Tom Wilson
February 1, 2004

Horse Sense:
Don't try these bolt-on tricks on pre-'99 Mustang V-6s. Before it was reengineered for the '99s, the 3.8 breathed with asthmatic cylinder heads, intake manifolding, and camming. Hopeless without lots of work, those earlier 3.8s don't respond as well to bolt-ons.

There are good reasons-most of them associated with your money-to keep a '99-or-later V-6 Mustang in the garage. Less expensive to purchase and operate-definitely to insure-the base Mustang also offers reduced front axle weight; naturally lighter, more responsive steering; and stealth, should you want it. On top of that, the V-6 is not that far behind the V-8 when both are stock. They're certainly not that far apart in the slog of urban traffic or other daily realities.

Don't get us wrong. Big horsepower and pole-position lap times are V-8 phenomena, but for light-duty, daily driver fun, the V-6 is a bargain. This works whether you're a starving student (or magazine editor) who simply can't afford a turbo'd 408 Windsor and T56 combination, or you're the parent of a student who wants to keep the horsepower-per-testosterone ratio in check, or you're simply looking for a second car for the household.

Of course, a stone-stock, 190hp, 220-lb-ft 3.8 is a good place to begin, but what can you do to it? Bolt-ons.Forget big-power modifications-that's what V-8s are for. But perking things up with some easy bolt-ons makes sense.

To get an idea of what bolt-ons you might want, we worked with BBK Performance and Brothers Performance Warehouse. BBK got the ball rolling with the introduction of its prototype V-6 header. After agreeing to try it on the Brothers Performance Warehouse Dynojet, it didn't take long to figure out testing the full range of V-6 bolt-ons offered by BBK and Brothers was the V-6 testing opportunity we'd been hoping for.

Mike Galley, who works the counter at Brothers, provided the test mule-an '00 five-speed coupe. He had a few trinkets already installed on his car, but for the test he removed all of them to return the car to stock. Strapping his blue coupe to the Dynojet rollers netted a baseline of 154.3 hp at 5,100 rpm.

Cold-Air Kit
Our first bolt-on was one of the most popular-BBK's cold-air kit. This is metal tubing and an open-element air filter that replaces the stock air filter, the airbox, and the corrugated rubber hose that leads to the mass air meter. It also remounts the mass air meter, which is attached to the air-filter housing on the stock V-6. BBK's cold-air kit retails for $179.99 through Brothers and promises more power via reduced inlet restriction

Frankly, we saw more power from the cold-air kit than we were expecting. The peak power rose 8.8 hp to 163.1 hp, with power up across the rpm range. Clearly the open-element air filter has less restriction than the stock paper element sitting in the tight, stock plastic housing, so some of the power gained is made there. But with this large an increase, the smooth metal tubing must also offer a remarkable reduction in induction turbulence compared to the corrugated rubber hose.

About the only tradeoff from this kit is increased induction noise, but this is mainly noticeable only when the throttle is opened wide, and then you're ready for a little honk from underhood. As induction systems go, this one is quite civilized.

70mm Throttle Body
Moving downstream in the air path, we next came across the mass air meter. From previous experience, we figured the stock air meter still had more air-flow to offer, and one glance at our huge Pro-M Univer air meter said it was too large for the sub-200 hp we were making. Considering the cold-air kit's hoses weren't going to stretch around the oversized meter opening anyway, and since at $449.99 the Univer is likely not a first-round bolt-on, we decided to continue with the stock air meter until we had considerably elevated the power level.

That meant the next item was the throttle body. BBK has a 70mm throttle body for the 3.8 V-6 for $279.99, so on it went. The larger throttle body requires a slight enlargement of the upper intake manifold inlet, which can be done with a round file, or faster yet with a Dremel tool. If the manifold inlet is not enlarged, the throttle will open only a few degrees before the throttle blade hits the intake, which obviously doesn't work.

With the installation complete, it was something of a surprise when the larger throttle body didn't turn up any horsepower. In fact, we saw a 5.2hp loss, which is a real curiosity. We've seen plenty of mild V-6s and V-8s that didn't need any more throttle body diameter, but losing horsepower from a modest increase in throttle body diameter was a first. Figuring we simply weren't making enough horsepower yet for the larger throttle body, we made a note to revisit this part later.

Underdrive Pulley
Our next player was a $169.99 underdrive crankshaft pulley from Auto Specialties. Unlike V-8s, the V-6 Mustang engines are supported only by a smaller crankshaft pulley, so there is no underdrive water pump or alter-nator pulleys. Another difference is the 3.8 V-6 crank pulley and harmonic dampener are a single piece, so the Auto Specialties part includes both the smaller pulley and a damper prebuilt into an assembly.

Not included is the required, shorter serpentine belt, although the necessary belt part number is specified in the pulley's instructions. A trip to the parts store netted us the required belt.

Installing the new damper/pulley combination is accomplished by removing the electric radiator fan, the shroud, and the water tank-all of which is no big deal-then putting a puller on the stock damper and cranking it off. Due to the deep-dish design of the stock pulley, you may need to "modify" the puller to fit. That means we had to whiz-wheel off some of our puller's ears.

On the dyno, the underdrive pulley paid off like a slot machine, giving a boost of 10.4 hp and 5.4 lb-ft of torque to the bottom line. That brought the power peak to 168.3 hp, or 14.0 hp ahead of the baseline. This is with the larger throttle body still in place, so it was a fairly large gain.

Short-Tube Headers
Our next move was to head under the car and the exhaust. Traditionally, V-6 Mustangs have responded hugely to exhaust modifications because they collect everything into a single muffler and tailpipe. Opening this to a dual system has thus proved an easy and efficacious power builder. Unfortunately, V-6s have long been saddled with a Y-pipe, but his can easily be corrected with an adapter from Pacesetter.

On a happier note, the factory exhaust manifolds are nice. Beautifully crafted from heavy-gauge, stainless steel tubing, these neo-headers are definitely in the running for the best-ever exhaust manifolds fitted to a Mustang by Ford. Thus, BBK knew it had an uphill fight when building its V-6 headers. The advantage BBK has with the prototypes we tried is the company fits its head pipes into a 3-into-1 collector, unlike the stock manifolds that simply join the first pipe in line to the second, and that pipe into the third.

Things had been going so well we knew a piano was going to drop on us any minute. Sure enough, as soon as the Mustang was raised on the hoist we saw a nonstock, muffler-shop fabricated after-cat exhaust system on our test car-something everybody involved in the test figured had been recently replaced with a stone-stock V-6 system. The stupid thing used 2-inch pipe in places instead of the 2 1/4-inch stock stuff, and it deleted the bolt-together connection at the end of the Y-pipe so we had no place to attach our after-cat system to. Grrrrrr. Would our tests so far be invalid? Only an extra test using a stock Y-pipe versus the one on the car would tell. Brother's jumped on the phone and procured a Y-pipe from a local wrecker in about two hours.

In the meantime, the headers were swapped and tested. The combination of cold-air kit, larger throttle body, underdrive pulley, and headers delivered 165.8 hp and 196.9 lb-ft of torque. This was another power loss-but a minor one-just 2.5 hp and 2.3 lb-ft down from the underdrive pulley test.

Unfortunately, there was no power gain from all that work, but there was no meaningful power loss either. After repeated dyno pulls, we concluded that at this power level and in their present configuration, the headers were a wash with the stock manifolds. Perhaps at higher power levels the headers would prove more helpful.

Open Exhaust
Because it fit our testing schedule, the next thing we did was loosen the dyno tie-down straps, and send Mike Galley under the car with an air chisel to separate the exhaust pipe downstream of the Y and upstream of the muffler. This was quick and easy to do-if a bit noisy-and would tell us how much total power was locked up in the muffler and tailpipe.

If possible, it's good to know how much power is hidden in a system. That way, when you do make some power with a new part, you'll have a good idea how much of the total was realized.

Besides a good bit of blatting exhaust noise from the mufflerless exhaust, we netted 176.6 hp and 198.4 lb-ft of torque from our experiment. That was 10.8 hp and 1.5 lb-ft better than the last test, and 22.3 hp and 5.9 lb-ft better than the baseline. It was definitely the sort of power increase that can be felt in the real world. Now, if we could retain even just a third of the 11hp power increase with a mellow, street-friendly, dual-exhaust system compared to a totally mufflerless, tailpipeless, test arrangement, we'd be overjoyed.

Next, we wanted to see if the funky muffler-shop work had hurt us. So, the mangled Y-pipe was replaced by our junkyard dog. We were much relieved when the dyno showed a tiny-to-insignificant 1.0 lb-ft of torque gain and a 0.8hp loss from the previous Y-pipe test. That meant we could continue testing and comparing the numbers to come with the tests already run.

After the monkey motion with the Y-pipe, it was nice to revert to a simple after-cat installation .

The $566.90 Dual Exit System from MagnaFlow we used is a sano, stainless steel affair with two deceptively simple straight-flow-through mufflers and MagnaFlow's sharp-looking polished stainless tailpipe tips. The install followed standard Mustang practice and was accomplished with no surprises.

Back on the dyno, the MagnaFlow-equipped Mustang spooled out 170.4 hp and 194.3 lb-ft of torque. Sure, that's a loss from the nonexisting exhaust system we had just tested, but that was expected. Realistically, it was a gain of4.6 hp and a 2.6 lb-ft of torque loss from the header test, which was the last real-world configuration we had run. So, count on a modest gain from a good after-cat system such as the MagnaFlow, which uses straight-through mufflers and mandrel bends for maximum flow.

The other gain was a sportier exhaust note. It's louder than stock, but quiet enough for a daily driver because the system really doesn't sound off until the throttle is wide open.

At this point, our V-6 was wearing all the parts we had thrown at it so far and was making 16.1 hp and 1.8 lb-ft of torque more than stock.

Nitrous Oxide
OK, the usual bolt-ons gained some polite power, the sort that would give a little something extra for a daily driver Mustang. Reasonably quiet and not affecting driveability, the mods tested so far would be at home on any daily driver Mustang. Combined with another notch of rear-axle ratio, these mods could elevate a 3.8 out of econo ranks and into light street-performer status.

But to really put some get in your get-along, a little hiss of nitrous goes a long way. To see how a V-6 Mustang would respond, we had Venom bring one of its goof-proof, dry-manifold nitrous systems down for a try on the dyno rollers.

The Venom system offers an electronic control unit, which works in closed-loop with the Mustang's oxygen and throttle-position sensors. By varying the duty cycle of the V-6's injectors, it can control the nitrous mixture. It's full of safeguards to prevent overly rich or lean mixtures, too slow an engine rpm for nitrous deployment, and so on.

We tested the most basic Venom system-the VCN1000 kit. Brother's sells it for $699.99; it differs from the VCN2000 by not offering laptop or Palm Pilot tuneability. For a simple system, the VCN1000 would seem to offer all the street-jollies necessary, with minimal hassle and cost.

If you're looking to make power with your V-6, let's say nitrous will do the job. "Pilled" with purple anodized, 0.040-inch nitrous jet, we saw 232.5 hp. That's a 62.1hp jump and a leap right into the V-8 power level.

Even better news can be seen in the torque column. While people commonly reference nitrous' horsepower-making ability, the stuff does wonders for torque as well. On our test car, for example, torque jumped from 194.3 lb-ft at 2,800 rpm to 289.8 lb-ft at the same low rpm. We don't have to tell you a 95.5 lb-ft increase is something you'll definitely feel. That's approaching a 40-percent increase in power, after all. It's like getting smacked by a baseball bat, or what we'd expect from a good supercharger installation.

Going for Broke
Of course, with larger nitrous jets just begging to be installed, who's to stop at a mere 62hp gain? Certainly not enthu-siasts with a test victim strapped to a dyno-clearly our next step was fitting the 100hp nitrous jet. Unfortunately, at this point the data we can offer (due to operator distraction and what was ultimately retrieved off the dyno) differs from the straight science of one-change-per-test methodology. More precisely, for the test data we have, the stock throttle body was reinstalled and the nitrous jet increased to the 100hp size. Two changes, in other words-and in case you're wondering why, the throttle body was fitted in preparation of swapping it again for the 70mm BBK part, to determine what the larger throttle body might be worth at this power level.

So, with the stock throttle body and 100 hp worth of nitrous, we let her rip. But we ended up running into the detonation demon and suspected overtaxing of the fuel injectors. For the record, the numbers were 293.1 lb-ft of torque for a minor 3.3 lb-ft improvement and a 13.4hp gain to 245.9 hp. But with detonation in the picture, those numbers would definitely have been higher given normal combustion. It doesn't matter, however, as detonation and nitrous in the same sentence only ends one way-the expensive way.

Mass Air Meter
Our next piece of hardware was the Pro-M Univer mass air meter. This is an annular breathing air meter, meaning there is no central obstruction, so it is a free-flowing unit.

Naturally, once we heard the first hint of detonation on the previous test, the first thing we did was revert back to the 70hp nitrous shot. It took only a minute to swap the larger nitrous injector back to the 0.040-inch jet we first tested with.The stock throttle body was also on the engine at this point.

All hooked up, the Univer yielded 258.0 hp and 309.5 lb-ft of torque with the 70hp nitrous shot and stock throttle body. That's a tire-frying 25.5 hp and 19.7 lb-ft gain over the straight 70hp shot, so it looked as if the V-6 was ready for more air through the meter at this power level.

Without a datalogging system on hand, we can't say if there were any timing or air/fuel ratio changes associated with the Univer (both effects as possible, and probable, with an air meter change).

Finally, we came to the last test for which we have data. Again, we unfortunately have a two-change test here. The 70mm BBK throttle body went back on, as did the stock exhaust manifolds. For once we were figuring on a power loss with this test and we got it. The figures were 243.7 hp and 287.2 lb-ft of torque, for a loss of 14.3 hp and 22.3 lb-ft from the previous test. So, with what we figured was the better-breathing 70mm throttle body (but not proven at this power level), the stock headers were well behind the BBK parts. Even if you take the most conservative approach and say the larger throttle body lost 10 hp-twice what it lost way down at the 150hp level-the BBK headers are still worth approximately 5 hp and 10 lb-ft of torque combined with the nitrous

Sorting It Out
Do you really want a 100hp increase in your V-6? A dumb question for all you raging-hormone types. And if insurance premiums and V-8 costs in general have you pushed into a V-6 corner against your will, then-hey-fit all the parts as the budget allows, go to the strip, and squeeze till you sneeze.

What if your V-6 is a second car or the spouse's daily driver, and stuffing groceries around a nitrous bottle is an issue? Then we'd fit the cold-air kit, the underdrive pulley, and the after-cat exhaust. After everyone gets used to that, we'd sweet-talk the nitrous bottle into place. After that, it's simply a matter of eventually fitting the rest of the parts to support the 250 hp or more you'll have on tap.

Photo Gallery

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On the Dyno
StockCold-Air Kit70mm Throttle

Open ExhaustAfter-Cat

Nitrous OxideMass Air MeterStock Headers