maf sizing in +05's

Hey guys,

Here's my Holiday present to everyone. Our friend Kevin at Clevenger Ford parts here sold me a 08 Bullitt Mustang intake. From there I installed it on two different cars, an 05 and 06 Manual Gt, as well as taking it to C&L Performance to have it flow tested and to compare it to the stock airbox as well as their air intakes too.

First the fitment and installation. Very nice, but I wish I had an 07 to try it on as Ford redesigned the coolant hose routing on the 07 and newer Mustang GT's and I think that was the issue here. Not that it won't fit an 05-06, it will, but its just a tight fit with the two resinator boxes on the bottom of the Bullit air intake tube. I LOVE the airbox, it fits over the front of the cars headlights and seals to the hood completely isolating the airfilter from under hood air temps. The air filter is a non-oiled type as it reseambles that from an airaid system but it has a 4" opening and is around 9" long. The airtube itself if the factory plastic with two huge resinators below it which are there just to help quite the air flow. The MAF section is right around 81-83mm in diameter, just abit larger then the GT airbox. I've included photo's below so you can review it as well.

Tuning, needed or not? YES! I made the dyno runs like this, on the first car I installed the stock air box and ran it three times and then installed the Bullitt airbox and did the same. With both intakes I had the stock tune installed in the car. Sure enough wtih the stock airbox and tune it went rich down to the high 11's and low 12's like normal. When I installed the Bullitt airbox it went lean, very very lean, in the mid to high 14's. Yes, this intake requires a tune. Any tuner can verify this as well by looking at the stock Bullitt tune, which SCT has in their database, and noting that the MAF adjustments are different for the new Bullitt air box.

Power, how much did It gain? Since I had to tune for the Bullitt intake I did so with the 91/93 octane tune file so I could compare it with a C&L Racer intake tune.

First I stared with the car completely stock with the stock airbox and stock tune and made a surprising 269 rwhp and 285 rwtq, this is actually a little high but for a stock tune it is what it is. Most make 260-265rwhp and 280-285 rwtq.

Next I installed the Bullitt intake and my high octane tune adjustments and set the a/f around 12.7-12.9 and it made 280 rwhp and 305 rwtq at best, it made a few lower Hp numbers but these are the best.

Finally I reinstalled the C&L Racer intake and used the EXACT same tune as far as spark timing and commanded a/f goes and we made 288 rwhp and 308 rwtq.

So as far as dynotesting goes it shows that there is a definate gain over stock using the Bullitt intake but it does REQUIRE a tune because the a/f is very lean without one. Also the gains from the intake aren't as much as a normal C&L intake with tune.

The max number gains are only 11rwhp and 20 rwtq but the gains in the midrange are well over 15rwhp and nearly 30 rwtq at different points on the graph using the Bullitt intake over the stock one.

The gains of the C&L Racer over the Bullitt are right around 8rwhp and 3 rwtq and the Hp gains are mostly above 4000rpm's and there is a gain of around 7 rwtq over 5000rpms using the C&L Racer too.


Flow numbers Lee Bender of C&L Performance was nice enough to flow test the Bullitt intake to compare it with the stock intake flow numbers and of course the C&L Products too. The stock airbox maxed out at just over 551 CFM. The Bullitt waa huge improvement over stock at 823 cfm. The C&L 83mm Street intake with the " No tune Option" insert flows 885 and without the insert 997 cfm. Then the Racer with its 95mm housing flows more then a 1000 CFM.

I was there and helping with the flow testing and all numbers are unbiased and I stand behind them.

So in conclusion, the Bullitt intake will be a nice addition to any 05 and newer Mustang GT. The airbox is the coolest on the market, the airfilter is the un-oiled type for those of you worried about that, truly it means very little but either way. The fitment is a little tight but it does go. Horsepower numbers are right there with alot of other kits on the market like K&N, Airaid, and AEM. I'm sure I may be able to squeeze a bit more out of it too with some more mods on a car.

These tests were performed using the Diablosport Predator and my custom tunes.

Thanks, and happy new year to all!

Doug904.

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