lucas287

Awesome update. Thanks for your thoroughness. In regards to the above - are you saying it shifts completely fine if the trans doesn't get too hot and THEN the shift quality degrades? For example it drives great until it's above 170* and then it gets rough? If so, I'd be plumbing in an external cooler before replacing the valve body. Though the latter is actually quite simple. I've done several on auto trans in the past installing shift kits, etc. and it's not hard at all. From a tuning perspective, the 8L90 can be dialed in quite nicely with some small changes so if I were you I would consider that also. Surprisingly the trans responds most noticeably to changes on the engine side. Once that's dialed in (since it's all torque-based) the stock trans tuning is actually pretty damn good (minus the awful torque converter lockup schedule). Anyways - just rambling and maybe you'll find something helpful

VIKINGS!! VIKINGS!! VIKINGS!! I keep telling myself to do a write-up on these here but I never make the time. A few months back I put on a set of ViKing's Warrior Double Adjustable shocks in the proper length and bushing size (can get you the part # if need-be). What I realized is that everyone and their butt is different. Why not tune it the way YOU like it? Instead of having the shock manufacturer dictate the valving. Their build quality it TOP NOTCH. These things are made out of solid billet aluminum and almost looked too nice to install haha. The adjustability it not a gimmick either. The difference is felt with each click, no joke. I've tried a lot of different settings but keep coming back to wide open on both adjusters. 0c/0r. It's just so ridiculously smooth for 95% of the stuff I encounter. The other 5% needs more rebound damping but I mean just a little. If I'm going on the highway for a trip I crank it to 4c/4r and it feels very planted up to 90 MPH. Considering there are 19 clicks of adjustment on the compression and rebound side you can see I spend all my time at the lower end of the spectrum. With that said, if I could do it again I'd go with the ViKing Voyager valving as it's specifically designed for ride comfort (my goal) and not a dual-purpose shock. Current supporting mods to the rear: flipped overloads and RC Traction Bars. Rides killer and I get ZERO axle wrap ever. My dad is a Ram guy (think coil springs and 5 link) and even he is impressed with the way I got this leaf setup to perform.

Just gonna drop this here....

Sorry, I didn't mean to imply that. With an aux trans cooler I can't imagine why temps would be such a problem to necessitate additional fans. I just meant the factory set point for the factory efans can be adjusted down to accommodate a lower coolant stat. Which of course will keep oil temp down and trans temp down too. I've had up to 3500 stall before and never struggled with temps even in TX.

With HP Tuners you can just adjust when the existing e-fans come on. Best/simplest solution since you want a colder stat!

4 credits, yep. It's pretty rewarding to do it yourself. But also can be a serious distraction while you're learning. My wife has rolled her eyes many times

Not really worth while IMO. Get HP Tuners and pay someone to remote tune it. With a little time on their forum you'll quickly see who knows their stuff. Proper changes would be to the MAF/VVE tables and then TB area as well. None of that can be done via handheld. Everything that's in closed loop fueling will eventually run decent enough but in open loop, power enrichment, aka WOT, it will never change and that "could" be bad. Stock PE values are pretty rich though so that's your saving grace from going too lean on the top end.

@mikeyk101 I do all my own tuning via HP Tuners and have taken my truck in for two different powertrain warranty issues and they diagnosed/replicated the issue and fixed the problem with no questions asked. And one of those times I was too lazy to load the stock calibration back. This is ECM and TCM tuning, btw.

100% Deaver or Atlas. Here's a link to Atlas' site: https://www.mcssl.com/store/atlassuspension1991/atlas-leaf-springs_modified/performance-leaf-springs/chevygmc-performance-leaf-springs/1973-1979-k20k2500-suburban-4x4/2007-2013-silveradosierra-1500-performance-rear-springs

LT (Gen 5 direct injection) stuff is quite a bit more complex than LS. For example, locally here in San Antonio, Nelson was once highly regarded as being a great tuner. That's not the general consensus on the newer stuff. Just saying... I had a 3500 stall, with a strong lockup clutch, in my old setup and I had two different torque converter strategies. Normal driving I kept it locked most of the time and then I'd click tow/haul and the converter stayed unlocked pretty much full time under 4000 rpm. Best of both worlds. A good converter and a good lockup schedule will make even the stock cam drive nicer so I wouldn't even consider a cam without one.

That's awesome! Thanks for bringing that up! If it's advice from Higgs - I pay attention. I trust that he's cussed and fussed over it. I wonder how that works with the stock cam and stock VVT settings? Let me bounce this off the folks on here: Let's say the stock cams retards 20 degrees at 1500 RPM and low load. That means the intake and exhaust valve will open 20 degrees "later" right with respect to straight up? With the stock SOI table, it's roughly correlated to cam advance/******. On the stock cal it appears that GM advances SOI when the cam retards. Again, talking low rpm/low load. You would think they'd spray fuel LATER, right? So, by setting SOI at 280 it might be 40 degrees LATER than stock, but to me that seems good. Less chance of detonation right?

I second the added crankcase pressure. Maybe look into the LT4 pcv setup and see if there's a difference?

my dad calls those the good ole days does the same thing every time, predictable. you guys would freak if you saw all the different tables that affect spark and fueling in these ECMs. even humidity plays a factor! That's why some people swear these vehicles have multiple personalities - because it really will run different in the morning compared to the afternoon.

Yep - nailed it. All about valve events. For everyone else - read about Atkinson cycle. VVT in a single cam OHV setup (our engines) cannot independently control the exhaust valve events though - which is rumored to be a significant contributor to combustion chamber deposits. I digress though.

even worse - it's 11.5:1 - but it's not really apples to apples compared to port injection. direct injection cools the chamber much better and therefore knock resistance is inherently increased. It's all in the design of the chamber, and how the valve events work together. I remember when Mazda debuted Skyactiv - that little 2.5 4 cylinder had 13.5:1 compression and ran fantastic on 87 octane (we had a little CX-5 for many years). Yep - also agreed with the ethanol blend. I have a flex fuel sensor and have all those tables calibrated and such and I get equal performance and economy on e20-e30 as 93 octane for a LOT less money.

Nothing stated in the manual contradicts what was stated above.

Any claims about an L86 being incompatible with 87 octane fuel is nothing but rhetoric and hearsay. I've data logged A LOT and tried many different octanes and timing advance curves. My educated opinion is that it can, and will, run just fine on it. You won't bust a ring or piston if your sensors are working. That's what knock sensors are for. The stock sensor calibration is VERY sensitive. Fill with 87, the knock sensor will immediately start pulling timing if it's over 3* of knock. The spark tables will oscillate between the low and high octane tables at any given rpm/load and extrapolate according to detected knock. In the summer on 87 octane in top gear rolling down the highway you'll probably be running single digit advance on slight grades. Does the 6.2 have the torque to not care? Yep. Is it the best running setup? Nope. Will it spontaneously explode because of it? Nope. Mine hasn't anyways. I almost exclusively run 87 or some concentration of ethanol up to e80. 89 or 93 just isn't cost effective for me. Alright, off my soap box. And I mean no disrespect @swathdiver. Like others have said, oil pressure is fine. I run 5W-30 since that's the same weight my wife's turbo SUV calls for so I just buy oil in bulk. I've noticed I get quite a bit more pressure compared to 0w-20. I also burn less throughout a 5k mile OCI. I've never liked the way my truck idles. Bumping the RPM can help quite a bit. I'm at 625 right now and it's pretty good. Mostly, though, these torque-based ECMs are finicky. They want expected airflow to equal actual airflow. When there's a disconnect - they start acting weird. For example, let's say because of sensor degradation and your combination of air filter, exhaust flow, etc.. you're making more torque at idle than it's expecting. It will pull timing (torque management advance is the PID) to reduce torque to the "expected" amount. but then it will make too little torque, so it adds advance, and then pulls it again. Just watch your timing advance. it's not the like old days with distributors - it will jump around a lot. The closer reality is to expected, the smoother it will be. This goes for all the quirkiness of my truck. I've been able to make it run significantly smoother (and peppier) with a lot of datalogging and tuning. trial and error. and it's taken over a year and still not perfect.

UPDATE: I've been tinkering lately and trying to find the best combination and I "think" I found it. I couldn't help but recall just how nice my truck rode without the overload springs in. But at that time, it came with too many downsides, mainly axle wrap. Also, the spring perch on the axle is maybe 5" wide and not providing a wide enough base for the main springs and they were forming into a 'w' shape. Fast forward to current state. I have traction bars now, long bar style, not caltrac style. So axle wrap isn't a problem at all. I figured, why not? I started wrenching and stumbled upon something! The overload leaf isn't perfectly flat. As it comes from the factory it has a slight arch to it. However, if you flip it the other side is completely flat. So that's how I installed them. Simply yanked them out, drove the alignment pin through with a hammer to the other side and reassembled. Now the main springs have a nice long, flat base to engage on compared to 'no overload' just engaging on the spring perch. And this way you could still get some engagement with a heavy enough load, albeit greatly reduced from stock. The result = oh yeah, it's better for sure. It's been a week now and it's definitely not placebo. Bear in mind I have Viking Warrior rear shocks too. I've actually been able to turn them up a good amount to levels that were simply unbearable before. In conclusion, don't remove the overloads, just flip them over. However, be prepared for axle wrap. Last thought: we're currently moving so yesterday I pulled a 6x12 Uhaul trailer around back and forth (25 miles each way). This setup did great. Still no axle wrap and pretty darn good ride quality. Being able to independently adjust rebound and compression made a massive difference. I was only a couple inches from the bumps, so I dialed in more compression and then the rebound just didn't feel right so I cranked it and was blown away with the difference. Most people's first solution for towing/hauling performance is spring-related...my experience yesterday shows me that a good set of adjustable shocks makes it so much livable. As usual, I don't document anything but feel free to ask any questions.

That's correct. It'll just hit the limiter and fall flat on it's face until you do something about it.

Yep. There's something in the the truck-based OS that prevents it from auto-shifting on the 1-2 when in manual mode. I've tried and tried to change that via HP Tuners with no success. Other vehicles I've driven just automatically shift for you even in manual mode.

Yep you do. Probably at 6000 is my guess though I'm not too familiar with the 5.3. You're welcome to try it out it's quite dramatic when it hits because it cuts fuel not just spark like some limiters. You won't hurt anything by hitting it.

A tune makes a world of difference on these trucks. And I'm not talking about a handheld tuner either. I'm talking about a good, reputable custom tuner - or yourself - after spending months of dialing it in (like I have). Once spark, fueling/airflow tables are dialed in these 8 speeds come to life. Make a few changes on the trans side and it gets even better. It all works together and contributes to the driving experience. The main issue is that the 2018 folks have to spend WAY more money on tuning that I did on my 2016. It only cost me $100 in credits from HP Tuners.

That is AWESOME! I don't have a 3D printer though. What are your thoughts on printing and selling to members?

@Justin88 or you could save the money on the re-gear and put it towards a blower. That torque would 'almost' solve your problem. 8th gear would still be useless under 75 MPH IMO. I have 32" tires, 6.2/8 speed and 3.23s - and I'm not too fond of 8th gear. It puts it in a load range that's sensitive to KR at such low RPM.

I might have to eat crow on that statement! https://www.nitro-gear.com/GM-Truck-with-5-3L-V8-Nitro-Gear-Package-p/gpsilverado-1-select.htm