The Mégane II Owners' Club

Got my cat hollowed out after some deliberation, turbo had gone and i had the egr return pipes welded up on the manifolds.
However, now i have massive turbo lag. OBD is throwing up codes for fun at the moment. MAF, Fuel rail pressure, Fuel temp... etc.
Pretty sure i've got rid of too much back pressure with the decat.

Can anyone confirm if i'm missing something. I've run diagnostics, turbo pressure is bang on when running, maf is showing readings and so is fuel pressure. So i know they're all working.

Decat buggered it and i need another remap, or get another cat?

I don't know much about this stuff, but I'm guesing by removing the cat AFTER a remap you've disturbed the settings as the remap was based on what was on the car at the time.... I'd try to get the mapping people to check it out (but would probably 'forget' to mentionthe cat was removed subsequently )

I do believe that they are going to introduce in to the MOT the fact that if your car was manufactured with a CAT it must have one. Still doesn't stop you from removing it but it does make it hellishly expensive as you'll need the necessary pipework with a CAT as well as without and whenever you change them over you'll need a remap so that'd be 2 remaps a year if your car is at or over 3 years old plus the hassle of changing it over and then changing it back.

You need to check on the MOT site to get confirmation.

Going off-topic slightly here, but some remapping places offer to change between maps free of charge for servicing so will probably offer the same for MOT, but having to put the cats back on is a separate matter.

Also depends on what the MOT tester recognises as a cat as well, for example, my brother's car has three cats (2 on the manifold and one post lambda), but the MOT station was adamant that the 3rd cat is not a cat. Indeed, even after it was taken off, th insides were nothing like a cat (no mesh etc), but the dealers refer to it as a cat, and at £600 it better be a cat!

Hmmm, i'll look into the mot regulations then!
However, i have since solved my issue, i put a new cat on! haha it works perfectly again.

Decat pipe is for sale for anyone if they're up for remapping after.

Anyone know anything on shaking under acceleration?
Fine when cruising, just when accelerating, will get tracking checked but i dont think its that.

Cheers guys

Mine shakes a tad at lower rpm's under acceleration. I have always put it down to the flywheel.

Shaking or vibrations? And is it apparent between a certain rev range or is it road speed related?

I would say more a shake than a vibration and It is rev's related definitely. I'd say it's between 1500-1800 rpm's approximately.

Reason I asked is because I had something similar on a 97 Laguna many years ago. Definitely a vibration but quite violent between 2500-3000rpm. Many garages failed to diagnose it, and made me changes various engine and gearbox mounts. In the end, I took it to a local garage and this chap found that the gearbox itself (bellhousing) where it attaches to the engine had bolt's missing and was only just held in place.

Replaced the bolts, all tightened up and the vibrations went away.

Bent driveshafts could also cause similar I've heard

Ah right. Well I'm going to be changing the clutch and flywheel myself soon so will definitely be having a poke around down there, see what's what

Mines more of the higher revs, 2500-3000, but still noticeable slightly in the lower range.
I thought driveshaft but they're both brand new. They look fairly fine too.

I'll look into the gearbox thing though. You could be onto something, especially if its a little bit loose somewhere.

Cheers anyway peeps.

maybe the clutch plate is warn?

Can that cause excessive wobbles? Hmm might look into that after christmas.
Was looking at a ceramic clutch next year anyway. Hmmmm.

I am getting a stage 2 clutch (which I think is kevlar) from a company called 'Drive Torque' through Larkspeed soon. Once that is on with a new flywheel I can return to RS Tuning so Paul can 'turn it up' a tad more

The factory fit clutch in these cars are really quite weak. I guess that's why they limit the torque so much on these 1.5's. Atm it is pushing 120bhp and 285Nm torque, I'm sure more could be extracted with the stronger clutch fitted