I just bought an 06 H3 for my 16 year old. And it’s been a money pit so far. Good news is we’ve spent a lot of quality time wrenching.

Truck has 104k miles on it, the engine was replaced with a used Colorado 3.5L that had 50k on it. I’m surprised just how gutless the motor is. Yes I know I should have got the 3.7L.

We just put 33x11’s on it and boy did it rob the engine of power. Is this normal? I know compression and everything was checked and done by a solid mechanic.

 

What's more important to you, for your 16 year old>>>drive fast or drive in a 5-Star Safety Rating?

 

Since I’m on the Hummer forum and not the Mustang forum, fast is not on the priority list. I’m sincerely asking if something could be wrong with my engine. It strains a little to get up some of the hills around town. Unfortunately I didn’t test drive any other H3’s as a baseline to compare.

 

Stock from GM: 0-60 on the 3.5(220HP) is around 2s slower than the 3.7(242HP). You increased tire size=more weight and rolling resistance=less power+changed ACTUAL SPEED(60mph=62.39mph). I can get 0-60 in 8s on my 33's('07/3.7 stock) when empty(I've removed the rear seats, spare tire & mount, and nerf bars).

 

Another straight 5 critic. What you are not thinking about is the monster amount of TQ those little motors put out down low. Which is where you want it for wheeling.

Add some performance mods. The I5s respond very well to and intake, cat back, pcm tune and an Efan conversion can free up a bit of HP/TQ.

When you get the PCM tune, you can add in the change in tires to get shift points back in line.

 

Lacking? Compared to what?

Compared to a 2022 GMC HD Denali? Much less power/acceleration.

Compared to a 2006 Ford Ranger 4 cylinder? About the same power/acceleration.

Compared to a 1975 Mustang II stick? Far more power/acceleration.

Our 2006 H3 base model (which I bought in 2010 w/ 41K for $18,000 from a GMC Dealer) now has 205K on it. Mostly all original except radiator (cracked @ 100K), idler pulley, plugs @ 100K and 200K, exhaust manifold ($$$$), fuel vapor canister, (1) wheel hub, fuel line (from top of engine). And several pads, calipers, rotors. Stock 265 x 16 tires. Certainly putting 33s on this thing will look cool, significantly hurt performance, make an already noisy truck noiser and make the dismal fuel economy even dismalier.

The 3.5 doesn't feel lacking to me and it doesn't struggle to get up hills or do 70 on the highway. If it did/does, there is something wrong.

 

I tow daily and even with a trailer full of equipment the lil 5 banger can hustle.

 

Keep in mind that your asking a little I-5 to pull a 5,000lb truck around, using 4wd, and now with significantly larger tires (in addition to more weight/rolling resistance, the tires geared it up for even less bottom end). As Doc suggested, these trucks are designed to go anywhere, not go fast! Relax, and enjoy the ride.

 

I've read the same. Swap the chip, swap the air cleaner to one that draws air from outside the engine bay like the K&N type, replace exhaust behind the cat to a free-flow, and switch to the multi-contact platinum plugs. It won't be a Lambo, but it's supposed to be noticeable.

 

I would not bother with a "chip" and would instead recommend a PCM Tune. K&N Intakes draw from inside the engine bay, hence they are a warm air intake. I5s do NOT do well with any spark plug other than OEM Iridium plugs and even if they did, GM dyno tested about every miracle spark plug on the market maybe 12 years back and none of them made any measurable improvement.

You are on the right track though.