Sponsored

Are headers worth it over just going catless + catback

K4fxd

Well-Known Member
Joined
Apr 2, 2020
Threads
122
Messages
13,482
Reaction score
12,301
Location
NKY
First Name
Dan
Vehicle(s)
2017 gt, 2002 FXDWG, 2008 C6,
Boosted and rotten egg smell = cats going bad. If you daily I would look at going with high quality cats, like GT500, Ferrari, Lambo or ???. If not a daily, remove them and live with the smell. Seems like the design pulls a vacuum and exhaust gets pulled into the cabin, most noticeable when at WOT. I extended my exhaust tips and it helped but I still get a cabin full of cat stink when I go WOT. No cats and this will be hydrocarbon smell. Might stink in the car even when not at WOT. Have not tested this so I don't really know.
Sponsored

 

Bob Lob Law

Well-Known Member
Joined
Apr 18, 2023
Threads
9
Messages
854
Reaction score
1,337
Location
417
First Name
Jeff
Vehicle(s)
'22 GT 401A ESS A10
I don't get any noticeable smell in the car at all with the windows up without cats. I do smell it outside or if I have the windows down when stopped and no wind.
 

JTM88

Well-Known Member
Joined
Aug 14, 2024
Threads
3
Messages
143
Reaction score
358
Location
Tulsa, OK
First Name
Jason
Vehicle(s)
'20 Mustang GT ESS G3/G4 PP1
Only reason I went catless LTH was because I have an ESS and was getting rotten egg smell when I drove hard.

After that I spent the next 4 months trying to find an exhaust combo that doesn’t sound like absolute dogshit.

As far as catless smell I only really notice it if I sit in the garage for a little bit after at startup, which I avoid
 

Sponsored

JTM88

Well-Known Member
Joined
Aug 14, 2024
Threads
3
Messages
143
Reaction score
358
Location
Tulsa, OK
First Name
Jason
Vehicle(s)
'20 Mustang GT ESS G3/G4 PP1
OP
OP

Truekrry

Member
Joined
Apr 23, 2026
Threads
4
Messages
18
Reaction score
1
Location
Louisiana
First Name
Kerry
Vehicle(s)
2018 A10 gt premium
if they melt
No cats and 93, horrible. No cats and e85, glorious!
u talking about the smell or gains I assume smell but honestly I never understood people saying 93 smells bad it just smells like a less stronger 87 to me which is just regular gas smell 🤷‍♂️
 

BullittBoy

Well-Known Member
Joined
Feb 4, 2026
Threads
1
Messages
78
Reaction score
116
Location
Annapolis
Vehicle(s)
2020 Bullitt-2024 F150-2002 Corvette Coupe
This is one of the better video's regarding bolt ons and what gains you might expect too see. Key here is doing the testing in as close to same environmental conditions as possible to get a better comparison. when I did my LTH w/cats, H pipe and tune on my 2020 Bullitt, I got almost 40 hp gains over the stock numbers. Bullitt has GT350 intake and TB and a 6spd manual, so some difference over a stock GT with the 10spd auto. Mine is tuned for 93, not E85, so i would have hit 500 probably with a E85 set up. Mine came out 485Hp/435tq. He also address' dynamic advance which can be a variable.

Every Mustang 5.0L Bolt-On Part Dyno Tested Back-to-Back! Intake, Headers, Ported IM, etc.
 

Sponsored

GregO

Well-Known Member
Joined
Mar 5, 2018
Threads
41
Messages
3,344
Reaction score
2,482
Location
Illinois
Vehicle(s)
S550 GTPP
Does anyone here run 87 in a mustang?
Not too long ago I pulled up to fuel up at Costco, premium was 6 something a gallon…. I put in Regular that day so I’d have some extra lunch money.
 
Last edited:

robvas

Well-Known Member
Joined
Nov 18, 2023
Threads
16
Messages
3,573
Reaction score
3,378
Location
MI
Vehicle(s)
2011 GT
if they melt

u talking about the smell or gains I assume smell but honestly I never understood people saying 93 smells bad it just smells like a less stronger 87 to me which is just regular gas smell 🤷‍♂️
87 smells the same as 93. Get out of your car and it's like you've been mowing lawns all day
Sponsored

 
 








Top