This is no ‘67! 2015 GT Auto premium, Ruby Red


Doing a play on words in the title here.
Many know my 2006 GT has a personalized plate that reads 67 Again.
Well the 2015 is quite different from the 2006, so the build title reflects this.

I had a 2017 Fusion sport that I bought in 2016.
This past spring I reflected on the fact that the Fusion had been stored the past three winters.
Basically being treated as a Mustang.
Well, that being the case, I reasoned that if I had two cars spending winters in my garage, I prefered it be two Mustangs rather than a Mustangs and a Fusion.

Post retirement, many now also know that I work at my cousin’s Ford dealership in Grand Falls.
Last fall, the dealership took this 2015 GT on trade in from a customer I knew well.
I knew the car had not seen any winter and been well cared for.
It was also relatively low mileage at 19500 km.
The dealership put the car away last winter.
When we took it out of storage in the spring, we gave it a place of distinction in the showroom.
After a couple weeks of this, and upon consultation with my wife, “We” traded the Fusion for this nice 2015 Mustang.

It is a premium GT, automatic, which my wife liked the idea of, in Ruby red.
It has all the creature comforts such as heated and cooled power seats, navigation and so on.
So it was a nice replacement for the Fusion, for road trips.
It was also bone stock, making it a nice car to personalize.
Above are a few pics of the car unmolested and in stock form.
It has black leather interior found in premium models.

The stock wheels leave a little to be desired and wear narrow tires for a sporting car in MHO.
So first mod was a set of Forgestar 19 X 9.5F and 19X11R wheels finished in Gunmetal.
I dressed these up with Michelin Super Sport treads in 265/40/19F and 305/35/19R sizes.
A few reasons for doing these sizes.
First they both maintain near OE overall diameter to keep speedo and tranny happy.
As well as maintaining reasonable ground clearance for future suspension mods.
The front width will also keep tram-lining on public roads relatively quiet compared to a square setup.
The original diameter of the OE 235/50/18 Pirellis was 27.2”.
Meanwhile the diameter of the new hoops is 27.4”.
Close enough for me.

Find bellow a few pics of the wheels and the car with them on.
No suspension yet.
These photos were taken after I put the wheels on on September 1st.
I took them on the 2nd while driving to Pickering to get more work done to the car by my friends at Dasilva Racing.
I needed the wheels to clear the Brembo brakes I was planning on installing.
I drove the car out there because I could not load it onto my trailer in short notice.
The 2015 in stock form sits lower than the S197’s and the front facia and splitter extend much further forward so I needed to revise my ramp setup.
I did not have time to do so in the couple days of lead time I had because my wife and I had plans for the labor day weekend.
Ok. So the mods I did were suspension, brakes, CAI + tune and an H pipe resonator delete.
All of which to set the car up for future HPDE’s, or track days.

It’s time now to reveal that I bought this car without as much as taking it around the block for a test drive.
I just knew it was a good car for me.
Well the first thing I noticed on the drive home after taking delivery was that, as the S197 before it, the S550 was also a good candidate for improvement in the suspension department.
I notice a vague, floaty feeling in the front end and steering.
There was also a not so vague bounciness in the rear suspension after driving through bumps or hollows.
The rear would rebound higher than its starting point.
I did not like this at all.
I knew right away springs and dampers were priority for me.

Because the S550 is low, as I described above, I did not want to slam the car.
My priority was to improve handling. The only way to achieve this in the aftermarket world is with springs, all of which lower a car.
My research led me to Steeda minimum drop springs which lower the car a half inch front and rear.
Also to BMR minimum drop springs which lower the car a half inch in back and 7/8” in front.
Both sets are stiffer than PP springs on Mustangs, so good start for handling.

Initially I was leaning toward Steeda but both Ted Lewchuck of Mustang Direct and Dasilva counseled against it.
They both stated they had done a few customer cars with these and the results were less than stellar.
Chiefly that it still left the car a little nose high, like they are out of the factory.
Both suggested Eibach Pro kit as an alternative.
I did not jump at this recommendation because I thought the Pro kit a little too low for my liking at 1.1”F and 1”R drop.
I spoke to Lewchuck about this at Atlantic Nationals in Moncton at his trailer display.
So I decided to go with the BMR because I did not like the front end higher than the rear look.
A little technical information on the spring rates.

The stock GT springs, which is what this non PP car was born with, are linear 160 lbs/inch front and 668 in the rear.
The PP springs are linear 165 front and 728 rear.
The BMR Min. drop springs, which I chose, are linear 170 front and 740 rear, with 7/8" and 1/2" drop respectively.
The Steeda Min. drop springs, the other consideration here, are linear 200 front and 750 rear with 1/2" drop front and back.

As you can see both the BMR and Steeda, being stiffer than stock or PP springs, will improve handling.
The BMR, being a bit softer of the two, will give slightly more forgiving ride, and in my opinion, a much better stance.
I don't have a picture of it, but next time you see a stock GT with same size tires front and back, have a careful look at the stance.
The wheel to fender gap is slightly larger in front. The Steeda springs would have carried that look.
Note: The PP cars mask this a bit by having taller tires in the rear. So despite the gap being smaller in the back too, the car looks flatter than a non PP GT.
The BMR springs address this issue by lowering the front a bit more than the rear, making the gap a fraction smaller in front.
This gives a classic Mustang or Muscle car look.

See bellow a few pics of the car with suspension done.
Like with all lowered cars, the roll center changes so sway bars become more important to keep the car flat during cornering.
Mostly for performance driving situations because for street driving, the stiffer springs are enough to keep the car flat.
For this car, like my 2006, I chose Eibach adjustable sway bars front and back.

A change to stiffer and lower springs works much better when paired with quality dampers with appropriate valving for the springs.
Here, to my own surprise, I did not go with Bilsteins.
There's basically two reasons for my decision, and I don't think there was a bad choice to be made.
Both my choices would have been good.
I went with the Ford Performance Track dampers.

Reason one is that Bilstein was very late to the party in releasing their B6 dampers for the S550.
Like late 2017 into 2018 release and even then they only released the rear shocks first and the struts came out later.
The full set has only been available for about a year or slightly more.
This made me wonder if the S550 was not important to Bilstein

On the other hand the FP dampers have been out since day one and I found plenty of positive feedback on forums.
They paired well with all aftermarket lowering springs, including Eibach, Steeda, BMR and of course their own FP track springs.
The only thing that kept me from getting the FP springs was their drop, the same as Eibach at 1.1"F and 1"R.

Second reason is I e-mailed Kelly Aitken, lead engineer at BMR, and to my surprise he responded.
Through a couple exchanges he assured me I would love the ride, handling and stance of the BMR springs, and that the FP dampers paired excellent with those springs.
In fact, he said when BMR do springs and dampers on their customer cars, their go to dampers are the FP track dampers.
A less significant coincidental bonus was that the FP dampers were a bit less expensive than the Bilsteins.
Approximately $150.00 on the set of four.

Note about the rear OE shocks on non PP GT's.
I found information on forums that they have too much or a lot of rebound built into them.
This is what causes the rear to rebound or bounce after hitting dips or bumps in the road, like expansion joints.
This is consistent with my experience.

A few pics of the springs, dampers and sway bars bellow.
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Car looks great, I enjoy the read and the thought process you took
to reach your decision. I have said on many occasions understanding your uses
and end desire helps a lot in which way to go.

Seeing the car this weekend it looks great, stance is on the money, the wheels really suit it as well.


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To round out the suspension build, I included Maximum Motorsports caster-camber plates.
This to have ability to dial in my alignment, but also to replace the rubber bushing of the OE strut mount with a spherical bearing, which resists deflection of the top of the strut in hard cornering.
I also did this to my 2006 and noticed much better steering response.

I also did the Ford Performance strut tower brace from the GT350 with the included firewall brace to add chassis stiffness.

Lastly, whereas the S550 is renowned for rear wheel hop upon loss of traction or spinning of the wheels, I did a few things to address wheel hop and to better secure the rear suspension cradle.
Upon advice from Kelly Aitken, again, I did the BMR cradle lockout and vertical link with spherical bearing at both ends.
This was buttoned up by replacing the rear toe knuckle bearings by ones from Ford Performance which are part of their complete track suspension kit, and I believe, although not verified, standard fare on the GT350’s.

A few pics bellow of these parts.
You will see the knuckle bearings before installation and the hole in the knuckle in which they go.


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I finished up with a JLT CAI and a Mishimoto resonator delete H pipe.

Deleting the resonator sheds about 30 pounds of weight and helps the engine breathe easier. This mod can net 8 to 10 rwhp on its own.
The resulting sound from the H pipe is about 10% louder but much throatier or deeper, like a classic muscle car sound.
I kept my OE mufflers because there are new noise restrictions at circuit Mont-Tremblant, where I go for track days.
I understand, according to Ted Lewchuck, that the limit is 85 decibels.
This was the result of long time complaints from home owners who have built homes near the track over the years.
The track has always invoked the fact that they were there first but the area is a popular resort destination with big money involved.
This likely means I can’t attend with my 2006 anymore.
I may do conservative axle back mufflers in future after I know more about the noise restrictions. Something like a street or touring option.
The car is really not loud with this current setup.
Barely more than stock.

The combination was good for a 26 rwhp gain, which on an automatic car is roughly equivalent to 32 hp at the crank.
Better yet there was clear torque gain down low. Nearly as much as the power gain.
The throttle response and shifting was also livened up by the tune.

Having driven the car there, I believe I got some old or less than optimum gas along the way. Likely at my last fill about an hour east of destination.
This was evident on the dyno where timing was being pulled from about 5000 rpm on up whereas it was adding timing bellow that.

They worked the tune to where it added timing all the way through, but it is not a maximized tune. We estimated leaving about 10 hp on the table due to the bad gas.

This is when I regretted driving the car there instead of trailering it. I have much better gas in my area at Shell with V-Power supreme. We discovered this last time I tuned my 2006 where a test with a 93 octane tune and racing fuel additive only garnered 2 hp over my 91 octane tune using my local gas.

So, a trip next summer on the trailer is already being planned for a re-tune with better gas. Likely will do 3.55 gears at the same time.
The car now has 3.15 gears and 3.55’s are an available factory option from Ford.
Pics bellow of engine bay before and after with CAI and H pipe underneath.
The resonator can be seen in a box along with other OE parts after removal.
It is about 2-3” thick, 5-6” wide by 30-36” long.
I’ve read some people on forums refer to it a the suitcase.
It’s kind of a good description.


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I forgot to mention the actual dyno results.
The car put down 383 rwhp and 367 rwtq.
On an auto car this is around 467 hp at the crank.
With better gas and retune it should approach Bullitt numbers, near 480 hp.
After attending the fall run this past weekend, I can happily report the handling goals have been fully met.
Suspension is comfortable but very stable and responsive.
Handling much better than S197 can achieve.
I love my 2006 for certain reasons.
But this 2015 now has equal admiration for different qualities.
I have the best of both worlds.