lowered performance with new cat back?

[TB Rich]

Forgive me if I'm being a thick ****, but in the thread in the Engine section, you said you had manifold replaced not system.

Seems you had it all replaced then? Except I guess the cat and centre?


Renault sell you the system in pieces now not really because of a revised designs (i.e you wont get poor running from fitting a new system), but because of how the cars are built on the production line - it's cheaper and easier to fit a single system to the car as a whole (rear axle lifts later down the line).
However parts distribution and cost of not supplying cats every time the end user needs a new system, mean that it's easier to sell the exhaust as sections for replacement. It's seems that's how most manufactures seem to do it nowadays not just Renault.

Renault actually do a genuine part number which is a sleeve to mate the new system to the cut up original. If RSC maybe welded it up instead, perhaps the welding is pig **** and causing an impedance on the flow? Only reason I can think it might cause loss of power (assuming OE item and not some generic kwick fit aids).

 

[montana]

Providing the part that was fitted is ok (to replace the above) the only tell tale sign that something is wrong is a blowing from the exhaust.

What's the condition of the rest of the exhaust like ?

Can you get it in the air at all to check for yourself what they have done ?

Have you changed anything else (except exhaust) ?

 

[shells2074]

Replaced manifold and yes section not entire system. I can get a mate to get it on a ramp and look ( mechanic ). It's not blowing either as previously was a tad.

 

[shells2074]

Nothing else done but that.

 

[shells2074]

They mentioned to me a sleeve, as I didn't want another crap weld job doing in the first place. I'll get it looked at.

 

[TB Rich]

That manifold picture you posted is the biggest bodge ever. No wonder it cracked with no flexi's!

If you have the old manifold still or access to it, knowing it's been 'played with' - check it hasn't had the pre-cat internals removed. This is actually what the Cup Racer Clio's do, so if the previous user did this and now you have fitted a standard manifold with a working pre-cat. It would explain why it feels slower - pure speculation though on the state of the old manifold.

 

[shells2074]

Yeah its a mess. I'll ring in the morn about it. Only did it on Fri. I'll ask if still got it.

 

[shells2074]

Thanks guys you've been really helpful. TB Rich if your theory is correct, what's the next best move?

 

[shells2074]

Update: spoke to garage who fitted manifold, taking it back Fri for a check. I asked relevant questions prompted by you guys, so he's going to drive it and see. Either way whatever happened it's running less than perfect since manifold fitted

 

[TB Rich]

wait and see what they find and if you can view the other manifold or not still? Hard to say as there are a few variables still at play, such as if its all fitted ok, if the items fitted are not damaged and original, if the old manifold was infact tweaked or not? Get answers to those first, then after that there is only one way to quantify really and thats stick it on the rolling road. Id suggest going to RS Tuning as it's pretty local, accurate and there a load of other results from Clio's on this forum so it makes comparing easier (though not perfect as comparing results done on different days is never an exact science!).

 

[shells2074]

They haven't got the old manifold and assured me fitted correctly but then they would say that. Anyone local to Accrington on Fri?

 

[shells2074]

TB Rich you are a wealth of info, much appreciated. Thank you. Feel a bit less confused now

 

[shells2074]

If I get the car on the ramp tomor and take pics, I know it's limited with just photos but would you guys give me your opinion on the work if I post said pics?

 

[montana]

Yeah post them up

 

[Pav]

do it..will give it a go...

 

[shells2074]

Cheers

 

[shells2074]

Ok so being a girl and trying to learn mechanics on these motors, if the power has been lost since manifold replaced, could it be that it was like running decatted ? So running like a rally car lol. Now its 'fixed', I've lost the pull. It's going on a ramp this aft but they keep assuring me it was a matter of pipes replaced and it looks how should. Yes it's quieter but the numpty thinks cos I'm a girl I'm getting confused with quiet and less power. No its lost power d I c k he ad

 

[montana]

Ok so being a girl and trying to learn mechanics on these motors, if the power has been lost since manifold replaced, could it be that it was like running decatted ? So running like a rally car lol. Now its 'fixed', I've lost the pull. It's going on a ramp this aft but they keep assuring me it was a matter of pipes replaced and it looks how should. Yes it's quieter but the numpty thinks cos I'm a girl I'm getting confused with quiet and less power. No its lost power d I c k he ad

Yeah, thats what TB Rich suggested.

 

[shells2074]

So its unfortunate it's happened and to get it right would probably involve remap? Anyway waiting for ramp to free up. Any questions I should be asking? Look like I know what I'm on about and nod and stuff. Seriously though if any ideas to throw at him. Oh and they did a track rod end at the time too and steering out slightly. Don't think they could be arsed at the time

 

[montana]

So its unfortunate it's happened and to get it right would probably involve remap? Anyway waiting for ramp to free up. Any questions I should be asking? Look like I know what I'm on about and nod and stuff. Seriously though if any ideas to throw at him. Oh and they did a track rod end at the time too and steering out slightly. Don't think they could be arsed at the time

The only way your going to replicate how it was before (if it was decatted - we wont know for sure as they dont have the manifold anymore) - is if you get your new manifold decatted. Not sure if a remap with a catted manifold would give you the same gains. Not even sure how much real world gains a decated manifold would make anyway - for the amount of effort involved.

If the steering is out slightly then it could suggest they didnt get the wheel alignment (tracking) done at the time - ask them if they did.