70 C-20 4x4 Suburban Father/Son project

[1leglance]

Yeah I have to go back and fix more pics....
silly host site

Chilli these burbs are around....even a 2wd is the same frame just add the 4wd bits and you are good.
Sometimes I wish I had all 4 drs but not a real big deal.

Does but a smile on my face when I walk out the house which is a nice thing

 

[Martinjmpr]

Sometimes I wish I had all 4 drs but not a real big deal.

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Whaaaat? :Wow1: SACRELIGE I SAY!!!!!! :Wow1::Wow1::Wow1:
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Seriously, 3 door 'Burbs are awesome. My very first vehicle, ever, was a 3 door Travelall (yes, they made them but only for a couple of years between about 1957 and 59 I think.) Mine was a '57, 4x4.
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If I had unlimited time, money and mechanical skills I would totally rock a 3 door 'Burb. There are a bajillion 4 door SUVs out there, but those 3 door Suburbans are unique.

 

[Woofwagon]

I love the '67-72 Burbs. Most of these were rode hard and put away wet and they thus rotted away. I saw one back at my home town in Idaho. Wish I could have bought the thing. Even though I love my '89, the body styling back then just looked good. I've only seen a couple of two door Burbs from that era, all the rest were the stock 3 door variety. I like the barn doors better as I don't have to worry about the rear window not rolling up and then getting hosed due to a sudden rain storm.

 

[1leglance]

The latest efforts are all on me...well I am pretty sure Nick will be wrenching on this thing sooner or later....like when it reset my dizzy before I started my new insanity.

So rather than keep sending chips to Howell for PROM burning I figured I might try learn DIY ECM tuning...scary.

Will keep everyone posted and happy to hear from anyone who has done ECM programming


The vehicle...
1970 Suburban bought with carb'd "300hp" crate motor...specs can be posted.
Junkyarded my way to a factory 350 TBI setup.
Howell harness to tie it all together and Howell burned my first few proms.
That was ok but still too much fuel at idle and no power going up hills.

Trans is a 700r4, NO VSS sorry

I ordered the DynamicEFI EBL Flash, have it running with my Acer Notebook and datalogging, flashing and all that seems to be working well. Even have my other laptop in the rig to search and post to forums while playing in the driveway....love WiFi

I started with the EBL Flash 2011 BIN as that was a basic 350 TBI, 700r4, fed from 1988 so sounded generic enough.
The EBL calc utility helped me refigure some numbers based on 20lbs of fuel pressure and my 61lb/hr injectors.

TurnerPro helped me reset my BPC-BPC vs VAC and BST-BPC vs Boost, double check my Intial Spark Adv was 0...anything else I should change??

The 2011 BIN has a nice smooth VE low table...

However when I do a VE Learn and flash the new BIN I end up with a bumpy mess......should I do anything in TunerPro to fix it or just keep going through VE Learns and let things work themselves out?

So ECM gurus.....
What changes should I make so the ECM knows I don't have any speed sensor or does that matter?
Right now I am working on idle and around town stuff before I tackle highway power on hills.
I will be putting in the DynamicEFI TT-1 Wideband now that I understand in goes in addition to my current AC Delco Narrow band....put that will happen next week I think.

I will try to upload my current BIN and a datalog

 

[1leglance]

Here are the cam specs if anyone was curious
Camshaft, Hydraulic Flat Tappet, Duration at .050 in. Lift 212/ 222, .435/.460 in. Lift, Chevy, Small Block

 

[1leglance]

So I got my TT-1 WB (wide band O2) hooked up and I admit it does make it very interesting to see a deeper view of what is going on.

After a few more runs and meeting up with a buddy who actually understands what much of this data means I am getting a much better running setup.

Here is my current VE low table

And this is where I am at for SA (spark advance)....this is after manually adding about 10-15 degrees after doing some long highway miles on a camping trip this weekend.

I am finally getting small amount of knock...I still need to figure out how to tell the BIN that I have NO Charcoal canister, NO EGR, NO VSS (although I am seriously thinking of adding one) and NO gear selector...would love to tell it I am in drive all the time at least.

All thoughts welcome.

 

[Seanmiller063]

this rig is amazing

 

[justcuz]

Lance,
That cam seems pretty big, if your lobe separation angle (LSA) is not at least 112 degrees your going to get some overlap and scavenge reversion at normal highway operating RPMs. Check your manifold vacuum at idle, compare it to the pickup or any other similar V8. Then check your vacuum at 1,500 to 2,000 RPMs steady state. If your vacuum readings are lower than other comparible vehicles, your cam is too big
Look at cam specs for a 5.7 LT1 engine out of a 1996 Impala SS and you will see what I mean.
I installed a .398/420 lift cam with 194/204 degree duration in the 5.7 rebuild in my sons 350 in his 1993 Siverado 4x4 and it runs nice and clean. The engine is otherwise a stock rebuild with all computer settings and injectors and fuel pressure being stock. It pulls strongly to about 5,200 RPM as opposed to the factory cam that fell off around 3,700. We do have a EGR/EVAP/VSS system on this truck as it is all factory stuff. The truck effortlessly pulls up to freeway speeds, cruises easily at 75 MPH and gets 16.5 to 17 mpg with 3.73 gears and 285/75x16 tires. The tailpipe is so clean you barely get any residue on your finger when wiping inside the pipe.
Even though Nick increased your fuel pressure and you have bigger injectors, I personally feel the cam is too big.
Your 4.11 gears at highway speeds in overdrive become 2.90's, your engine at cruise is a long way from the power band of that camshaft. That is the biggest mistake folks do to engines is overcam them, especially in newer fuel injected engines with overdrive. The factory cams are seriously anemic on factory TBI engines, but I would personally never put anything bigger than a 78 Corvette 350 cam in a TBI engine. This same cam is used in the 305 HO engines used in Camaros and come in a flat tappet or roller cam. Pretty sure the lift specs are 403/415 about 204/214 duration and 212 degree LSA @ 050.
Larry just went through these same troubles with his RayLar cam on his 8.1 liter engine. Even though the RayLar has a lot of LSA his programmer could not get it to run correctly.
Frankly engines today don't normally run above 2,500 rpm at cruise and rarely need to rev more than twice cruise speed in lower gears to put power to the ground. Any engine today designed to run more than 5,500 rpm for daily use is not necessary.
I know I threw a lot of info out there, but just break it down and bounce it off your computer programmer and see what he thinks.

 

[justcuz]

Your spark knock is because you have too much initial advance. I would stay between 0 and 5 degrees BTDC nothing more. If you check with a timing light, the minute you plug the wire back in after timing it at TDC the timing jumps to about 15 degrees BTDC. When you add timing at static, the minute you plug that wire back together you are going to over 20 degrees BTDC on timing at idle.
A big B body Impala SS had a 418/430 lift cam with 191/196 degrees of duration with a 111 degree LSA. That engine produced 260hp and 330ft lbs of torque on 87 octane with a 9.5/1 or 10.0/1 compression ratio. This is a roller cam.
I have a 1968 Chevelle wagon with a 1975 4 bolt 350, stock 8.5/1 compression and a 415/430 lift cam I bought from Johnson Marine in Monrovia, Calif. it has a 112 LSA and 204/214 duration. The car has a 3.08 12 bolt rear axle and gets about 20 mpg on the flat. It has a recurved HEI distributor, dual exhausts and a built Quadrajet on a factory cast iron manifold. That is absolutely the biggest cam I would ever install in a 350. This is a flat tappet cam. See how close it is to the factory B body Impala SS cam?
I also have a Edelbrock 420/442 lift cam in a 400 inch small block and it is just right also.
My motto on cams is to stay within a couple sizes of stock for driveability and economy.
Again, the biggest mistake folks make building engines is too big a camshaft for the desired use of the engine.
The cam you have in your engine is not much smaller than a 350/350 hp cam in a 1970 Z28 Camaro which was 450/460 lift, 220 degrees duration on both intake and exhaust and 112 LSA on a 10/1 compression ratio engine running a high rise aluminum intake and a bigger Holley carb with factory low restriction dual exhausts. It was designed to haul butt in a car weighing half of what your Suburban does running more fuel and less exhaust restriction.

 

[1leglance]

great info to about, thanks....
I am at SEMA right now with my sons but as soon as we get home I am sure Nick and I will have some good chatter about all this....

It is so easy walking around this show to just think about dropping a LS package in...but then reality sets in and I realize I can get what I want with a bit more work on my current setup.

Thanks again and keep the ideas coming

 

[justcuz]

One of these years I want to go to that show. I hear you can't see it all in the duration of the show, that you need to be selective about what you pick out to see.

See if you can find Harris Performance Inc. at SEMA or look at his website. He has a ton of experience with TBI modifications and has cam, injector and exhaust specifications. He burns custom chips also. I would send him an e-mail with the exact specifications of your engine, including ignition and injection modifications and see what he recommends. Also read his troubleshooting section of his website along with his data mapping info.

One last word about cams. Roller cams and flat tappet cams are the difference between an egg and a grape, literally when you look at the shape of the lobes. The roller cam does not need the gradual ramp of the flat tappet cam, so higher lift, less overlap and more vacuum can be achieved by roller cams. It is not unusual to have 117 degree LSA in high performance roller cams.

LS engines are great, but anyone who has done the conversion and is honest with you will admit to a loss of bottom end power. LS engines generally have their rated torque peak 1,000 RPM's higher than a 5.7 liter. I own both so I am very familiar with the engines. In fact if someone ground a cam to bring an LS engines torque peak down to 2500 RPM, I would be an owner of a couple of them.