Ecoboost Performance Forum

Ecoboost Performance => Performance => Topic started by: Gray Brick on November 15, 2015, 10:11:15 AM

Title: Exhaust restriction
Post by: Gray Brick on November 15, 2015, 10:11:15 AM
Has anyone tested where the restriction is on the Ecoboost 3.5 exhaust?

I have non-catted 3" downpipes and want to know if the 3rd cat, resonater, or mufflers are the next bottleneck.

When I say tested I am referring to installing a pressure gauge between each of these items.

Title: Re: Exhaust restriction
Post by: ZSHO on November 15, 2015, 10:50:23 AM
The 3rd cat and resonator are not as restrictive as most people might think as oppose to the mufflers which is somewhat more constricted out of the bunch,followed by the 3rd cat.  Z
Title: Re: Exhaust restriction
Post by: Gray Brick on November 15, 2015, 12:35:21 PM
Is there any data to back this up?

Most to least restrictive; mufflers, cat, then resonator.
Title: Re: Exhaust restriction
Post by: ZSHO on November 15, 2015, 02:54:46 PM
Quote from: Gray Brick on November 15, 2015, 12:35:21 PM
Is there any data to back this up?

Most to least restrictive; mufflers, cat, then resonator.
Data is a big question mark.  Z
Title: Re: Exhaust restriction
Post by: CroR1 on November 15, 2015, 03:35:36 PM
I highly  doubt any company will go through so much to record such information for SHO. As it has been proven time after time that an aftermarket exhaust after cats adds about 3hp in general on the v8s. I can't see the 3rd cat netting more than  3 hp on the SHO. And if someone would ask me the question if it was worth over $1000. I would say not to me due to loudness of the exhaust tone that I would have to live with  every day.
Title: Re: Exhaust restriction
Post by: Gray Brick on November 15, 2015, 07:57:17 PM
3hp on a stock V8 I am assuming.
Title: Re: Exhaust restriction
Post by: Gray Brick on January 05, 2016, 11:59:10 PM
I should have some info soon on the exhaust backpressure testing.
Title: Re: Exhaust restriction
Post by: QuickSilver on January 06, 2016, 03:49:52 PM
I did my downpipes and exhaust all at the same time so not sure which helped more but it was a huge improvement in spool up response and power production.  As you know Brick, turbo vehicles get a much bigger power gain by reducing backpressure than a NA motor does. On other turbo projects I've seen the boost go DOWN and the power still goes UP when getting away from a restrictive exhaust system.  I'll be interested in your backpressure results, some of the guys on the turbo-mopar boards are doing testing of backpressure pre-turbo to help select the right size hot side of the turbo.
Title: Re: Exhaust restriction
Post by: Gray Brick on January 07, 2016, 12:36:08 PM
Quicksilver,
What exhaust did you go with?
Title: Re: Exhaust restriction
Post by: QuickSilver on January 09, 2016, 06:22:17 PM
I had my exhaust guy build it  from the parts I collected, a couple sticks of 304 SS from Jegs, dual 2.5 IN/OUT flowmaster, some mandrel U bends,  couple 2.5" strait thru resonators also from Jegs.  It's perfect, except for 1900-2100RPMS, the  dreaded drone under load.  So if I'm going less than 80MPH on the highway, I'm in 5th :-[


Tried to load a pic, file size too large. Most forums I belong to resize automatically. No wonder I don't load pics here >:(  I know there's pics on the 5th Gen Explorer forum of serious explorations, I'm sure you can search my posts with just a couple clicks there.
Title: Re: Exhaust restriction
Post by: SHOdded on January 09, 2016, 07:08:50 PM
AJ, the only way currently to get pics on here is to embed an offsite link to the pic (whether it's Tapatalk or Photobucket or Flickr or ...).  So there shouldn't be a size restriction, but if you want to PM me the link, I can take a look to see what the issue might be.
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