Is the S550 Coyote output Really any different from the S197 Coyote?

[ATLalien]

So we all know the published numbers on the S550 and S197 motors:

2011/12 GT = 412hp 390fpds
2013/14 GT= 420hp 390fpds
2015 GT = 435hp 400fpds

However most of the dyno figures I've seen don't seem to substantiate the increase in published horsepower over the years. The RWHP/Torque numbers between the output levels seem to have a very similar range. Not something you would expect to see with the published numbers going up. On paper there's a 23hp difference between the 2011/12 cars and the 2015's.

You can find numbers between 360 RWHP up to 395hp for all 3 motors. Now most of us also know that dyno numbers can vary wildy; lots of variables affect the numbers, and different machines are calibrated differently. But even still, it would be reasonable to expect at least a few higher RWHP numbers on the 435hp motors and a few lower ones on the 412 hp for a even a randomly selected, somewhat suspect, group of internet dyno results.

The '11/12 Coyote motors were generally thought to be underrated by a healthy amount. The line from Ford is the '15 motors achieved higher outputs through use of Boss 302 parts from the previous gen. If this is true, it doesn't seem to have affected RWP output. What say you? Could Ford have massively underrated the original Coyote and just increased the published numbers without doing anything substantial to increase output?

I'll say upfront that this thread is only intended to provoke interesting discussion; I had seen all of the links below and more before buying my '15. I traded in my 2012 because I liked the new body, IRS, amenities, and knew I'd still have the same, great, straight line performance to boot (or close to it). Love my S550 regardless, but I wonder.....

Results on S197 Coyotes:
http://www.edmunds.com/car-reviews/track-tests/2011-ford-mustang-gt-50-dyno-tested.html

This one from C&D actually estimates the actual output of the original coyote at 435...
http://wot.motortrend.com/mustang-power-we-dyno-the-2011-ford-mustang-50-v8-and-37-v6-8060.html

http://www.mustangevolution.com/forum/f358/t304094/

2015 Coyote:

[ame]

http://***************.com/106/2015-ford-mustang-gt-power-increases-sct

http://www.mustang6g.com/?p=3369

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[Mustang1260]

435-412= 23 HP at the crank. Rear wheel dyno (inaccurate as all hell) gotta reduce by 20% for drive train loss... so now your at a difference of 19-20 rwhp. NO way you can find that difference in sample..way tooooooo many variables in rear wheels dynos, set up, temps, etc etc etc...

 

[ATLalien]

Understand the difference between crank and rear wheel and the associated line loss, but I would still expect to see a small difference between the highest RWHP of a 435 crank rated motor vs a 412 crank rated motor.

Personally, I suspect the lack of a difference is possibly down to some combination of:
1. IRS vs SRA: The IRS may have more line loss
2. There is less dyno data for the 2015's to date since they're new
3. The S197 Coyote was way underrated while the 2015 may be closer to published figures.

Just my own suspicions but still interested to see what others think

That's just my own suspiscion

 

[Trackaholic]

I think a statistical analysis of many stock dyno results would be necessary to determine if there was a shift in the average.

As you say, the numbers are close enough that the variability in dyno/environment is probably larger than the difference in performance.

-T

 

[blkandgud]

I think the 412 HP figures for the 11/12 were underrated, which is why there was no difference when the 13/14 hit.

The 2015 could have a slight tiny bump, but like someone else said, you're dealing with SRA vs IRS as well.

 

[Chameleon]

Yes it is different, lots of BOSS goodies. CJ cams I think as well.

 

[ATLalien]

Yes it is different, lots of BOSS goodies. CJ cams I think as well.

That's a cool view of the engine. More than a couple of those parts should increase hp, but it seems much of it doesn't hit the pavement?

 

[azsnake]

I think theirs A LOT left in this motor. No way all the upgrades to the intake, cams, change motion controllers etc etc equate to 435hp. I suspect Ford has quite a few bumps in this motor that will simply unlock via a different tune when Ford decided a bump is in order. In all reality the car hasn't been in the publics hands that long, and from what I heard the 2015 ECU isn't as easy to crack as prior units. Time will tell but I don't think 465-485 hp out of this motor via basic tuning and maybe some simple bolt-ons will be out of the question. I recall how much money I had to toss at my 98 Cobra to get 25-50RWHP...exhaust, CAI, pulleys, tune, etc etc. Finally I gave up and bought a centri SC. That's what I should have done from the get go, but these new cars are so potent......just waiting to pop the cork

 

[Sinister]

Understand the difference between crank and rear wheel and the associated line loss, but I would still expect to see a small difference between the highest RWHP of a 435 crank rated motor vs a 412 crank rated motor.

Personally, I suspect the lack of a difference is possibly down to some combination of:
1. IRS vs SRA: The IRS may have more line loss
2. There is less dyno data for the 2015's to date since they're new
3. The S197 Coyote was way underrated while the 2015 may be closer to published figures.

Just my own suspicions but still interested to see what others think

That's just my own suspiscion

Typically an IRS robs less power than an SRA.

 

[Five Oh Brian]

The same RWHP of the S197 & S550 is explained easily with a simple formula...

435 hp + IRS = 412/420 hp + SRA

Mystery solved; close thread.

 

[bobbyh]

I think a bunch of the "Boss" internal upgrades are more for durability/future power if anything. The Boss Mustang's were only rated at 444 over the 412/420 GT's. The Boss intake may be responsible for most of the difference.

I bet the 2015's extra HP isn't going to translate to performance due to the increased weight not the IRS; on a stock car.

 

[40calcobra]

Typically an IRS robs less power than an SRA.

Always heard it the other way around

 

[Todd15Fastback]

Always heard it the other way around

This! IRS has more drivetrain loss vs. Stick axle.

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