I've read a few threads talking about the Colorado, its platform, Isuzu, etc.. And some people have stuff just plain wrong..

1. No other engine was designed to fit into the platform but the I5. No V8, no V6, no I6.
2. Isuzu's involvement with the development was broken off 6 months into the partnership. The Isuzu truck was being designed for a mostly asian market while the Colorado was a US application. Totally different goals. So, much of what your hear about Isuzu engineering the Colorado, is false.

I know this because i attended the media introduction of the Colorado/Canynon last August where i spend hours driving the trucks with Engineers riding shotgun.

 

but the Isuzu D-max has a 24v DOHC V6

 

Read point #2. The trucks are different enough.

 

But the size of the trucks is the same right? They share interior parts and are both on the GMT355 right? Cabs and beds look the same. Why wouldn't under hood dimentions be the same? THe D-max doesn't look wider in the front

 

All i know is the GM engineer specifically stated to me that nothing but the I5 would fit. Also, GM does not have a Truck V6 anymore besides the 4.3L which is being phased out. Not sure what to tell ya other than what i was told.

 

But they need to say that to defend the I5. Otherwise what else would they put it in and who would option it into their new vehicle?

Most truck buyers want power. Just the sound of "V6" says more power than "I5" to the subconcious mind... even if the I5 has more horsepower and torque. How many here would want a 5th Gen Camaro SS with a V6... even if the V6 had as much hp as a V8? Almost no one.

If GM were able to fit a V6 into the Colorado, the majority of I5's sold would be the entry level stripper models.

Give it a few months. Someone will come up with a V8 conversion for it.

 

...and it doesn't

The I5 is 220/225 the 4.3 in a Blazer is 190/250.

I wonder if someone can enlighten us as to why GM didn't develop a V6 off the new V8?

 

Because the 4.3 was a horribly primitive engine? Every one Ive ridden in was noisy, vibration-heavy, and generally unrefined.

They're also reliable as hell and pretty powerful considering their simplicity. I think GM just looked at them and realized that they couldnt meet consumers' rising demands of refinement and comfort in trucks with the old engine.

EDIT: Duh, I answered the wrong question...

 

Why is my experience so different? I found 4.0 liter Ford is as you describe ...and early 4.3's may have been that way, but the 4.3 in our 96 Sonoma is smooth and quiet as was our 98 Jimmy ...the I6 in our Envoy sounds like a diesel when it's cold ...and it pushes the transmission into the passenger footwell, making for an extremly uncomfortabe seating position.

 

the 4.3 in my '96 sonoma has always been loud...ESPECIALLY when cold. Has been a great motor though.

 

My dad had a 4.3L in his 91 fullsize Chevy, I thought it was ok.

I always wondered why a V6 version of the LS1 was never built. I guess it was because it is a 90° block and 60° is best for a V6.

 

The 4.3 is a 90* V6. Its 3/4's a 350.

 

I know. The 3800 is a 90° too, but every new V6 is 60°. 60° blocks are more balanced for a V6 than 90°. Too bad because a 300HP LS2 based 4.5L V6 would be sweet.

 

uh, there's already a 290hp 4.7L V8 for the trucks, other than fitting the ginormous (internally) 6 for one application in the Colorados, what would be the point?

I'd bet the I5 is going to get a bump in displacement in a year or two and there are always the turbo rumors flying around... having said that, I'd think it would have been a good idea to offer a Diesel in the Colo.

 

that 4.7 you speak of is teh 4.8 making 285hp. That 4.8 is on its way out. It would have made for a great V8 for the 355 twins. I think the I-5 needs more power. I dont think that we need to go with a V6, the I5 seems to quite well. 250hp would be great for the 3.5. 200 for the I-4, and 285 for the I-6.