Originally Posted by Kanga
Karn,I thought that would be the case.People (JUG) keeps harping about needing back pressure otherwise you lose torque,it's nonsense,they wouldn't make hi flow cats and free flowing exhaust systems if that were the case.When I changed my system with hi flow cats and a free flow exhaust the car pulled like a train.
Jug is right (in theory anyway), if you don't have enough back pressure you do lose torque at low revs (to do with exhaust gasses not properly leaving the system or something)
High-flow cats and free flowing exhaust systems are primarily for track cars and performance cars, where it doesn't matter about low-end torque cause your always at high revs, where the free-flowing exhaust will improve power (by maintaining peak torque higher through the rev range)
The question is, without the cat is there still enough back pressure to maintain the torque at low revs? From Karn's response, it seems there might be. And bearing in mind mines a modifed 3.0 running through a (partially) stock 2.5 exhaust system, I don't think lack of cat converter will negatively affect torque at low revs (at least noticabley anyway)
But I've decided I'm going to wait until after MOT time (June) before I get this done
Weekend toy: Alfa 156 3.0 24v V6, Silver with red leather, Q2 diff, GTA Teledials, headlights & inlet manifold, AutoDelta carbon intake, BMC CDA, decat pipe and SuperSprint rear box, FK coilovers, Dastek Unichip - my 245bhp beast!
Gone but not forgotten: Alfa 156 2.4 JTD Veloce, Vela Blu, Angel 'mad map' & BMC CDA, Ferodo DS2500s - the fastest tractor in town!
AO 'Bratpacker' No 5.
