Muscle Mustangs & Fast Fords
Yo Ken! Technical Questions - February 2013
Strut Your Stuff
Do you know of a strut tower brace that will fit an '06 Mustang GT that has a Whipple Supercharger installed? I am not able to find one that fits so far.
Kirk, unfortunately you cannot use a strut tower brace with a Whipple supercharger and a stock hood, because there is not enough clearance. Steeda does make a brace that fits, but you will need a cowl hood for clearance. You might consider Steeda's Street cowl hood—it looks great and you will get the clearance you need.
Rollin' On 20s
My dad has an '06 Mustang GT, and he ordered the Forgestar 20x10.5 wheels in the rear and 20x9 up front. What are the biggest tires we can fit in the rear? The car is lowered with Eibach Proline springs. It is Procharged and putting 450 hp to the ground, so he needs a little more rubber.
Matt, the consensus for the '05-to-present Mustangs is 305/35 for the 20-inch rim. It does depend on how much your Mustang is lowered, but 1.5 inches seems to be the limit. Make sure your offset is not less than 50 mm or you could have tire clearance issues.
I have an '11 5.0L with a six-speed manual transmission. Since new, it has what seems to me to be excessive backlash in the drivetrain. It clunks badly, especially when down-shifting, if I don't give it enough gas—worse when running the A/C, as if because of the additional load on the engine. The Ford dealer tells me it's within spec.
Even if Ford won't fix it, is there something I can do to correct this? I've become pretty good at driving it so that the clunking is minimized, but I would really like to fix this if possible. I haven't had a car do this before.
Larry, I suspect your ring and pinion is out of spec. The pinion depth or carrier side clearance will cause excessive noise and/or clunking when letting the clutch out. It's unusual for your GT to be out of spec. Most manufacturers do a very good job in setting up the differentials. Either you insist Ford take apart and inspect your differential, or take it to a qualified technician, but it will need to be checked.
A gentleman suggested I remove the air chambers from the air intake tube on my Bullitt so I could better hear the throttle response, and control engine speed. I agreed with him at the time, but then I got to thinking about it. Since these chambers quiet the intake air stream, they must also make it smoother. It would seem that smoother airflow at the throttle body would be better. Is there a performance difference either way?
Hot Springs, AZ
Mike, you will not notice any performance loss by modifying your air intake. The factory air intake is designed for acceptable sound along with performance. It's a compromise between both performance and sound quality, leaning towards the sound quality.
Air going into the intake can be tricky, not only on how it gets in, but how fast also. Air speed is very important, as important as volume with a naturally aspirated engine. In your case, very minimal gains, if any, will be seen when modifying your air intake. You would be better off purchasing an aftermarket air intake. These kits have been designed and tested to get the most power out of the induction system.
I have used your magazine for help building my '88 notch since 1990. I am installing mini-tubs with the aid of your “Chop, Drop and Roll” series. Can you tell me where to get the offset lower trailing arms for the rear, as well as the mounting location for the lower mounts on the narrowed axle housing? I am building a tribute 10-inch-tire car and this will finish up my fabrication problems.
Thanks for any help you may be able to pass along, and thanks for a super magazine, teaching tool, and inspiration. I am putting a 557ci big-block and Powerglide in my '88 notch and hope to show it to you when finished.
Jim, check out Team Z Motorsports. It has everything you need to mini-tub your Mustang—the offset lower control arms, along with the associated components and tech info. A mini-tub install is the most economical way to go and will work great with your tribute car.
I'm working on an '89 Mustang with a 70mm turbo kit, 42-lb/hr injectors, MSD ignition, aluminum radiator, and a freshly rebuilt engine and trans. It has the stock computer and has not been tuned.
The car will idle but is running very rich. If you get on the throttle while driving it, the motor will blow black smoke and has little power. It only has a stock MAF sensor. If I put a 76mm 42-lb/hr MAF on it, will it correct the problem, or does it still need to be tuned to run with the turbo and larger injectors?
Steve, you absolutely need to get your '89 Mustang tuned. You do need to have your MAF calibrated for your 42-lb/hr injectors with your new 76mm MAF, and it will help, but tuning is a must with your combo.