Downpipes Upgrade, Worth it?

DetroitST · Jul 21, 2021

I've done a fair share of research and I have found a couple vendors who are making "upgraded" downpipes so my question obviously goes to, "Is it worth it?" As someone who maxed out a platform (Fusion Sport) prior to this one, I can say with absolute certainty there were a few "upgrades" that didn't do much or anything. Ultimately I love the ST but am getting bored in its stock form, I miss being fast. With my Fusion I was one of very few who did the things I did to my car but it came with a heavy price tag to be a guinea pig. I'm hoping with this platform we have a more refined upgrade path that yields consistent results. In a more conscious effort to be more efficient in my spending, I defer to this group's experience to point me in the right direction.

Assuming I want to upgrade the intercooler and do a tune, arguably two of the most sense making upgrades, are our downpipes a restricting factor? Are they restricting in stock form or at what point down the upgrade path do they become necessary to modify? Even on my Fusion I don't think they did anything and I had upgraded fuel system (XDI pump/injectors) and turbos (TurboRevolution). Please only chime in if you have upgraded your downpipes or can cite gains from a reputable source. I don't care for speculation and don't want a pissing match of emotions or opinions, just looking for experience and results.

Thanks in advance!

UNBROKEN · Jul 21, 2021

I picked up ~2/10 on 93 with SPD DP’s…IC and tune were already in place. Dropped down to 12.0’s-12.1’s. Then went E50 and dropped to 11.7’s

DetroitST · Jul 21, 2021

Did you happen to ever get a baseline stock 1/4 mile?

UNBROKEN · Jul 21, 2021

No…13.7’s-8’s is pretty normal.

DetroitST · Jul 21, 2021

Did you go with catted or catless and why? Thanks!

eec78 · Jul 21, 2021

No tuner will touch you if you're catless - and there's really no need

DetroitST · Jul 21, 2021

How would a tuner know or why would they care? The tune doesn't do anything to change emissions, if you run catless you manipulate the O2 sensor physically to bypass them. I don't see how it would involve anyone else, could you elaborate?

The difference between a pipe with nothing in it and a pipe with a honeycomb in it is very different in terms of air flow, if what is being said is there's a bottleneck stock, (and I'm basing this on my experience buying aftermarket catted downpipes) I would assume that bottleneck would only be partial alleviated by high performance cats and would be better alleviated by no cats at all.

So back to my original question, it sounds like Unbroken picked up about .1-.2 tenths in the 1/4 mile with catted, is it being argued that there isn't anything more to gain by going catless?

TMac · Jul 21, 2021

I think it depends on your goals. Intercooler and tune can put you into low-mid 12s. @UNBROKEN 's experience is 2/10s on the downpipes. Personally, (yes an opinion) due to labor costs, etc. I wouldn't touch the down-pipes unless I was also upgrading the turbos.

DetroitST · Jul 21, 2021

I was in the high 11's with my last car so I'd be happy to land there with this car. It does sound like it will take a bit more than just an intercooler and a tune, hence the purpose of this thread. If intercooler, and e50 tune would do it, I'd be happy to stop there then. Mixing fuel does suck I did it for a while before switching to straight E85 but it's manageable.

eec78 · Jul 21, 2021

DetroitST said:

How would a tuner know or why would they care? The tune doesn't do anything to change emissions, if you run catless you manipulate the O2 sensor physically to bypass them. I don't see how it would involve anyone else, could you elaborate?

The difference between a pipe with nothing in it and a pipe with a honeycomb in it is very different in terms of air flow, if what is being said is there's a bottleneck stock, (and I'm basing this on my experience buying aftermarket catted downpipes) I would assume that bottleneck would only be partial alleviated by high performance cats and would be better alleviated by no cats at all.

So back to my original question, it sounds like Unbroken picked up about .1-.2 tenths in the 1/4 mile with catted, is it being argued that there isn't anything more to gain by going catless?

Regarding the first part of your question - I would defer to Adam @ZFGracing as to why a tuner would care if you're running catless.......

UNBROKEN · Jul 21, 2021

With the available high flow cats for these things there’s zero reason to go catless. Single digit HP differences between the 2 and no hassles at all dealing with defoulers, crappy exhaust smell and emission crap.
SPD’s 5” body 400 cell cats flow every bit as well as FenFabs 4” body 300 cell cats. With the EPA crawling down everyone’s throat I’ll never recommend a catless DP…I actually wanna keep modding vehicles well into the future.

TMac · Jul 21, 2021

UNBROKEN said:

Well said. Unless you're running a full race vehicle (which is doubtful on an ST), keep your cats.

DetroitST · Jul 21, 2021

Thank you all for this info. Emissions aside it is good to know there's such little difference between catted and catless. So with the small gains we've talked about how's the install time and difficulty? Anyone tackle this in the driveway or is this a lift only install?

twin001 · Jul 22, 2021

Get an E-22 female Torx socket first. Driver side isn’t too bad, but the pass side is tough. Many have removed the stock heat shields off the cats for a little more clearance and others have loosened the transmission to lower one end for additional clearance. There is a VERY informative thread on this that is worth reading in its entirety.

https://www.explorerst.org/threads/spd-performance-downpipes.588/
anyone have pics of how you lowered the transmission?

ZFGracing · Jul 22, 2021

eec78 said:

If you are catless you will not be getting a tune from us. If you had a tune before and go catless you will no longer have our support.

Sent from my SM-N986U using Tapatalk

DetroitST · Jul 22, 2021

Thank you ZFG, that was informative. Does your reply here indicate you're back to tuning? I checked your website yesterday and there was a waitlist. While you're here, maybe you could chime in on the topic at hand? Are downpipe upgrades a necessary modification? Are they a bottleneck after a tune and intercooler upgrade? Getting the experience of one of the most reputable tuners would go a long way in this discussion.

BigRichard · Jul 22, 2021

UNBROKEN said:

Sorry if I'm misquoting you, but haven't you said in other posts that the .2 sec pick up was with DPs AND a 3" exhaust?

UNBROKEN · Jul 22, 2021

BigRichard said:

My 3” exhaust was me shooting for a particular sound. These things done need it at all. I’d fully expect to see the same gains with any exhaust.

DetroitST · Jul 22, 2021

So was the .1-.2 from the cat back or from the downpipes? Are our downpipes a restriction? If they are at what horsepower figure do they become a bottleneck? Maybe that's a better way to word it. Thanks.

UNBROKEN · Jul 22, 2021

I would attribute it 99% to the DP’s. The stock parts are a restriction as far as comparing them to a high flow cat. The rest of even the stock exhaust is wide open and even the stock sized dial exhaust will support the power levels myself and most others are at. Only a few might actually need a larger exhaust.

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Downpipes Upgrade, Worth it?

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