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Feeling down on power - Evora S

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So...while I am reasonably competent at changing parts out on a car, I am no mechanic and my diagnostic skills are woeful.

I noticed, during a long (and spirited 😉) drive home a few weeks ago three changes.  They occurred mid-drive and hence my senses picked up on the changes quite easily:

1) A marked change in the exhaust tone.  The car sounds more droney now, but less so in sport mode.

2) Fuel consumption - While subjective, it's markedly worse, based on what I usually achieve from it it - which normally between 200-250 miles a tank*, particularly as I've been driving very carefully as I try to listen in on the car. I'm now seeing less than 200miles.

3) Power. Its basically lacking and across the rev range but most notably between 5000-7200 (red line) while still fast its lost the urgency, that little moment where you really pile on the speed.  For example, in third gear, round to the red line it felt like I was just revving it out with no further power being developed from ~5500.  As peak power is generated right at the top end of the rev range as you would expect from a supercharged engine.  I plan on doing a little video of this and posting it for comparisons / timings.

So initially, I'd really appreciate some suggestions, things to check, things to try and if anyone is able, some comparisons!

My current thoughts are exhaust, manifold or catalyst issues.  I don't have any warning lights and my OBD scanner shows everything responding normally.  The dealer gave it the once over but I don't think did anything more than what I've done RE plug in to diagnostics.

 

*for the record I got 29mpg on a long run to Wales at a steady speed over about 230 miles - which used less than three quarters of a tank.

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If its not mis firing, which could be plugs / coils etc, I would also look at possible Cat issues - esp the pre cats in the manifolds, although I don't know how you would test to see if they are breaking down - short of removing them. Sounds like a main dealer visit - any warranty?

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Might be a stuck thermostat.

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Only thoughts I had were:

Pre-cats melting or breaking up;

Loss of wool packing in silencer changing back pressure;

Loose supercharger hose.

You might be able to check the pre-cats by dropping the de-cat/cat pipe and using a borescope from underneath.

Hope it helps,

Steve

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Packing in silencer is a good idea, and worth checking the hose for sure!

 

Unfortunately I don't have a borescope, but will read up on other symptons of failing Pre-CATS.  I am suspicious of those, the driving that day had been a bit (ready very) full on, the most I've pushed the car, full-throttle wise, and it was a VERY straight road 😉 so I do think I may have cooked them!  The cars on 63000 miles now too.

 

 

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I bought my borescope from Amazon (other vendors are available) and it was very reasonable at £30, so a good investment. The cat/decat is very easy to get off so should be possible to do without taking it in somewhere.

Good luck!

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get a compression check done on each cylinder just in case the piston fail problem

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Armchair diagnosis - sounds like manifold-cat collapsing (but i might expect that to throw a code?) or exhaust valve stuck on quiet?

 

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