LS vs Coyote 2, Episode 4: A Winner Crowned In Dramatic Dyno Session

LS vs Coyote 2, Episode 4: A Winner Crowned In Dramatic Dyno Session

So far in this competition, we’ve heard a lot of talk – some good, some bad, some outrageous (we’re looking at you on those last two, internet), but now, the time for talking is nearing an end. We headed to Westech Performance Group in Mira Loma, California to hook the engines up to Westech’s “polygraph” – an upgraded Superflow SF-902 engine dyno – and put the proverbial rubber to the road

Westech Performance Group might sound familiar to you – they are one of the most trusted dyno facilities in the country, and are used by a wide variety of manufacturers and media outlets to perform engine testing. They are also the facility we used for the first LS vs. Coyote Budget Shootout testing.

For this test, we had both Late Model Engines and MPR Racing Engines ship their entries to Westech, where we fabbed up some intercooler plumbing for the dyno – with tubing, flanges, clamps, and couplers from Race Part Solutions – and put the finishing touches on the engines before hooking them up to the dyno and wringing them out.

These words above the dyno cell at Westech Performance Center really say it all. No more talk, just real data and real power.

However, before we jump right into the testing, Here’s a quick recap of the rules of the LS vs. Coyote 2: Supercharged Shootout:

  • $15,000 budget for the engine build (based on Summit Racing’s current pricing), not including the basic machining, supercharger, injectors, or electronics. Any advanced or unique machining (like porting or sleeving) will come out of the budget.
  • Functioning hydraulic roller valvetrains.
  • VP Racing Fuels’ C85 fuel to be used.
  • Both engines will be tuned with a Holley Dominator ECU, by an impartial third-party.
  • Any ProCharger supercharger may be used, with a maximum 12-rib serpentine belt drive.

The engines will then be judged in three key areas of performance from their dyno pulls:

  • Peak horsepower and torque
  • Average horsepower
  • Horsepower per cubic inch

A full breakdown of the competition’s rules can be found here.

Thanks to all the V-band flanges, V-band clamps, silicone couplers, T-bolt clamps and tubing from Race Part Solutions, with a little fabrication, we could use the same intercooler on both engines to completely eliminate one variable from the competition.

Intercooler and Plumbing

To make everything fair across the board, we used the same ProCharger intercooler on both engines. To do this, we had to fabricate charge piping for the Coyote to match the LS routing, for an easy swap. For that, we turned to Race Part Solutions for the supplies needed.

  • ProCharger WI1005A-001: 1,800-horsepower Air-to-Water Intercooler
  • ProCharger 3FASS-010: ProRace Valve
  • RPS 90A-400-16:  4.0″ 16-gauge aluminum 90-degree 6.0″ CLR elbow (x3)
  • RPS 45A-400-16: 4.0″ 16-gauge aluminum 45-degree 6.0″ CLR elbow
  • RPS SAL-400-16: 4.0″ 16-gauge aluminum straight 3-foot tubing (x3)
  • RPS 913040: 4.0″-3.0″ aluminum transition
  • RPS 483440K: 4.0″ aluminum V-band assembly (x2)
  • RPS 333413: 4.0″ T-bolt clamp (x2)
  • RPS 333313: 3.0″ T-bolt clamp (x2)
  • RPS 300BLK: 3.0″ Silicone coupler
  • RPS 400BLK: 4.0″ Silicone coupler
  • RPS 2904357: 4.0″ ID to 3.75″ ID insert

Tuning the Engines

To make the competition as fair as possible, it was decided that an impartial third party would be used to tune both engines. For that job, we tapped Matt Bell, owner of Redline Motorsports. “I started tuning on my own stuff in 2006. Then in 2010, I purchased a chassis dyno and started doing it professionally,” explains Bell.

Also a long-time small-tire drag racer, Bell has significant experience using these kinds of combinations, in addition to tuning them. “After racing in NMRA Drag Radial, I raced X275 for several years, and then moved to 8.5-inch-tire racing,” says Bell. “I won a bunch of 8.5-tire races, then built a new car and started racing in Limited Drag Radial, and have won several races in that as well.”

We tapped long-time small-tire drag racer and professional tuner Matt Bell, of Redline Motorsports, to tickle the keys on both of our engines for this competition. Familiar with both combinations, he is an impartial third-party who only wants to see one thing – more horsepower!

At his shop, Bell sees combinations similar to these, day in and day out. “These combinations are very typical of the average cars that I tune daily and weekly. The only difference is most LS motors that are in street cars have a smaller blower,” says Bell. “The cars I tune that use the F-1X, generally don’t use serpentine belts to drive them. They use cog belts or even gear-drive units for all out race applications.” Bell knew right away that the belts were likely to be a key challenge to overcome in this competition. But they were required by the rules.

For the competition, both engines will be running VP Racing Fuels’ C85 ethanol blend. While C85 comes in a drum, it is an analog to good pump E85, which is wildly popular thanks to its low cost and solid performance potential.

To tune the engines, Bell will be using a Holley Dominator EFI system. Composed of two main parts – the Dominator ECU and the Holley EFI V5 software – the Holley system is not only more than up to the task of handling both engines, but is one that Bell is extremely familiar with.

“The Holley Dominator is an outstanding ECU and it does its job as much as you allow it to do,” Bell relates. “The response and correction rate is excellent, and it has quite a few safety and advanced features built in to the software, such as a timing retard based on manifold air temp and/or coolant temperature.”

This is the Holley Learn Table. The numbers in the cells are the percentage of adjustment the closed-loop system had to make to the base map, to achieve the commanded AFRs. The system is powerful enough to make huge corrections, but the closer the base map is, the smaller the correction required. The smaller the required correction, the faster the system is to respond and the more horsepower is made.

Part of the Dominator’s appeal, is that it is a very versatile system, allowing the tuner to tune in whatever style is preferred, but with the ability to automate and help in areas that are tedious and time-consuming in other systems. “It has 2 types of correction: closed loop and learn table,” Bell explains.

“It will apply the closed loop corrections for fuel based off of the target AFR and timing that you have specified. Then as it sees the closed loop it will populate a ‘learn table’ in the background. That table stays in there unless you clear it or transfer it to the base fuel map.” Bell does point out that while powerful, you still need to be on your game as a tuner. “Obviously, the closer you are with the fuel and timing map you start with, the more power you’ll make and smaller the corrections it makes will need to be.”

The Holley Dominator EFI system runs off of the Holley V5 software, which is not only powerful, but very user friendly. On the left is one of the software's advance features, which is the ability to pull timing based off of Manifold Air Temperature. On the right is a sample of the internal datalogging abilities of the Dominator.

MPR Racing Engines’ Coyote Engine

The first engine up on the Westech dyno was the Coyote engine built by veteran engine builder and drag racer Tim Eichorn of MPR. Coming into the competition, it is definitely the “David” in the “David vs. Goliath” matchup, as it only measures 1.67 cubic inches over the stock configuration, thanks to a minor ten-thou overbore. That is the prevailing theme with this Coyote build, however, as it retains a number of stock components, both to stay within the extremely tight $15,000 budget, and because there just aren’t aftermarket parts available for some Coyote components.

The rotating assembly is comprised of an OEM crankshaft with a 3.650-inch-stroke, which has been used in applications making far more power than this one is planning on making. Stock-length Manley Pro Series I-beam rods, made from forged 4340 steel specifically for severe-duty applications, were bolted to the crank with ARP2000 rod bolts to handle the expected cylinder pressures. Hanging off of those beefy rods are a set of Mahle forged 2618 aluminum pistons, with a stout -plus10cc dome, to bring the compression to 12.25:1

The Coyote utilized a ProCharger F-1A-94 supercharger and a ProCharger Coyote kit, which is pretty conservatively rated from the factory at 1,200 horsepower. The F-1A is a perfect match for the Coyote’s displacement and 9,000 rpm power band.

Housing the rotating assembly is an OEM aluminum block from a second-generation Coyote engine out of an F-150, which has been machined by MPR to accept a set of ductile-iron sleeves from Darton Sleeves. The sleeves not only add brute strength to the block, they also increase dimensional stability of the whole assembly. Although the sleeves can take up to a 3.700-inch bore, MPR decided to stay with a minor .010 overbore for a final 3.640-inch bore size.

Up top are a set of OEM Gen-2 castings off the same truck engine, which received a ton of work from MPR. First, the castings were tossed in the CNC machine for MPR’s “blower port” porting program. Then a new set of oversized CHE valve guides were fitted to house the 1mm larger intake and exhaust valves from Ferrea. Manley valvesprings, locators, and retainers were used to beef up the valvetrain, while the OEM lifters and rocker arms were retained.

Keeping the spark lit in a high-compression supercharged combination is no easy task. With the high-output Holley SmartCoils and MSD Super Conductor plug wires on board, along with the E3 DiamondFIRE spark plugs, which have been designed specifically for a supercharged Coyote application, the 5.0's ignition is all set for 30-plus pounds of boost and 9,000 rpm.

A quartet of custom Comp Cams bumpsticks were optimized specifically for the supercharger, and were installed along with billet MPR camshaft lockout plates and actuator block-offs. A set of .045-inch-thick Cometic head gaskets seals the heads and block, coupled with a set of ARP head studs, made from ARP2000 material, to ensure that the heads stay put under an enormous amount of boost.

For the boost, ProCharger and MPR decided on the F-1A-94 supercharger, which is the head unit of choice for ProCharger-powered Coyotes to match the engine’s relatively small displacement and high operating range. Both of those factors would be a poor match with a larger F-series supercharger. While the spec sheets say the max horsepower for that supercharger is 1,200 hp, everyone involved expects far more than that from this engine. That boost is crammed into the heads via a Holley Sniper EFI intake manifold and 90mm mechanical throttle body, and fuel is provided by Deatschwerks 2,200cc fuel injectors. The final tally for MPR’s budget used is $14,668.52 based on Summit Racing’s current pricing.

The Ford Performance Cobra Jet high-RPM pulse ring is designed to clean up the engine speed signal to the ECU in engine builds that will see north of 7,700 rpm.

A few last minute upgrades to the engine to get it ready to run on the dyno were an upgraded Ford Performance Cobra Jet High-RPM pulse ring, overnighted to us by Summit Racing, along with a set of MSD Super Conductor plug wires to connect the Holley SmartCoils to the E3 Ignition DiamondFIRE Racing plugs, designed specifically for the supercharged Coyote application (PN: E3.112). While the DiamondFIRE ground strap configuration is unconventional, the open  design better focuses the spark and flame kernel propagation, in addition to combating spark blowout at the elevated combustion pressures seen in this type of application.

“We’re using the Holley Smart Coils to aid in spark for this engine, and they are a very strong coil with plenty of spark energy for this project,” says Bell. “And while the Dominator can control the variable cam timing for the Coyotes, these cams are mechanically locked out, so we don’t need to use that feature.”

Since the Coyote wasn't broken in prior to leaving Florida, the Westech team performed the break-in process on the dyno. We used Royal Purple 10W-30 Break-In Oil for that process and the N/A pull. Then, the Break-In Oil was drained and replaced with Royal Purple XPR 10W-40 for the actual power runs.

Getting the Coyote Fired Up

One of the first things that had to be done, was an initial break-in of the Coyote. With the compressed timelines, MPR hadn’t had a chance to break the engine in prior to shipping it to Westech, so that fell to us. We grabbed a case of Royal Purple 10W-30 break-in oil, filled the engine and oil filter up, and disconnected the blower charge pipe. Contrary to Royal Purple’s normal performance oil, the break-in oil uses highly refined mineral oil as a base, and is then fortified with zinc and phosphorus additives traditionally found in break-in oil. The formulation is designed to promote proper seating of the rings in the cylinders, while the followers and cam lobes wear in with one another.

Matt Bell whipped up a N/A base tune to run the Coyote N/A during the break-in process, and fortunately for us, the SuperFlow 902 has a “break-in” program that varies load and RPM automatically to make sure everything seats the way it’s supposed to. “With the break-in map, we’re just trying to obtain a good AFR so we don’t wash the rings out, and we get the engine sealed up before adding boost,” says Bell.

The SuperFlow SF-902 has an automated “Break-In” mode, where it varies RPM and load in a specific preprogrammed pattern in order to ensure perfect ring seal every time.

While the additional load on the engine from the supercharger might have helped the break-in process, one of the main reasons it was left on was to ensure serpentine belt alignment, as there had been some question as to the pulley arrangement during set-up. Once the break-in program was complete, a quick N/A pull was performed to make sure everything was looking good on the base map.

The break-in oil was drained, and replaced with Royal Purple XPR 10W-40 for the power pulls. The XPR — which stands for “eXtreme Performance Racing” — oil is Royal Purple’s premier line of performance engine lubricant. It is a full-synthetic oil that is formulated not only to withstand the rigors of a competition engine, but to also work well with alcohol-based fuels, resisting the dilution and displacement effects alcohol can have on engine oil. Since we’re using C85 fuel, that’s a big plus for us.

For the first pull on the Coyote with the supercharger and intercooler plumbing connected, it was decided to make a relatively short pull from 4,000-7,000 RPM, with the larger 4.50-inch blower drive pulley installed, and a very safe tuneup in the Dominator.

The first pull on the Coyote was over 1,000 horsepower, and at 7,000 rpm, peak torque hadn’t even been reached yet.

We quickly realized that the engine was barely getting started at 7,000 rpm, as the engine hadn’t even reached peak torque yet. With the first easy test pull netted 1,034 horsepower and 776 lb-ft of torque – and still climbing – with only 22 psi from the F-1A-94. A quick huddle with Tim Eichorn to verify how exactly how high he wanted us to spin the engine resulted in an RPM ceiling to work towards – 9,000 rpm.

In addition to poring over the data on the laptop, Bell pulled one of the E3 plugs to ensure that everything looked good before he started pouring the coals to it. “My initial map was within six-percent, so I started trimming it out on the next pull,” recalls Bell.

Before making big timing and fuel changes, Bell pulled a plug to read it, and make sure the plug reading matched the data popping up on the computer.

With all of the indicators saying everything was good to go, Bell tweaked the maps slightly and the RPM of the sweep was bumped up to 4,500-7,500 RPM. When the numbers flashed on screen, there were smiles, as the slight tweaks and 500 additional RPM netted over 200 more horsepower, with the graphs peaking at 1,233 horsepower, 864 lb-ft of torque, and 25.5 pounds of boost – and all of the numbers still climbing. It was apparent that the Coyote loved RPM just as Eichorn predicted.

With that promising pull, the next part of the plan was swapping the ProCharger 4.50-inch supercharger pulley for a 4.375-inch version and shoot for the moon. From the beginning, it was pretty clear that the Coyote’s game plan was to overspin the blowers to try to make maximum power, even though that carries with it some significant risk. The dyno was set for a 5,500-8,500 rpm pull, and the throttle was slammed open. Unfortunately, the gremlin that everyone was worried about finally reared its ugly head – belt slip. There’s a very good reason ProCharger recommends cog belts at these boost levels.

While the curve looks significantly better than the previous pull up to 7,200 rpm, making a peak of 1,242 horsepower 300 rpm earlier than before, it was at that point that the belt started slipping and the engine started losing boost, dropping to 16.2 psi at 8,500 rpm. It was always a concern that the smaller pulley would cause the slip, when overspinning the blower this hard, and the team decided to try a shorter belt to increase tension to combat the slip.

Swapping the blower pulleys was a relatively simple affair, allowing the team to swap back and forth between sizes, along with different belts, while trying to eliminate belt slip. As you can see on the right, the 4.375- and 4.50-inch pulleys don't offer a huge visual difference, but comes to light when you start doing the math.

Unfortunately, the shorter belt that was obtained from the parts store down the street to try and cure the belt slip, was just a regular 8-rib belt, and broke in exciting fashion only 300-rpm into the next run.  We had no choice but to go back to the larger pulley. So the F-1A-94 got the 4.50-inch pulley and ProCharger-brand 8-rib belt reinstalled.

The next pull was set to be another 5,500-8,500 rpm pull, but with the larger pulley on it. Bell tweaked the air/fuel ratio on this run, making a little more power, in fact, the curve matched the previous run’s power curve and boost curve exactly (even with the larger pulley on it), until 7,200 rpm, where the bigger drive pulley started surpassing the smaller one’s numbers, due to a lack of slippage. In fact, there was no slip at all.

As the pull was being made, we all had smiles on our faces because it was apparent the Coyote was going to punch in a strong number — we had talked about the potential for the Coyote to make 1,500-plus horsepower.  It was heading that direction as all four cams were howling and the boost was being packed into the Coyote at a furious pace.

Then all hell broke loose.

At 7,800 rpm it was apparent that something was wrong. Very wrong. The Coyote shuddered hard enough to cause Eric at Westech to yank back the throttle and end the test early. Our worst fears were confirmed.

Rrrrrrr. Rrrrr. Nothing… The engine didn’t want to restart.

Removal of the passenger side valve cover revealed a broken secondary timing chain, and two destroyed lifters. This was the end of the run for the Coyote. We were sure more damage lurked inside.

As you can see, a broken secondary timing chain has pretty catastrophic effects on the valvetrain. This is only the damage visible from the exterior of the valvetrain. We never even got to see what happened in the cylinder.

When you try to make 1,500-plus horsepower on factory parts and on a $15,000 budget, crap happens. We knew this. MPR knew this. Everyone knew the risks of trying to make huge power on a budget. At the same time, disappointment coursed through our veins as we knew the engine could put up a bigger number.

It was probably the belt slip that caused the damage to the chain, and in trying to win, the team had tried to spin the blower harder and faster than ProCharger recommended. Perhaps that was the recipe for victory, but also a pathway to breakage? “It’s hard to say for sure, but this is definitely a known issue in the Coyote world when you’re getting after it; and we were getting after it,” Eichorn says. “With all that belt slippage happening and the harmonics and load being introduced from that, it’s not a big surprise.”

A quick glance at the Coyote dyno run gave us a surprise – 1,307 horsepower and 903 lb-ft of torque – and it was nowhere near out of breath. “I don’t think the engine performed quite to its peak. We were having issues getting it to make the boost needed to make the power it needed to make. I knew from the get-go that the serpentine belt was going to be a problem,” says Eichorn of the engine’s performance. “I’m not happy with it, but I’m not upset with it, either, because it showed some potential.”

While we may not have gotten to see the full potential of the Coyote in this test, Bell was pretty impressed with the engine. “I think we could have gotten to 1,400 [horsepower] fairly easily, and maybe even tickled 1,500,” says Bell.

We hadn’t even leaned on it, but the Coyote was done. “We don’t expect that the damage is too bad. Maybe some valve guide work and replace a few valves, put it back together and let it eat,” concluded Eichorn.

The dyno results would remain a secret to all outside the room, and especially the team at Late Model Engines and Bryan Neelen. The team was completely was blind, and was getting ready to rotate the world with their budget LS.

This is the final power pull for the Coyote. For only getting started on the fuel and timing adjustments, and dealing with belt slip, these are impressive numbers. Matt Bell thinks that if everything had stayed together, 1,500 horsepower wouldn’t have been out of the question.

Late Model Engines’ 427 LSX Engine

Two of the inherent benefits the LS engine platform enjoys over the Coyote, is a larger abundance of aftermarket parts availability, and the ability to increase displacement easily and inexpensively. That is what makes the LS platform a Goliath.

The LME 427 LSX starts with a strong cast-iron Chevrolet Performance LSX engine block bored to 4.125 inches, the team at LME maximized the budget in the rotating assembly. Starting with an OEM Chevrolet LS7 crankshaft, which is a forged 4340 steel, 4.00-inch stroke crank, LME added a set of Saenz Performance Billet I-beam 6.125-inch connecting rods. They then attached a set of Mahle PowerPak flat top pistons and rings for a final compression ratio of 11:1

Moving to the heads, LME started with a set of Brodix BR-7 “porter’s castings” and then worked their CNC magic on the intake and exhaust ports. The team then fitted a set of 2.200-inch LME titanium intake valves and 1.610-inch stainless exhaust valves into the chambers, using dual valvesprings and LME titanium retainers and locks.

The rocker arms used in the LS were OEM LS7 pieces, actuated by a custom-ground Comp Cams LS cam and Manley Performance 3/8-inch pushrods. Sealing the heads to the LSX block are a set of Cometic 6-bolt head gaskets, designed to allow the use of the LSX block’s extra cylinder head fasteners. The 6-bolt design gave LME the confidence to save some budget on the fasteners and utilize a stock set of head bolts to clamp the whole assembly down.

For the LS, we tapped into E3 Ignition's entire catalog, using the E3.101 DiamondFIRE plugs, 8.5mm spiral-core race wires, and DiamondFire LS coils.

Directing the boost into the engine is LME’s custom billet aluminum intake manifold, designed specifically to clear the hood of a Corvette, while still providing big flow. Attached to the manifold is a Holley Sniper EFI 102mm throttle body, and a set of 2,200 cc/min Deatschwerks injectors, identical to the ones in the Coyote. All said and done, the LME entry used $14,985.37 of the budget, based on Summit Racing’s prices for the included parts.

The team at LME selected the ProCharger F-1X supercharger for their application at ProCharger’s recommendation, due to the larger displacement of the LME entry. LME also choose a massive 28-percent overdrive crank pulley and a 4.50-inch supercharger pulley, which will provide 30-plus psi of boost to the engine. The key in this equation is the F-1X. It’s a bigger blower than the F-1A-94, but one which is rarely run with a serpentine belt.

Unlike the Coyote, the larger F-1X was a better fit for the LS, both with the larger displacement but also the durability of the LS crankshaft and engine package. Like the Coyote – the LME team had plans to overspin the F-1X out the gate. Those of us who knew the F-1X’s power potential looked at each other and wondered, “why?” But it wasn’t our ballgame. It’s was LME’s game plan, and they seemed intent on spinning the F-1X to the moon in the quest to take this $15,000 engine into the winner’s circle.

For the LS engine’s ignition, E3 coils, wires, and plugs were used to keep the candles lit under extreme boost, and received praise from Matt Bell. “I’ve seen stock-type LS coils have issues with spark and loads over 25 psi, but with the E3, this wasn’t an issue at all,” says Bell.

Both engines used identical Deatschwerks 2,200 cc/min fuel injectors. Between the massive power potential of the combinations, coupled with E85’s additional fuel requirements, the big squirters were a necessity.

Spinning Up The LS

With the LS engine broken-in before being shipped to Westech, all that needed to happen before the engine came to life was to fill it up with Royal Purple XPR 10W-40 oil, and have Bell load the initial tune onto the Dominator. That done, an initial 1,500-rpm pull was made.

As we all looked at the dyno computer, heads shook. The numbers glowed on screen.


Yes. 1,417 horsepower at only 5,800 rpm.. “The first pull made more power initially than I anticipated, and the fuel correction on the Holley was around 10-percent,” Bell says, of the Dominator’s ability to correct the base map to achieve a target air-fuel ratio.

The F-1X supercharger is a staple in the X275 and Street Outlaw ranks, but isn’t usually found being driven by a 10-rib serpentine belt setup. While capable of big things with a cog or gear drive, the serpentine belt proved to be the horsepower fuse.

With not much done to the tuneup, other than cleaning up the base map where the Holley made the corrections, a 2,000-rpm pull was the next order of business. We knew the the LS had just out powered the Coyote, but LME didn’t know.

The 4,500-6,500 rpm sweep was borderline mundane, and resulted in an impressive 1,552 horsepower at 6,500 rpm, and still climbing.

At that point the injector duty cycle was getting deep into the nineties, and timing hadn’t even been touched yet. So for the next run, Bell commanded an increase in base fuel pressure to get some additional breathing room on the duty cycle, and added two degrees of additional timing, coupled with adding 1,000 rpm of engine speed, running the engine up to 7,500 rpm.

This is the second dyno run on the LS. A scant 2,000-rpm sweep, with base fuel and timing, and the engine broke the 1,500 horsepower mark, requiring more base fuel pressure.

On that pull, the team was rewarded with two things. The first was 1,686 horsepower and 1,370 lb-ft of torque. The second was the dreaded belt slip, courtesy of the over-spun F-1X, starting at approximately 6,600 rpm, the boost peaked at 34 psi, and then started tapering off to 32.7 at 7,500 rpm.

For the fourth pull, a new Gates Green belt was installed, along with a little adhesion promoter grip spray on the belt. It appears to have worked – at least earlier in the pull – and the boost ramped in quite a bit faster and the belt didn’t start slipping until 7,000 rpm, netting a shocking — wait for it — 1,751 horsepower and 1,418 lb-ft of torque.

From E85 (C85). With a 10-rib serpentine belt. With OEM hydraulic lifters.

This is the graph from the fourth pull. While not making the most peak power, it was the highest power pull that met the rules for the average power numbers.

However, this time, the belt didn’t just slip, it did a full-on burnout on the pulley, actually leaving chunks of rubber in the teeth of the pulleys, which had to be cleaned out. Once again, the belt was swapped, and a little bit of the spray was applied to the belt. Also for the fifth pull, some minor tweaks to the base fuel and timing tables were made, along with bumping the sweep by 500 rpm, for a 5,000-8,000 rpm test.

Apparently the engine liked those changes, while the belt did not, starting to slip at around 6,900 rpm, not making the same peak boost as the previous run, and tapering off to 29 psi at 8,000 rpm with the belt being defeated by physics. However, the peak numbers netted on that pull were better, coming up with 1,784 horsepower and 1,422 lb-ft of torque.

As you can see, the “burnout” run actually left chunks of the belt’s rubber in the grooves of the pulley, much like the quarter-panels of a car after a burnout.

At that point, everyone agreed there wasn’t much more to be done, as the belt slip was getting extreme at that point, because of how hard the massive crank pulley was over-spinning the F-1X blower. That is, until someone noticed that the ProCharger tensioner could be clocked an additional 120 degrees, putting a significant amount more tension on the belt.

This was that moment where maybe a little power greed from the team overtook common sense. “Why not crank on the belt a little more? What could happen?”

The tensioner was reoriented, the belt was reinstalled, and fingers were crossed. It was decided to lower the sweep range to 4,500-7,500 to give the belt a fighting chance. Looking at the data from the run, the additional belt tension was the ticket.

While the belt was happy, the extra boost from the tension did something horrible. It overcame the stock head bolts, and they decided to let go in spectacular fashion.

The fifth pull of the LS was the most powerful complete run, making 1,784 horsepower and 1,422 lb-ft of torque. Notice the shape of the curve past 6,900 rpm. That’s not the engine laying over, that’s the supercharger belt slipping hard on the pulley and losing boost.

With a dramatic spray of coolant, a loud racket, and combustion shooting out of the front corner of the number one cylinder, the pull was over in exciting fashion at only 6,400 rpm. The cylinder pressure got the best of the OEM fasteners, which stretched enough to allow combustion to burn through the gap between cylinder one and three, torching the head and block.

“This is not what we were expecting, but it wasn’t far off of what was in the back of our minds, either. We flat out exceeded the strength of the head bolts, even though we had six per cylinder,” Neelen says of the failure. “This is definitely a testament to why we use upgraded fasteners. While making this much power on stock head bolts is an amazing feat, the last thing I want is for people to view this as an endorsement of using stock head bolts in big power performance applications.”

“I think we were on track for an 1,850 horsepower pull if the engine had stayed together,” Bell says after reading the data from the sixth run. “We might have even gotten to 1,900. It was on the edge of running out of injector though, so to really find the limit, it would need bigger injectors as well.”

This may be the highest horsepower serpentine blower engine in history. We wouldn’t doubt it.

LME did something amazing with this engine.

“All in all, I’m totally stoked about the results of this,” Neelen says, smiling. “In addition to the engine holding up so well on such a relatively small budget, this says a lot about ProCharger’s product. So many of our customers use their product, that it’s great to be able to use one in a test like this to really see what they can do.”

The head gasket failure alone (left) didn't look so bad. That is, until we pulled a head and saw the torched aluminum between the number one and three chambers.

The Final Tally

Peak Power

Coyote: 1,307.0 hp, 903.1 lb/ft – Combined total for score: 2,210.1
LS: 1,784.6 hp, 1,422.6 lb/ft – Combined total for score: 3,207.2

Winner: LS, 4 points

Average Power

Coyote: 957.16 hp (four zeroes had to be added to the run to make the full data set)
LS: 1,463.0 hp (calculated from pull four, as the more powerful fifth pull didn’t qualify)

Winner: LS, 3 points

With the engine failures, a decision was made to use a 2,500 rpm sweep below peak power and 500 rpm over peak power because we never got (on either engine) to do a proper 3,000 rpm sweep ending at the engines’ peak power. It was still a 3,000 rpm sweep, but the only way to really get good useable data. It wouldn’t have mattered anyways in the points.

Horsepower Per Cubic Inch

Coyote: (3.640 bore, 3.650 stroke = 303.86 ci) – 4.3013 hp/ci.
LS: (4.125 bore, 4.000 stroke = 427.65 ci) – 4.1730 hp/ci

Winner: Coyote, 2 points


LS: 7 points
Coyote: 2 points

The two final runs compared with one another. That power disparity is probably a combination of blower size and displacement. To find out for sure, we’ll be rebuilding the engines with some durability upgrades and retesting both of them with identical F-1A-94 head units to see what how they compare.

It’s Not Over Yet

We learned a lot of valuable lessons about $15,000 engines that make 1,500-1,900 horsepower. We also learned, perhaps, that this question wasn’t so much whether the LS or Coyote platform was better, but which could take a larger supercharger and survive.

We are going to do two things at this point.

One, we’re sending the engines back to their respective builders and having them upgrade the failure points. As long as a change doesn’t affect power-producing potential, and only increases reliability, it’s an allowable change. Right off the bat, LME will be upgrading to ARP head studs, and MPR will be upgrading to the double-roller “blower” timing chains. The rest of the repairs won’t be determined until the builders receive the engines and can do a full autopsy on them.

The second thing we’re changing for the retest, is that both engines will be running the F-1A-94 head unit, for a more apples-to-apples comparison. Oh yeah, and we’re letting them run cog belts so that belt-slip won’t be an issue anymore. This way, we can get a legitimate, no-excuses comparison of the two engines.

MPR will be dyno testing their engine and LME dynoing their engine. While it won’t be an official “third round” at an independent test site, it will be monitored, and we’ll do a full story with the new results and some dyno videos.

For the moment, the answer is clear. With these rules, and with these engines, the LS took the crown.

Backed by some of the biggest names in the automotive aftermarket — including ARPBMR SuspensionCOMPCovercraftDiabloSportDyna-BattE3 Spark PlugsHolley Performance PartsMAHLEMickey ThompsonProChargerQA1Royal PurpleSummit RacingTCIWeld Racing, and others, the final installment of Horsepower Wars: LS vs. Coyote, Part 2 has made for an exciting battle. Stay tuned for additional editorial as we dyno test the engines one last time. In the mean time, we have the next season of Pony Wars on deck.

About the author

Greg Acosta

Greg has spent nineteen years and counting in automotive publishing, with most of his work having a very technical focus. Always interested in how things work, he enjoys sharing his passion for automotive technology with the reader.
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