I am going to fit a stainless exhaust, headers and CAI kit to my v6, and hopefully get a custom tune.

However where does the MOT fit into all off this?

If I fit all of these will the car pass an MOT? Or will I need to put the standard exhaust and cat back on, and if so will I have to get it re-tuned for the MOT?

provided you buy a good system and put in a cat it should have no problem

where would I get a cat from? Would it come with the headers? or would I have to purchase it separately?

thanks

headers come with a decta unless you pay extra and buy 1 with them, i used the standard cat off the old exhaust and had that fitted, passes mot easlily

does the standard cat fit the same as the decat or does it have to be modified.

thanks

the easiest way is if you get the SSA/XS power etc headers, they come with a "race cat" this is a 2.5" basically blank tube with flanges on - easiest way is to get your cat, either sports or stock and get them to cut it off, and weld onto race cat flanges - good if you want to then get another race cat made up for cat/non cat easy swap.

The only other thing to note is the noise levels - mine barely passed and got an advisory for my catback, and that is real quiet. So check with the tester before booking as if they are grumpy farts then they wont pass on noise levels...

However, its reputed that a sports cat only gives less than 2bhp power compared to decat, so i'd suggest getting a cat welded in (cant say compared to stock cat though, even though you lose the 2 pre-cats aswell, as there are 3 all together)

Also, for tuning, technically if you get it leaned out then yeah, it should produce less emissions - depends what you get it tuned at. You going to run piggyback like the neo or SMT ro ripping the whole lot out for a standalone?

the decat wont pass mot, u need to get a cat in there, the standard cat will have to be slightly modded to fit basically the bore is smaller than ur headers and catback so if you just have flanges put on and bolt it in your gona get a bottle neck at the cat, this isnt good for power gains, the end will have to be made wider then the flanges put on, my guy charged me £50 for the pleasure, trust me once that ctas in you wont take it back out, the thing with the decat is it makes the noise very raspy, the ca takes this away and you wont see any difference in power, infact lower down it will be better as the extra back pressure will give slightly more torque but may lose abit at top speed but realistically when is any 1 gona be hitting 130mph +

androo007

I get all of the cat thing now. however I am not getting the last part of your reply. I dont understand what the following means - sorry for being so thick.


"Also, for tuning, technically if you get it leaned out then yeah, it should produce less emissions - depends what you get it tuned at. You going to run piggyback like the neo or SMT ro ripping the whole lot out for a standalone?"

thanks again

I hereby stand as living proof that a car can indeed pass with no CAT, I have a CAI, full motoria system and the headers go own real soon. I found that after taking the CAT out (bolt in de-CAT) the cound was awesome, real good rasp and run-off sound. Yes you can fail on noise, emissions and just for having no cat though. Please no 'snidey' replies to this. Just saying that there is a chance you will pass. Depends what you want I guess.

sorry i should have said, yes you can pass, as macker did, BUT macker was only just under the requirement, mine was 3 times more than is allowed, this may be as the later v6 has vvt and the early 1's dont

cazza, what androo is saying is, when you put the headers on with or with out a cat your car will be running rich, this is because the headers have cats in them and you cant replace them like you can with the 3rd cat under the car, the way to get round this is to have a piggy back ecu fitted and tuned, you cant tune a coupe without a piggy back (smt), when they tune the car they will alter the permissions and the timing ect.... this will lean the fuel out so there is just the right amount of petrol going through, too much petrol is running rich and running rich will raise the emissions...... hope that helps

Hit the nail on the head there S12 CRG - IMO, it's not the absent cat that will cause the fail, it's the readings that the test meter reports.

This is what I have done on the Rover. Regulations state that a Cat has to be present, but they don't test the function of it on diesels. So I whipped it off and drilled all the ceramic out of it, and the other stuff in there too. Refit and noone is the wiser - this could work with the petrols too. The cat is 'still' there, but there is no restriction any more - and the tester is happy coz it's passing emissions. Win.

If the engine is capable of reliably passing without a cat fitted, then who is to know that there isn't one there without a detailed inspection. I council against the decat on N/A 2.0L engines because the lack of backpressure kill the torque - but if I had a V6 and it'd pass without a cat fitted and it performed well without one, I'd decat it.

Just got to watch that noise level, as mentioned previously...

The car is totally standard at the moment - it is a v6. I am going to put a performance exhaust on with ssa headers and a CAI kit.

I now know that I should put a cat in the exhaust system, and there are various ways to do it.

Now another question - yes another question. How does the piggyback ecu get fitted?

thanks

i see you have a thread on the piggyback going on so i wont add anything ere bout that but as far as the headers and cat go, fewposts up should xplain why ull need a cat in

delivered today, took 5 days. no imprt tax. sweet

well what are they like?

yeah alright. Mandrel bends arent the best..... but pfft nothing like a crush bend so thats alright. All bolts up as it should, welds seem adiquate, seems solid construction. They are the XS power ones, i think there is no such things as the V2 - theres nothing to suggest it is - AND they even have XS power stamped on the side.

i think the V2 thing was made up as there were so many fitment quibbles, so they say theyre a new version to get people buying again.

But, they all fit - its just little tight spots that m,ight need adjusting.

Will be fitting it on Saturday

thanks for that keep me posted.