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Cat bypass pipe

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Hi there, better fuel economy as I have still have my standard exhaust so I am driving car just as normal. I am getting upto 8 MPG on a run now.

Once I get my new custom made sports exhaust, this will most probably go back down as I'll be putting my foot down a bit more to hear the exhaust sound more!

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Thinking about doing the 3rd cat delete on my 2011 S.

I would like just a little more ferocity from the exhaust when the occasion calls but don't want to completely overpower the supercharger whine and want to keep the noise level neighbour-considerate. 

I know I'm in the minority but i also  like the look of the standard oval tail pipe and don't want the expense of complete new back box and pipes

Looks like my current decat pipe options are

Larini - £149 delivered (elise-parts)

2bular - £185 delivered (2bular direct)

Any new advice / warnings from others that have had these fitted?

Or other alternatives?.. or any reason I shouldn't bother at all?

Thanks

Warren

 

 

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I am confused now!

My 'new' Evora NA SR has a 'sports button' that, amongst other things, opens up a valve in the exhaust.

Can someone tell me;

1: Where this valve is, what section of the exhaust? 

2: Would fitting a de-cat pipe make any difference with the valve both 'open and closed'?

3: Or with the valved exhaust, there is no value in having the de-cat pipe fitted?

Many thanks!

Pete :>)

 

 

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Hi Pete.  The valve is in in the back box, which switches the route that the exhaust gasses take.  It switches automatically to the more open (louder)  position after about 3000rpm i think, but with sports mode on, it will always be open.

So you can fit a decat pipe and retain the valve operation as cat is further north.

It you wanted to change the back box and pipes, there are exhaust options with and without valve operation.

Where it gets a little hazy for me is when and for which models, Lotus deleted the 3rd Cat as Standard.  I'm sure it was deleted in the 2012 S, but I've seen posts / videos for folks in other parts of the world that have seemingly done the decat on newer NA cars.  I'm sure someone here will have the answer to that.

Edited by w022a

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Excellent many thanks!

So all I need to find out now is do I have the '3rd Catalyser' on a MY14 NA Evora? 

If I do, then reading on here, the de-cat will certainly be replacing that, given there are the 2 other cats in the 'headers'!

Cheers, Pete. :>)

 

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I have 2014 NA Evora SR and mine definitely doesn't have the 3rd cat so probably nothing for you to do on that front.

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Looking at the evora model year / milestones page on the playground, I think 3rd cat was deleted all non-us cars for MY012, but never deleted for the US cars. So pete, I think you're already golden.

I still would like some persuasion either way as to whether to do mine :)

Edited by w022a

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Cheers! 

I may then go for a 2ubular or Larini backbox but will live with the existing for a while first. 

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The third cat was needed to meet US emissions regulations, hence why Lotus later left them off non-US cars but had to leave on for US market.  The decat pipe is a constant bore section in an S shape that drops into the space of the third cat.  There are only minor differences between the two options: 2bular is a single pipe bent to shape, Larini is three sections joined together.  The 2bular therefore looks more elegant, but you aren't going to be looking at it after it's fitted!

I did mine (2011 S) shortly after I bought it and do like the extra throatiness it's got.  It's still fairly neighbour-friendly, although my family say they know it's me coming down the road to home!  It's still just within noise limits for "quiet" trackdays at Goodwood, provided I don't follow too close to another car going past the drive-by sound meters.

It's a cheap and easy upgrade and you get to do childish stuff like this: 

 

 

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On 3/2/2018 at 06:48, w022a said:

Thanks Tom.  I'm sold!

I should have a 2bular one for sale in the next week or so if you're in no desperate rush.

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11 hours ago, Benmac said:

I should have a 2bular one for sale in the next week or so if you're in no desperate rush.

@Benmac I'm in no rush so I would be interested if you are selling one. I'll pm you, cheers

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Had my NA decatted yesterday with a 2tubular pipe.

Soundwise it was a marginal improvement.  Nothing significant.  If it isn't as cheap as it is to do I would not bother.   Other benefits include a few kilos shaved off the weight of the car and theoretically a slightly cooler engine bay.

Definitely do it for under £300 (1hours labour) but anything over and it isn't worth it.

Edited by Registered

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1 hour ago, Registered said:

Had my NA decatted yesterday with a 2tubular pipe.

Soundwise it was a marginal improvement.  Nothing significant.  If it isn't as cheap as it is to do I would not bother.   Other benefits include a few kilos shaved off the weight of the car and theoretically a slightly cooler engine bay.

Definitely do it for under £300 (1hours labour) but anything over and it isn't worth it.

Thanks for the reality-check.  Ben has agreed to sell my his old decat pipe and i'll have it fitted when the car will be in for it's Service anyway.. so i'll be paying a modest price and I will expect only a modest difference.  I will record the before and after sound with some decent recording equipment and post the results here.

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Had Silverstone do my 2011 S.  Best bang for buck mod I’ve ever done 

 


Previously owned :Exige 380,  Exige 350,  Evora 400,  Exige V6S,  Esprit GT3,  2-11 SC,  Evora S,  Elite 501

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Sounds bloody great! 

The worm that took the video also deserves a 'Best Cinematographer' award! B-) 

  • Haha 1

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