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My brother's truck has been knocking away for over 20k miles so he finally brought it to me. 2013 GMC Sierra Denali 1500 AWD 6.2L (L9H) Here is how it went/is going. I've been busy working and had a few vacations to I've been putting off starting this thread, so at this point I have a good head start.
Anatomy of a build:
Performance mods are a slippery slope. Engine noise? Piston slap? Refresh engine, with new pistons/rings, polish the crank and throw in some new main/rod/cam bearings topped off with a new oil pump. Oh wait, there is this new intake design where instead of polymer, it's aluminum and has a pulley sticking out of it. They call it a supercharger. Well the supercharger comes out of the box spinning quite slow to be used on stock engines with stock hypereutectic pistons. How about we upgrade the new pistons to Forged and set ring gap up for boost? Putting in forged pistons, and planning boost may as well upgrade the connecting rods. We are going to have a stout short block that can take boost so upgraded ARP fasteners are a great idea.
With over 100k on the stock balancer which tend to wear out/wobble. While buying a new one, may as well buy a larger diameter one that will add 10% rpm to the supercharger resulting in the ability to run a larger diameter supercharger pulley to stave off belt slip. On this configuration the 10% OD balancer is equivalent to .3" on the blower. Now, we are looking to put the upgraded rods/pistons to work and while boost is certainly a good way to do that, it's a small and someone antiquated design that puts more heat into the charge air than it's newer counterparts. So rather than spinning the blower X amount....we could back off the blower rpm a little and gain let's just call it 100 hp by upgrading the camshaft and running a nice full length header. Less pressure, less heat and less belt slippage issues and less parasitic loss through driving the supercharger.
Now to help keep heat off a set of thermal spacers to go between the cylinder heads and the supercharger will aid in stopping head transfer from the heads to the blower. Toss in a heat rejection blanket on the underside of the lower blower tub to help keep that rising heat out at the engine valley. Now we need longer blower bolts. Oh and possibly a longer blower belt (now coupled with possibly longer belt due to the increased balancer diameter.) While on the subject of balancer diameter and camshaft, the more aggressive than stock cam will require many "accoutrements." Things like a stiffer pushrod, better valve springs, rocker trunnions, etc. Also the cam and supporting upgrades will raise the RPM limit of the engine. Rather than let's say a 6,100 rpm limiter with a high 5k shift point we may be at a 6,600 rpm limit with an over-6k-shift point. Multiply that by the extra rpm the 10% OD balancer will give and now we could be in the "shorten the life of the alternator territory." So add an underdriven alternator pulley to slow it down. Alternator shaft speed should be similar to stock considering 10% OD lower PLUS increase idle speed due to the camshaft even of it's only about 50 rpm.
Now the OD balancer is 8 rib....which works just fine with all the stock 6 rib stuff and a factory-width 6 rib belt along with Magnuson Superchargers supplied 6 rib supercharger drive pulley. What if we go 8 rib on the alternator underdrive pulley? At that point we can just get an 8 rib power steering pulley, a couple idlers and a nice aluminum grooved 8 rib tensioner pulley to replace the crappy plastic pulley Magnuson provides. I mentioned headers. They have to fit well, so what's available for headers? Well after much digging there is a few, none of them aren't A LOT OF MONEY plus availability sucks. Long story short Stainless Works makes a really nice 1-7/8" x 3" with catalyst option that works with their AGAIN $$$ true dual exhaust with an X pipe to tailpipe. Inherent design of headers coupled with horsepower = heat. I don't want that under the hood of a street driven/PD blower application, we need to get the headers coated. Jet-Hot 2000 it is. The cat-back portion of the exhaust utilizes 2 turbo "S" mufflers....I don't want noise. To make it as quiet as possible I contacted the manufacturer directly and got them to send the exhaust kit with their quieter "chambered" mufflers. With 600hp+ running through them, they'll make noise I promise.
Okay so where are we? The snowball is growing.....quick. How about managing blow-by and cleaning it up at the same time to minimize junk in the intake tract and keep the blower brick cleaner so a catch-can installation is in order. Now let's talk transmission. 6L80 has many known issues and a few companies out there like Transgo and Sonnax have come out with lots of nice parts/fixes for them. How about Circle D doing their thing with the transmission in the form of a stage 2.5 kit along with the billet output carrier they offer. Being that this is a truck, it's heavy....somewhere around 5,500 pounds I'd estimate and on top of that is all wheel drive....all the time so traction will be plentiful therefore it will be harder on drivetrain parts. Bolted to the engine through a Circle D billet flex plate since the stock flex plate is known to crack. One of the leading causes of premature 6L80 failure is the shitty JMBX converter with it's single clutch. A good way to keep the truck street friendly and like-stock would be a factory GM converter off something like an LSA car, like a ZL1 Camaro/CTS-V which is a dual-disc 6-bolt converter with a few hundred rpm higher stall which while the camshaft works with stock stall, could only help.
Another hurdle to tackle is transmission fluid temp needs to be kept under control. The supercharger will rely on a front-mounted heat exchanger and the less stuff up front blocking it, the better. Planning on what cooler and where to put it. The more factory the configuration is, the easier it is to work on and more reliable it is. You can easily run up hundreds of dollars in fittings and hoses and heat protection for said hoses real quick. With a ton of planning I sourced a 37k BTU stacked plate cooler and can adapt it to work in place of the factory AUX cooler using the factory cooler lines in the factory positions/configuration.
Last edited by infiniticrypto; 08-04-2024 at 05:46 PM.
Transmission on its way to Circle D. Upgraded the intercooler tank to a eBay battery tray style tank for a Mustang application. They come with stupid NPT bungs that really limit you ID-wise. I drilled them out and had male AN12 bungs welded. The tank is slightly narrow to be able to use a factory battery hood down wedge so I simply added a small strap to the tank base and the hood down now works as intended. Also sold the Bosch IC pump
and went with a Pierburg CWA150.
AEM wideband and boost gauges.
Last edited by infiniticrypto; 08-05-2024 at 10:27 AM.
08-04-2024, 03:42 PM
Anatomy of a build ('13 Sierra Denali 1500)
