Sponsored

Ok… Question on bbk shorty headers

Mghoward74

Well-Known Member
Joined
Nov 21, 2018
Threads
5
Messages
352
Reaction score
305
Location
San Diego
First Name
Greg
Vehicle(s)
S550
There’s some contradiction going on here. If stock headers are the best, then why the need to modify them and the cats??
 

K4fxd

Well-Known Member
Joined
Apr 2, 2020
Threads
102
Messages
10,367
Reaction score
8,505
Location
NKY
First Name
Dan
Vehicle(s)
2017 gt, 2002 FXDWG, 2008 C6,

K4fxd

Well-Known Member
Joined
Apr 2, 2020
Threads
102
Messages
10,367
Reaction score
8,505
Location
NKY
First Name
Dan
Vehicle(s)
2017 gt, 2002 FXDWG, 2008 C6,
If you look around you can find many dyno graphs.
 

Sponsored

GT 550

Well-Known Member
Joined
Sep 4, 2017
Threads
31
Messages
2,076
Reaction score
1,756
Location
Australia
Vehicle(s)
Black GT MT S550
There’s some contradiction going on here. If stock headers are the best, then why the need to modify them and the cats??
Folks aren't necessarily saying that stock headers are THE best, it's that they're the best bang for buck by a fair margin on a NA car. IIRC apart from manufacturer claims there's not a lot of evidence (any?) via back to back dyno comparisons, race times or proper back pressure measurements that the relatively high cost of aftermarket headers - I'll throw in exhausts here too - is good value. For example most people probably couldn't tell you with any degree of certainty exactly where and by how much the stock exhaust is a restriction but they're happy to spend quite a bit of coin removing or modifying it.

It's not unlike CAI in that many folks rushed to put one on their car only to find that actually the OEM one is pretty good and is a lot less hassle/cost. Again, YMMV.
 

K4fxd

Well-Known Member
Joined
Apr 2, 2020
Threads
102
Messages
10,367
Reaction score
8,505
Location
NKY
First Name
Dan
Vehicle(s)
2017 gt, 2002 FXDWG, 2008 C6,
So no flow bench data or anything tangible to be able to back that up, in other words you have no proof.
Still not sure what you are going on about. It is pretty well documented the 18 up manifold is better in the high RPM area. Properly porting it will only make it better.

Still won't gain you any low end torque.

Seems like you have a pretty big chip on your shoulder for some reason.
 
Last edited:

WildHorse

N/A or GO HOME
Joined
Jun 28, 2017
Threads
216
Messages
8,471
Reaction score
6,536
Location
Home World: CLASSIFIED
First Name
ⓇⒾⒸⓀⓎ ⓈⓅⒶⓃⒾⓈⒽ
Vehicle(s)
'17 S550
Vehicle Showcase
1

Idaho2018GTPremium

Well-Known Member
Joined
Nov 20, 2018
Threads
20
Messages
1,506
Reaction score
1,312
Location
Idaho
Vehicle(s)
2021 Camaro ZL1 A10
I saw a before and after Dyno where the only change was from stock headers to shorty headers, and the gain was something like 1-2 hp. In other words, negligible. I can’t remember the source. I think there was a slightly larger torque increase but still single digits. You can have more hp difference between two back to back runs with no changes. Plus; to install the shorty headers you have to cut the cat off on one side of the factory header, install the shorty header, tack weld the car in place, then take it all off, weld it all the way around to the shorty header, then reinstall. Completely not worth it.
 

Sponsored

CorvZ061

Well-Known Member
Joined
Sep 9, 2020
Threads
18
Messages
407
Reaction score
392
Location
Oxford, Ga
First Name
Travis
Vehicle(s)
2022 GT
Still not sure what you are going on about. It is pretty well documented the 18 up manifold is better in the high RPM area. Properly porting it will only make it better.

Still won't gain you any low end torque.

Seems like you have a pretty big chip on your shoulder for some reason.

I'm saying there is a reason a lot of truck guys go to 18+ Mustang manifolds, because they're better. Flowbench says it moves more air at all air speeds. It's up to tuning at that point.
 

K4fxd

Well-Known Member
Joined
Apr 2, 2020
Threads
102
Messages
10,367
Reaction score
8,505
Location
NKY
First Name
Dan
Vehicle(s)
2017 gt, 2002 FXDWG, 2008 C6,
You are the expert.

WOT2.png
 

CorvZ061

Well-Known Member
Joined
Sep 9, 2020
Threads
18
Messages
407
Reaction score
392
Location
Oxford, Ga
First Name
Travis
Vehicle(s)
2022 GT
A Dyno graph of unknown origins doesn't prove anything. You yourself said a Dyno could be made to say anything.

The graph even showed you there's some trickery going on. The key at the bottom shows a date and time for the green graph and a red graph, yet there is no red graph.
 

K4fxd

Well-Known Member
Joined
Apr 2, 2020
Threads
102
Messages
10,367
Reaction score
8,505
Location
NKY
First Name
Dan
Vehicle(s)
2017 gt, 2002 FXDWG, 2008 C6,
Believe what you want.
 

K4fxd

Well-Known Member
Joined
Apr 2, 2020
Threads
102
Messages
10,367
Reaction score
8,505
Location
NKY
First Name
Dan
Vehicle(s)
2017 gt, 2002 FXDWG, 2008 C6,
Even the dude who does the y tube vids from Lund likes the 17 gt manifold on a street car better than the 18 manifold. At least on a gen 2.
Sponsored

 
 




Top