MK5 Golf GTI
All Things Mk5 => Modifications & Technical Area => Performance Modifications => Topic started by: Bassman1974 on May 15, 2025, 10:32:02 am
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Long time introverted lurker here !
So, my stopgap Mk5 that I bought in February 2024 has turned into a bit of a project. I'm lucky to have a company vehicle, so the Golf is a bit of a weekend hero now.
Now that I have all the tech and body sorted, with full refreshes carried out on suspension and brakes and a Stage 1 map amongst other stuff, I've decided to splurge on a BCS Powervalve 200 Cell Sport Cat and Prestige Exhaust. Now, it was never my intention to fit a sport cat, but I got a good deal from BCS and couldn't turn it down. Plus I've noted how crumbly those old OEM flexi's can get !
Question: Once fitting the cat, do I need an immediate remap? I'm honestly not that bothered about taking the K03 to the absolute limit of it's performance, and if it didn't need a remap, I'd likely be more than happy with the extra performance that the full system would give me. In all honesty, the Stage 1 map woke it up beautifully and I'm stoked with how it performs. BCS tell me, and they've been very helpful, that the system should cause no errors, but I'd be really keen to hear the view from owners who have done something similar.
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I would highly advise it. Every exhaust change on cars after 1990 should be mapped in. The k03 doesn't like to much boost though. The housing tends to crack. That makes everything over 240bhp is a lottery. :laugh:
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From what I've read yes you will need a remap or you will get over boost errors at the least.