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H3 Improvements for towing?

H3TDave

Well-Known Member
Messages
111
Location
West Virginia
Anyone have any suggestions to help improve my H3T alpha while towing my camper. It hasn't done too bad on previous trips but this one was rough. Needing some more power. Right now its pretty well stock with 33's. I'm wanting to move up to 35's so I'm thinking re-gear cold air intake and getting the ecm reflashed. Not concerned about fuel economy its never gonna get better especially towing my 3500 lb camper but I'd like to get a little better performance.

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H3TDave

Well-Known Member
Messages
111
Location
West Virginia
Aerodynamics
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Happy Hummer

Well-Known Member
Messages
1,300
Location
Wisconsin
31"-32" type/sizing depending upon rims might help a bit instead of the 35".
Regarding a re gear probably not needed mho. The oem air intake breaths pretty good already and the exhaust performance is adequate. So, lol short of getting out to push IDK....

I tow daily with a 3.7 H3 and it fairs okay. I'd say I'm getting close to the 3k weight range on my trailer, equipment and it is no slouch. It ain't gonna win no race either.

Maybe a replacement, reflash ECU could help.

The verdict is out on the cat back and CAI though. I've read and watched countless things and I'm just not sure.
 

Sennin

Well-Known Member
Messages
453
Location
South Africa
I'm running the following on my V8:

Cold air intake
free-flow exhaust with powder coated branches/headers
35" tires
4.56 diffs re-geared
HP tuners tuned PCM

but most importantly, is the 40,000 btu tru cool atf oil cooler - this is the killer you need to focus on. temperatures when towing goes insane.

in short all the mods assist to get a better towing experience, but the H3 still struggles compared to my diesel pickup
 

Jeepwalker

Well-Known Member
Messages
857
Location
WI
Nice-Looking setup!!

From a handling perspective, good stiff wall tires and the right tongue weight need to be paid close attention. If the new tires you buy are 10 ply side wall, they should work great for towing (vs a passenger rated tire). 6-ply isn't too bad, but the taller tire the more side-to-side wallow might be expected. Experiment with tongue weight to see what the best combo is with your rig ..move gear around in the trailer and box as much as possible to get the right combo. I'm sure you know all these things and have experimented already, but just a reminder.

I personally wouldn't blow money on any of those aftermarket intake/exhaust add-ons or chips. Many feel the intakes don't perform as claimed (per a lot of sites out there) and they probably just accelerate wear on your vehicle. But you would definitely get more acceleration out of chipping it. There's no doubt that a re-gear would change the RPM range you'd be in on the road. There's a lot of snake-oil pitches out there. Different guys are going to give ya different opinions, so take mine with a grain of salt. Maybe just driving more careful and conservatively during towing is the best and cheapest 'secret formula'. Finally, there's always the proven engine-performance mods (cam/heads, etc) you could consider.

Does you H3 have a overdrive lock-out button or towing mode? It's frustrating that in 07 (my year) GM didn't include features which had been common on other premium vehicles for several years back then (mainly Jeeps and P-U's). If your's doesn't have a lock-out button or towing mode, it should be possible to rig up a 5th gear lock-out. That might be the best and least expensive add for towing. You would preserve on-road fuel economy for the 90% of most driving, yet get towing power when you needed it.

You have a long wheelbase so the tail shouldn't wag the dog too bad.
 
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Jeepwalker

Well-Known Member
Messages
857
Location
WI
BTW, just curious when you go on your camping excursions, how much total weight in gear and people you estimate you are carrying? Not counting the camper.

Is there a tow/haul switch on the H3T Alpha? (or was one ever offered that could be installed after the fact?)
 

H3TDave

Well-Known Member
Messages
111
Location
West Virginia
BTW, just curious when you go on your camping excursions, how much total weight in gear and people you estimate you are carrying? Not counting the camper.

Is there a tow/haul switch on the H3T Alpha? (or was one ever offered that could be installed after the fact?)
Dry weight the camper is 3,200 lbs. I haul it with the water tank empty. Gear wise we travel pretty light. Maybe 2-300 lbs of extra stuff in the camper. 450lbs Of people and the kayaks are probably 150. Heaviest thing is probably the cooler with food, ice and drinks.

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amrg

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2,317
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By moving to 35s you are technically changing the gearing of your truck by making them taller, so a regear would be your best mod. Sadly you are limited by the front diff which can only accept 4.56 gears and you need both front and rear to match unless you are planning on converting the H3 into 2wd (by disconnecting the front drive shaft permenantly). This will also help keep trans temps inline with stock setup.
All other engine mods will try to overcome the reduction in torque at the tires (by the bigger size) by increasing the engine torque itself.
 

JTRX

Member
Messages
21
Location
Northern Virginia
I tow a small trailer about the same weight...I just picked up the superchips programmer for the tow mode. The shift points were driving me nuts which I think this will adjust. Not sure how it compares to having the ECU tuned. Haven't tried anything like this before but I'll give it a go this weekend. I'll let ya know if I like it, brick it, or can't tell a difference.
 

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
Definitely go with 4.56 gears. It makes a big difference on the Alphas including in daily driving. One of the best mods, regardless of towing needs.
 

JTRX

Member
Messages
21
Location
Northern Virginia
Not as far as I know. It was pre-wired for a tow controller but the actual controller has to be added. A tow mode would be great but I haven't seen that as a feature.
 

amrg

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2,317
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The H3 doesnt have a tow mode, unlike the 6L80/90 which do. Im not sure if you can add it, i know when I looked in the programming there is a provision for a different set of parameters that can be added and probably called upon when you need to (which the 6l80 has and can be activated using the tow/haul mode)
 

H3TDave

Well-Known Member
Messages
111
Location
West Virginia
I'm leaning towards a re-gear an additional cooler and either a ecm reflash or tuner. I'm gonna lose the winch to help with air flow.

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H3TDave

Well-Known Member
Messages
111
Location
West Virginia
When I'm just going kayaking they aren't too bad up top. But when its combined with the camper it's just too much wind drag on top of Hauling the camper.

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amrg

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If you go with a cooler bypass the oem one in the radiator as Ive read about several people having the internal cooler rupture mixing coolant with oil leading to trans failure. If you live in a cold environment get the oil bypass for the cooler too (helps keep oil warm in freezing temps)
 

Hunner

Well-Known Member
Messages
2,334
Location
Arkansas
I use a Superchips Flashpaq 2865 on my 08 Alpha set for tow mode. I pull a 3500 lb work trailer or my Whaler and it works great. I had some mods done to the tranny at the 100,000 mile rebuild and added some clutches. Works alot better even though the Alpha solved a lot of the down shifting that the I-5 did. I tried the performance mode after running some premium gas for a couple of tanks. I thought it was a bit much.
Keep in mind a "cold air" intake does not mean one that is an open container under the hood that sucks hot air after the fan blows over the engine.
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Hunner

Well-Known Member
Messages
2,334
Location
Arkansas
I use a Superchips Flashpaq 2865 on my 08 Alpha set for tow mode. I pull a 3500 lb work trailer or my Whaler and it works great. I had some mods done to the tranny at the 100,000 mile rebuild and added some clutches. Works alot better even though the Alpha solved a lot of the down shifting that the I-5 did. I tried the performance mode after running some premium gas for a couple of tanks. I thought it was a bit much. I also went back to 33's for hwy and that helped.
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