I put the cat on for the yearly MOT and haven't got around to swapping back to the decat while at work the last week.
What has surprised me is that with the cat on it has increased peak full boost from a nice steady 1bar / 15psi to 1.1 / 17psi.
Nothing else changed, using an HKS adjustable boost controller in tandem with the good old Bren device.
I realise that the pressures downstream of the turbo are altered by the presence of the cat but I rather assumed it would be the other way round, that the cat would slow down gas speed through the 'zorst and expected LESS boost as a result, not more....
Am I missing something very obvious or just being stupid... ?
It's not a problem, as I will be changing back to the decat just as soon as I have an hour or two spare to do the job, but it is puzzling me and if anyone does know then I'd be grateful to dispose of that niggle.
Cheers all
R