Greetings all.
I am seriously considering trading in my F150 this weekend for an H3. There is just something about the H3 that speaks to me. The only hesitation I have is the reputation of the 3.7L I5 engine being underpowered. Does anyone know of any effective reliable upgrades (chips, CAI, etc.) for this engine to boost the HP?

 

Sooo. Nobody has any advice?

 

I was worried about that as well, but the H3 I purchased didn't have the V8. I wanted this tactical version, so I bit the bullet and took the I5. It's really helped my driving, honestly. I use to speed, zip around even though I was in a V6 Chevy Blazer. Now, I'm calm, relaxed while I'm driving. I'm not in a hurry.

When I need the pick up, it goes. I've never had a problem merging into traffic or accelerating at a speed that I'm not satisfied with. It's great, and I haven't regretd the decision.

 

I have the 3.5 and it is underpowered at first but you get used to it. It has what I need and has been very reliable. I am certain that there are others that have added upgrades to help with power and hopefully they will chime in.

I will tell you that everytime I think of getting rid of my H3 for something bigger or faster I go for a ride and I know why I love this car. SOLID feeling and there is not another car that looks as good on the road. Good luck with your decision this weekend.

 

My wife and I have had two '06 H3's with the in-line 5cyl. engines. Now we have an '08 Alpha (5.3L V8). We loved all three.

I think owning a Hummer is like getting a tattoo: ADDICTING. You want more. Now we're pretty sure to add an H2 SUT soon.

The 5cyl. engines definitely had less power than the Alpha, but they were plenty good for us. Over 80,000 miles on the first one and about 45,000 miles on the second one before some idiot ran a stop sign and destroyed it (BTW it saved our lives---look at my album).

We now have 34,000 miles on our Alpha. We have other vehicles in our garage/driveway, but everyone seems to migrate to the Hummer when it's time to go anywhere.

I'm sure you won't regret purchasing one......unless you're reluctant to get the addiction!!

 

As long as you don't go too big on the tires, the I5 has plenty of power for the vehicle.

 

The I5s have *****. The L52 (3.5L) could use a bit more, the LLR (3.7L) is better, both respond to performance mods nicely.

Intake, PCMforless tune and Efan conversion, Cat back exhaust, ported/polished Throttle Body and you can easily run with V8s. There will be doubters, I have pics.

Do the searches RKSmith mentioned regarding performance mods in this thread. https://www.hummerforums.com/forum/h...de-info-26215/

People flapping lips about underpowered H3 do not understand how the platform itself works. It is a 5000# brick, not a car with a V motor. Inline motors make gobs of low end torque, but do not spool out HP like a V6 or 8. With full time 4WD/AWD, the power is spread front and rear, and obviously that soaks some too. Go test drive a stock 3 and see what you think, before you are done, on an appropriate road punch it when at 25-30MPH and hold it through 60. With the above mods the jump is much stronger and continues to pull through 70.

I had 350 V8 powered truck in the 70s rated at almost 100 HP less than the LLR.

 

We had concerns about the 3.7 I5 as well when we initially looked at the H3. When we took our test drive the sales guy had me accelerate onto the interstate entrance briskly with the pedal on the floor but without looking at the speedo. Only when we were fully merged did I look at the speed - 80 MPH.

It will never go like a sports car, but it has enough umph for normal uses. Mind you when you carry a heavy load up a steep hill, you will either have to slow down or rev the engine over 3K.