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Silverado build 3.0...or should I say 8.1

Posted: Sun Jun 16, 2019 10:52 am
by woody90gtz
So the wife went out to Colorado with her brother to bring her grandfather a bunch of stuff from the house he sold in NY. And I'll be damned if she didn't find me another sweet truck! haha

2001 Chevy Silverado 2500HD with the 8.1L gas engine and ZF6 manual trans. As much as I was looking forward to the build of my Cali truck...I couldn't pass up the deal for another gear and 146 extra cubes. What she really likes the suicide doors. And being over 8500GVWR, it's emissions exempt in NY so I can still do whatever I want with it!

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She says she wasn't even looking, but it popped up on her Facebook as a "you may also like". She had been looking at GMT800s while I looked at GMT400s because she had two of them in high school. I'd heard of the 496/6spd trucks...but never seen one in the wild. That ZF6 is kind of a strange pattern, but I got used to it after a day or so. R and 1 are where 1 and 2 are on my T56, and 6 is where R is. Granny 1 is about the same as my 1ton NV4500 in my truck, but it feels lower with a deeper rear gear and so much more displacement. Clutch pedal was super weird too. 2/3 of it was dead and all the friction was at the bottom. So I looked at it and removed the pivoting return spring and got rid of that 2/3. Now it sits at about the same height as the brake and is much easier to drive. Picked up a free grille from a buddy, but just started collecting some parts. I already have lots of ideas...

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Re: Silverado build 3.0...or should I say 8.1

Posted: Sun Jun 16, 2019 3:51 pm
by Rettax3
Pretty awesome. That 8.1 is a beast. I don't know how it stacks up against the 8.0 V-10 Dodge I have, but the fact that it is actually in a vehicle instead of on a stand in a garage does put you a few steps ahead right there. :lol: And the six-speed is new to me -I've never seen one and had basically written-off anything newer than the '90s trucks from GM as having anything but slush-boxes, unless slugged-down with the 4.3, so incredible find there, congrats! Impatiently waiting to hear some of your ideas. :beer:

Re: Silverado build 3.0...or should I say 8.1

Posted: Thu Jul 11, 2019 6:35 pm
by woody90gtz
Been collecting some parts for that big bastard. Bought a set of 16" aluminum wheels to color match and wrap with Duratracs. Got an aluminum spare too. Steel doesn't hold up so well under the bed... Got a jack kit for the spare and the bumper trim piece I need for the front and another grille in case the chrome removal doesn't go well. I have a plan B!

Gonna convert to electric fans and dump the big SOB on the water pump. Ordered the trans/tcase brace for the 6spd...apparently they crack when you vibrate the drivetrain being stupid (having fun). haha. Once it's in the garage I can cut off the stock muffler and do something proper. Can't have 496 cubes whispering...

Threw together a Photoshop of the basic plan. The source photo was shitty so it could be a lot better, but it gives me the basic visual I was wondering about. It will never look as good as a GMT400, but I should be pretty happy with it when I'm done.

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Re: Silverado build 3.0...or should I say 8.1

Posted: Fri Jul 12, 2019 8:08 am
by 3X00-Modified
ZF6.... You've hug out with Shawn too much...

Re: Silverado build 3.0...or should I say 8.1

Posted: Fri Jul 12, 2019 10:10 pm
by woody90gtz
Hey I created the fake "SS" long before shawn came up with "ZR6". And ZF6 is a real thing... that's the name of the trans. Way more rare than a Z71.

Re: Silverado build 3.0...or should I say 8.1

Posted: Sat Aug 10, 2019 12:25 am
by woody90gtz
Been trying to sneak a little work done on the truck while the house project was going on. But I can't really sneak anything without her seeing it...not even a picture! haha
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I did get the wheels and bumper mocked up. Wheels poke out a hair more than I like, but fitment is decent. I'm gonna run 265/75/16 and not the junk 285s on there. That will help just a little. I also picked up a used hood in my color for $50. It's not great, but it's a lot better than what I had. I found about a dozen more dents in the rusty one when I got it wet... Once I buffed some of the western sun damage out of the paint (just like the Cali truck) it matched pretty well.
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I de-molded and de-stickered it and got all the adhesive off the bed rails from a cap or whatever they had on it.
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I also degreased the engine so I can find the oil leak. Unless they're just that bad at aiming the oil fill, there's gotta be a leak at the intake or valve cover...
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Also hit up ebay for some mirrors, headlights and tail lights. I hated the stock tails and the LEDs are a nice upgrade. Headlights and signals can be changed out with zero tools! It's some clips and tabs and they're in there nice and tight. Who knew GM were such geniuses since the turn of the century?
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So with everything mocked up I got a better photoshop done. This weekend I hope to have the windshield replaced, wheels dismounted, bumpers off and getting everything ready for paint.
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Re: Silverado build 3.0...or should I say 8.1

Posted: Sat Aug 10, 2019 6:26 pm
by Rettax3
Looks good! I like those tail-lights, very sharp. Even the headlights look good, usually they just give the truck a pansy-ass duded-up look, but those actually have some class to them, nice job. :good:

Re: Silverado build 3.0...or should I say 8.1

Posted: Sun Dec 01, 2019 10:46 pm
by woody90gtz
Been a long time since any updates here. I guess a kid will do that to you?
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Got some beauty shots of the old beast a while back when I thought I was mostly done with it...but things don't always go as planned. More info on that in a bit.
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By the way...this thing tows like a CHAMP! I really liked my built Vortec 357 combo with the NV4500, but this stock 8.1 blows it away. I guess that's what another 150 cubes will do for you...and LS style cylinder heads. The ZF shift pattern is weird at first, but you get used to it...and the gear spacing is better than the NV4500. 1st and OD are about the same, but the gears in between are all a little tighter ratio. When I hauled the Beretta to the drag strip, 95% of the trip was in 6th gear. I needed 5th once on the highway and 4th once coming home up the mountain because there was a slowpoke ahead of me. But the low end grunt is pretty unreal.

Re: Silverado build 3.0...or should I say 8.1

Posted: Sun Dec 01, 2019 10:57 pm
by woody90gtz
Here was the "build"...

Got the wheels blasted but gave up on trying to strip the chrome on the stock bumpers. It was only like $250 to get a pair of new paintable ones...and I'm finding out my time is worth more now than it used to be. Peeled the chrome off the stock grille because there is no paintable version available for an HD. Used the color-match Raptor liner on the bumpers, etc and the color match sucked! So I sanded it off and took them in for paint with the wheels, grille and mirror caps. I also cut a hole in the rear bumper for the 2014+ style trailer connector. (The Curt XD hitch I bought doens't have the wiring mount like the stock one, but the stock one hangs down too low anyway.)
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Got some "2006 Chevy" N-Fab step bars from Facebook for $80! They're like $500 new! Once I got there to pick them up I realized they wouldn't fit and the guy admitted he bought them used for his 2006 Chevy but they didn't fit. Since I was already there I bought them anyway. I've got a welder.
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I got a front hitch from ebay since it looked like fabbing one from scratch would be a lot more difficult than the last truck. It was definitely lower than I wanted though, so I cut it up and rewelded the receiver tube about 4 inches higher.
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Found bondo cracking in one spot on the rocker. I guess somebody did a crap job of body work at some point. So I sanded and blasted that clean and used metal filler for it. Then I Raptor Lined the rockers and that body line down on the bed and fenders to match the plastic bumper trim.
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Stock chromey emblems weren't gonna cut it, so I broke them out of their shells, reproduced the bowties in plastic at work and cut new vinyl. The wifey's favorite color is orange and I already have a gray car with red accents, so I spray bombed the plastic and vinyl. It actually came out amazingly good.
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Re: Silverado build 3.0...or should I say 8.1

Posted: Sun Dec 01, 2019 11:25 pm
by woody90gtz
I put LED lighting in the interior and a set of exact-fit seat covers since the bulldogs stinkify the seats. Dozer always rubs his ass on the seatback and then turns around and licks it. Drives me nuts!
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After some driving it became apparent the front end needed attention. The balljoints were actually OK, but all the steering components were worn out, so I just did everything at once. That's a big pain in the dick job - especially the control arm bushings. In stock form the pitman & idler arms wear out super fast and the same for the tie rod ends - except they bend too. So along with all new parts I got pitman & idler braces from Cognito and a pair of HD tie rods. The bushings were Prothane.
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And after all that and a fresh alignment the steering was super precise, but I still had a vibration starting at about 50 and getting worse all the way to 85+. I borrowed a different set of wheels and it went away. So I had the shop rebalance my wheels and tires. They used balance beads the first time and stick on weights the second time. But the stick on weights hit the calipers, so I couldn't even try it out. Something about the lip on the wheel wouldn't let them use the lip weights either. So I was basically forced to buy another set of wheels. I decided to actually go with the factory alloy wheels. Some research showed they are much lighter, forged, and obviously hub-centric...all improvements compared to the old AR's I had bought...they just don't look as good. But I picked up a set local for $100 and aircraft stripped, blasted & sanded them for paint. Now the vibration is gone and all is well. It just doesn't look quite as good and I've got to paint a set of center caps and get them on.
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Re: Silverado build 3.0...or should I say 8.1

Posted: Fri Dec 06, 2019 9:38 am
by EPfiffner
Congrats on the baby, still finding time to mess around with cars and trucks in true gearhead fashion. The truck looks awesome. Nice how clean it is underneath.

I see the Mullet Camaro on the trailer, I thought it was at the paint shop?

Re: Silverado build 3.0...or should I say 8.1

Posted: Wed Dec 11, 2019 2:45 pm
by woody90gtz
I'm curious to see how long it stays clean. I coated everything liberally with Fluid Film. Heard lots of good things about it. I took the plastic fender liners out and even the gooseneck so I could make sure everything got a good layer.

Camaro update to come later...

Re: Silverado build 3.0...or should I say 8.1

Posted: Wed Dec 11, 2019 3:03 pm
by EPfiffner
I've been using the fluid film as well, but not long enough to provide any success story. Worth a shot in the rust belt, we need any help we can get.

Re: Silverado build 3.0...or should I say 8.1

Posted: Fri Jan 10, 2020 9:25 pm
by woody90gtz
Had a few weeks off from work to do the Mr. Mom thing...haha Gave me a little time to work on it during naps.
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Haven't had much snow to play in. But so far it performs admirably.
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I cut and painted some centers for the center caps...but my buddy still doesn't have them done yet! C'mon man...I'm gettin rusty nuts! I did grab a pair of rear fender liners from a Tahoe at the yard for $8 and made them fit. I originally bought a "direct-fit" pair made for the trucks but they don't fit with the gooseneck hitch. These Tahoe ones don't fit perfect, but they're better than nothing for this winter, and they do block a ton of salt. This spring I'll modify them for even better fit and function. Same with the stock fronts...they're basically only half a liner, but I can make them full with some plastic sheets from work.
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Wiring is quiet and baby-friendly, so I addded a rocker switch for the front axle to be capable of 2WD low range same as I did for the last truck. Also relayed in some fogs and wired the lows to stay on while the highs are on. Those LED bulbs are absolutely awesome - HUGE improvement over the ones I put in the Cruze and then took out cause they sucked. I de-pinned the door locks so the dog can't lock me out anymore - once is enough of that! Put some orange LEDs in the cluster and added one under the dash to be able to see the dogs at night. Was looking at converting the stock radio to an Android double din...but it might not be worth the trouble. Holding off on that for now.
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Re: Silverado build 3.0...or should I say 8.1

Posted: Fri Jan 10, 2020 10:03 pm
by woody90gtz
What got me looking at the Android head units is a little discovery from the 8.1 group on Facebook. Some dude has written an app to read and flash early OBD2 GM PCMs for free! And no licensing... (http://ls-droid.com/) The 411 in my truck is one of the supported computers, so I bought the bluetooth dongle needed and took a look. Total cost: $50...instead of $650 for HPTuners or $800 for EFILIve for $1025. It's mostly for LS swaps using truck computers and harnesses, but plenty of guys have successfully flashed their trucks with it. The tech is 20 years old now, it's about time somebody hacked it! haha
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You transfer the .BIN file it saves from your phone to your computer and open it in TunerPro RT, just like the OBD1 stuff. Gearhead-efi has the definitions needed to translate the raw hex code to English and tables. What I found surprised the crap out of me! But I searched the HPTuners forum and confirmed that the factory 8.1 tune only has 15 degrees of timing at WOT and the Power Enrichment mode is essentially turned off (doesn't activate until 90%TPS for 60sec or more). It also has really aggressive "burst knock" retard which pulls timing in anticipation of knock, before the knock sensors even go off. So actual timing at WOT ends up more like 10 degrees usually! I had 28 degrees in my old truck at 9.7:1...and the 496 is only 9.1:1 compression.
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Common practice is to turn off burst knock, turn on PE with 0sec delay at about 70%TPS and bump the timing table to 20-24 degrees at WOT. Apparently the Allison automatic tune for the 8.1s has a big dip in the spark table off idle everyone figures is GM's solution for basically traction control. There's also a lot of "torque management" to tame it down for the auto that wasn't in the stock manual tune. I remember my FIL's old 8.1 felt like a gutless POS...that's probably why.

I tweaked a new tune for mine now but haven't flashed it yet, cause I'd like to have a spare PCM around just in case. They're cheap at the junkyard but I haven't gotten to one yet. I guess a bench harness is suggested for flashing too...cause the BCM and stuff can interfere with the flash if you do it in the truck. But that's only like 6 wires and a PCM connector and an OBD2 connector, so that's easy to build. That also lets me clone any truck 4.3/4.8/5.3/6.0 PCM to the 8.1 and flash my modified tune after the clone.
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20 degrees at WOT, same table copied for "low octane" table
PE enabled with 0sec delay at 70%TPS with 2 degrees additional spark
Set PE AFR to 12.2 instead of 10.8
Burst knock set to a maximum of 0.5 degrees instead of 5
Set the IAT multiplier tables to only 25%...so at hot IATs it will pull 2 degrees instead of 8
Fixed speedometer for 265s
Set fan controls for when I wire in the elec fans and 180 tstat

I'm figuring that's most of where Blackbear Performance figures +30hp and 40tq for their 8.1 tune!