992 gts Headers
Drifting
Joined: Feb 2016
Posts: 2,090
Likes: 739
I don't disagree about sport cats and a tune providing more bang for the buck. Stock ones for reference. 
When Formula1 entered the turbo V6 hybrid era, Mercedes actually started with a log manifold. Easy, reliable, and there was tons of other stuff to spend time figuring out. If any of you recall the first practice session of the first year of the current engine era, most of the teams didn't even make it one lap around the track.
Of course, once all the complexities of the controls required to make everything work together, Mercedes spent the time to design and develop a proper tubular header.
Drifting
Joined: Feb 2016
Posts: 2,090
Likes: 739
I had vector performance headers on my Carrera T and full Akrapovic cats and pipe. Until I adjusted the tune to work with the headers it only helped a little In the top part of the power band. Changing from a standard log manifold to tubes increases air flow Deffo. Look into it as I am sure a lot companies can give you advise In that area.
matt
matt
https://rennlist.com/forums/992/1309...l#post18327816
Race Car
Joined: Aug 2020
Posts: 3,657
Likes: 2,347
Thanks. Unsure of value of comparing a 992 flat boxer production engine with factory exhaust to a Formula 1 Mercedes V6 racing engine without factory cats or exhaust. But, I do trust the opinion of John Gaydos of SoulPerformance. He is an expert in the field who designs and sells headers as well as many other excellent exhaust products. The only dyno runs I am interested in are those comparing a 992 with factory exhaust and turbos to a 992 with factory turbos but with aftermarket headers. See Brosef’s comment in post 5 above. Now, I have seen those dyno runs for the 991.2 but not the 992. I assume there is a reason for that. John says there is little room for improvement over the 992 factory exhaust manifold until you upgrade the factory turbos….and one of the exhaust products he sells is 992 headers. John has most credible opinion on this issue IMHO.
Last edited by Fullyield; Sep 10, 2022 at 02:52 PM.
Racer
Joined: Jan 2021
Posts: 309
Likes: 158
From: Texas
When Formula1 entered the turbo V6 hybrid era, Mercedes actually started with a log manifold. Easy, reliable, and there was tons of other stuff to spend time figuring out. If any of you recall the first practice session of the first year of the current engine era, most of the teams didn't even make it one lap around the track.
Of course, once all the complexities of the controls required to make everything work together, Mercedes spent the time to design and develop a proper tubular header.
Of course, once all the complexities of the controls required to make everything work together, Mercedes spent the time to design and develop a proper tubular header.
The BMW B58 has a variant where the turbo bolts directly to the cylinder head. They sacrifice 15 peak HP for torque that arrives 100rpm sooner.
This why Im surprised that Soul claims their headers (with larger and longer primaries) reduces lag. But, maybe theres some magic with the merge collector? Would love to see a dyno.
Anyways, I expect the real benefit of headers on a 992 is sound.
Drifting
Joined: Feb 2016
Posts: 2,090
Likes: 739
Many companies went to manifolds integrated into the head for a number of reasons, but they kill high flow and therefore power. The mani integrated into the heads are basically log manifolds. They do save costs, weight, and reduce the time for engine warmup which reduces emissions and fuel consumption, all things OEMs like. But as everyone has seen on the B58 engine, the variant with a traditional head and exhaust manifold (non-integrated) has way more power potential. If the 991.2 manifold is 0% and a proper max performance header is 100%, then the 992 log manifold is like 60%-70%. It's like going from an old steel wheel to a cast aluminum. But you can still go better with a forged aluminum, or baller magnesium.
