Yes, normally as close as possible, but the GPF apparently needs to be even closer in order to regen properly (it also needs heat to work), and the cat works better and for longer if particulates are reduced first... The cat can be kept hot enough by the ECU controlling fuelling - it knows the amount of O2 before and after in the cat, and I'm guessing that's enough data to calculate if the cat is hot enough, and can change the mixture for a period of time, to heat the cat up if necessary (lean mixture).Doesn't the cat need to be close to the engine to get enough heat to operate correctly?
I'm not sure, because the GPF is inline with the downpipe (it is in my NA engine, but it may be different in the GTi turbo engine).If the worst comes to the worst, I guess I could use the downpipe and put a more compliant exhaust system on instead?
I'm not sure, because the GPF is inline with the downpipe (it is in my NA engine, but it may be different in the GTi turbo engine).
I suspect, but don't know for sure, that the exhaust system you have bought is for pre-2018 cars, which is when I believe the GPFs became standard, so I think your first thing to do is query with the supplier if they have sent the right kit....
To be honest, I would think you can keep your existing downpipe and GPF, and that if it's a slightly smaller bore, it won't matter that much because the actual exhaust manifold is built into the head itself, and you are not altering the internal dimension of that - the bigger bore exhaust and silencer is therefore mostly about the sound, and not so much about performance. Don't forget, cars are way more sophisticated/complicated now than in the 80's, and tuning is not like it used to be! You can spend a £lot for marginal gains, and lots of dodgy claims!
Hi Sorencould you post some pictures when fitted, having the cat at tailpipe is something they did on the old rallye cars on the rallies that demanded it. it will only work when your alot on full trottle. but there is room to move it in front off the silencer