lowered performance with new cat back?

[Pav]

you tell them girl :swear:

 

[shells2074]

Oh can one of you sort it for me haha. I'll pay!!!

 

[shells2074]

[MENTION=51445]Kazumz[/MENTION] it wasn't Renault themselves, it's a Renault breakers but the mechanics are Renault trained. Supposedly

 

[shells2074]

[MENTION=29138]Chris91[/MENTION] thankyou. I'll mention what you said

 

[TB Rich]

So they put the flexi on between the main cat and centre silencer?? They would only have done that if they repaired the manifold which had no flexis' - but then I thought you said you had a replcaement manifold fitted - supposedly OE just 2nd hand?

I think it would help if you could just iterate in black and white whats come off and whats gone on, because between this thread and the other in general chat - I'm a bit lost as to what's exactly gone on here?

 

[shells2074]

 

[shells2074]

 

[shells2074]

Manifold replaced. OE. So they've put a flexi on where it wouldn't normally be it seems. How would that affect performance?

 

[shells2074]

Sorry and yes the original had no flexis on it. Botch weld instead.

 

[shells2074]

 

[shells2074]

Original one^

 

[shells2074]

 

[shells2074]

It's like this now.

 

[TB Rich]

thanks.

so before:

• Original manifold, botched with no flexis (as photo)
• Centre system had no flexis either (hence cracked mani!)

After:

• New manifold now a standard item with flexis
• System now has flexi in it between the main cat and centre silencer.

Seems totaly random as to why they put the flexi in the system, they had no reason to change anything there unless you had a crack or blow there?? But even then with flexi's now in the manifold it would have been better to use straight tubing in my opinion.

So, getting back to the power issue, unless as mentioned the pre-cat is blocked (unlikley but not impossible) then the issue probably lies with the change they made to the system. Now a flexi won't in itself cause a power issue, but that's assuming it's properly installed. How it looks on yours is well, a bit tardy
If I relate to a similar issue with mine, I had a centre silencer installed in an otherwise straight through system. I lost 10bhp from doing that, and it turns out the bore of the exhaust is reduced where they installed the silencer - i.e. they done a **** job! I'm suspecting a similar thing here. They have bodged that flexi in and probably reduced the bore on 1 or both sides of it. These cars are very sensitive to exhaust changes hence all the flat spot stuff people get with them. I've never had a car so sensitive to exhaust changes before however slight.

 

[Deaks]

Looks like a child has played with your car.

 

[shells2074]

Thankyou!! Much appreciated all this time you lot have given me re this problem. So that oddly placed flexi could be hiding the problem?

 

[TB Rich]

yep def the most likley culprit. Also just to say I meant to say the flexi is installed between the main cat and centre silencer, not between the 2 cats - I'll edit my post in a sec.

 

[shells2074]

Any ideas as to how I tackle this over the phone? Just ask that I have a straight pipe where that centre flexi is for starters? They're looking into the cat being blocked too.

 

[shells2074]

Yeah I get ya. At least now I feel armed and I caught them a bit off guard today when they looked at it on the ramp. I got involved under the car, asked questions and actually sounded like I knew what I was on about. I'm learning thanks to you lot.

 

[TB Rich]

Any ideas as to how I tackle this over the phone? Just ask that I have a straight pipe where that centre flexi is for starters? They're looking into the cat being blocked too.

Well it's hard to tell with an image over the net but it looks like the flexi isn't quite centred against the pipe coming from the cat (might be my eyes!?), and after the flexi - leading to the centre silencer, it looks like the bore does reduce in size??

Obvioulsy hard to tell from 1 pic, but regardless it doesn't look great. Also, as you were paying for the car to be fixed as standard, the standard car doesn't have a flexi there - so you could maybe mandate that it be removed and done properly as standard.

However.........in my opinion though, I'd just take the car to a local custom exhaust place, have a quick Google for say your local Powerflow place (someone on here local might have a place to recommend), because this is a 20min job for them to cut the old flexi out and install a properly sized pipe.
The expensive job was replacing the manifold, and thankfully that looks fine and because it doesn't require welding skills to install - there is very little scope for the fitment to be wrong. Pretty much there are probably about 8ish studs that centre the manifold flange to the head to locate it and only require tightning, and we can see the flexi's and pre cat visually look fine.

I'm sure many people would say get the original place to re-do it, but in my experiance it pays to take it somewhere else for a proper job and just avoid the first garage in the future. I know people shouldn't settle for being ripped-off but I'm all spent out with wasting time with ****'s in garages! Frankly if they were capable of doing a good job they would have done so first time, because we're not talking hard stuff here!!