[eschaider]

Originally Posted by Hawkeye_Pearce

What is everyone's thoughts on the current gen coyote motor? I come from a background of high revving imports - my style of driving is enjoying some curvy back roads (I'm not much of a fan of drag racing). Still currently in the process of selecting my options for the future BDR cobra order.

All the same stuff olddog said and I would not consider a small displacement engine w/o a positive displacement blower. The n/a torque is just too low. When we first get these cars they are so light that a small displacement n/a motor will wow most of us. You get used to the small n/a engine very quickly. There is a reason that most Cobra owners prefer 427 inches or bigger and it is the torque. Torque is what registers on your seat of the pants dyno.

The other consideration is engine speed while driving the car. If you need to run at elevated engine speeds to get the HP to move the car because you don't have the torque, driving the car becomes more like work, a lot less like fun and quite hard on your ears.

If you elect to supercharge the engine you have a wide range of new challenges from building to driving the car that stretch out before you. Some of the building challenges, in no particular order are, the head gaskets on supercharged Coyote engines are tender because the Coyote bore size is quite large for its 100mm bore space.

A standard bore 5.0L block has a 92.2 mm bore on a 100 mm bore spacing. That only leaves 7.8 mm of deck surface available to seal against. Most head gaskets leave another 1 mm of clearance between the edge of the bore and the edge of the head gasket. That means the deck surface used to seal the combustion chamber is now down to only 5.8 mm. 5.8mm is 0.228" or less than a quarter of an inch — this is a big problem on a supercharged engine. Guess what happens when you go to a 94 mm bore on the GT 350 version of the engine with the exact same 100 mm bore centers — do the math. It is stunning!

The Coyote block, last I checked, is on a generation 5 block and there are at least two if not three more generations since then. Each generation corrected a design oversight that produced engine failures for both the customer and Ford warranty services.

The large bore and small bore centers produced thinner than desirable cylinder walls for supercharged incarnations of the engine. The thinner cylinder walls would move around under s/c power levels sometimes cracking.

Ford's preferred fix for this when the engine went to the bigger bore GT350 engine with a 317 inch displacement was the removal of the cast inplace liners and the use of PTWA bore finish technology along with a hefty increase in aluminum everywhere except — you probably guessed it, between the cylinders. The reason? The bore centers are fixed at 100 mm.

The new block is not an inexpensive item. FRPP prices the empty block at $3.650, click here => Gen 3 Coyote block. BTW the heads have gone through a similar evolutionary process and the good heads you would want to use are priced at $1,995 for each head, click here => GT350 Head. In fairness the heads are also CNC ported by Ford.

Almost forgot those "good" heads have revised valvetrain geometry that according to Ford requires a "unique camshaft due to valvetrain geometry, 5.2L rocker arms and lash adjusters, and also requires piston modification for proper piston to valve clearance." The words translate into more money for special parts once again. The last item about piston modification is probably not a big issue if you will be using new application specific, purpose built aftermarket pistons.

The really good news is that when you are all done with purchasing all the "right stuff" you still have a head gasket sealing problem on the s/c engines. When s/c engines push out a head gasket it is a very different event than when a n/a engine pushes out a head gasket. There is a blue hot cutting torch like flame that escapes from the combustion event and exits between the head and block torching out a huge gouge from your $3,650 block and a correspondingly offensive gouge from your $1,995 cylinder head.

Aluminum can not be re-heat treated which means both those items are now headed for the scrap heap and you guessed it you are getting ready to buy two new ones. There are several other gotcha's but this next one is quite nice.

While you can repair a cast iron liner when you burn a piston (this is a s/c phenomena), a PTWA finished cylinder that experiences a burnt piston effectively trashes the whole block because, you guessed it, you can't re-heat treat the damaged aluminum and the cost to refinish the damaged bore makes a new block look good.

Then of course just to keep you on your toes there are other aggravating issues like timing chain and sprocket failures that have high dollar medicine required to fix or avoid. While we are still reviewing the nice extra's Coyote ownership brings we should not overlook the endearing feature that requires you to remove the cams from the heads to get to the head bolts or studs to remove a head. Then of course there is the ever popular need to redegree four yup, count 'em — four, cams each time you reassemble the engine.

In an attempt to head off continuing engine failures Ford has just recast the aluminum Coyote block in cast iron. The new block / engine carries the Ford assigned name Werewolf. Pricing has yet to be announced and an initial version was on display in Ford's booth at this year's PRI show — w/o pricing.

Yes you say but most of this is not a n/a issue, it is a s/c issue. You're right and in all but a very few instances, your seat of the pants dyno will quickly grow tired of your n/a version of the engine.

The character of the engine changes profoundly when it is supercharged. This is both good and bad. You have to be careful what you wish for here. The s/c Modmotor that I use was the predecessor to the Coyote and because of a smaller bore and stroke also doesn't share most of the frailties of the Coyote design. In a mild state of tune my 4.6 produces 655 ft/lbs of torque at 1500 rpm and 609 ft/lbs of torque at 7500 rpm. The blower makes for an extremely flat torque curve. Flat and fat torque curves make these cars both fun to drive and dangerous.

Quite a ride you might think. Yes and no. The seat of the pants dyno is absolutely impressed however, before you install traction control this kind of power in one of our cars is dangerous in the extreme. It was possible to smoke the tires in high gear at over 75 mph by rolling into the throttle — not mashing it, just rolling into it! The traction control made it both a safer car and a much more enjoyable car to drive. Moral of the story is two fold, don't under power your car, you'll be sorry and don't over power your car, you'll be sorry.

I would probably look at a different engine platform than a Coyote if I were in your shoes.


Ed