Modifications

[JollyWrench]

Interested to learn more, I have a Mustang GT 2015 Fastback Manual, Guard + Saddle

I have bought a Competition Magnaflow Cat Back X Pipe & A JLT CAI with a Custom Tune,

Wanted to know why the best Long Tube headers are, in regards to performance gains,

Also what's the best gear ratio to go with I've seen some around 4.5, although 4.1 is popular, any performance figure with each gear ratio?

How would I recalibrate the speedo?

What's the best Flywheel?

Any tips and mods to do for major performance gains? I want to keep it naturally aspirated ;D

Thank you In Advance!

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[bigb996]

I'm not as knowledgeable with the s550 but my 05 I had kooks headers and they were fantastic. You pay for them but they are of the highest quality. The 4.10 gears seemed to be the best for drag setups on the older cars but I'm not sure about the new ones.

A tuner will Allow you to fix the speedo by telling it your gears and wheels and such

 

[isedawishy]

The performance pack has 3.73 and it's a bit much due to high gearing in the trans. I'm going to end up with 3.31 down the road, but I'm FI. 3.73 may work out for you well if NA? I say they're a bit much and I use to have a fox body with 4.30s.

Whipple is the only one I've heard that have found a solution to correcting gear changes. They said they're expecting to release in the next couple weeks.

 

[Rubred50]

Stay with the 373s otherwise you will need to go to 5th gear in the 1/4 and loose time.

 

[JollyWrench]

Interesting, top speed isn't a major concern of mine, more interested in 1/4 mile and 1/2 miles is as far as it will go, it will be used for track days as well,

as for flywheels can anyone point me in the right direction?

I heard the MF comp gave the best performance gains for a cat back and it sounds so good and was compatible with most headers,

any other modifications you would suggest?

 

[JollyWrench]

Would the 2011 gears fit the S550? Both 8.8 and look very similar

 

[2015 Silver GT]

Stay with the 373s otherwise you will need to go to 5th gear in the 1/4 and loose time.

Just the opposite as those gears WILL have you shifting into 5th.

 

[krahooligan]

Stay with the 373s otherwise you will need to go to 5th gear in the 1/4 and loose time.

this is false.

3:31 is the longest gear. you will not need to shift into 5th. hell, im in 2nd gear and I can hit about 63 mph

 

[JollyWrench]

Any stats on this?
Gear Changes at what speeds, what RPM?

 

[isedawishy]

Would the 2011 gears fit the S550? Both 8.8 and look very similar

No they will not. Ford switched to the "super 8.8" in 2015.

 

[krahooligan]

Any stats on this?
Gear Changes at what speeds, what RPM?

the lower the ratio, the taller the gears.

in a car with 3:31 on launch, the car will feel "sluggish" because you will not reach the power band as fast as a car with 3:73. However, top MPH is increased with taller gears and you will not need to shift as much.

in a car with 3:73, your launch will feel snappier because your gears are shorter. It will feel like your car has more low end torque. the gears are designed to keep you in the power band. overall MPH will be decreased, but how often are you hitting top speed?

in 6th gear cruising at 70 mph, 3:31 gears will keep you around 1800 RPM (fact). good for gas mileage. not good for power.


in 6th gear cruising at 70 mph, 3:73 gear will keep you around 2400 RPM(estimated). Good for acceleration, not so good for MPG.

(EDIT) - 3:73 will have faster 1/4 mile than 3:31 by about 3 tenths of a second. 3:31 will out run 3:73 from a roll (done this at 60MPH. my car was in 3rd, 3:73 was in 4th)
both gear ratios have downfalls and benefits. you just have to decide what is better for you.

 

[2015 Silver GT]

These cars do not really respond to gearing much like the 2011-2014 cars. My 2011 went 11.2 N/A with 3.15's. Food for thought.

 

[JollyWrench]

What about 3.55?

 

[krahooligan]

What about 3.55?

it would be exactly where it sits in the ratios. right in the middle. usually people go for 3:73 or 3:31. I guess it would be a good compromise of both.

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