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Free Performance Increase

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PostPosted: Sun May 15, 2005 8:00 pm    Post subject: Free Performance Increase Reply with quote

Hi all,

I was reading one of the other threads regarding air filtration for the 50th the other day and I happened to be checking the levels under the bonnet yesterday when it dawned on me that the existing filter arrangement must actually strangle the V8's performance.

Essentially the air filter housing works fine but the cover plate and funnel must choke the engine as the inlet is probably only around 25mm diameter. As the 50th V8 sucks in 4 litres per go trying to get it all through the restrictive funnel can't be doing it any favours.

Anyway I ran her this weekend with the funnel off and I got an extra 10mph top speed up the local bypass (bit of a hill - dual carriageway). She'll normally do about 60mph full throttle while with the funnel off she did 70 no problem. The filtration is of the same quality as this is not affected. The only up / downside is their is a lot more induction roar.

I quite like it though so I think it'l be staying off...
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Joined: 14 Nov 2004
Posts: 1505
Location: Hampshire

PostPosted: Sun May 15, 2005 10:09 pm    Post subject: Reply with quote

Interesting point Allan, never thought about that.

Does anyone know if the ECU will adjust itself to these canges or would having the chip re-mapped be needed to make the best of it?

Best regards

GB 002
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PostPosted: Mon May 16, 2005 9:45 am    Post subject: Reply with quote

I have read a bit about the GEMS system but i'm still no expert.

As I understand it the management system always tries to optimise fuel / air intake based on whtever value is programmed in. The factory settings are set to run a bit lean in the mid range for international emissions regulations and when you get MA to re-tune it he provides a map based on achieving maximum power and efficiency rather than on emissions.

I don't think removing part of the filter will have any effect at lower revs as it will not be that restrictive however when the engine is really sucking in air at higher revs it may make the following difference;

If the engine is not able to suck enough air in then it will not be able to deliver as much fuel as it is capable of in order to keep the fuel air map balanced however it it is less restricted then it can suck more air in and deliver more fuel and therefore more power while still sitting withn the fuel map.

I know a lot of the TVR boys say that (because the TVR exhaust is free flow) the bggest restriction is getting air in and there are a lot of tuning products for the top end like carbon air boxes and different length trumpets to try and achieve this.

I tried to be objective when testing it as there is a lot of psychology with tuning your car but she definitely pulled at least another 8 mph up the bypass on Saturday. Razz
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Joined: 02 Feb 2005
Posts: 290
Location: Gloucestershire

PostPosted: Tue May 17, 2005 2:00 pm    Post subject: Reply with quote

Allan - I know it's kind of staring you in the face, so you probably already have - but have you approached Steve Brookes to see if he wants to swap his induction kit for your standard air box?


PS - interesting what you say about removing the funnel - I will give it a try too. I assume there just an increased chance of getting water/muck into the can in dirty conditions?
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PostPosted: Tue May 17, 2005 6:17 pm    Post subject: Reply with quote


The possibility of getting, primarily, water in there is the only down side as far as I can see. If you look at the bottom of the cylindrical housing there is a little rubber duck bill to let any water out that gets through the funnel. So to a certain extent they are capable of dealing with a little water. This air filter is also fitted to the diesel Defender and I think the Discoverys too which are better suited to deep water.

I regularly get mine dirty, see previous posts regarding my side step, and i have only ever got a few splashes of muddy water up that far, even when ploughing through water in a see who can make the biggest wave sort of way. If you're in so deep that there is a chance of getting water actually sucked in then the GEMS is going to go first...! So I don't think it is a major problem. But use at your own risk. Smile
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Joined: 19 May 2005
Posts: 217
Location: Doncaster South Yorkshire

PostPosted: Fri May 20, 2005 8:12 pm    Post subject: Reply with quote

bin the air box completely fit a splash guard on it if your thinking about deep water...better still don't!
using the 57i from K&N works a treat speeds things up nicely the roar sounds better than the OEM and the replacement which is now for sale if any of you guys want it cheap?
what abouot tuners any of you guys played with tuning yet?
i want to get mine set up bang on also on gas if possible.
Sadly not a 50th member any longer more like a hanger-on if you know what i mean.
Maybe one day i will return.
Ex number 093 owner.
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