BlackSSaz

The vehicle: Bone Stock 2001 GMC Yukon XL 2500 4x4, currently with an 8.1l/4l80e/3.73s

The challenge: Tow the "Jacumba" grade heading towards San Diego (where edmunds does their HD tow tests) pulling my 7500lb boat, with 700lbs of people/gear in the truck, with the Cruise control set @ 60mph, AC blasting in July with 115* ambient temps.

The budget: $6500

I bought this yukon a couple of years back with around 110k on the clock. It never pulled the boat right. Ive done all of the basics (except a tune), but still just don't like the way it tows. The engine uses oil, and I think my rear main is starting to go. The "cold start knock" is getting worse, etc.

I just can't bring myself to drop 20k on a clapped out 90s cummins, or 2000s ford 6.0, or a duramax with 300k+ miles on it. Much less the 100k+ or whatever that a new HD truck sells for these days (no hate, just sad I can't afford one!).

So lets build something. GREAT! Wait, what should we build?

Lets hear what you would build to throw in the truck. Its pretty much going to be a dedicated tow vehicle, so lets just concern ourselves with towing performance.

When we tow it's:
- Uphill both ways
- Never less than 2 hours
- Never under 115* outside

Just take a swag at real world pricing - realistic ball parks are fine, but none of the old "well my brother had a duramax laying around" stuff.

So, performance truckers - what would the ultimate budget friendly tow motor look like? A junkyard 5.3 with a turbo? Built 6.0? LQ9? What cam, heads, exhaust, and finally who tunes it? Give your basic build list, and rough estimate for prices.

McAllenSS

iTrader: (1)

I'd go with an lq4 and a used tvs1900 with a meth kit and headers. You'd still have money left over unless you decide to also add a cam and converter.

batboy

iTrader: (6)

There's no replacement for displacement.

quicksilverado

iTrader: (8)

Sure there is. Its called forced induction.

ZO6Ted

Lots of possibilities but I'd build the 8.1 with a better set of heads and a baby torquer cam with long tubes wrapped or coated. A ton of low end and reliability and no overheating. Best thing short of a diesel IMHO.

gamble686

iTrader: (3)

I would normally suggest some form of forced induction however knowing where you are talking about and seeing my mother in laws 3/4ton escalade hit huge temps pulling 5k up that same road in August I think iats would kill a lot of your power. Instead I would go with a LQ9 with some goodies. Cooling system will be key here including the biggest trans cooler you can manage. I would do a very mild cam. 212/216 comes to mind aka the Ht1 from sdparts. Pump the compression just a bit more by milling the heads. Long tubes and all the boltons of course. Most importantly gears. 4.10s if your tires are shorter than 32" or 4.56s for anything taller.

BlackSSaz

Ok, so help me out here and bear with me please. The story I have heard was that the 8.1l holds on to heat really well and gets heat soaked. once this starts, the computer starts pulling timing and performance tanks. As performance tanks eventually you end up in 2nd gear where the converter can't lock up, and then the trans starts to get hot, leading to a vicious cycle which leaves you going 20mph up a grade or on the side of the road trying to cool her off.

After overheating the first time I tried to pull Jacumba (all cocky with my new to me 8.1l) I totally believe this story.

Any credence to this, or just interwebs speculation? I only quote Z06Ted for the no overheating reference relate to an 8.1l.

BlackSSaz

I don't know if you read my other thread in the towing forum or are just a mind reader, but my previous tow vehicle was an 03 SS, lq9 and 4:10 AWD. That truck never ran out of steam pulling hills. Loved that truck and still miss her.

(un)funny thing was I sold it at the height of the financial crisis cause I needed more room and wanted to ditch the payment. Tried hard to sell for months and finally took like 13k for it in 2008 I think with like 65k. Of course premium was like 4.35/gal then... I see guys asking more than that for them now with 2x the miles.

As far as gears go, I think I would be more tempted to burn some more $$ and throw a 6 speed at it. Of course I have no idea what 6 speeds exist, if any would fit, etc, but I want one! If I went that far it would be 4wd delete too, as that just seems like a heavy time bomb waiting to explode and I think I have used it twice maybe.

gamble686

iTrader: (3)

Yeah lots of people got screwed in the financial meltdown. 4.10s will help relieve pressure on your transmission and will be much more efficient at pulling. 4.30s may even make you more happy provided your tires are taller than 30" and you don't plan on cruising over 80pmh. As far as 6 speeds go options are somewhat limited and not worth the hassle. 6L90e is the only decent option, but will cost a pile of money and time to do. You could swap in an Allison again lots of money, but more straight forward since it was offered in a 5speed with the 8.1L on some models. The 6speed Alison was offered later, but idk what that would entail other than a big pile of money.
To me the best band for your buck right awaywould be gears and cooling mods. After that a built 6.0

dirty_old_chevy

I believe Snow performance offers a meth/water injection system with a progressive controller that runs on MAF signal. I believe this would be a good addition to whatever you build to help fight heat soak. I would also use straight water, so the computer isn't always trying to adjust for it, and it will not matter if the system fails for whatever reason.