E-Fan?! 😬 🙉

It also looks like you are getting close to your GCWR. I think that it's 16,000 lbs?

 

I don't claim to he an expert about anything. I thought the e fans cooled better and reduced engine load?
I haven't looked at GVWR, for as long as I can remember no one has ever cared about GVWR except commercial vehicles. I know the Rams were seeing frame failures when bumper pulling and carrying a slide-in camper but those are the only GVWR failures I've ever heard of.
ok according to owners manual yes GCWR 16,000 and max trailer wr 9900. And it specifies 4.10 gears. So you are right I'm close but perfectly legal.

 

Hard to beat a mechanical for pure air flow volume. They don't really cool any better and sometimes worse if sized incorrectly. Easy enough to find a fan clutch at an auto parts store but not so much a new fan. If an e-fan fails it shuts off. When a clutch fails it's generally always locked and spinning.

And it's rated at 16k with 4.10's. Do you know what gears you have and does it say what it's rated at with those gears? 580lbs under max payload, I bet that truck is working like a dog pulling that thing.

 

Yeah, I think you are right. I suspect the GCWR was limited by the transmission on these trucks looking at the manual. The GCWR seems a bit higher on the trucks equipped with the Allison. As far as I knew, the frames were the same across the HD lineup irrespective of engine/transmission combination.

Regarding the E fan conversion, I've read several threads of guys overheating when towing. I think GM would of used E fans on HD trucks if they thought it would work. Not sure if it was an airflow, simplicity or reliability issue or what? 🤷 I don't think it's a HP free-up but rather a cooling issue.

 

Did you try the tune i sent you?

 

Yes. I tinkered with it a little. I also ended up tinkering with the throttle cracker like you suggested. It doesn't really enhance engine braking idon't think but it does sound cool on decel . It does keep the tcc locked up for a bit when I let off in normal mode in 4th at interstate speeds.

 

That trailer looks brutal to tow through the mountains.

@RDF1 just curious you touching timing much in this case? I know those stock early LQ4s have very low timing, not sure if more would help at all.

 

Yea I used the spark table I have in my 04 2500hd. I've spent a fair amount of timing towing with it and tinkering with AFR and timing.
Spent a few hours on another stock lq4 on the dyno playing with timing and AFR at 500 rpm internals from 1000 to 5000rpms. So I kinda base it off of that but I run TR6 plugs instead of the tr5 heat range. Seems to make a little difference on knock and getting aggressive with the tune on 87 octane and towing

 

@RDF1 you adjusted timing on the time you sent me? I'm running 87 or even 85 and haven't heard any knock.
random codes keep popping up when she's doing work at high rpm and load. Always historic and I just clear them.

 

You can look at the RPO codes in the glove box, GT4 is 3.73 and GT5 is 4.10, but you almost certainly have 4.10 gears.

I don't think gearing is really the answer, you're already on a perfect sized tire for towing/performance and puts you into the power band as it should.

I say get a custom tune on the truck, bigger transmission cooler and maybe you could upgrade to the Duramax fan clutch/fan for maximum cooling. E fans are not THE best for heavy workloads, like towing and towing in heat/mountains. I have E fans, and basically the same truck as you. The E fans haven't really failed me but I think under high stress I would rather have the mechanical fan. Yes they will rob some power fully locked up, but also spinning that big fan at 3-4k RPM is moving tons of air.

Beyond the few things I mentioned, actual power upgrades for towing that are worthwhile... forced induction probably. A very small camshaft could help some, in that 2500+ RPM range could get some more power but whether it's worth it, I guess it depends what the truck is for.

Oh and run premium gas when towing. My truck responds well to the higher octane.