Muscle Mustangs & Fast Fords
1985 Ford Mustang SVO - No Slow SVO - Tech
Uncorking Ford's Turbo 2.3 Unleashes Four Cylinders Of Fury.
For decades, people have tried to change the Turbo 2.3's perceived lack of power and refinement. It has long been considered the redheaded stepchild of the Ford performance world. It's unfortunate that since its last year of production (1988), it still lives with that stigma.
But it's not like we haven't done our part. Throughout the years, we've coaxed and covered several 2.3L buildups and even featured several 10-second four-bangers. Truth be told, the vast majority of our readers seemed not to care. As the Ford performance movement gravitates toward the newest 4.6L V-8s, less attention has been given to the 2.3 engine, which is about half the size. So, we've decided to give it yet another shot with this update on the '85½ SVO Mustang that we purchased a couple of years ago. We've lived with it for quite some time to find out what all the hoopla was about, and today we can give you a thorough evaluation of what's to like and dislike about these baby Fords.
Without getting emotionally attached, let's take a step back and look at this engine from an objective point of view, coupled with cold, hard facts. Born from racing convenience rather than racing pedigree, the turbo-4's biggest problem is its inherent design. Ford chose to use this engine platform for many of its motorsports efforts rather than invest in an all-new engine design. Even with modern multiport fuel injection, then-current turbocharger technology, and intercooled enhancements, the engine was still an iron-headed engine with ancient and pedestrian roots from the pokey Pinto econocar. This may sound harsh, but let's call it what it is. With a poor-flowing two-valve head and a rather restrictive intake port design, the top half of the engine is a major hurdle to achieving big horsepower numbers. Luckily, the bottom end is rather robust, and with a nice-sized bore and stroke combination, the 2.3 (and larger 2.5 version) has a solid foundation.
Don't take everything that we're saying to heart-we still love these engines and the cars they're anchored to because they wear the Blue Oval. Just like any Ford engine, with a few choice mods and realistic power goals, you could still build a car that can run with modern-day muscle-even those with double its displacement. With this in mind, we'll move ahead with some more upgrades to our SVO.
From Yesteryear to This Year
When we first introduced you to our humble SVO, we upped its dyno performance with the help of Forced4 Motorsports and Mustang Magic to get our Pony up from 150.9 to 191.7 rwhp. The simple removal of the stock airbox and the addition of an open-element air filter added a solid 14 rwhp, and a boost controller upped manifold pressure from 12 to 18 pounds to coax another 25 hp from the furious four-cylinder. Fiddling with fuel pressure allowed us to negotiate a total of 40.8 hp gain at the rear wheels. Torque gain was even greater, jumping from 213.6 at 3,250 rpm to 280.5 at 3,400 rpm. We were certainly not disappointed with our first round of mods that emptied our wallets by only $500.
Moving on, we're now going to chase power in the next logical step by freeing up the exhaust tract. Many folks will tell you that you need some kind of backpressure to make a car run better, especially a turbo car, arguing that a restriction will boost midrange power. On a naturally aspirated application this may be true, but on a turbocharged car, we can't agree. Anytime we've removed a restriction from the outlet side of a turbocharger, there have always been power increases and even torque increases in the midrange. As a matter of fact, the more backpressure we've removed after the turbo, the results have always been positive with more power gained. The only place where you can tune for more torque on the exhaust is by playing with the nozzle (A/R size) of the turbine housing and the manifold or header pipes coming from the cylinder head, leading into the turbo. So, the best bet is to put the largest pipe on the outlet side of the turbine housing you can possibly fit and to run the pipes and mufflers as large as possible to the rear of the car.
Our SVO is still straddled with the original downpipe and quasi-dual exhaust that splits after the hugely restrictive factory catalytic converter. This combination worked marginally well from the factory with its 205hp rating, but our '85½ is already making more than that with just a few bolt-ons (192 rwhp is about 221 flywheel horsepower given a 15 percent drivetrain loss). For our test, we contacted the 2.3L turbo fanatics at Stinger Performance and ordered its 3-inch mandrel-bent downpipe assembly that replaces the entire downpipe and catalytic converter assembly, which then splits into two 2.5-inch pipes to match the dual exhaust of your choice. This replaces the restrictive 2.25-inch factory downpipe and really frees up the engine, allowing it to breathe for more power.
Stinger Performance's downpipe assembly is made from aluminized piping that is mandrel bent for optimum flow. Bolting up to the stock turbocharger's 2.5-inch elbow and swelling to a full 3 inches in size as it goes under the car, it promises to promote all-around performance and give the car a much-needed infusion of sound. The fit was excellent, and all we had to do was connect it to our new Edelbrock after-cat exhaust. We went with the Edelbrock because in our other project cars, we've been entirely satisfied with its deep and mature, but not-too-loud sound. This would be a perfect match for our car because we wanted to inject testosterone to the car's soundtrack, doing away with the wimpy sound that often accompanies four-cylinder cars. Plus, it comes with 2.5-inch mandrel-bent pipes, which are a perfect match for the smooth Stinger Performance pipes upstream.
Although we didn't perform this upgrade, replacing the stock cast-iron exhaust manifold with a tubular header has been a proven part for improved performance. On all '83-'85½ EFI turbo Fords, a cast-iron manifold designed for quick spooling response was known as the E3 casting. In 1986, Ford introduced an improved version (known as the E6 casting) that had a larger outlet at the turbocharger's mounting flange. The E6 is certainly the more desirable factory piece, giving little in exhaust velocity for a much-improved gain in overall flow, resulting in more power all the way to redline. Forced4 offers a really nice tubular header made by Rod's Headers that features stainless construction throughout and robust flanges for optimum reliability and performance. But for our test, we stuck with the E3 casting that our car came equipped with for consistency and to measure the gains that would come from just freeing up the exhaust after the turbocharger. To see what a header can do on a more modified car, read the accompanying sidebar.
So, with the Stinger downpipe assembly and the Edelbrock exhaust system in place, we got the car up and running and trailered it back to Mustang Magic for more dyno time. With the car strapped down onto its Dynojet 248c, we went for an initial run. To our surprise, we witnessed the boost gauge jump to nearly 22 pounds-a lot more than it originally had. Technician Joe Lauzardo quickly let off the throttle, and we lowered the boost pressure to 18 psi to avoid harmful damage to the engine. As we let the car cool and went for our next run, we could hear the car spool up much quicker, and the car really began to make power. Halfway through the run, however, we quickly noticed a plume of smoke coming from under the hood. It didn't take long to realize something was amiss when the car began to fall on its face. Our day was over.
It was apparent that our first run with too much boost had caused some damage to the 90,000-mile engine, and there was no turning back. Back home, we found 40 percent leakdown in the two middle cylinders-a sure sign of a blown head gasket between the two bores. Without adequate time to properly fix the engine for our deadline, we decided to give you what we had and (try to) write a halfway decent story instead of spending our late nights thrashing on the engine to get it running. So, the car sits, and we've thrown together some words for your pleasure.
The good thing is, we were able to salvage some of the dyno data up to 4,250 rpm, and it was encouraging. Compared to our previous dyno pulls, we found an incredible jump in torque starting as low as 2,400 rpm. This proved that the turbo was indeed spooling up sooner, making more boost earlier. By 3,600 rpm, we witnessed a 32-lb-ft increase in torque compared to the previous peak of 280.5 lb-ft, and at 4,250 rpm-the highest rpm point we could record with our wounded soldier-we saw an incredible 37 rwhp gain. This means at just 4,250 rpm, we already were making over 200 rwhp where it used to be just 164 rwhp without the new exhaust setup. Had the car been able to rev cleanly all the way up to redline, we're confident that a 45-rwhp gain would have been realized at about 5,300-5,400 rpm.
Despite being sidestepped by mechanical maladies, we uncovered a few things in this test. For one, the SVO factory exhaust components, consisting of a small-diameter downpipe, a choked-up catalytic converter and some crush-bent tailpipes, were incredibly restrictive and robbing us of power. Had we known how much power was being bottled up in the first place by the exhaust, we probably would have performed these mods first before the first bolt-on was ever secured to the topside of the engine. Secondly, we proved that by freeing up everything after the turbo, torque and horsepower gains can be found not just on the top end but throughout the entire rpm range. As boost came in earlier, torque also swelled. Of course, this was all before the engine decided that it was time to call it quits on us.
Which brings us to the next part of the evaluation. After having lived with this car for about two years now, we can fully relate to the turbo-2.3 experience and have drawn a conclusion-the car is certainly reliable as a daily driver and is fun to own. Its reduced heft over the front wheels can be felt when negotiating turns, and its "dare to be different" attitude certainly says a lot about itself and its owners. But as these cars approach 20 or more years in age, there are factors that come into play that cannot be directly blamed on the engine's design. In all fairness, any engine, no matter who makes it, will need a thorough going-over when it's 20-plus years old. Because time is never kind to any car, consider a quality refresh or engine rebuild a part of the ownership experience. Aside from the leaky gaskets we've had to deal with, engines tend to need a little more care in their old age. But in the end, these are excellent alternatives to the 5.0 if you're looking for something different that benefits from modern-day turbocharger technology.
Chalk this experience up to, well, experience. As die-hard 302 fans, we gave these cars a strong benefit of the doubt. But as the Ford performance market now shifts to Three-Valve 4.6L V-8s, we'll have to say goodbye to our favorite four-cylinder, the turbo-2.3 and shift our efforts to what is undoubtedly the future of Ford, the modular V-8. Well, for the time being.
Down The Tubes?
Since we were unable to get solid numbers from our own SVO, we called the helpful turbo-2.3 gurus at Forced4 Motorsports to help us find a car that would represent how an SVO with the Stinger exhaust pipes would work on the dyno. What they brought was their own test mule, an '86 SVO that had also been fitted with a Rod's Headers tubular header that is available through Forced4, and Forced4's own front-mounted intercooler system along with a slightly larger turbo.
On the dyno, spool-up time was noticeably slower, but the horsepower the car was pumping out was certainly newsworthy, considering the amount of money that Eric Klein of Forced4 invested. His SVO belted out 281 hp at 5,900 rpm, and torque was steady at 304 lb-ft at 4,100 rpm. Compared to our own SVO, that's a difference of 89 hp and 23 lb-ft of torque. The power increases were sizeable, but the turbo lag was certainly noticeable. The power gain at the peak readings occurred at higher engine speeds. Torque did not suffer as much as we thought it would. What we can attest to is that, given the amount of power gained on the top end, this would certainly be the best way to hustle your car down the track. Turbo-4s for everyone!