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Engine Upgrade For Our 5.0L Stock-Block - Back To Basics
Our Mildly Modified 5.0L LX Gained 44 RWHP, 58 RWTQ, And We Shaved Almost A Second Off The E.T.'S For Less Than $600.
You can't beat the good 'ol five-liter Mustang. For speed, simplicity, and ease of modification, it just can't be beat. Sure, Ford has produced some faster, safer, and better-handling Mustangs since the trusty Foxes of '79-'93, but as far as affordability and fun, the Fox Mustang is the way to go.
As advanced as OBD-II Mustangs ('96-up) and its engine control modules are, EEC-IV-controlled 5.0L Stangs ('86-'95) remain some of the easiest Ponies to upgrade with little effort or expense. In fact, there are so many aftermarket parts available, trying to pick which ones to purchase can make your head spin. What is also so wonderful about EEC-IV is its quick reception and response to upgrades without a programmer or a reflash.
With a great response from past 5.0 projects, we decided to keep going, this time with a '93 LX SSP (Special Service Package) coupe. Originally some kind of Fed car (according to the VIN tag), this one is unlike most SSPs. It's equipped with an AOD; power windows, door locks, and mirrors; and even a power driver seat. Much of the original SSP-specific upgrades are gone (the odometer is tipping 175,000 miles), but it's still cool to have. The original 2.73 gears (for high-speed chases) are gone and replaced by 3.73s. The differential is a 31-spline Traction-Lok out of a '95 Cobra R, complete with five-lug axles and the 11-inch brakes. Front brakes and spindles from a '96 GT, aftermarket rear lower control arms, and a 2-inch lowering kit complete the chassis upgrades.
Under the hood, the stock-block 5.0L recently received a freshen-up. New chrome-moly rings and bearings, cylinder honing, and a new oil pump were the only changes made to the bottom end. A pair of stock GT-40P cast-iron heads from a '98 Explorer and an FRPP Cobra intake manifold help our Pony inhale, and a set of 1 5/8-inch shorty headers, an off-road H-pipe, and Bassani race mufflers with dumps allow it to exhale.
The engine also received a mild cam (similar to the FRPP E-303 stick), new hydraulic lifters, a new timing chain, along with an aluminum radiator with electric fan. The stock throttle body, MAF, 19-lb/hr injectors, fuel pump, and fuel pressure regulator remained. Even the ignition system is stock, except for the FRPP 9mm wires. The stock airbox has been removed and a performance air filter was attached to the end of the mass air meter, and the smog pump has been deleted. The stock AOD hasn't been touched, neither has the original torque converter. It's quite similar to thousands of Mustangs on the road right now.
Our coupe recently received fresh two-tone charcoal and Tungsten Gray paint with a burgundy stripe to accent the bone-stock Ruby Red interior. Stock '96 SVT Cobra wheels with 245/45R17 rubber replace the 10-hole stockers. It looked nice, but really wasn't very peppy. In an effort to raise the fun factor, we took an old-school approach to performance. The basics for making power on a budget may not yield huge gains with the Mustang's newest version, but the Fox-bodies still respond exceptionally well to minor changes. Many years ago, MM&FF implemented what was termed the 10-Minute Tune-Up. Those simple, yet effective, tricks worked then, so why not see if they'd still produce the desired results.
Prior to making any changes, we wanted to see what our LX could do on the chassis dyno and at the track. After strapping the coupe in place on our Mustang dyno, we made a pull and the pony struggled to spin the rollers to a full pull. Our Stang produced a disappointing 199 rwhp and 220 lb-ft of torque. With the oil warm and engine temperature up to 175, we made another pull, which yielded 205 rwhp and 222 rwtq. For our quarter-mile times, we visited the ultra-sticky Gainesville Raceway in Gainesville, Florida. On a scorching-hot, mid-July day, we made a best run of 14.522 at 97 mph. Backup runs were 14.774 and 14.873 at 96 and 95 mph respectively.
Sticking with our plan to kick it old school, we headed back to the dyno to make our changes. We started with ignition timing. First, we cleaned the harmonic balancer with sandpaper and marked the crankshaft at 10, 14, and 16 degrees before top dead center (BTDC). Then we removed the SPOUT connector (located in the ignition harness near the distributor), and using a timing light, we found the timing to be set at the base timing of 10 degrees BTDC. Removal of the SPOUT (for SPark-OUT) allows timing adjustments while the engine is running without the ECU interfering. Ensuring we had 93 octane in the tank, we rotated the distributor clockwise until we achieved 14 degrees of timing advance. We reinstalled our SPOUT and spun the rollers with impressive results of 219 rwhp and 254 rwtq, a 14 hp and 32 lb-ft gain. We then advanced the timing another 2 degrees to 16, yielding 221 rwhp and 255 rwtq, a gain of another 2 hp and 1 lb-ft of torque.
The results of our timing advancement left us stoked and hungry for more power. We had a stock airbox on hand with the silencer removed, so we threw it on with a fresh K&N air filter. The dyno results were good, but surprising: 224 rwhp and 260 rwtq, an improvement of 3 hp and 5 lb-ft. We attributed the gain to cooler air from outside the engine compartment.
The next order of business included a few simple bolt-ons, so we gave BBK Performance a call. Being a leader in Mustang performance, BBK knows a thing or two about making power. Its prices are very competitive, fitment is great, and the components look nice. Our stock airbox experiment gave us the idea for our first product: BBK's fenderwell mounted cold-air kit. After a quick installation, we went back to our chassis dyno for the results. We noticed a gain of 3 hp, but a loss of 6 lb-ft off peak torque, which brought our output to 227 rwhp and 254 lb-ft, however, it was impossible to realize the gains offered by such a system while the car was stationary on the dyno, as it's designed to work best at speed. And even though peak numbers weren't impressive, average horsepower and torque increased with the cold-air kit.
A new BBK 76mm mass air meter was our next weapon. The meter is calibrated for our 19-lb/hr injectors, and the stock wiring harness plugs right in. With our engine temperature still warm (175 degrees) from the previous step, we made another pull on the dyno. The mass air meter upgrade gave us an extra 6 hp and 11 lb-ft of torque, bringing our running totals to 233 rwhp and 265 rwtq.
Next, we removed our stock throttle body to make room for BBK's 65mm version. At just 5mm larger than stock, it fits the opening of our Cobra intake perfectly. Like the mass air meter, the TB connects easily and bolts on in minutes; it even comes with the necessary gaskets. After warming the engine to 175 degrees, we made another pull and were pleasantly surprised to see an increase of 3 rwhp (to 236) and a gain of 6 rwtq (to 269).
Even though we just gained 31 rwhp and 47 rwtq in a couple of hours (including dynamometer runs), we wanted to push it a little further. Don't we always? Having spent less than $600 on our parts, we ran down to the local parts store and picked up a 71-inch engine drive belt for about 30 bucks so we could bypass the power steering pump (the air pump was already bypassed). We installed it and made another run. Peak rwhp and rwtq were essentially unaffected, but we saw a gain of about 5 rwhp and 5 rwtq down low, which tapered off around 4,000 rpm. The gains would be closer to 10 or 12 had the air pump been in place.
In a last ditch effort to scavenge as much power as possible, we tossed a 10-pound bag of ice on the intake and let is soak for about an hour. With the engine coolant temperature needle buried on the (cold) peg, we fired up our LX. Our second consecutive pull was the best: 243 rwhp and 278 rwtq. That amounted to increases of 44 hp and 58 lb-ft from our baseline numbers earlier in the day. Needless to say we were stoked, and couldn't wait to get to track to see what our newly found power would equate to.
After a day of commuting on the new tune, it was clear our pending track visit was going to require some different rubber for the rear of our coupe. Traction has been greatly reduced, and our 245s just won't cut it. So we loaded a pair of 275/40R17 M/T ET Street Radials into the truck, along with a jack and some tools, and headed to Bradenton Motorsports Park (Bradenton, Florida) for its test and tune night. As we suspected, our traction on normal street-rubber was limited-even on the dragstrip. Sporting a poor launch, the initial run of 14.421 at 102 mph with a 2.622 60-foot time proved immediately that we needed to swap wheels and tires.
After a long cool-down, a tire swap, and a bag of ice on the intake, we headed for the staging lanes again. Now, traction was not an issue, and after a bunch of high 13s, we clicked off a best of 13.669 at more than 103 mph. After backup runs of 13.681 and 13.709 at 103 mph, we were able to leave the track very satisfied.
In the end, we shaved 0.853 seconds off our e.t. for less than $600. Of course we cheated a little with the drag radials, but without traction we couldn't get an accurate e.t. Our LX now has quick throttle response and impressive acceleration, along with 44 extra rwhp and 58 rwtq. Not bad for a couple of old school tricks and a few bolt-ons. The best part is almost anyone can perform these upgrades.