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Started by Randy Stinchcomb, October 30, 2016, 08:44:28 PM

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Randy Stinchcomb

2015 X-Sport, haven't stuck a Vacuum gauge on it yet but how many PSI iz stock?

This iz my 1st "street car/truck" with Turbos, so boost iz important to make HP/TQ. I sea where they make aftermarket exhaust that are 2.50" vs the factory 2.25", now I know it's Only a 1/4" difference but does engine boost relate to backpressure?
So if by increasing the exhaust pipe diameter promotes better exhaust flow, will it hurt or cut into boost pressure?

Sorry, just trying to justify  $1500.00 or so for exhaust


sholxgt

Stock boost varies from 10 to 14 psi depending on multiple variables.

There is NO justification for an aftermarket cat back other than sound and bling.  It will not decrease or increase boost.  The ECU has complete control and it will hit targeted torque demanded and use the amount of boost required to do so regardless of exhaust systems.

Downpipes do more than the cat back and still the only real gain is potentially getting into boost sooner.  I have catted PPE downpipes and have no complaints, but the power gain is negligible/possibly zero.  Tune and fuel choice will do more than anything else you can modify.
Current - 2019 F150 Platinum FX4 3.5 EB
Formerly -2013 MKS Ecoboost Premium
PPE Catted DP's, 170 Reische TS, K&N Drop In, AJP Tune only at track - 12.87@106

derfdog15

As said above, catback will do nothing except add ear candy/eye candy. Downpipes will allow for boost to come in quicker, but will not really be beneficial on the stock tune (negligable benefit).

On an aftermarket tune, however, you will see nice gains with the downpipes as you can increase the boost targets, change how boost comes on, and utilize boost being available at lower RPM. 2.5" downpipes allow for a much better spool than the stock ones.
2015 Tuxedo Black SHO PP -(SAE corrected): 369.4/451.4 - Gone to the automotive graveyard but not forgotten

2016 F150 FX4 Sport - 3.5L V6 Ecoboost - Stock for now

2003 Redfire V6 Mustang - Building to be an 11 second car

Randy Stinchcomb

Ok, so then you can bolt-up the larger 2.5 dp to the 2.25, that makes things more doable, $$$ wise.
Now next question, if I do that, iz there any need to cut in an X pipe into it aft of the cats?

sholxgt

I'm not familiar with the exhaust on the X-sport, but on my MKS there is a third catalytic converter immediately after the downpipes that acts similar to an x-pipe.  Also, the diameter of the 2.5" downpipes matches the diameter of the piping on the third cat.

I see very little room for improvement over the stock exhaust.  It is fairly large and has acceptable bends.  I'm not surprised by the dyno results that show practically no gain with cat back exhausts for the MKS/SHO, but maybe the X-sport is different?
Current - 2019 F150 Platinum FX4 3.5 EB
Formerly -2013 MKS Ecoboost Premium
PPE Catted DP's, 170 Reische TS, K&N Drop In, AJP Tune only at track - 12.87@106

derfdog15

2.5" downpipes will bolt up no problem to stock set up.

For the exhaust (on the SHO), stock has a cat on each downpipe, then a third cat on the midpipe portion(dual in dual out) and then the stock resonator (dual in dual out), then goes to the back. Not sure on the explorer sport if its the same, as the SEL taurus with 3.5L and AWD only get dual pipes at the rear and have a single pipe for midpipe, no clue if your explorer is truely dual or not.

Either way, if you want a little more growl, you can cut out the 3rd cat, and resonator, and replace that section with an X pipe. I left my 3rd cat, due to not wanting to tune for it/shop not wanting to cut it out, and it still sounds nice with the resonator replaced with an X pipe, and Summit Race mufflers in place of stock.

But, stock, there should be a resonator (which is basically a muffled X pipe, and the 3rd cat) if you have a true dual setup
2015 Tuxedo Black SHO PP -(SAE corrected): 369.4/451.4 - Gone to the automotive graveyard but not forgotten

2016 F150 FX4 Sport - 3.5L V6 Ecoboost - Stock for now

2003 Redfire V6 Mustang - Building to be an 11 second car

hawkeye93

Explorer Sport has dual exhaust with 2 cats, one on each downpipe.  There is no third cat on the Explorer.
2015 Ford Taurus SHO PP 12.219@112.84
PPE catless DP, Gearhead IC, SP-534, Reische 170, 3 bar, hybrid meth system, tunes from Unleashed, Livernois, Brew City Boost & AJP

1965 Ford Mustang Convertible 289 4V/T5Z/3.55
1955 Ford Fairlane Club Sedan 272 4V/Fordomatic

Randy Stinchcomb

Right, its a true dual exhaust system and the mid pipes run side-by-side for about 4' and looks like the perfect place for a X-over. Well I think it's doable and as stated above the rest of the exhaust iz done well, 2.25 thru out and no sharp bends.
One thing I've noticed about Fords over the last 15 or so years, Ford can build sum pretty good exhaust systems when they want to ie: Shelby, Cobra, GT, Lightning, RS, SHO