Not long ago we brought you the details on the short-block build of our Carb’d Coyote Cobra Jet engine. Now it’s time to turn our attention to the top side, and get things in order. We’ve enlisted the help of some of the top companies in the industry to help us with this phase of the build. The list includes Comp Cams, Livernois Motorsports, Rich Groh Racing, Ferrea, Holley, L&R Engines, Cometic, Meziere, ARP, and Westech Performance.
To recap, one afternoon at the Power Automedia office we were kicking around ideas about what kind of radical build we could do next. We realized that as of right now, no one has yet brought to the Mustang and Ford community a buildup of a hardcore Coyote engine that wears a mechanical mixer on top. That’s right, a carburetor and a 8,000 rpm+ operating capability from an engine based on the same one that powers the current Mustang GT. To make the engine even more different, our 5.0 has actually been turned into 314ci via Livernois’ big bore block package. Best of all, we wanted an engine that was going to be streetable and not an all-out race engine.
As wild as our engine looks and sounds, we can’t emphasize enough that we went with a very street friendly combination. This engine could be easily converted to fuel injection and run in the same long-block configuration seen here with good drivability. In-fact we plan on converting this engine to EFI for a future story. The low lift and conservative cam duration, combined with BOSS 302 compression ratio no-doubt cost us some power, but in the end will payoff when it’s time to use this engine on the street.
For our cylinder heads we turned to the experts at Livernois Motorsports. The crew at Livernois has performed countless hours of research and development on the Coyote engine platform, including involvement with the Cobra Jet program. Since there is no aftermarket cylinder head for the Coyote engine, Livernois was tasked with machining our cylinder heads from a production casting.
We spoke at Length with Eric Weihman at Livernois with regard to the Coyote cylinder heads program. Weihman explained the process of developing the CNC programs that racers and enthusiasts are relying on from Livernois.
Livernois takes each cylinder head port design through an extensive R&D process that begins with head porting by hand – continuing through flow-bench and computer analysis – before finally being tested for real world performance on the engine dyno. “You can easily obtain high flow numbers but you’ll end up killing your low and mid flow numbers. The key is to get good low and mid flow and great high flow numbers,” explains Weihman.
You can do a lot to get high flow numbers but kill your low and mid flow numbers. The key is to get good low and mid flow and great high flow numbers. -Eric Weihman, Livernois Motorsports
It takes more than just bringing in a new set of cylinder head castings or cores and putting them in a CNC machine to create the cylinder heads that come from Livernois. All of the cylinder heads go through a thorough cleaning and inspection, which is repeated multiple times throughout their time at Livernois. They’re also deburred to make them both easier to handle, and help prevent cracks. Weihman says often times cracks in engine components originate from a sharp edge.
All of the heads have their work verified on the flow-bench to ensure that they’re going to meet customer demands.
Filling the heads are a set of valves from Ferrea, which happen to be the exact same pieces we used in our recent turbocharged Coyote engine build. These valves were designed in conjunction with Rich Groh Racing, and are sized 1mm over stock. The intake valves, part number F2243P, are 38.1mm or 1.50-inches.
The exhaust valves, part number F2245P, measure 32.05mm or 1.242-inches. These are the largest valves we could put into our cylinder heads without having to go through the expense of further machining the heads to accept new, larger valve seats. The size of these valves also helps increase flow without going too large and causing unwanted induction turbulence.
The Ferrea intake valves are made from high strength VV50 material, while the exhaust valves are made from their Nimonic 90 alloy. Both of these alloys are likely overkill for our application as we’re not using forced induction. Ferrea’s Zeke Urrutia explained, “With multi-valve engines like this, you usually want to stick with a specific size, which in this case is 1mm oversized from stock – the intake valves [PN F2243P] are 38.1mm (1.50-inch) in diameter, and the exhaust valves [PN F2245P] are 32.05mm (1.242-inch) in diameter. The reasons for the larger valves are twofold; on the intake valve you’re increasing flow on the front side of the combustion chamber, and on the back side, you’re allowing for quicker flow out of the exhaust port. By going larger than these sizes, you can get into an area where it can hurt flow due to the induction turbulence.”
At Livernois, every valve on every head has its lash individually checked and set using a cam and collapsed lifter. A special jig is used to grind the tip of each valve in this process, and the critical lash setting is checked and set properly.
Livernois also took the time to install our Comp Cams beehive valve springs and titanium retainers. We chose to go with Comp Cams part number 26113 for our springs, which is a step up from the factory springs. These high seat load springs are rated at 93 pounds closed, and 198 pounds open. They will stand up to the rigors of our high RPM Coyote engine without requiring further special machining to get them installed.
Once our heads had made their way through the Livernois CNC program, they’re capable of flowing an incredible 347.1 cfm at .700 lift on the intake side, and 226.3 cfm at .700 lift on the exhaust side. This is an increase of 37.1 cfm on the intake side over stock and 36.4 cfm on the exhaust ports.
Contributing to the good street manners for our engine are the cams we spec’d from Comp Cams. “When we made this selection we knew we wanted something very streetable,” says Comp Cams’ Billy Godbold.
The cams are a custom grind from Comp, but according to Godbold they’re very similar to the off-the-shelf NSR pieces that Comp sells. Our intake camshafts feature a gross intake lift of .512, with a duration of 240 at .050. On the exhaust side, the camshafts area also .512 gross lift, with duration spec’d at 246 at .050, while 128 degrees of lobe separation is the number on both the intake and exhaust sides.
The process of specifying a set of custom camshafts involves looking at a complete picture for a vehicle. Godbold says this can become somewhat tricky for a dyno engine like ours. According to Godbold, a custom grind will usually look at valve timing, intake runner length, exhaust type and diameter, vehicle weight, usage, gearing, compression ratio, cylinder head flow, RPM range, transmission type, and more.
In our case we needed to skip most of the vehicle info and focus on what Comp has found to work in Coyote engines. Godbold also stressed the importance on a dyno engine of thoroughly exploring what effect making changes to camshaft events will have on power.
Consulting the flow data from our cylinder heads we can see that they will be pulling just over 330 cfm on the intake side, and 220 cfm on the exhaust side given the gross lift of each cam.
In order to get our compression ratio where we needed it to be we turned to Cometic for help with our head gaskets. They provided us with a set of custom .060-inch thick MLS head gaskets. The stock Coyote units are slightly thinner at .040-inch. This difference would bump our compression ratio up to 12.5:1. Since we wanted to keep the engine more street friendly, the thicker gaskets from Cometic will yield the 12:1 street friendly ratio we’re looking for.
I have never seen a domestic engine that liks RPM like the Coyote. -Billy Goldbold, Comp Cams
We devoted an entire article this past fall to our one of a kind Rich Groh Racing Engines Carb Coyote intake manifold. While we detailed it at length previously, the highlights are worth repeating for this story.
Using the information we provided him about the rest of the engine, Rich Groh utilized advanced computer software to determine the necessary plenum volume and runner length for our specific engine. Groh focused on making the intake plenum the right size to allow for the proper volume of air and fuel mixture to always be present. This allows each cylinder to draw in the needed mixture when their intake valves are opened. According to Groh too small plenum will cost power.
Through his computer design, and calculations he also determined that an intake runner length of six-inches was necessary. To maintain velocity for the air-fuel charge, the runners taper from a cross-section of 3.07-inches at the plenum down to a cross-section of 2.698-inches at the cylinder head.
The end result is a radical looking, but functional intake manifold that will allow our engine to make power throughout our target RPM range, without dangerously leaning out cylinders, or conversely dumping too much fuel into them
Holley Ultra HP Carburetor
To feed the air/fuel mixture to the engine, we needed a carburetor that was up to the task. For that we turned to Holley for an Ultra HP 950 carburetor. Part number 0-80805BK features a 97-percent aluminum construction including billet metering blocks.
Fuel bowls that are 20-percent larger than the standard Holley HP carburetors will ensure we don’t go lean. Fuel inlet ports sized at -08, a fuel trough to keep the jets covered, and shelf below the needle and seat to prevent aeration also contribute to providing the fuel.
The billet metering blocks also feature integrated pry-points. Those pry-points along with drain plugs on the bowls make for quick and easy jet changes for tuning this carburetor.
To ignite the incoming air-fuel mixture we turned to Accel for a set of their Super Coils, part number 140060. These offer more spark energy than the stock units via their optimized windings and magnetic steel cores. We’ve seen several dyno tests showing improvements with these coils, and their epoxy filled design should stand up to the vibration of our 8,000 rpm engine.
We again turned to L&R Engines to complete the long-block build. Installing the heads and intake manifold were relatively simple and straight-forward. The degreeing process on the locked out cams does take some time though.
Up on the top side of the heads L&R initially degreed our intake cams in at a 109 centerline, with the intake cam advanced four degrees, and the the exhaust at 110 degrees. One of the beauties of a dual overhead cam engine is with separate intake and exhaust camshafts, one camshaft can be adjusted without affecting the other. As Goldbold tells us, “With a cam-in-block engine, when you advance the intake side, you are also advancing the exhaust side since the lobes are on same camshafts. With a dual overhead camshaft arrangement intake and exhaust events can be independently tuned without a change in one directly effecting the other.”
Test, Tune, Repeat
With the intake buttoned up and a Holley Ultra HP 950 cfm carburetor up top we began our testing at Westech Performance. Initially we set timing at 26 degrees initial. We found that the 950 carb was just too much for our engine, and stepped back down to a 750 HP that Westech had on tap.
In carbureted form, we found that our Coyote liked a lot of timing. We advanced as far as 36 degrees of total timing, though ultimately we stepped back to 34 degrees total timing, which we found made the engine a little happier on the dyno in-spite of losing one horsepower over the 36 degrees setting.
After testing the engine at the stock 109 degree intake centerline, we advanced the intake cam 4 degrees. The Coyote wasn’t happy with advancing the intake cam and showed in the dyno numbers and the way the engine reacted to load, horsepower sank to 550.6 hp, torque was down as well to 427 ft-lbs.
From there we went backwards from the stock 109 ICL retarding the intake cams by four degrees. This worked a little better than advancing the cams as power rose close to where it was with the stock 109 centerline to 568.4 hp, and 428.1 ft-lbs torque. In the end it would seem COMP Cams was right, and a 110 ICL was ultimately what we went with.
Satisfied with our intake camshaft setup, we began working on the exhaust side. Much like the intake we decided to retard the exhaust cams taking out four degrees for an exhaust centerline of 106 degrees. Seeing an improvement we decided to push things further and pull two more degrees from the exhaust cams for a final ECL of 104 degrees. This yielded even more power bumping our engine up to 574.9 hp at 7,900 rpm and 432.1 ft-lbs of torque at 6,600 rpm.
This ended our cam settings with 107 degrees of lobe separation – 110 ICL and a 104 ECL. What we ultimately learned with this engine was that it liked the tighter lobe separation, rather than spacing the intake and exhaust events farther apart.
When it was all said and done, on regular racing fuel we had made an initial pull of 568.5 hp and 428.9 ft-lbs of torque. After our cam and timing tuning we were up to 574.9 and 432.1 A gain of 6.4 hp, and 3.2 ft-lbs of torque respectively.
Breaking It Down
Cam Tuning By The Numbers
Below are the differences in power, broken down by each of our tests.
109 ICL, 110 ECL : 561.6 hp, 428.9 ft-lbs
105 ICL, 110 ECL: 550.6 hp, 427 ft-lbs
113 ICL, 110 ECL: 568.4 hp, 428.1 ft-lbs
110 ICL, 104 ECL: 574.5 hp, 432.3 ft-lbs
Q16 fuel: 590.6 hp 447.3 ft-lbs
- Below you will find a parts list of everything that went into the Carb Coyote Cobra Jet long block:
- Livernois Stage 3 Cobra Jet Spec CNC Ported Coyote Cylinder Heads, Intake 347.1 at .700, exhaust 226.3 at .700
- Ferrea 1.500 Stainless Intake Valves – PN F2243P — 1.262 Exhaust Valves – PN F2245P
- Comp Cams Custom Ground Intake Camshafts, .512 Gross Lift, duration 240 at .050, LSA 128.
- Comp Cams Custom Ground Exhaust Camshafts, .512 Gross Lift, duration 246 at .050, LSA 128.
- Comp Cams Valve Springs, -PN 26113, 93 pounds closed, 198 pounds open.
- Ford Stock Coyote Rocker Arms, -PN BR3Z-6564-A.
- Cometic Custom Cylinder Head Gaskets, -PN C5287-051 Left, C5286-051 Right, .060 thickness for 12:1 final compression ratio.
- Rich Groh Racing Engines Custom Sheet-metal intake manifold, 6-inch tapered runners, custom volume intake plenum.
- Holley Ultra-HP Carburetor, -PN 0-80803HB, 750 CFM.
- Innovators West Coyote Harmonic Balancer/Crank Pulley, -PN817, Stock Diameter.
- Accel Super Coils For Ford Coyote, -PN 140060
- FAST XIM Ignition Controller For Ford Coyote, -PN 301313
- Moroso Coyote Sheet-Metal Oil Pan, -PN 20572, 8 quart capacity, stock pickup.
- Meziere Coyote Electric Water Pump, -PN WP343S, 50 GPM flow rate.
- Driven Racing Oils, BR30 break in engine oil for late model performance engines, 5w30.
- VP, Q16 oxygenated racing fuel.
Thirsty For More With Q16
Wanting to wring every last horsepower we could from our combination we turned to VP Racing Fuels for their Q16 race fuel. This is an oxygenated race fuel which required adjusting our carburetor jets to add more of it. The fuel change paid off in spades for us pushing the final power numbers on the last dyno pull to 590.4 hp at 7,800 rpm and 447.3 ft-lbs of torque at 6,500 rpm. Well worth the investment. This gave us a total net gain of 15.5 hp and 15.2 ft-lbs just by switching to VP Q16.
One Wild Coyote
We made several observations while working on and tuning this engine, which may help guide us on both it’s future use and future builds, as well as just being interesting points to note.
First was that this engine like to run on the rich side, especially for a modern, naturally aspirated engines. We found that on the dyno the engine was happiest with an air fuel ratio of 12:1.
We also noticed that in-spite of it’s high winding nature the engine was making excellent power at lower RPM’s, meaning it was well suited for usage other than as a drag or circle track type engine, given it’s relatively low compression for an NA engine making these power levels it’s very street friendly. At 5,000 rpm the engine made 414 ft-lbs of torque, and was pushing horsepower of 394.5. At 6,000 rpm those numbers had both jumped significantly to 435.7 ft-lbs of torque, and 497.7 hp, respectable and usable for any street car.
With more compression, and longer duration cams, we’re confident this engine could push well over the 600 hp mark. In fact in our conversation with Godbold, we discussed how horsepower per CFM of intake flow was a good measure of engine efficiency in gasoline fueled engines. Most street engines make 1 to 1.5 horsepower per CFM of intake airflow. Hardcore racing engines, depending on design typically make around 2 hp or slightly more per CFM of intake flow. Given our 590 hp number, at 330 cfm, we’re making 1.79 hp per CFM. If we could push this to 2 hp per CFM we’d easily be at 660 hp.
We’re far from done with the CCCJ, stay tuned as we prepare to take another step with this engine in coming months doing even more dyno testing and comparisons on it. We’ll be adding AEM’s new Infinity fuel injection system as well as a Ford Racing Cobra Jet intake manifold to replace our RGR carb intake setup. We’ll also rebuild the cam phasers and bring the Ti-VCT timing system back into play. Later we hope to find a project to drop this beast into as well.