• Feb 20, 2006

Readers of Autoblog know that I'm not a huge fan of the naturally-aspirated Ford modular V8s that are available here in the US, but stick a supercharger on these motors and my opinion changes substantially. Let's take a closer look at the two forced-induction versions; the lame-duck 5.4L DOHC engine used in the Ford GT, and its closely-related sibling that will soon see use in the Mustang Shelby GT500.

Due to this engine's similarities to Cadillac's supercharged Northstar, it's tempting to make comparisons between the two engines, and so I'll do exactly that.

A look at the camshaft chain drive shows that one large chain drives the exhaust cams off the crankshaft, while a short intermediate chain then transfers rotation to the intake cams. This strategy allows the use of a smaller sprocket on the intake cam, and the subsequent reduction of bulk at the upper corners of the head (compare this to the Northstar, which uses two equally-sized sprockets on each cam). The downside is an increase in length, complexity, and noise; this is a huge "small block" engine, despite its modest displacement.

See that log-style cast-iron exhaust manifold? To the eye, it sure doesn't look very efficient. It'll be interesting to see how much room is left in the S197 engine bay by the time this tall-deck DOHC monster is shoehorned into place, but hopefully there's enough space to squeeze in a pair of proper headers.

The serpentine belt is also used to drive the supercharger. It'll be interesting to see how the aftermarket modifies that to allow the use of a cogged belt to drive the blower.

That fuel rail appears much larger than what we'd typically find (the Northstar's rail looks tiny in comparison), and it feeds one injector per cylinder.

This is a lovely-looking Roots blower, but how long until someone mounts a twin-screw unit? It'll be interesting to see what Whipple and Kenne Bell offer for those sickos who just can't be satisfied with smaller blower pulleys. Note that the blower discharges downward into the intercooler, which is a bit more typical than Cadillac's upside-down airflow path.

There's the oil cap, and just above and behind it is the crankcase breather. Follow that tube up to the blower housing, and you can see the vacuum actuator for the supercharger bypass valve right behind it. When the throttle is closed enough to draw a vacuum, this system bypasses the compressor for additional efficiency.

Is that a reduced-diameter multi-plate clutch that we see? Yummy - hopefully it's enough to hold up to the sort of abuse that this engine will be capable of doling out at the dragstrip. The skeletonized flywheel looks to be much lighter than what we'd normally see in a production application. I'm thinking that this engine will provide the definition for "throttle response".

Note the relatively deep sump - hopefully that's sufficient to maintain oiling during high-g cornering, as I suspect that many owners will want to do more than just quarter-mile straight-line blasts.  

That's one beefy bottom end, but we can see just how small the pistons are in relation to the exterior dimensions of the engine. That 3.66" bore limits the engine's ability to breathe, even with four valves, but this becomes much less of an issue once that supercharger starts to work its magic. Regardless, note that Ford isn't really keen on showing off the intake and exhaust ports in its cutaway displays.

The dish in these pistons is larger in diameter and not as deep as those found in the Northstar's pistons. That lends itself to a bit less desirable combustion chamber shape, but likely also allows for a higher pin position and more thickness in the piston crown (the latter is especially important to those who will be pushing this engine to the limit). This is a fine example of the tradeoffs and compromises that must be made when designing an engine.

Now, on to the Ford GT engine:

 

See that big cogged belt, mounted low on the engine? That drives the pump for the dry-sump oiling system, which is employed to reduce the packaging height of the engine. The sump that we pointed out on the Shelby's engine is eliminated, allowing the engine to sit lower in the chassis. It brings with it some oiling improvements as well, especially under high lateral loadings. 'Tis not inexpensive or simple, however.

Methinks there are more than a few horsepower to be found by replacing those exhaust manifolds with a proper header.

If you're an oxygen molecule that was unfortunate enough to enter the GT's intake track, this is one of the last things you see before you die:

 

After a trip through the dual 70mm throttle body (I'd estimate its rated airflow somewhere well north of 1250 CFM), the intake charge is compressed in a twin-screw supercharger:

There, it's discharged downward through an intercooler. Note the use of two fuel injectors for each cylinder. Only one is used at idle and low throttle openings, which allows for fine metering of the injected fuel. Get into the loud pedal far enough, and the second injector comes online to ensure that sufficient fuel is available to keep up with the supercharger's cylinder-filling efforts.

At the upper edge of this photo, we find the four black coil-on-plug (COP) assemblies. Once again, note the relatively small size of the cylinders relative to the overall bulk of the complete package.

To no one's surprise, we find the same cam drive arrangement.

The transaxle is seriously gorgeous - it seems a shame that it likely won't see use in other Ford products.

As we can see, there are indeed differences between these two engines, but they're not huge. The Ford GT puts down well over 500 HP to the rear wheels despite its 550 HP rating; will the Shelby prove its 475 HP rating to be equally pessimistic? We're anxious to find out, and it should be interesting to see how much work is required to bring the Shelby's output up to the same level as its much more expensive cousin. We're betting that it won't take much.



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    • 1 Second Ago
  • 21 Comments
      • 8 Years Ago
      "Lame duck? Are you high?"

      I used the term "lame duck" as the GT is soon leaving production, and that particular engine goes away with it. Other than that fact, there's nothing lame about it.
      • 8 Years Ago
      Mike, you are absolutely talking nonsense. There are many of them running 3-400K in taxi's (and they have a pretty good reputation). Northstars will NOT do that.

      As far as comparing them to GM pushrod small blocks , well, I would rate GM higher. Physically smaller, simpler, and they make more power without using more fuel.
      • 8 Years Ago
      Bad reputation? You've got to be kidding. Ford's mod motors have a great reputation because they go forever, and rarely break under normal driving conditions. Have you ever seen how many miles those taxi modulars have on them? 300K is the norm.
      • 8 Years Ago
      Of course a mod motor will smoke after taxi duty, any motor would.. I have first hand experience owning and tuning ford's mod motors... It's balls above anything that GM can muster...
      Older they get the better they become..
      • 8 Years Ago
      The size of this thing is ridiculous for its displacement. I'll take a northstar anyday. Ford modular V8's have an terrible reputation. Look at those crown vic taxi cabs. They all smoke (if they live that long!!)
      • 8 Years Ago
      Since when did a MUSTANG ever wander onto a track and finish a lap???
      Carmine Galletta
      • 8 Years Ago

      I own an 05 GT prchased new and thank goodness I have not found any oil leaks as of yet. However I would like to inform you of my experience, As an all America muscle car collector I purchaesd my GT with great expectations and I really love the car. But with about only 500 miles on the car, I found that the lower passenger side rocker panel began to buldge just below and behind the passanger side door. Concerned I called my dearlership where I purchasd the car, and brought it in for inspection. After 2 days they called me an told me that after a few attempts they could not service the car because their lifts could not accomodate the car. Furstrated and amazed at their excuse, I brought the car home and on my low profile buddy lift that I bought at the Atlantic City Auction I was able to get the car in the air with no problem at all. I proceded to remove rear the under panels and after removing what seemed 1000 screws, I was able gain assess to the oil pan and inside rocker panels. In the passanger side rocker panel I found that all of the piping for the coolent, power steering, and brake lines -- as much as 5 or six lines were jammed into this small area. The large coolent line was pushing outward onto the other lines causing the buldge ans stressing the plastic panel. I re-adjusted the 2 large clamps to reduce the outward pressure on the rocker and also secured the rest of the lines that were rubbing together with nylon tension ties. By preventing the lines from rubbing on eachother, you will in turn prevent friction leaks in these lines in the future this very important! I then contacted the Ford GT hot line and the woman requested that I email the pictures of what I have found so she could forward them to her technical department. About 4 months have passed and still no response, no fix no explination from Ford. The dealership has not even called me to follow up. These lines would have without a doubt broken thorugh the rocker, I have stress cracks in the panel where the lines were pushing outward. Oh yeah I performed my own oil change as well paying just shy of $300 for the oil and filter from Ford. I recently inspcted a new 06 GT on the showroom floor of the dealership where I purchased my car and found that the aluminum lines near the passanger side rocker panel under the rear deck lid were not even in the factory clamping and just floating in the air. What is wrong here? This is a brand new car. I hope this helps someone. So keep an eye on your rocker panel this most likley is inherent in all of these cars. I hope this helps. PS before you buy a GT ask the selling dealer if they have the proper facility and knowledge to service your car. It sad that a Ford dealershi can sell their so called flagship vehicle and not be able to service it. This is my first Ford car and it may be my last. In my opinion there is just not enough respect for these cars when they arrive at the dealership for service. Training is key and there should be criteria that a dealership should be required to meet before a car like this is even allowed to roll into ther showroom. The American way I guess sell it and worry about servicing it later. Talk about putting the cart before the horse. Good Luck and safe drivig to all.
      Carmine Galletta
      • 8 Years Ago

      I own an 05 GT prchased new and thank goodness I have not found any oil leaks as of yet. However I would like to inform you of my experience, As an all America muscle car collector I purchaesd my GT with great expectations and I really love the car. But with about only 500 miles on the car, I found that the lower passenger side rocker panel began to buldge just below and behind the passanger side door. Concerned I called my dearlership where I purchasd the car, and brought it in for inspection. After 2 days they called me an told me that after a few attempts they could not service the car because their lifts could not accomodate the car. Furstrated and amazed at their excuse, I brought the car home and on my low profile buddy lift that I bought at the Atlantic City Auction I was able to get the car in the air with no problem at all. I proceded to remove rear the under panels and after removing what seemed 1000 screws, I was able gain assess to the oil pan and inside rocker panels. In the passanger side rocker panel I found that all of the piping for the coolent, power steering, and brake lines -- as much as 5 or six lines were jammed into this small area. The large coolent line was pushing outward onto the other lines causing the buldge ans stressing the plastic panel. I re-adjusted the 2 large clamps to reduce the outward pressure on the rocker and also secured the rest of the lines that were rubbing together with nylon tension ties. By preventing the lines from rubbing on eachother, you will in turn prevent friction leaks in these lines in the future this very important! I then contacted the Ford GT hot line and the woman requested that I email the pictures of what I have found so she could forward them to her technical department. About 4 months have passed and still no response, no fix no explination from Ford. The dealership has not even called me to follow up. These lines would have without a doubt broken thorugh the rocker, I have stress cracks in the panel where the lines were pushing outward. Oh yeah I performed my own oil change as well paying just shy of $300 for the oil and filter from Ford. I recently inspcted a new 06 GT on the showroom floor of the dealership where I purchased my car and found that the aluminum lines near the passanger side rocker panel under the rear deck lid were not even in the factory clamping and just floating in the air. What is wrong here? This is a brand new car. I hope this helps someone. So keep an eye on your rocker panel this most likley is inherent in all of these cars. I hope this helps. PS before you buy a GT ask the selling dealer if they have the proper facility and knowledge to service your car. It sad that a Ford dealershi can sell their so called flagship vehicle and not be able to service it. This is my first Ford car and it may be my last. In my opinion there is just not enough respect for these cars when they arrive at the dealership for service. Training is key and there should be criteria that a dealership should be required to meet before a car like this is even allowed to roll into ther showroom. The American way I guess sell it and worry about servicing it later. Talk about putting the cart before the horse. Good Luck and safe drivig to all.
      • 8 Years Ago
      The Center for Automotive Safety reports serious oil leaks with this engine. Ford has been less than helpful.
      • 8 Years Ago
      I have been driving my mom's '92 Town Car which has a 4.6 modular motor.

      I use this as my company car to service my military foods brokerage business centered out of Louisville. I have to travel as far as Detroit, Nashviile, St Louis and Chicago. Now at 197,000 miles, the car runs very well and averages between 20.5 mpg and 21.7mpg.

      The only motor issues have been:
      - a small oil leak developed at oil filter housing. fixed by having a new gasket installed,
      - intake manifold egr track had to be cleaned by the dealer to clear a check engine light,
      - simple electric contact problem where the spade like starter wires plug into starter,
      - car will smoke a little only when reving after it has been sitting at an idle for several minutes,
      - spark plug wires.

      The car has never failed me or left me stranded on the side of the road. Even at almost 200,000 miles I have complete faith in the old girl and just installed new 70,000 mile Bridgestone Turanza LTSs and front wheel alignment.

      I am very impressed with the reliability and durability of Mom's old Lincoln Town Car Cartier. the exterior and interior are in remarkable shape! Almost like new! This was my mom's first luxury car that Dad replaced in '97 with a new Town Car. Well Mom is gone now but I think her old car, which I'm sure made her feel proud, may live on for many miles.

      • 8 Years Ago
      Great review and fantastic pics too, thanks!

      Chris
      http://amateureconblog.blogspot.com/
      • 8 Years Ago
      Corvette can kill the mustang? ITS SUPPOSED TO, dummy. It also costs a frig of alot more. HAHAH. It must be that plastic red cover they put on it, adding 20hp. Unfortunately the LS motors do not always win even in Vettes. There have been a few mustangs recently that could give the Vette a good run on a track, road course, for a lotta bux less. Compare the 2002 (C5) Z06 with the 2003 Cobra available from Spring 2002. I'll take mine in mystichrome please. Whatever happened to the Vette motor that was DOHC? It had big valve covers too. There is nore valve gear in a DOHC up top, small price to pay for excellent breathing.
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