19 2011 5.0L Mustang BOSS 302 Intake

Alternative Auto took the time to recently install and test the new FRP; BOSS 302 intake on our own 2011 5.0L GT. We tried to do the most down to earth and conclusive test possible by re-baseline testing the car on our own DynoJet, and then simply install the new intake while the car was still on the dyno in a one day session. And tune accordingly if needed after the install. (which is unlikely being that these cars are now equipped with wide-band O2’s stock).

Our 5.0L GT has: our own in house 93 octane tune, Long tube headers, cat’d X-pipe, C&L air box kit, 4.10 rear gears, and a slightly looser stock TQ convertor. All of this got us 12.0’s@113mph in the ¼ mile at the end of the 2010 drag race season. This was achieved with a full weight car (just under 3900lbs with driver) and with 20in rims and tires on all four corners (a true street car in every sense). Throughout the 2010 season our automatic equipped 5.0L produced just over 390rwhp with all that is listed above done to the car. Comparable manual trans cars will usually put down about 415 to 420rwhp on our dyno.

When testing our own automatic car, and many other automatic trans cars on our chassis dyno – we always do our best to try to program the engine and trans management computer to lock the converter in whatever gear is as close to a 1 to 1 ratio (4th in the 5.0 car) and also set it up so that when going WOT on the dyno so that the automatic will not downshift into a lower gear. This produces the most accurate pulls from typically 1500rpm all the way to whatever redline happens to be on the particular cars on our dyno.

For whatever reasons our 5.0L car re-baselined a bit lower this summer during the test than it did in the summer of 2010. Either way we did make several base runs just prior to installing the new BOSS intake manifold.

After the new manifold was installed after only about two hours or so. We immediately started the car and began sneaking up on a full pull, after we insured on a couple of small pulls that the WOT air fuel ratio was going to stay where it was originally…and it did.

Basically we found that the new manifold suffered as one would expect in the midrange as much as 25 to 30ft lbs of torque depending on where you look at the curves from roughly 2500rpm to even as high as 5000rpms. This loss in mid range rpm, and potentially lower rpm’s had we tried it — is un-recoverable no matter what anyone says with tuning or anything at this point on this motor. The new manifold simply has shorter runner then the stock unit, and simply physics will tell you it can’t be fixed. Our Tune has already pushed the ignition timing as far as we think we can, and we chose not to go any further with it on our locally available 93 octane.

On the plus side the new BOSS intake gained as much as 25rwhp horsepower over 7000rpms. And possibly more as you get closer to 7500+ rpms. How much of this is usable for the average GT equipped with a 5.0 is to early to tell. Our car has a slightly looser then stock TQ convertor, combined with the big 1st gear of the new 6-speed auto, and the 4.10’s in the rear. After adjusting the WOT shift points a bit and extensively road testing, our car does feel better seat of the pants so far to some degree at very high RPMs as one would expect. And whatever losses there may be in the mid range doesn’t seem noticeable at all with our automatic setup using a slightly looser stock TQ convertor. Manual trans guys may feel this quite a bit more while short shifting and lugging around town.

As far as 1/4 mile results go – Not very impressive at all for the most part. Our 5.0L car only gained a small amount of MPH, and averaged about 113mph, to just over 114mph. But only managed a best ET of 12.09, never really beating the previous best of 12.08. On a good note the 12.08 was achieved in much colder 50 to 55 degree temps. Whereas throughout the 2011 season we never got a good break with the temps and always seemed to get stuck with temps well into and above the 80’s with more humidity. But the MPH is up over all, and I’m confident with much cooler temps that this manifold could prove to be about a 1.5 tenth increase, which we would hope to see a 11.9_ something out of this car.

But in conclusion; I really don’t feel this manifold is worth much considering the losses in low to mid range TQ you will suffer in the most usable range of all when street driving it.