Four Wheeler Magazine 2007 H3 Test
#1
10-07-2006 | 01:07 PM
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Four Wheeler Magazine 2007 H3 Test
Power Play - 2007 Hummer H3
More muscle for the '07 Hummer H3
By Ken Brubaker
Zipping around in the Hummer H3 just got even more fun thanks to the introduction of a new, more powerful 3.7L five-cylinder engine. This new powerplant boasts a welcome 22 more horsepower and 17 lb-ft of torque than the engine it replaces. This translates to 242 hp and 242 lb-ft of torque.
How They Did It
Hummer’s Daryl Ehrlich, Development Engineer, Energy and Drive Quality, summed up the goals of the project by saying: “Our goal was to improve acceleration performance and driveability with the new 3.7L engine, yet minimize impact to fuel economy by implementing new technologies like Regulated Voltage Control and a high-efficiency alternator.” With goals set, the team increased the cylinder bore from 3.66 inches to 3.76 inches. Of course, this increase in diameter necessitated bigger intake and exhaust valves, so larger 1.52-inch intake valves replace the previous 1.45-inch intake valves, and larger 1.32-inch exhaust valves replace the previous 1.18-inch exhaust valves. Engineers also revised the profile of the dual overhead camshafts to optimize valve lift and duration in accordance with the larger valves. Naturally, these modifications require more airflow, so engineers increased cylinder head airflow to match the demand of the larger valves and revised camshaft. Major attention was paid to creating a quieter engine too. The list of noise-reducing changes includes a connecting-rod oiling system, aluminum camshaft cover, and tighter-clearance balance shaft bushings. Finally, as stated earlier, fuel economy was also a major concern. With that said, the team integrated Regulated Voltage Control into the mix. Quite simply, this system shuts down the alternator when voltage isn’t needed, thus elimin- ating drag on the engine. The result is a larger engine that makes more power than its predecessor but suffers no decrease in overall fuel economy.
How It Drives
We figured that the best way to gauge the power of the new engine was to compare the current 3.5L and the 3.7L engine back-to-back. With that said, we borrowed a 3.5L-powered H3 from the Chicago press fleet and we drove it to the Hummer Homecoming in South Bend, Indiana. We then hopped into a 3.7L-powered H3 for a run from South Bend to Silver Lake Sand Dunes near Mears, Michigan. After testing on the dunes, we jumped back in the 3.5L-powered rig for the return trip to our Four Wheeler Midwest Bureau.
On the road, we immediately noticed two things about the new 3.7L engine. First, it definitely seems quieter, both at idle and under load, thanks to the host of noise-reducing changes. Second, the new I-5 engine generates a power-to-weight ratio that is more in line (no pun intended) with the vehicle’s 4,700-pound curb weight. It won’t take your breath away, but it doesn’t stand out as obviously needing more beans. As we wound our way north on Highway 31 toward Muskegon, we noticed the 3.7L’s 242 hp also kept the Hydramatic 4L60E four-speed automatic transmission happier—it wasn’t demon- strating the propensity to shift out of overdrive to hold highway speed on hills as often as the 220hp 3.5L-powered H3.
The fact that Hummer turned us loose on the soft, power-sucking sand of Silver Lake Sand Dunes says a lot about their confidence in the performance of the new 3.7L engine. Of course, the first thing we did was head for the tallest hill we could find. With the transfer case in 4-Hi and the auto trans in Second gear, we easily climbed to the top of Silver Lake’s tallest dune. Over the course of three hours, we Baja’d the H3 over every obstacle we could find. It never exhibited a gross lack of power, though on long hillclimbs it seemed to be happiest yowling near its max horsepower- making rpm of 5,600. Throttle response was very good and the tuning of the drive-by-wire system was excellent, even on the roughest of ter
More muscle for the '07 Hummer H3
By Ken Brubaker
Zipping around in the Hummer H3 just got even more fun thanks to the introduction of a new, more powerful 3.7L five-cylinder engine. This new powerplant boasts a welcome 22 more horsepower and 17 lb-ft of torque than the engine it replaces. This translates to 242 hp and 242 lb-ft of torque.
How They Did It
Hummer’s Daryl Ehrlich, Development Engineer, Energy and Drive Quality, summed up the goals of the project by saying: “Our goal was to improve acceleration performance and driveability with the new 3.7L engine, yet minimize impact to fuel economy by implementing new technologies like Regulated Voltage Control and a high-efficiency alternator.” With goals set, the team increased the cylinder bore from 3.66 inches to 3.76 inches. Of course, this increase in diameter necessitated bigger intake and exhaust valves, so larger 1.52-inch intake valves replace the previous 1.45-inch intake valves, and larger 1.32-inch exhaust valves replace the previous 1.18-inch exhaust valves. Engineers also revised the profile of the dual overhead camshafts to optimize valve lift and duration in accordance with the larger valves. Naturally, these modifications require more airflow, so engineers increased cylinder head airflow to match the demand of the larger valves and revised camshaft. Major attention was paid to creating a quieter engine too. The list of noise-reducing changes includes a connecting-rod oiling system, aluminum camshaft cover, and tighter-clearance balance shaft bushings. Finally, as stated earlier, fuel economy was also a major concern. With that said, the team integrated Regulated Voltage Control into the mix. Quite simply, this system shuts down the alternator when voltage isn’t needed, thus elimin- ating drag on the engine. The result is a larger engine that makes more power than its predecessor but suffers no decrease in overall fuel economy.
How It Drives
We figured that the best way to gauge the power of the new engine was to compare the current 3.5L and the 3.7L engine back-to-back. With that said, we borrowed a 3.5L-powered H3 from the Chicago press fleet and we drove it to the Hummer Homecoming in South Bend, Indiana. We then hopped into a 3.7L-powered H3 for a run from South Bend to Silver Lake Sand Dunes near Mears, Michigan. After testing on the dunes, we jumped back in the 3.5L-powered rig for the return trip to our Four Wheeler Midwest Bureau.
On the road, we immediately noticed two things about the new 3.7L engine. First, it definitely seems quieter, both at idle and under load, thanks to the host of noise-reducing changes. Second, the new I-5 engine generates a power-to-weight ratio that is more in line (no pun intended) with the vehicle’s 4,700-pound curb weight. It won’t take your breath away, but it doesn’t stand out as obviously needing more beans. As we wound our way north on Highway 31 toward Muskegon, we noticed the 3.7L’s 242 hp also kept the Hydramatic 4L60E four-speed automatic transmission happier—it wasn’t demon- strating the propensity to shift out of overdrive to hold highway speed on hills as often as the 220hp 3.5L-powered H3.
The fact that Hummer turned us loose on the soft, power-sucking sand of Silver Lake Sand Dunes says a lot about their confidence in the performance of the new 3.7L engine. Of course, the first thing we did was head for the tallest hill we could find. With the transfer case in 4-Hi and the auto trans in Second gear, we easily climbed to the top of Silver Lake’s tallest dune. Over the course of three hours, we Baja’d the H3 over every obstacle we could find. It never exhibited a gross lack of power, though on long hillclimbs it seemed to be happiest yowling near its max horsepower- making rpm of 5,600. Throttle response was very good and the tuning of the drive-by-wire system was excellent, even on the roughest of ter
#8
10-08-2006 | 07:21 PM
Senior Member
Joined: Sep 2006
Posts: 559
RE: Four Wheeler Magazine 2007 H3 Test
Hey thats right by where I live!! I just drove past that today on my way back from my first H3 road trip to some other lake michigan dunes...where I blew out my knee after jumping off a 20 foot dune..But the H3 is a blast in the sand!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
#9
10-09-2006 | 08:57 PM
Senior Member
Joined: Aug 2006
Posts: 143
From:
RE: Four Wheeler Magazine 2007 H3 Test
Though the 06 was the first H3 model year, I bought anyway because the power train essentially consisted of a proven GM components. I felt waiting a year wouldn't get me anything but a price increase. So much for that theory. Reading the quoted article, I'm amazed at how far Hummer went in reworking the Vortec 5 for a relatively minor increase in output. I don't think GM put that much engineering effort into improving the old 350 warhorse in 20 years!
H3 media response continues to be almost all very positive, and thats good. It means Hummer Div. can focus on real improvements vs. supeficial marketing-driven changes, and it means our H3s should benefit from very good resale value three or four years out. I just hope GM leaves Hummer as their niche offroad vehicle and avoids temptation to "luxurify" it.
H3 media response continues to be almost all very positive, and thats good. It means Hummer Div. can focus on real improvements vs. supeficial marketing-driven changes, and it means our H3s should benefit from very good resale value three or four years out. I just hope GM leaves Hummer as their niche offroad vehicle and avoids temptation to "luxurify" it.
