alternator would create as much or more of a draw vs the waterpump mounted fan? I know alot of people have said electric fans are better but I don't always believe what I hear (or read for that matter). I am thinking about going with a dual fan and wiring it so one fan comes on when it gets warm, and only having the second fan come on when it is needed for the A/C. There is a dual fan setup on summit that draws only 19 amps. Of course it doesn't specify 19 amps each or total. If it is total, that should create less of a drag on the motor than a waterpump fan. Or there is a single 16" fan that pulls 13.8 amps.

SweetK30 - Ok, lets assume I do already have a trans cooler (This I am not sure on, I will have to double check). My trailer is a 4x8 utility trailer that will weigh no more than 1000lbs. Is it safe to tow in OD with the torque converter lockup NOT engaged. I know anytime I hook up my car trailer OD will not be used. But for the lightweight trailer, will I be doing damage to the trans if a cooler is already installecd?
 
http://www.aaroncake.net/rx-7/efanmyth.htm

Wow look, an internet link! Only an idiot would take everything there as a gospel, (or discount everything there if part of it is wrong) but it is certainly opposite of the sales hype you hear for the fans, isn't it?

Properly operating clutch fan will draw almost NOTHING with a vehicle at speed. If you want to play around, take off your fan and go for a short drive. (leave it and tools in the rig if you are worried)

Did this test in my truck, and on flat ground, 25MPH was more than sufficient to NOT need a fan at all. That tells you that unless you are under some serious load, or very low speeds, (or poor condition cooling systme) where electric fans sometimes have problems keeping up anyways, your clutched fan will simply be slipping.

I've got dual electric fans, and I thought it was a fun/cool project to do, but entirely pointless in any other way. I do run them with the ECM, so one on at whatever temp I choose (220*) and one on a failsafe switch at 240*. One fan on is enough to drop the engine temp 10* in a short period of time. Smaller fan (less draw) would simply have to turn faster or longer to accomplish that of a larger (more draw) fan, so either way you are drawing similar amounts from the alternator and thus the engine.
 
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