302 cubes for Suburbia

[EagleMark]

Looks like plenty of torque for driving.

Have you played with this PCM yet? Lack of parameters is unimpressive to say the least. I think it was given up on as a 5600 RPM limit has not been broken. 0411 PCM swap is popular.

[1project2many]

Almost all of our one ton GM vans use black box pcm's. I'm ok with the system's limitations. I believe main reason for giving up is Jet DST seems to be losing popularity war and HPTuners doesn't do much with black box. For many trucks the black box is more than sufficient but on forums they seem to think you need all the bells and whistles just to start and drive.

[EagleMark]

EFI Live and TunerCat/RoadRunner OBDII both handle them. Actually TunerCat has more usable paremeters.

I don't need a swap but have hit a 16 MPG highway wall, so I'm swapping to 0411 for the Lean Cruise.

[1project2many]

I've got an 0411 at the shop if I want to swap out. It's funny that you mention 16mpg... that's what our S10 Blazer got with the 4.3 and 3.42 gears. I told my wife "If we're going to get 16mpg we should at least have enough room to breathe."

The code for the black box has been partially disassembled and made public. I believe fast355 from thirdgen posted a copy. It may not be the best one to work with but I don't know of any others that are this far along. It's kind of like the 7747 was in the beginning.

[EagleMark]

I've got a couple 0411 to use but thanks for the offer. Or did you need on?

Shouldn't an S10 get better then that? I got a Suburban that gets' 15 around town?

There's a Vortec Hack here somewhere from Dimented247 is the only one I have seen. But others have done it too and still gave up because they can't beat the 5600 RPM limit? With the engine having injector issues and no aftermarket intake it ended up a dead horse.

I think it will be fine for you except the last bit of HP in your simulation looks to be a few hunder RPM short. Since your not building a race car, but a tow rig? Who Cares?

[1project2many]

I'm just saying that I've got the parts for a pcm swap if I need it.

Blazers are 16-18mpg. These are 4200-5300 lb vehicles that sit fairly high being powered by a 4.3 so they generally don't do that well. This last one was our 4th starting with an 86 or 87 TBI. Best mileage I was from 4.10 gears swapped into a 91 4.3 TBI which would net 20 or so on long trips. Maybe the last ones before the Trailblazer got better but I don't think so.

I'm sure the hack you're talking about is the same one I have. I've only ever seen one. Funny how people gave up on the Vortec intake and pcm but still work with TBI. Stock L31 setup can make over 400hp before larger injectors are needed. Seems like plenty of power for many trucks. It's good for torque so a 383 or 400 with low end cam that can pull stumps would be a great choice. TPI was the same way and people are still playing around with that one. I think the surprise of finding the rpm limit was big news. If you accept the limit and build accordingly then you won't be disappointed.

[1project2many]

So the build is moving along but not without hiccups. First was timing chain. I built the engine not expecting to use a crank sensor then had to switch over. Took several tries before I got the heavy "truck" roller chain. Then the dang key issue. LT1's use a non-keyed balancer hub so the woodruff key is notched so it won't engage the balancer hub. I forgot I had that key in place and couldn't for the life of me determine why I couldn't get the crank reluctor wheel to engage the key. Then the timing cover issue. Turns out this isn't the L31 block I'd though it was. The timing chain area is missing extra material for the modern plastic cover to seal against. So I just finished making an adapter to sandwich in between cover and block. Next is to get the coolant straightened out with bypass holes if needed.

<sigh>

[EagleMark]

I'm sure the hack you're talking about is the same one I have. I've only ever seen one. Funny how people gave up on the Vortec intake and pcm but still work with TBI. Stock L31 setup can make over 400hp before larger injectors are needed. Seems like plenty of power for many trucks. It's good for torque so a 383 or 400 with low end cam that can pull stumps would be a great choice. TPI was the same way and people are still playing around with that one. I think the surprise of finding the rpm limit was big news. If you accept the limit and build accordingly then you won't be disappointed.

Oh I agree! They will do what a truck needs.

But still can't shake the 16 MPG highway with the Vortec but can hit 18+ with a TBI? I've only read that a 0411 swap with lean cruise will do 21... we'll see soon.