Hi All,

What brand hi-flow cats do people recommend. Is a 2.5" a good size and what about the cell count, is 200 ok? For those with hi-flow cats, how much were they installed? Also, since I already had an SKR tune, do I really need another one after fitting the cat? I am planning to fit straight oval tips as well with the bumper cut on the outline.

Cheers all.

Not worth the extra time and $ of retune. You *may* be able to grab and extra 1-2deg up top under load if that. 200cpi is the norm for street legal hi-flows. 100cpi is available but check with the mfgr re emissions compliance. 2.5 or 3" will suit a 3.5motor. I run a 3" 200cpi metalcat on my SC'd AWD if that's what you're wanting to hear. I got it at trade and fitted myself. Typical rrps vary considerably from $200-$450 so shop around. A magna cat change is pretty straight forward but takes a bit of time as flanges need to be cut, cleaned and rejoined.

Just to add 2c, I got a Magnaflow 200cpi 3" cat Supplied and installed on the TR for $260, inc flanges and gaskets. Not bad at all

Are the 2.5 Magnaflow 200 cpsi on ebay a reliable source? and good price or should they be avoided? Anyone know.

Are the 2.5 Magnaflow 200 cpsi on ebay a reliable source? and good price or should they be avoided? Anyone know.

Got this for about $165 off ebay and fitted for $50.

http://i576.photobucket.com/albums/ss201/hookupoz/DSC01778.jpg

Part # 54309M 3" IN/OUT 15.25" LENGTH
• 100% Stainless Steel Construction
• 200 Holes per Square Inch Catalyst
• Polished Oval and Round Heat Shielded Catalyst
• Bullet Style Spun Body Catalyst for optimal fitment

every one with hiflow cat, do they change your exhaust note at all?

Not on mine it didnt

every one with hiflow cat, do they change your exhaust note at all?

it did with mine, it made it the note deaper and louder up top in the rev range

Dont mean to hijack Vlad but just thought of this while I was reading this thread...

I currently run a 200cpi (at least thats what they told me) on my blown 3L. I'm slowly getting it ready for engineering and want the emissions to be less than stock, or about the same. Would it be difficult to run two cats on the exhaust and should this help reduce emissions? Or would it just be easier to replace my current cat with one with a higher cpi count?

As for a retune I wouldnt bother. If you're running a stock exhaust 2.5" will be fine and cost wise a few years back I got pacemaker headers, hi flow cat, canon and pod installed for $1200 so it pays to shop around :)

about the best advice i can give you is to have a very conservative power tune when you go for engineers, make sure the cat is in good condtion and reduce psi infavour of a leaner tune.

2 cats will work provided they are able to be heated, as thats how they work, stainless inside and out cats last longer at higher temps so it can be placed closer to the engine and this helps emissions. The further back inthe system the longer it takes to reach optimal remp.

Cheers for that :) I was thinking putting a very conservative tune, kick in the boost control solenoid (maybe down to say 5psi) and throw in an additional cat straight after the headers. Not too sure on whether I'll do the tune first as I'll try and make it legal so when I'm driving it if it gets pulled over to the pits its still alright. Hopefully will get some time off to talk to the engineer soon. Thank god emissions tests in NSW are free, just gotta travel for them :(