precat removal

Mordoklej

Atm I'm very happy with my car power wise. I don't know how much bhp it's got but it's the fastest car I've ever owned. It rockets up to 100mph easily and quickly (private road), compared to what it was without mods.

There is still one thing I haven't done to it - precat removal. Do I have it at all? I've read storys that people who were removing them found that they didnt have them at all. Any way to say it's got precat or not without opening it up?

Do I need any special tools/parts before I start removing the down pipe ie. new bolts? I'm a bit afraid of doing it.. I can picture myself cursing at rounded rusty bolts already lol

My car:
2004 Z22SE with straight through centre section (standard diameter) and Irmscher back box, Veccy C intake pipe, derestricted airbox, foam panel filter, egr blanked.

MikeS

pre cat removal is a free cheap mod but has led to lambda / cat problems

if you like how it is running then imo I would leave it alone

Mordoklej

MikeS said:
pre cat removal is a free cheap mod but has led to lambda / cat problems

if you like how it is running then imo I would leave it alone

Yeah. I'm happy how the car is running. I'm just a bit concerned about the reports that precat can cause exhaust manifold cracks due to overheating.

I planed two 2500 mile round trips for this year. What the manifold will have to take is 17-18 hour journey at 100-120 mph speeds with breaks only for pertol, loo and sandwich. My old Z16XE was fine with that but it had no precat and reported manifold failures. The manifold was glowing like a light bulb after 17-20 hour journeys though haha

astra22bertoneauto

Well i got through 3 exhaust manifolds! They all cracked in same place, but i didnt know about the precat then. A manifold should last the life of the car but Vx would not take any responsibility, typically :thumbdown:

After i found this site it was 1 of the first things i done and not looked back since 😃

Mordoklej

astra22bertoneauto said:
Well i got through 3 exhaust manifolds! They all cracked in same place, but i didnt know about the precat then. A manifold should last the life of the car but Vx would not take any responsibility, typically :thumbdown:

After i found this site it was 1 of the first things i done and not looked back since 😃

What are the symptoms of cracked manifold, mate?

astra22bertoneauto

slight smell of petrol fumes but the worst 1 was it sounded like a nasty blowing exhaust but from the front. You can check by putting your hand down the back of the engine bay.

MikeS

yah effin stinks when it leaks around manifold / downpipe

Mordoklej

Well mine is not cracked yet then :thumbup:

Once I separate a downpipe with cat from the manifold will I need new bolts, gaskets etc?

astra22bertoneauto

i never did need bolts or gasket, bolts are built inth the manifold. the garage obv heated up the nuts to undo them, or if you do it yourself go for a short drive. crack them loose while its cooling down always works for me :thumbup:

Mordoklej

Ok.. Cheers mate. I'll try it I think :thumbup:

solorider

looking at your profile car a 2004 astra 2.2 will not have a precat,vauxhall removed the precat on 2003 and on cars,if your car does not have a egr valve it wont have a precat (unmodified cars only)

Mordoklej

solorider said:
looking at your profile car a 2004 astra 2.2 will not have a precat,vauxhall removed the precat on 2003 and on cars,if your car does not have a egr valve it wont have a precat (unmodified cars only)

That's what I was told a few days ago on AOC forum as well.. However my car had EGR valve.