Pre cat removal advice
Discussion
Hi
My car seems to be running quite nicely at the moment so I was wondering what to do next and thought that a little extra noise would be good, I believe everything is standard and from what I have read removing the precats seems to be the favoured first step.
I think I will try and remove them with the manifolds in place after removing the sensors, I have read many threads and the most common method seems to be to drill as many holes as possible and then get brutal with screw drivers, chisels and crowbars, but how are they actually held in place, spot welds or similar?, how about drilling a few holes to get a slide hammer in and try to pull them out?, also everyone seems to use masonry drill bits, are normal steel ones no good, or just generally too short?
Can anyone confirm the docket size for the sensors, 17mm? I figured I would slot a box wrench, but are they still strong enough?
Any recomendations on what sounds a very unpleasant job are greatly appreciated
Thanks
Paul
My car seems to be running quite nicely at the moment so I was wondering what to do next and thought that a little extra noise would be good, I believe everything is standard and from what I have read removing the precats seems to be the favoured first step.
I think I will try and remove them with the manifolds in place after removing the sensors, I have read many threads and the most common method seems to be to drill as many holes as possible and then get brutal with screw drivers, chisels and crowbars, but how are they actually held in place, spot welds or similar?, how about drilling a few holes to get a slide hammer in and try to pull them out?, also everyone seems to use masonry drill bits, are normal steel ones no good, or just generally too short?
Can anyone confirm the docket size for the sensors, 17mm? I figured I would slot a box wrench, but are they still strong enough?
Any recomendations on what sounds a very unpleasant job are greatly appreciated
Thanks
Paul
17mm for the sensors I sacrificed a deep socket and sliced it with an angle grinder.
I only did this 2 weeks ago after reading about lots of peeps doing it in situ. I am not sure if I am just crap or it was because the cats were in perfect condition and well affixed but I had a total nightmare. I used a right angled chuck with masonry bits, a selection of pry bars and crow bars, screwdrivers and long nose pliers and took a solid 4 hours for one side and not much less for the other. I would never do it that way again and would make the effort to take the manifolds off. I reckon it would have been quicker and less stressful, snapped bolts aside!
You couldnt remove the cat in one piece due to the bend and realistically you can't drill to mane holes due to the angle. Not sure how they are fixed but they had welded themselves to the manifold.
I also hoovered them out frequently and jacked the car up at the back to reduce the risk of getting any crap back into the cylinders. I think there is very little risk of that though due to the configuration of the pipes and the shorter more risky ones being at the top. After removal there was very little only a short way inside. A full Hoover again before start up.
Good luck!
I only did this 2 weeks ago after reading about lots of peeps doing it in situ. I am not sure if I am just crap or it was because the cats were in perfect condition and well affixed but I had a total nightmare. I used a right angled chuck with masonry bits, a selection of pry bars and crow bars, screwdrivers and long nose pliers and took a solid 4 hours for one side and not much less for the other. I would never do it that way again and would make the effort to take the manifolds off. I reckon it would have been quicker and less stressful, snapped bolts aside!
You couldnt remove the cat in one piece due to the bend and realistically you can't drill to mane holes due to the angle. Not sure how they are fixed but they had welded themselves to the manifold.
I also hoovered them out frequently and jacked the car up at the back to reduce the risk of getting any crap back into the cylinders. I think there is very little risk of that though due to the configuration of the pipes and the shorter more risky ones being at the top. After removal there was very little only a short way inside. A full Hoover again before start up.
Good luck!
Edited by Danblez on Tuesday 7th June 20:31
There are two sides to this, and at the end of the day it's down to what kind of driving you plan on doing.
You can make these cars seriously loud, and then find it intolerable on lengthy drives.
Also too noisy is a no-no for track based events.
But if you like tunnel runs, you feel like the poor relation without major noise output.
However, I would point out that Speed 6 cars and AJP engined cars make a lot more noise a lot more readily.
The RV8 cars are the gentlemanly TVRs where noise is concerned.
You can make these cars seriously loud, and then find it intolerable on lengthy drives.
Also too noisy is a no-no for track based events.
But if you like tunnel runs, you feel like the poor relation without major noise output.
However, I would point out that Speed 6 cars and AJP engined cars make a lot more noise a lot more readily.
The RV8 cars are the gentlemanly TVRs where noise is concerned.
Paulprior said:
Hi, what stage were you at with that photo, is it nearly out?
How do find the sound now? Is it worth the hassle
Paul
Yep nearly out, the bHow do find the sound now? Is it worth the hassle
Paul
d fought me to the very last minute. Mine already had a decat y piece and cherry bombs so was already quite loud. It is now a touch louder and a bit more raw sounding. Pops and crackles even more pronounced, it sounds epic. Not driven any distance yet to know if it's annoying now. No regrets so far.
The bend in the manifolds makes it difficult to drill, I used a masonry bit in a proper hammer drill, various small chisels etc,
As said earlier use a mask and gloves.
Be careful not to hammer to hard or you risk piercing the manifolds as it's very thin.
It's simply about taking your time, dirty job and does take a couple of hours at the least per side. I found one came out fairly easily and the other took twice as long!
It's like honeycombe so I just slowly broke them up until it came out in bits.
It's a very worth while thing to do as your under bonnet temps will be lower and th exhaust flows easier, slightly more power and sound, better pops and cracs etc.
It's also far easier when manifolds are removed but that's another task to remove them in itself.
Goodluck
As said earlier use a mask and gloves.
Be careful not to hammer to hard or you risk piercing the manifolds as it's very thin.
It's simply about taking your time, dirty job and does take a couple of hours at the least per side. I found one came out fairly easily and the other took twice as long!
It's like honeycombe so I just slowly broke them up until it came out in bits.
It's a very worth while thing to do as your under bonnet temps will be lower and th exhaust flows easier, slightly more power and sound, better pops and cracs etc.
It's also far easier when manifolds are removed but that's another task to remove them in itself.
Goodluck
Yep you need to seal the 3 joints on the Y piece. I used high temp silicone. I imagine any exhaust jointing compound would do.
One other issue you may encounter is getting the Y piece to line up with both manifolds. I had a ratchet strap and don't think I would have been able to get it to seal without!
One other issue you may encounter is getting the Y piece to line up with both manifolds. I had a ratchet strap and don't think I would have been able to get it to seal without!
Edited by Danblez on Wednesday 8th June 09:11
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