metroplex

My 2007 GT manual still has the original factory Pirelli's (235/55R17) with the original 17" Bullitt wheels. I was thinking of eventually doing a blower install.


Will I need a new clutch and flywheel? I'm thinking twin-disc clutch? Any recommended brands?


Should I upgrade the front brakes to Brembos? They are still the stock sliding 2-piston calipers.


I have the stock exhaust manifolds, but mated to the Pypes O/R X-pipe and FR500S mufflers which sounds totally awesome with zero drone. Do I need shorty or long-tubes? I'm thinking with the blower that the stock logs should be sufficient.


The tires are 10 years old at this point, and it got me thinking of either going to 245 wide Michelin Pilot Super Sports on the 17" wheels. But will these provide enough traction for a blower? The GT500 came with 285s in the back but these might be too wide for the stock wheels. I looked at some wheel upgrades, and saw some staggered setups with 255s in the front and 285s in the back. Should I just go with new 19x8.5/19x10 wheels and Michelin Pilot Super Sports in 255/285 staggered setups?


The car is mostly driven on the street and for cruises/meets, with some drag racing and the random road course race.

sqidd

Read this:
http://departmentofboost.com/tech/boosting_3v.htm

At 450rwhp needing a clutch will come down to how you drive. But chances are you will need one.

Single disc is fine for anything under 650rwhp. You don't need a flywheel unless yours is trashed.


Brembo's won't do anything for you unless you put a lot fatter rubber on the front and you plan on making repeated high speed stops. The Brembo's advantage is not in over all power (they do have a little more though). Their advantage is that they dissipate heat a lot faster than the stock brakes so they can be used repeatedly, like at the road course. Most people with Brembo's don't need them.


Read the linked article.


If you're spending the money on wheels/tires go with a 10" wide square setup running either 275/295's or 275's all the way around. The Pilot's are fantastic tires, and quite pricey. If you're not looking to hand corners hard (unless you have had some high performance driver training you won't be cornering HARD) go with a much less expensive tire like a Nitto NT01. There are lots of choices though.


Just saw this, the Pilots are a great double duty tire. Definitely go with a 275/295 combo on 10" wide rims.

metroplex

Thanks!

Can the 07 GT work with 10" wide rims up front and still turn with 275s in the front? Americanmuscle shows that they recommend 8.5" wide up front with 255s (kind of like what the 07-up GT500 used).

sqidd

Yes, 10" fronts with a 275 are run all the time. In fact you can fit 11" fronts with 315's with a little trickery.

Read this:

There is a lot of confusion on how wheel offsets work, what wheels will fit, etc. I’m going to skip the tutorial on how wheel offset works and go straight to what offsets work with what width rims. This is not because I don’t think you should understand offset, it’s because I don’t feel like typing all of that. I recommend doing a google search on wheel offset and getting yourself familiar with how it works so you can figure this stuff out in the future.

I would also like to add that I don’t consider wheels/tires that stick out past the fenders or are even with the fenders right…..because they are NOT! Yeah, tires/wheels that are flush mounted with the fenders look cool, but there are WRONG. During semi hard cornering they will rub, period. And if they can rub, they are wrong. There is no excuse to have tires that can contact the fenders. You can run 315’s at all four corners with no rubbing if the wheel is offset correctly. Having 275-295’s that can rub, there is no excuse for.

There are a TON of “Mustang” rims out there that don’t fit! Do not just blindly take a manufacturers/vendors claims at face value. Research the fitment yourself and make sure you are getting rims/tires that fit correctly.

Here are the popular wheel widths and the offset range you want to run them in to fit CORRECTLY. Wheel diameter doesn’t matter:

Front:

There is a little more leeway with the front because the wheel/tire is tipped in at the top (camber) which allows the use of a wider rim w/ less offset than if they were perfectly straight up and down. Push these minimum offset numbers (the smaller of the two) at your own risk. Cars with 2.5deg+ of camber will be a lot more forgiving than cars running the stock 1-1.5deg of camber.

9.0” rim 33-38mm offset
9.5” rim 39-44mm offset
10” rim 44-50mm offset
10.5” rim 50-53mm offset

Rear:

9.0” rim 35-38mm offset
9.5” rim 41-44mm offset
10” rim 48-51mm offset
10.5” rim 55-58mm offset
11” rim 62-63mm offset

m05fastbackGT

I run 9.5" rims with 45mm offset square, both front and rear with 275-35-20" tires.. My car also runs the stock -1.1 deg camber..

So my question is.. According to the chart you posted, the max offset for 9.5" rims are 44mm.. However my wheel offset is 45mm, therefore would that be considered as being beyond the max recommended offset

07 Boss

All I can say is build from the ground up. Tires, wheels and suspension first. Then drive train and then the blower. I spent 4 years building a solid foundation before slapping the blower on my car.

You will probably need to upgrade the clutch.

A good set of pads/rotors, some braided lines and good fluid is all you will need for brakes. Tires tend to make a bigger difference in stopping distance than the actual caliper rotor combo unless you are stressing it with road or autox racing. i have stock brakes with EBC pads and rotors along with braided lines up front. I've never had an issue stopping.

Stock exhaust manifolds can/will work fine but remember, your motor is like a giant air pump. the more air you can flow through it the more fuel you can burn and the more power you can make. Headers are not necessary but they will help.

Tires are the most important choice you can make when modding your car. It puts everything else you done to the car to the ground and is usually the limiting factor in how fast you can go. Compromise can be hard as sometimes you have to give up more than you want. I have seperate street and track wheel/tire set ups because I got tired of the compromise.

metroplex

I saw a video of a 05 GT at the Norsdschleife course and midway through his brakes overheated. I recall hearing that this wasn't an isolated incident. Granted, I'm not going to Germany anytime soon, but I always thought it was because the stock brakes were undersized since they are also used on the V6?

My 2014 SHO's stock wheels are 19x8.5", 5x4.5" bolt circle, with 39mm offset. Out of curiosity, would these work on my 07 GT? The stock tires are 255/45R19 so they are going to make the car ride about 0.4" taller. I probably wouldn't go this route since the SHO is a daily driver and I wouldn't want to use aftermarket wheels.

sqidd

Not on a stock shortblock.

sqidd

Those are my own personal recommendations. But when you get up into the really wide stuff they are facts.

As far as your 1mm goes that is going to be down to what tires are run and how hard the car is pushed. All 275's aren't the same width. They vary as much as 10mm. And then there are varied heights. And there are varied shapes. On the street with the "right" tire 45 or 46mm is fine. On the track with the "wrong" tire and 45 or 46mm and you have contact.