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Discussion Starter · #1 ·
Hi guys

My F VVC feels quicker with the top off then when up - is this my imagination or is there some aerodynamical proof to back this up.

Also, I've fitted a 52mm TH and a K&N AIK - sounds nice but as for being quicker i'm not convinced, if anything it's a little more hesitant from a standing start. I've bought a cat bypass but have since read test reports that suggest it makes the car lose power in stead of gain - any opinions welcome.

Cheers
 

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Its in your mind unfortunately, it will be slower with the hood down.
You will also notice your fuel consumption goes up a bit with the roof off.
 

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welcome scuzza..........

your imagination I think :D

I thought the VVC had a 52mm TB fitted in the factory ??

cat bypass can indeed give a less power.
 

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SHARKYMGF said:
Its in your mind unfortunately, it will be slower with the hood down.
You will also notice your fuel consumption goes up a bit with the roof off.
I must admit, I had expected the fuel useage to go up much more than it does with the top down, that was a pleaseant surprise.
 

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Discussion Starter · #5 ·
thanks for reply guys - the VVC came with 48mm plastic TH as standard - the Trophy then TF's came with 52mm as standard.
 

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The 52mm TB will definitely improve throttle response and acceleration.

The K&N can improve these also if fitted with a few minor adjustments.

For instance: Have you fitted anything to assist heat shielding?
Have you got the supplied hoses fitted with a good source of cool air?

If the filter is just sucking in warm air from the engine bay, this would explain the lack of performance.
 

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Discussion Starter · #8 ·
Hi Krisxf

Can you expand a little on this as it's very interesting.

I have two pipes that go from the the cone (about 2" away) down to the bottom of the car and facing downwards/forwards (about 45 degress) - This was as per instructions so i presume is correct.

What would recommend regarding heatshielding - is it kind of like a refelctive foil or something ?

Cheers
 

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scuzza said:
Hi Krisxf

Can you expand a little on this as it's very interesting.

I have two pipes that go from the the cone (about 2" away) down to the bottom of the car and facing downwards/forwards (about 45 degress) - This was as per instructions so i presume is correct.

What would recommend regarding heatshielding - is it kind of like a refelctive foil or something ?

Cheers
Yep that is correct, but the pipe inly work when the cars is moving, thus if you are sat stationary for any length of time, the filter will be sucking in hot air. This can mean that from a stationary start, you will have less power with a K&N than with a standard filter.
The way to overcome this is as Kris says, to shield the filter either by fitting a heat shield between the filet and the engine or by enclosing the filter completely in an airbox thus isolating it from the hot air in the engine bay.
try searching the forum and you should come up with a few solutions ranging from carbon fibre airboxes to fan ducting and flower pots ;)
 

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Discussion Starter · #11 ·
ok, i'm just applying very very basic logic here, but, if you enclose the filter in an air box are you not restricting the air that comes from over avenues when moving - side vents etc..
 

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scuzza said:
ok, i'm just applying very very basic logic here, but, if you enclose the filter in an air box are you not restricting the air that comes from over avenues when moving - side vents etc..
When enclosing it (thus creating a vacume) you're better off using the side vent, and running the pipe down to that rather than under the car, this also allows for lowering without ripping the thing off at every speed bump.
 

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Discussion Starter · #13 ·
sorry guys - change of subject - i'm new !! - how do i get my pic up on screen like you guys ?
 

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I'd agree with JamesC's comment about fuel economy - I was expecting to see a major difference between roof up and roof down consumption - I'm very happy to report that it's nowhere near as bad as I'd feared. What I do fear is the fact that it's always bl**din' raining for the minute!

Damn you, Mr Weatherman! :irked:
 

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I've had my K&N on for 8 months (doesn't time fly?!) and to be honest, I've never noticed any problems pulling away from standstill. I can't really remember what it was like before I fitted the K&N but there certainly hasn't been a loss in performance. Whilst moving forward, it made it feel sparkier. Nothing earth shattering but there definately something there.

This is the enclosure. I got this one from abroad, but as mentioned above, you can make one yourself.




If you want a bit more power get a sports exhaust. Since fitting mine it's gone mad. Never realised that it would make that much difference, but it does!
 

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scuzza said:
hi Emma - so does the rounded bit go at the top, on top of the filter cone ?
Yep. :)

As mentioned previous, people have pretty much invented their own way to do this.

My way was to buy a Cadbury's cookie tin, munch all the cookies then throw away the lid, cut out a hole in the bottom big enough to fit the metal circular piece which comes with the kit and basically trap it in place between the filter and the tube. Then cut a 2.5" strip out of one side. This is where I have aimed all three* induction hoses so that the cool air is circulated inside the tin all around the filter.

*I have bought another tube from Halfords for £5 which I have run from the passenger side air vent.
 
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