Sloppy Mechanics Make 1,076 Horsepower With Stock Bottom End LQ4

They finally did it! They finally hit 1,000 rwhp on a stock bottom end LQ4—one with 264,000 miles on the clock no less. Or should we just say he did it? When we refer to he/they, we are referring, of course, to none other than Matt Happel—the proprietor of Sloppy Mechanics and all around budget-horsepower genius. We’ve been bringing you updates of Matt’s exploits since we did a feature on his 2005 Chevrolet Colorado which he stuffed a 250,000+-mile LQ4 into and added a bunch of boost. After impressing us with each new iteration, he has finally managed to eclipse the four-digit mark with a shot of giggle gas added to the equation.

Gettin’ Sloppy

When we first met Matt, his Colorado was making a “mere” 796 rwhp on parts that would make most people laugh. The first incarnation of the build started with a different LQ4 paired with an On3 Performance 7876 turbo. However, this combination suffered a cataclysmic event when a ring land gave way while Matt was admittedly running out of fuel.

This sent him back to the junkyard to source another LQ4 that he could continue to push the limits on. He found one in an Express van that, at the time, had 250,000+ miles showing on the odometer. Undeterred, Matt brought the mill back and set to work cleaning it up. However, as we’ve mentioned many times before, he merely cleaned all of the sludge out of the engine and reassembled it using the stock rod bolts, head bolts, bearings, and even head gaskets—everything about the engine remained stock.


Since he fragged the On3 turbo on his previous run for glory, this time around Matt opted for an VS Racing VSR 80 mm billet T6 turbo, which is virtually a clone of an S480 Borg-Warner turbo, which Matt has affectionately taken to calling a “Bog-Weiner”, a title which he has prominently stenciled on the turbo in Sharpie.

After the engine and turbo swap, and with improvements made to the fuel system, Matt was rewarded with the 796 rwhp that we previously mentioned. While most would be more than satisfied with that amount of power out of a junkyard bullet, Matt’s appetites were merely piqued with this number. So he decided to keep pushing.

Next, Matt continued to test the boundaries by converting the truck to a Flex Fuel system in order to run E40 and allow him to safely push more boost through the second-hand LQ4. He again found the limits of his fuel system when he hit 895 rwhp—virtually maxing the 1100 cc FIC fuel injectors out in the process. With the mythical 1,000 horsepower mark within sight, we knew he’d be back.


Takin’ It To The Limit

After swapping out the “puny” 1100 cc injectors in favor of a set of 210 pound squirters—and a change to all out E85—Matt was back at the rollers. This time around, he made just north of 900 rwhp before he realized he was again running out of fuel system. With 1,000 rwhp painful close, he decided to push his luck and was rewarded with 993 ponies at the tire. This, however, was the straw that broke the camel’s back. On his final attempt Matt lifted the heads and bent four connecting rods in the process.

Needless to say, we, Matt, and every Sloppy Mechanics fan out there were pretty bummed to see him come so close to the 1,000 horsepower mark and not get there. We thought that might be the end of Matt’s story, but we should have known better.

Matt got the truck home and immediately tore into it to find out exactly what damage he had done. As we previously mentioned, the LQ4 had four bent rods. Miraculously, nothing else in the motor seemed to have sustained any damage. In true Sloppy Mechanics fashion, several of Matt’s fans stepped up and donated a set of stock 6.0-liter connecting rods and bearings to get the engine put back together. Again, he opted for a used set of head gaskets and head bolts to put the engine back together—this time, however, he did re-hone the cylinder walls to make sure the worn LQ4 had a good seal on the rings. While the engine may have borrowed four rods from another motor, for all intents and purposes it is, in fact, still just a stock bottom end LQ4 with 250,000+ miles and a few parts with unknown milage.


Fueling The Dream

Matt swore he wouldn’t fall prey to the same trappings as previous attempts and tore into the fuel system for what he swears is the last time. He upgraded the fuel rails to a set of aluminum Chinese pieces a fan sent him. He also had a buddy that gave him an Aeromotive fuel pressure regulator. From the pump forward, the entire fuel system was replaced with -10 AN or 5/8-inch fittings and push-lock hose. Twin pumps feed a custom aluminum distribution block that should be more than enough to feed more than 1,000 rwhp.

With his previous fueling issues solved, Matt was ready to get back on the dyno, or so he thought. After getting the engine back together, he ran into a few hiccups that have taken some creative problem solving to work around. For instance, Matt had to weld another waste gate directly to the turbine housing to alleviate boost creep issues. He also switched over to a Holley Terminator EFI system from the previous Megasquirt to simplify tuning and aid with the addition of nitrous. He also had some issues with a MAP sensor during some shake down pulls on the dyno and ended up having to re-ring the engine. After sorting out all of the problems with the new system and rod replacement, he was finally ready to take a shot at 1,000.

Before Matt hit the rollers again, he added a plate kit from Nitrous Outlet to the equation. Instead of plumbing the wet plate for both fuel and nitrous, he decided to run a 50 horsepower dry shot on both sides. The nitrous would ensure he would hit his goal, but keeping them both at 50 horsepower a piece would also be relatively “light” on the engine and allow him to stagger their introduction. The Terminator EFI system allowed him to independently control each stage and ensure that it is being brought on as safely as possible.


The Final Hit

With all of Matt’s problems sorted, he headed back to “Dream Killer Rd”—an ironic name for his dyno. After starting with some shake down runs to make sure everything was in order, Matt sprayed the first stage of nitrous on one of the runs at just 4 pounds of boost to see what the giggle gas would add. While the pill he used is rated for 50 horsepower, due to the affects of the boost and intercooler, he was rewarded with more than 90 horsepower at the wheel.

On his next run, the truck put down 820 rwhp maxing out the boost controller at 23 psi. Instead of increasing the boost, Matt decided to see what the spray would gain him on his next run—this time with both kits turned on. As you can see in the video, as the nitrous comes on, a visible puff of something come out from under the hood—this was the second kit blowing loose. Nevertheless, Matt broke into the 1,000-horse range putting down an astonishing 1,076.85 horsepower and 1,027 lb-ft of torque with just the one kit of nitrous.

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Satisfied with breaking 1,000 horsepower, Matt headed home with the truck to make sure everything was in order to discover the nitrous kit had blown itself off of the truck as one of the lines came undone during the run. The truck is fine and. Matt says that it will be back to make even more runs toward glory. How far can this LQ4 go? We’re not sure, but we are sure that Matt will find out for us.

For more info on the entire build and saga see part 1, part 2, and part 3.

About the author

Chase Christensen

Chase Christensen hails from Salt Lake City, and grew up around high-performance GM vehicles. He took possession of his very first F-body— an ’86 Trans Am— at the age of 13 and has been wrenching ever since.
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