Are 325KW headers an upgrade?

[abuch47]

who does high flow converters that bolt between the hsv system?

 

[abuch47]

The 340 is a 2.5inch outlet.

also what the difference between 317 and 325?

 

[426Cuda]

The 340 is a 2.5inch outlet.

also what the difference between 317 and 325?

No difference in the headers. They are the same.

 

[426Cuda]

who does high flow converters that bolt between the hsv system?

I bought a set of bullet style cats and got flanges welded up to fit.

 

[lmoengnr]

The 340 is a 2.5inch outlet.

also what the difference between 317 and 325?

The mid section. 317kw version has the same mid section as an SS/SSV/Redline.
325kw version has the true 2.5" mid section.

 

[panhead]

who does high flow converters that bolt between the hsv system?

Everybody....


At least everybody in the exhaust game who knows their business can knock up a set.




.

 

[rognvald261]

who does high flow converters that bolt between the hsv system?

There are a few threads here detailing the optimal downpipe from the HSV headers and cat dimensions, price, etc., to the stock catback flange.
Worth also looking at the argument for relocating that catback flange in favour of a proper tuned secondary / cat position (also available via search).
Sourcing the 4” spun steel Chinese barrel cats is easy, the dimension and form of the downpipe from header merge flange extending pre-cat (secondary) depends whether your tuning target is skewed to HP vs torque.
Be careful bolting on high HP bits requiring fine tuning, there’s always a trade-off, so without a custom tune mods like this may result in poor overall performance.

 

[blackve76]

'Decent price' is up to you to decide... I think it's too much, as the cats are basically worthless, but that's only my opinion.

Get about $40/50 per cat at scrap joints (ring around).

Personally for the effort of changing etc look at a good set of headers, if $$$ a concern some wreckers have heaps of crashed commodores with quality systems for reasonable $$$

 

[abuch47]

There are a few threads here detailing the optimal downpipe from the HSV headers and cat dimensions, price, etc., to the stock catback flange.
Worth also looking at the argument for relocating that catback flange in favour of a proper tuned secondary / cat position (also available via search).
Sourcing the 4” spun steel Chinese barrel cats is easy, the dimension and form of the downpipe from header merge flange extending pre-cat (secondary) depends whether your tuning target is skewed to HP vs torque.
Be careful bolting on high HP bits requiring fine tuning, there’s always a trade-off, so without a custom tune mods like this may result in poor overall performance.

I have read through those and picked up the full hsv system to sort me out for the mean time. According to those the try y (4-2-1) design was better than 4-1 but the stock collector and cat position is flawed. He who shall not be named believed 180° equal length headers were the best for the LS firing order and he has publicly stated $6k for a system from himself.

I love the idea of 180 degrees but finding someone who can make that and perfect everything else would be hard pressed and I'd probably ask the pirate.

 

[rognvald261]

I have read through those and picked up the full hsv system to sort me out for the mean time. According to those the try y (4-2-1) design was better than 4-1 but the stock collector and cat position is flawed. He who shall not be named believed 180° equal length headers were the best for the LS firing order and he has publicly stated $6k for a system from himself.

I love the idea of 180 degrees but finding someone who can make that and perfect everything else would be hard pressed and I'd probably ask the pirate.

Just saying the importance of the bit between end of primaries and catback is worth reviewing.
Dirk is on FaceBook BTW, has a group called All Motor Legal.