302 cubes for Suburbia

[1project2many]

I've picked up a 99 Suburban with a bad engine to replace our 95 Blazer. It would be easy to replace the crank, rod, and bearings and put it back on the road with the original 350 but I've had this purple 302 sitting in my barn since '04 waiting to be installed in something. The 302 was originally built for the S10 and had a ZZ4 cam but for Suburbia I need a lower rpm torque peak. After many, many late hours I believe I've accurately modeled enough components to put something together. Here's the configuration:

L31 four bolt main block, L99 crank and 5.97" rods, H631CP pistons at .030" = 306 ci
L31 heads, stock valves and ports, guides machined for over .525" lift and upgraded LT1 springs
9.0:1 compression
14097395 HT383 cam
1.6 rockers
.040" quench
Single roller timing chain
small harmonic balancer
shorty OBX headers
Mercruiser dual plane ceramic coated EFI manifold

Still working on...
Torque converter choices
Exhaust configuration

The simulation shows one of the roundest torque curves I've ever seen.

[JeepsAndGuns]

Ok, this has nothing to do with the post, and its just out of curiosity because I have seen it on another screen shot of yours.
Seamonkeys?

[1project2many]

Seamonkey. No "s". Internet browser. I used Netscape for years. Netscape code was eventually released to open source and formed the basis of Mozilla. Mozilla was distributed as a standalone browser for a while but was eventually dropped in favor of Firefox. Firefox changed the look and feel of Mozilla considerably so a group of developers decided to continue along a path closer to traditional Netscape / Mozilla with Seamonkey. I have both browsers on this machine and although they use much of the same code, Firefox feels foreign to me.

[EagleMark]

edit...

Just me but sounds like a lot of work and expense for a daily driver.. what about smog there? You should rebuild the engine in the Surburbia and send me that intake...

[JeepsAndGuns]

Seamonkey. No "s". Internet browser. I used Netscape for years. Netscape code was eventually released to open source and formed the basis of Mozilla. Mozilla was distributed as a standalone browser for a while but was eventually dropped in favor of Firefox. Firefox changed the look and feel of Mozilla considerably so a group of developers decided to continue along a path closer to traditional Netscape / Mozilla with Seamonkey. I have both browsers on this machine and although they use much of the same code, Firefox feels foreign to me.

Wow, interesting. Never heard of seamonkey web browser.
Back to your thread, sory about the hijack.

[1project2many]

Suburban's not going to be daily driver. It's the luxo-liner when we take the kids for long trips and it's the tow vehicle that's finally large enough to haul the stuff I put on the car trailer. I'd have to build a turbo four and still keep it below 55 to afford it as a daily.

The 302 is already built. I'm just changing the cam (and shortening the balancer, and adding the crank sensor, but no big deal there). Smog is easy here. Plug state computer into OBDII port. If computer sees enough readiness monitors and doesn't see codes, then all is good. I don't believe I'll have any problems with that. LS engines use a divorced EGR so I can follow that path here. I have to connect the purge line somewhere but that's not likely to be an issue, either.

Besides, using the 302 in Suburbia frees up a set of Vortec heads. I'll swap in a set of 2.02/1.60 stainless valves I have here from some faulty Bowtie heads, throw on a set of big springs, bolt them onto the old school roundy round car block with a big Lingenfelter retrofit roller cam that's hanging around and put the Chevelle back on the road with the other marine intake I've got and the six speed that's been collecting dust since '03.

Also, if you watch Ebay there are Vortec style Marine intakes that show up from time to time. Prices are a bit steep for me but they're still cheaper than some of the aftermarket L31 intakes.
http://www.ebay.com/itm/310473716029...84.m1438.l2649

[EagleMark]

So what engine was in the Subrban? Or more importantly what PCM? Didn't 99 come with Vortec and LS engines (still badged Vortec)?

That is a strange tourque curve, really opens up gear choice, what's in it and where will it be running RPM wise?

[1project2many]

This has an L31 5.7 right now. Pickups changed body style in '99 but Suburban waited another year. Rear gear is 3.42. Here's the highway speed vs engine speed chart with the current tires.

Vehicle RPM RPM
Speed Drive Overdrive
55 2040 1420
60 2225 1549
65 2410 1687
70 2596 1807
75 2781 1936

When these tires wear out I'll probably switch from 245/75 16 to 225/75 16 which is what we run on most of our fleet vehicles. They're 29" tires vs 31" so the highway rpm will increase a small amount.

Torque curve comes from ability to run successive models with changes like header primary length, intake runner length, collector length, etc so I was able to look at what products were available and do my best to model the same parts in software. Every comparison I ran showed no matter what cam, the short stroke / long rod engine liked short intake and exhaust lengths for maximum torque between 1500 and 4500 rpm. Long headers fell very short after about 2k but came back strong starting about 4500 and mid length had a weak area from 3k to 5k. Stock L31 and other long runner intakes boosted torque to about 2500 but really died after that. For max power the dual plane intake doesn't have enough plenum volume but for the truck it's sufficient.

[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>