Pre cats out.........all good
Discussion
Got round to putting my manifolds back today after removing the precats,well one had decided it dident like living in the manifold and got jammed in the Y piece,wondered why the power tailed off before winter lay/up,fitted with ARP bolts & Reinz gaskets(nice kit)crappy job.Yes the under bonnet temps are def cooler around the manifold area,dont appear to get that blast of air when you first open the bonnet after a good run and the fans cut in,especially around the manifold area (obviously)the manifolds have more of a ringing sound on idle than before also,hard to make any back to back comparisons,but the peformance is all their,all in all time well spent just got to get on with all the other jobs now,ahh well no peace for the wicked,saw a couple of chims around the headcorn area on my travels too,would recommend doing this job if your considering.Feels great to be out in the old girl layed/up since last years winter salt gritting session(seems like ages).
Edited by That Daddy on Saturday 10th March 23:16
Edited by That Daddy on Saturday 10th March 23:21
That Daddy said:
Got round to putting my manifolds back today after removing the precats,well one had decided it dident like living in the manifold and got jammed in the Y piece,wondered why the power tailed off before winter lay/up,fitted with ARP bolts & Reinz gaskets(nice kit)crappy job.Yes the under bonnet temps are def cooler around the manifold area,dont appear to get that blast of air when you first open the bonnet after a good run and the fans cut in,especially around the manifold area (obviously)the manifolds have more of a ringing sound on idle than before also,hard to make any back to back comparisons,but the peformance is all their,all in all time well spent just got to get on with all the other jobs now,ahh well no peace for the wicked,saw a couple of chims around the headcorn area on my travels too,would recommend doing this job if your considering.Feels great to be out in the old girl layed/up since last years winter salt gritting session(seems like ages).
Edited by That Daddy on Saturday 10th March 23:16
Edited by That Daddy on Saturday 10th March 23:21
Now all you have to do is remove the main cat and you will be super cool...or is that super loud....doesnt matter....just do it!!!
No way Andy,problems with MOT time is not my bag(Emissions)times i see rice burner owners trying to get thru the test without the cats(they dont)yes i am next door to an MOT station.Anyways enough of that how you doing with that build of yours Andy?
Edited by That Daddy on Saturday 10th March 23:50
That Daddy said:
No way Andy,problems with MOT time is not my bag(Emissions)times i see rice burner owners trying to get thru the test without the cats(they dont)yes i am next door to an MOT station.Anyways enough of that how you doing with that build of yours Andy?
Edited by That Daddy on Saturday 10th March 23:50
I bet you drive it at 70 on the M1 as well Daddy
Pasco said:
That Daddy said:
No way Andy,problems with MOT time is not my bag(Emissions)times i see rice burner owners trying to get thru the test without the cats(they dont)yes i am next door to an MOT station.Anyways enough of that how you doing with that build of yours Andy?
Edited by That Daddy on Saturday 10th March 23:50
I bet you drive it at 70 on the M1 as well Daddy
Pasco,how did you know....
that daddy said:
Pasco said:
That Daddy said:
No way Andy,problems with MOT time is not my bag(Emissions)times i see rice burner owners trying to get thru the test without the cats(they dont)yes i am next door to an MOT station.Anyways enough of that how you doing with that build of yours Andy?
Edited by That Daddy on Saturday 10th March 23:50
I bet you drive it at 70 on the M1 as well Daddy
Pasco,how did you know....
you Tree Hugger 
Pasco said:
that daddy said:
Pasco said:
That Daddy said:
No way Andy,problems with MOT time is not my bag(Emissions)times i see rice burner owners trying to get thru the test without the cats(they dont)yes i am next door to an MOT station.Anyways enough of that how you doing with that build of yours Andy?
Edited by That Daddy on Saturday 10th March 23:50
I bet you drive it at 70 on the M1 as well Daddy
Pasco,how did you know....
you Tree Hugger Shhh Pasco,dont tell everybody you will ruin my street cred,,,,,,,,,,Blinging guy!
BenBlackwood said:
I asked my MOT tester (usually honest and turns a blind eye to the odd thing on account of the car being so sweet)and he said he would definately not pass my Chim with the cat removed. Whats the best alternative to achieve more noise without spending too much?
Remove the precats...cut out the rear silencer and put some straight thru pipes in....!!!
What are these pre-cats you speak of? Mine is a 96 Chim (only had it a week) but I think it may have had a later exhaust fitted at some point. All I can see down stream of the 4-1 joins is 2 big sweeping pipes (where the llambda sensors are) which go into a big dustbin which I assume is the cat.
BenBlackwood said:
I asked my MOT tester (usually honest and turns a blind eye to the odd thing on account of the car being so sweet)and he said he would definately not pass my Chim with the cat removed. Whats the best alternative to achieve more noise without spending too much?
Do a forum search for Cherry Bomb
The Chimaera is fitted with 3 cats as standard. The main cat is located in the large dustbin shaped section just behind the radiator, below where the two manifolds join (the 'Y' piece). The pre-cats are smaller units designed to clean-up the exhaust gasses on start-up, before the main cat has fully warmed up, and these are located in the manifolds in the short smooth sections just after the 4 primary's join together, but before the curved section with the Lambda Sensor.
The Pre-cats can be taken out to help the exhaust breath a little better, and by removing the pre-cat element, it often reduced the temperature in that section of the system. The pre-cats sometimes glow, but that's a sign or a partial blockage, in which case best to take them out. The pre-cats make no difference to the MOT emmisions, as cars should always be tested 'warm'.
Pre-cats can be removed DIY by knocking out the element (with care, and do a search on here for details), or you can buy modified manifolds with the pre-cats already removed (try Tim at ACT)
Arse, beaten by Nick...., what he said....
The Pre-cats can be taken out to help the exhaust breath a little better, and by removing the pre-cat element, it often reduced the temperature in that section of the system. The pre-cats sometimes glow, but that's a sign or a partial blockage, in which case best to take them out. The pre-cats make no difference to the MOT emmisions, as cars should always be tested 'warm'.
Pre-cats can be removed DIY by knocking out the element (with care, and do a search on here for details), or you can buy modified manifolds with the pre-cats already removed (try Tim at ACT)
Arse, beaten by Nick...., what he said....
Edited by The Surveyor on Monday 19th March 12:14
Just had my Chim MOT'd on Saturday. Flew through with "near perfect" emissions and my Pre-Cats were taken out last year. As I say, the MOT tester said the emission level was as near perfect as he could have wished for.
The MOT tester and I actually wondered why they bothered putting them into the car in the first place. They muffle the exhaust noise (a bit) but when you take into account they sometimes melt in-situ and cost hundreds £££'s to then remove - why have them.
IIRC it will cost (approx) £500 to get them out as its a 5-7 hour job (I'm told by Austec Racing) but if you wait till your manifold gasket(s) go they can get them out much more cheaply then as they are in that area whilst replacing the gaskets anyway.
Straight through pipes is what I went for - Unfortunately having the Main Cat out means you'll have to re-fit it every year prior to the MOT - unless you've money to burn or your own workshop to D.I.Y. is it worth it? I didn't think so but each to his own.
Here's a big 'thumbs up' to Dan at Tanbury Motors in Southwater, West Sussex - not your average tester - got me involved in the testing and inspection of the car - talked me through and showed me everything he was testing as he did it. Took me underneath to inspect the Chassis with him etc...top bloke.
im said:
.....£500 to get them out as its a 5-7 hour job.....
...i took mine out myself....was about a 2hr job and this was the first time i had ever done it...now i know i know what to do i cant see it taking much longer.the hardest part was taking the y section out. So really you are saying £500 for the precat removal and possibly £140 for the cherry bombs if you went that route...glad it cost me £25 for the straight thru tube and a few hours of my time....
im said:
The MOT tester and I actually wondered why they bothered putting them into the car in the first place. They muffle the exhaust noise (a bit) but when you take into account they sometimes melt in-situ and cost hundreds £££'s to then remove - why have them.
IIRC it will cost (approx) £500 to get them out as its a 5-7 hour job (I'm told by Austec Racing) but if you wait till your manifold gasket(s) go they can get them out much more cheaply then as they are in that area whilst replacing the gaskets anyway.
Straight through pipes is what I went for - Unfortunately having the Main Cat out means you'll have to re-fit it every year prior to the MOT - unless you've money to burn or your own workshop to D.I.Y. is it worth it? I didn't think so but each to his own.
The pre cats are fitted as part of TVRs efforts to meet EU emissions tests.
Over in Europe land a car must pass an emissions test from cold and thats where the pre cats come in
this is not as yet required in this country hence you can take the bloody things out without an issue. All IMHO. andy-w said:
im said:
.....£500 to get them out as its a 5-7 hour job.....
...i took mine out myself....was about a 2hr job and this was the first time i had ever done it...now i know i know what to do i cant see it taking much longer.the hardest part was taking the y section out. So really you are saying £500 for the precat removal and possibly £140 for the cherry bombs if you went that route...glad it cost me £25 for the straight thru tube and a few hours of my time....
Yep that was the quote from Austec Racing - I think they factor in extra hours in case it turns into a 'nasty' job as I'm told sometimes the Cats come out easy and other times they have to be chiselled out as the have welded themselves in. At that point (apparently) its a bitch of a job.
IIRC the price reflects the fact that they don't know what they are going to find. The price also includes Gordons cut dont forget.
Pasco said:
im said:
The MOT tester and I actually wondered why they bothered putting them into the car in the first place. They muffle the exhaust noise (a bit) but when you take into account they sometimes melt in-situ and cost hundreds £££'s to then remove - why have them.
IIRC it will cost (approx) £500 to get them out as its a 5-7 hour job (I'm told by Austec Racing) but if you wait till your manifold gasket(s) go they can get them out much more cheaply then as they are in that area whilst replacing the gaskets anyway.
Straight through pipes is what I went for - Unfortunately having the Main Cat out means you'll have to re-fit it every year prior to the MOT - unless you've money to burn or your own workshop to D.I.Y. is it worth it? I didn't think so but each to his own.
The pre cats are fitted as part of TVRs efforts to meet EU emissions tests.
Over in Europe land a car must pass an emissions test from cold and thats where the pre cats come in
this is not as yet required in this country hence you can take the bloody things out without an issue. All IMHO. Nowadays to meet Euro IV with a big engine you have to have exhaust gas recirculation, secondary air injection as well as a cat-fest in the exhaust pipe. Regs are the same for new cars for the whole of Europe as we are all covered by EU4. SVA and MOT are different.
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