belfastboy0 Posted July 13, 2020 Share Posted July 13, 2020 My cats and y pipe were a bit worse for wear so snagged a Stillen y pipe from someone on here and Zmanalex hooked me up with some (we think) unbranded hfc for free since they had been badly bent... Anyway, I didn't want to keep my oem cats/y pipe and priced around different scrapyards. Received offers from £80 right up to £300 (which I took). That more than covered the cost of my replacement parts, but made me think even if anyone was just looking to swap to hfc, it could be done for very little money. ... Just in case anyone's on the fence and needs a nudge in the right direction 1 Quote Link to comment Share on other sites More sharing options...
davey_83 Posted July 13, 2020 Share Posted July 13, 2020 You might need them back if you cant pass emissions................. Quote Link to comment Share on other sites More sharing options...
SHEZZA Posted July 13, 2020 Share Posted July 13, 2020 I’ve considered selling mine a few times over the years but held on to them for that reason, just in case. As well as all the oem parts I’ve removed. Quote Link to comment Share on other sites More sharing options...
davey_83 Posted July 13, 2020 Share Posted July 13, 2020 Always good to have a plan b Quote Link to comment Share on other sites More sharing options...
msitpro Posted July 14, 2020 Share Posted July 14, 2020 To be 'safe' you need 2x HFCs in each side.... They might pass for a couple years but with very narrow margin. Thing is, even if you put in 4x 2.5" into 4-5" body HFCs in the Y branches, the flow is still waaaaaay higher than the ceramic stock cats and good for 1000hp in all likelihood before becoming more than a 1% bottleneck. I have 2 issues - I went the HFC route like you and couldn't pass with the ones I had installed without an additional HFC added after the Y. Initial tests were 0.37% CO, then right on the 0.2% CO limit after adding the third HFC. What I'll probably do is move that latter one to one side of the Y branch and buy another for the other side like I mention above. The other issue is the noise - because they're virtually unrestricted flow (very close to de-cat flow) the car is insanely loud. Not helped by my 3" single exhaust. Might struggle for track days, which is my immediate issue. Quote Link to comment Share on other sites More sharing options...
belfastboy0 Posted August 27, 2020 Author Share Posted August 27, 2020 On 13/07/2020 at 11:28, davey_83 said: You might need them back if you cant pass emissions................. I thought I saw someone on here at a stage offering 'help' when it came to passing mot with hfc... My car does about 2k miles a year and is excellently maintained mechanically so I wouldn't feel too guilty about getting an easy mot tester (pms welcome lol) Quote Link to comment Share on other sites More sharing options...
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