Downpipe ONLY gains?

[naterizzle]

I’m curious what kind of performance gains can be had from ONLY a GESI catted downpipe like the AA or AMS? I want max reliability, no CEL ever. What kind of gains can be expected with just that single mod on stock ECU? Also, how much more sound with stock exhaust? Thanks in advance!

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[Avarela99]

Minimal performance or sound with everything else stock… and definitely not $1400. I would go armytrix catless personally it’s way cheaper def more sound and no CEL

 

[CortC]

AA catted downpipe with a good flowing exhaust like the AA or Magnaflow will get you about 14-18 HP once the ECU adapts...

 

[RyanA90]

I have intake and DP but i doubt the intake adds anything especially without a tune...

https://www.supramkv.com/threads/ryan’s-‘23-a91mt-burnout-slow-build.15409/post-264648

 

[Axix23]

10-15whp at least

 

[Fuji808]

I’m curious what kind of performance gains can be had from ONLY a GESI catted downpipe like the AA or AMS? I want max reliability, no CEL ever. What kind of gains can be expected with just that single mod on stock ECU? Also, how much more sound with stock exhaust? Thanks in advance!

< 2 lbs.

 

[Extreme Power House]

I recommend the Active Autowerke catted downpipe; it's proven to work with no CEL.
Cold start and wide open throttle are noticeably louder than stock
regular driving is almost unnoticeable unless you are a car person.
The car sounds sportier but not obnoxious with downpipes, as it should have sounded from the factory.
It also has a higher flow than stock, providing an additional ~20whp increase in power.

 

[Awales74]

IMHO you'll want a tune to go with it to make it make sense dollar and cents wise. There's a measurable (dyno, dragy) but butt dyno won't notice much (it's hard to notice < 10% gains). A JB4 with just the regular mappings at first can leverage it. And you have a fun mod path to follow; tune, flex fuel and mile e30 tune, meth or LPFP and tune, etc.. You'll never make the big numbers the guys going with the full tune, big turbos, rebuilt motors etc.. But those guys are on a whole other plane of commitment. With the catted dp and jb4 you can work your way up into the 500hp land a few hundred dollars at a time.

And please, keep a cat for a daily driver. If you get AA for 1400 and then sell your OEM cat to the recycler for 700 then you're having a bit of fun for 700 and helping to keep you city clean

 

[DGINR8supra]

My 2022 auto with downpipe only no tune was really good/ fun. Ran 11.62 @ 120mph. Traded in that for a manual 2023 and dynoed downpipe only no tune was 408whp/402whtq

 

[B58_ hwAyaq]

Dragy gains on a 2020: https://www.supramkv.com/threads/cg-precision-ds-1-catted-downpipe-only-log-review-dragy.13284/

Short answer: minimal gains. If you want sound with stock-like reliability, just get a catback, especially for as much as high end catted DPs already cost.

 

[bushido]

I’m curious what kind of performance gains can be had from ONLY a GESI catted downpipe like the AA or AMS? I want max reliability, no CEL ever. What kind of gains can be expected with just that single mod on stock ECU? Also, how much more sound with stock exhaust? Thanks in advance!

using different diction to help provide a more straight-forward answer

no CEL ever - need a 400 cell, which is AA. deeper exhaust tone, louder pops, but in everyday driving it's practically unnoticeable.

however, it's hard to justify its $1400 price, for practically no gains anywhere. stock vs AA DP, you're about half a car faster

i've heard several people, from several regions, use the Armytrix catless DP with a 'cat simulator' that have thousands of miles on it and no CEL. for $600 and from a performance perspective, this is the better choice, imo

i believe there's a video on youtube of catless DP vs stock, it's more than a car faster

 

[DrSupra]

Not answering OPs question but it is definitely one that I have had and so I appreciate the responses here, and am hoping to just add the question of:

Is any reliability lost with the ECU needing to adjust and remain adjusted to a catted or catless downpipe? I imagine any change in reliability would be extremely limited, but also don't know! I saw a catback recommended to get more sound but I'm thinking that a catted downpipe could potentially be harder to spot by a dealer during routine maintenance and maybe easier to remove if something went wrong (if I were to continue going to a dealer for service - I know that could be seen as a silly rationale, but still). I imagine the catback would be spotted more easily. Because I'd rather just avoid any dealership based nonsense, it's probably best for me to just leave it stock but the mod itch is getting me already.

 

[Awales74]

it's probably best for me to just leave it stock

I'm convinced warranties are the Rorschach test of car guys. There really is no wrong answer. And with your level of apprehension, I'd agree that it's probably best you leave it stock.

As far as long term reliability. Negligible to none. Less restricted flow, means more power, means more stress. But understand your car is designed to drive on the top of Pike's Peak and bellow sea level in Death Valley. The air density changes alone allow for similar variance in power. In other words, it's built and designed for it. As far as your ECU being smart and adjusting -- it's built to do this for the air density changes I spoke of, the slow deterioration of cat, etc.. So your not stressing the ECU out or anything like that.

But to say none is a bit rich. But for the small sample size (your one car) you won't know if a failure was caused by a lead foot, car gods, or this particular mod. You won't blow a trany 20k miles from now and say "oh snap, i shouldn't have gotten that down pipe"

As far as what the dealership notices or what not. That's a crap shoot either way. Sometimes they care. Sometimes they don't. Sometimes they'll make stuff up because they don't want to work on the Supra/BMW. You can't ever tell what response you'll get from those guys. Only thing I encourage is to understand the law, understand your mod, be polite but persistent in protecting your rights.

 

[Meraki Autoworks]

Power gains posted above from AA's dyno graphs also on their site.

We're running a group buy on these downpipes, have 7 left.

-Josh

 

[Mr. Jonathan]

I’m curious what kind of performance gains can be had from ONLY a GESI catted downpipe like the AA or AMS? I want max reliability, no CEL ever. What kind of gains can be expected with just that single mod on stock ECU? Also, how much more sound with stock exhaust? Thanks in advance!

You'll gain about a half-a-cup

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