Can someone gut my precats? :P
Discussion
Just got a sports exhaust fitted onto my MR2 at Turriff Tyres today. I asked them about possibly gutting the precats (as this is a known weakness of the Mk3 MR2) but was met with much 
If I wanted to get this done does anyone have any recommendations?
If I wanted to get this done does anyone have any recommendations?
There is only one man to talk to about MR2's
OBLERJ
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A fair few people over on mr2roc have fitted stainless manifolds that don't have any pre-cat fitted, they're available for around £100 on fleabay (would post a link but can't access it on works PC at lunchtime!) and are apparently identical to the Che ones from America. A couple of people suspected they would be crap due to their cost and crack around the welds, but no one seems to have had any problems with them as far as I know. I'm going to get one fitted when (if) I upgrade the exhaust on mine and get rid of my gutted manifold.
There are companies selling the same one online for £hundreds so watch out for them stinging you.
Out of interest, what exhaust did you have fitted, or was it a custom jobber?
There are companies selling the same one online for £hundreds so watch out for them stinging you.
Out of interest, what exhaust did you have fitted, or was it a custom jobber?
Hello. I best get my username sorted.
Yes, definitely worth gutting the pre-cats. Fairly simple job unless the exhaust studs snap. Which they will. You'll need to go through the same to switch to the che type manifolds so worth upgrading, as roger says. You're looking about £70 to remove the pre-cats and gut them from most places that know the job. What year is your Roadster?
I'm pretty snowed in with the house work at the minute so i can't take it on really but happy to throw any advice i can your way.
The heat shields can be a b
h too as they are always rusted to hell.
The problems come when the manifold to mid section studs snap and need to be drilled out. Horrible job. If that happens, you'll find garages then up the price as it's more hours work.
Yes, definitely worth gutting the pre-cats. Fairly simple job unless the exhaust studs snap. Which they will. You'll need to go through the same to switch to the che type manifolds so worth upgrading, as roger says. You're looking about £70 to remove the pre-cats and gut them from most places that know the job. What year is your Roadster?
I'm pretty snowed in with the house work at the minute so i can't take it on really but happy to throw any advice i can your way.
The heat shields can be a b
h too as they are always rusted to hell.The problems come when the manifold to mid section studs snap and need to be drilled out. Horrible job. If that happens, you'll find garages then up the price as it's more hours work.
Thanks for the responses 
Was considering getting a CHE header or one of the £100 ones then getting a garage to fit. I heard Turriff Tyres were good for exhaust systems so thought they would know how to gut the pre-cats but didn't seem sure about it. They were also concerned about taking the rusty heat shield bolts off I think...
MR2 is a late 2004 - from what I've read pre-cat failure is much less common on facelift cars?
Exhaust is a custom Powerflow job by Turriff Tyres, not as loud as I was hoping but is nicer than standard
Was considering getting a CHE header or one of the £100 ones then getting a garage to fit. I heard Turriff Tyres were good for exhaust systems so thought they would know how to gut the pre-cats but didn't seem sure about it. They were also concerned about taking the rusty heat shield bolts off I think...
MR2 is a late 2004 - from what I've read pre-cat failure is much less common on facelift cars?
Exhaust is a custom Powerflow job by Turriff Tyres, not as loud as I was hoping but is nicer than standard
The thing is, pre-cat failure is blamed for the early engine serial implodingness, it's a bit of a mibbes if that's the cause or not. Personally i think it's caused a few but it's not the main cause.
Either way, they have been known to start to fall apart on both early and late cars and having ceramic pieces floating about your exhaust is a bit too close to the engine for me.
The heat shield bolts u'll be able to see if they're rusted to hell or not. I've seen me grinding them off and then having to tack weld the heat shields back on, not great but it works.
Once the manifold is off, it's simply a case of poking around inside it with a big screw driver to remove the ceramic honeycomb and cotton wool type material and then washing it out. The issues are definitely with removing the manifold in the 1st place though. If you're replacing the manifold though, the only thing u need to worry about is the manifold to head nuts and studs but they "should" be alright on a 2004 if u use the correct 6 sided sockets and plenty plus gas.
Either way, they have been known to start to fall apart on both early and late cars and having ceramic pieces floating about your exhaust is a bit too close to the engine for me.
The heat shield bolts u'll be able to see if they're rusted to hell or not. I've seen me grinding them off and then having to tack weld the heat shields back on, not great but it works.
Once the manifold is off, it's simply a case of poking around inside it with a big screw driver to remove the ceramic honeycomb and cotton wool type material and then washing it out. The issues are definitely with removing the manifold in the 1st place though. If you're replacing the manifold though, the only thing u need to worry about is the manifold to head nuts and studs but they "should" be alright on a 2004 if u use the correct 6 sided sockets and plenty plus gas.
OlberJ said:
The thing is, pre-cat failure is blamed for the early engine serial implodingness, it's a bit of a mibbes if that's the cause or not. Personally i think it's caused a few but it's not the main cause.
Either way, they have been known to start to fall apart on both early and late cars and having ceramic pieces floating about your exhaust is a bit too close to the engine for me.
The heat shield bolts u'll be able to see if they're rusted to hell or not. I've seen me grinding them off and then having to tack weld the heat shields back on, not great but it works.
Once the manifold is off, it's simply a case of poking around inside it with a big screw driver to remove the ceramic honeycomb and cotton wool type material and then washing it out. The issues are definitely with removing the manifold in the 1st place though. If you're replacing the manifold though, the only thing u need to worry about is the manifold to head nuts and studs but they "should" be alright on a 2004 if u use the correct 6 sided sockets and plenty plus gas.
The annoying thing is its all incredibly vague this pre-cat issue - some people say they've done well over 100k miles in early cars without issue and other seem to fail within 10k miles. I would also like to think if it was really a big issue (isn't this engine also used in the Corolla?) then Toyota would have done something about it? Actually how many confirmed cases have there been in facelift models (2004 and newer)?Either way, they have been known to start to fall apart on both early and late cars and having ceramic pieces floating about your exhaust is a bit too close to the engine for me.
The heat shield bolts u'll be able to see if they're rusted to hell or not. I've seen me grinding them off and then having to tack weld the heat shields back on, not great but it works.
Once the manifold is off, it's simply a case of poking around inside it with a big screw driver to remove the ceramic honeycomb and cotton wool type material and then washing it out. The issues are definitely with removing the manifold in the 1st place though. If you're replacing the manifold though, the only thing u need to worry about is the manifold to head nuts and studs but they "should" be alright on a 2004 if u use the correct 6 sided sockets and plenty plus gas.
I've got basic tools but no grinders or welders... is there anyone you would recommend (ideally around Aberdeenshire) that could help remove the exhaust manifold and gut the pre-cats for me?
Edited by MarkRSi on Thursday 24th March 20:21
The thing is, the early cars, pre-2003 have engines built with faults in them. Chocolate bottom end, tolerances out and bores which go oval in no time.
The facelift is a much better engine with most of the issues solved.
The pre-cats are common across both and can or can't cause issues. Rarely if issues occur are they actually diagnosed, simply guessed at.
Would always remove the pre-cats though, just in case, not worth the risk.
Your best bet is to look on the roc forum, you'll find it on google easy enough, there's a thread running in there with companies who will do it for you. Unfortunately you might find the closest is me but worth a look.
Got a customer up your way with one of my V6's, be warned, it starts with gutting pre-cats
The facelift is a much better engine with most of the issues solved.
The pre-cats are common across both and can or can't cause issues. Rarely if issues occur are they actually diagnosed, simply guessed at.
Would always remove the pre-cats though, just in case, not worth the risk.
Your best bet is to look on the roc forum, you'll find it on google easy enough, there's a thread running in there with companies who will do it for you. Unfortunately you might find the closest is me but worth a look.
Got a customer up your way with one of my V6's, be warned, it starts with gutting pre-cats
OlberJ said:
The thing is, the early cars, pre-2003 have engines built with faults in them. Chocolate bottom end, tolerances out and bores which go oval in no time.
The facelift is a much better engine with most of the issues solved.
The pre-cats are common across both and can or can't cause issues. Rarely if issues occur are they actually diagnosed, simply guessed at.
Would always remove the pre-cats though, just in case, not worth the risk.
Your best bet is to look on the roc forum, you'll find it on google easy enough, there's a thread running in there with companies who will do it for you. Unfortunately you might find the closest is me but worth a look.
Got a customer up your way with one of my V6's, be warned, it starts with gutting pre-cats
Soooo still a maybe then? The facelift is a much better engine with most of the issues solved.
The pre-cats are common across both and can or can't cause issues. Rarely if issues occur are they actually diagnosed, simply guessed at.
Would always remove the pre-cats though, just in case, not worth the risk.
Your best bet is to look on the roc forum, you'll find it on google easy enough, there's a thread running in there with companies who will do it for you. Unfortunately you might find the closest is me but worth a look.
Got a customer up your way with one of my V6's, be warned, it starts with gutting pre-cats
Yeah checked that MR2roc thread out - someone mentioned Huntly but that post was in 2006...Mmmmmmmmmmmmmmmmmmmm V6 you say......
Actually there is something else - I've also been thinking about getting a custom air intake (mainly for noise
). From what I've heard A'pexi do the best ones - where would be the best place to get one?Edited by MarkRSi on Thursday 24th March 21:40
Get in and about ebay for a universal one and the 3" adapter (think it's 3" on the 1zz, you'd need to check)
Then just a bit of rubber hose to connect your AFM to the intake. All ebayable for well under £100 i should imagine.
I'm knee deep in a house refurb, have a tarmac rally car to build and 2 Mk2's sitting on my drive awaiting engines being fitted. If i could, i would mate.
Happy to chuck any help your way by instruction if you wish to give it a bash or give details to a garage to do the job.
Then just a bit of rubber hose to connect your AFM to the intake. All ebayable for well under £100 i should imagine.
I'm knee deep in a house refurb, have a tarmac rally car to build and 2 Mk2's sitting on my drive awaiting engines being fitted. If i could, i would mate.
Happy to chuck any help your way by instruction if you wish to give it a bash or give details to a garage to do the job.
OlberJ said:
Get in and about ebay for a universal one and the 3" adapter (think it's 3" on the 1zz, you'd need to check)
Then just a bit of rubber hose to connect your AFM to the intake. All ebayable for well under £100 i should imagine.
I'm knee deep in a house refurb, have a tarmac rally car to build and 2 Mk2's sitting on my drive awaiting engines being fitted. If i could, i would mate.
Happy to chuck any help your way by instruction if you wish to give it a bash or give details to a garage to do the job.
Aye I spotted one of these on fleabay - got a 3" adaptor tooThen just a bit of rubber hose to connect your AFM to the intake. All ebayable for well under £100 i should imagine.
I'm knee deep in a house refurb, have a tarmac rally car to build and 2 Mk2's sitting on my drive awaiting engines being fitted. If i could, i would mate.
Happy to chuck any help your way by instruction if you wish to give it a bash or give details to a garage to do the job.
http://cgi.ebay.co.uk/APEXi-POWER-INTAKE-AIR-FILTE...
What about the rest of the bits though?
(sorry for being such a n00b, I could ask on the MR2roc if you think that would be better)Thanks for your help btw
That's a billy bargain!
I'll measure my spare AFM 2moro, think it's 3" you need. If so, all you need to add to your list is this : http://cgi.ebay.co.uk/Silicone-Coupler-pipe-Induct...
and 2 x jubilee clips.
Remove all the hard plastic intake, with the filter inside etc.
You'll be left with the AFM on the rubber elbow that goes to the throttle body (not lost you yet?)
On the side of the AFM nearest to the exhaust you are fitting the silicone pipe, with both jubilee clips and then fit the adapter and filter on the end.
You'll have throttle body > rubber elbow > AFM > silcone pipe > adapter > Filter
You might have to work out a way of supporting the whole assembly with cable ties or fabricate up some bracket from the gearbox etc.
Cut the silicone pipe down so it's as short as possible and is just a connector.
That should see you alright.
I'll measure my spare AFM 2moro, think it's 3" you need. If so, all you need to add to your list is this : http://cgi.ebay.co.uk/Silicone-Coupler-pipe-Induct...
and 2 x jubilee clips.
Remove all the hard plastic intake, with the filter inside etc.
You'll be left with the AFM on the rubber elbow that goes to the throttle body (not lost you yet?)
On the side of the AFM nearest to the exhaust you are fitting the silicone pipe, with both jubilee clips and then fit the adapter and filter on the end.
You'll have throttle body > rubber elbow > AFM > silcone pipe > adapter > Filter
You might have to work out a way of supporting the whole assembly with cable ties or fabricate up some bracket from the gearbox etc.
Cut the silicone pipe down so it's as short as possible and is just a connector.
That should see you alright.
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