340 headers VF2

[dimetime]

Aftet having fitted the Roto-Fab CAI, and previously a Gen-f2 2.5" centre section I'm about to book my Motorsport in for a tune at Gentech in Canberra. At the same time, I will have the 340 headers fitted.
So, my questions are about the cats. I understand the VF2 cats are 400cell? But, it appears they flow quite well up to beyond 300rwkw, which is my upper target. I like the look of the stock cats and would.like to retain them if I can. Has anyone used these with the HSV 340 headers and if so, what were your results? What mods were required to fit them to the HSV headers?
Any advice appreciated.
Thanks all.

i believe the flanges dont line up, i couldnt see you getting around 300rwkws with a otr and any exhaust be it a hsv one or a quality aftermarket system. 400cell cats will be the main restriction, id consider just getting some 200cell cats made up if you are going to muck around with the cats anyway!

 

[lmoengnr]

Aftet having fitted the Roto-Fab CAI, and previously a Gen-f2 2.5" centre section I'm about to book my Motorsport in for a tune at Gentech in Canberra. At the same time, I will have the 340 headers fitted.
So, my questions are about the cats. I understand the VF2 cats are 400cell? But, it appears they flow quite well up to beyond 300rwkw, which is my upper target. I like the look of the stock cats and would.like to retain them if I can. Has anyone used these with the HSV 340 headers and if so, what were your results? What mods were required to fit them to the HSV headers?
Any advice appreciated.
Thanks all.

Been trying to find out details about the Euro 5 cats on VF2's, read somewhere they are 600 cell cats, but cant confirm it...
I have big Ballistic cats on the Maloo, same size as factory, in the same position. They flow well!
Will the 340 headers fit around the oil heat exchanger on the Motorsport?

 

[3rspecB]

Been trying to find out details about the Euro 5 cats on VF2's, read somewhere they are 600 cell cats, but cant confirm it...
I have big Ballistic cats on the Maloo, same size as factory, in the same position. They flow well!
Will the 340 headers fit around the oil heat exchanger on the Motorsport?

Pic courtesy from Supercoach. He fit 340 R8 headers to his motorsport. From memory he trimmed the header flange to allow more clearance to the heat exchanger.

 

[lmoengnr]

Pic courtesy from Supercoach. He fit 340 R8 headers to his motorsport. From memory he trimmed the header flange to allow more clearance to the heat exchanger.

View attachment 200497

Thanks for finding that pic, its very informative!
I had the Magnum on ramps, so I got underneath, and held up a 325 header without cat.
It looked like it would be 'really close'...

 

[426Cuda]

Thanks gents!
Ok, well if they're 600cpi, they've got to go.
@dimetime - I'm basing that on the gains I got in my VF Redline (L77 auto), with similar mods. It went from about 205rwkw stock, to about 260 with these mods and tune (inc 200 cell cats). The auto LS3 stock in the MSE seems to be about 245rwkw, so adding 55 should get me near enough to 300, give or take. I'll post up the results.
@Imoengnr are your cats 200cell? What rwtq & kw did you achieve? I'm assuming it's not cammed...are there any ground clearance issues with the Ballistics?
@3rspecB yeah, the pic you shared is before any trimming. So they do fit, albeit tight. So, I was going to grind off a couple of MM to allow a bit more clearance.
Thanks again blokes.

 

[3rspecB]

Yes before trimming. PM supercoach, I think he took pics of the trimmed flange, so you can see the clearance he achieved.

 

[lmoengnr]

@Imoengnr are your cats 200cell? What rwtq & kw did you achieve? I'm assuming it's not cammed...are there any ground clearance issues with the Ballistics?

They are 100cpi cats, on Sureflo headers. Same size and position as factory cats, no clearance problems at all.
Had to get a flange welded to the Maloo catback, to replace the factory swivel joint to mate to the cats.
With an OTR and tune, it gained 42kw, from 243 to 285, and enough torque to ruin rear tyres and make me spend most of 2013 as a pedestrian...

 

[426Cuda]

They are 100cpi cats, on Sureflo headers. Same size and position as factory cats, no clearance problems at all.
Had to get a flange welded to the Maloo catback, to replace the factory swivel joint to mate to the cats.
With an OTR and tune, it gained 42kw, from 243 to 285, and enough torque to ruin rear tyres and make me spend most of 2013 as a pedestrian...

Haha. Naughty, naughty, very naughty.

 

[lmoengnr]

Haha. Naughty, naughty, very naughty.

It must be LS3's, it was 4 months this year, driving a stock Magnum... But now my licence has zero points!

 

[Rikster71]

Well if anyone was interested in the update my redline ended up making 385kw with VCM OTR, 340 headers and 2.5" centre section and tune so pretty happy with that. Sounds great with bimodal fuse gone.

Hey Nico, just catching up on all these posts, great result, which cats did you use, an also what 2.5 mid section did you use, and im guessing that was into the standard bimodal cans