43 replies to this topic

[Jester666]

Hi All,

 

What is the best air filter for a Stage 2 VXT conversion. Some on here seem to say stay with the standard filter.

 

Are there any free flowing filters by other manufacturers and are they any good (and where can you get them) ? Obviously I don't want to risk any engine damage from really poor filtration.

 

ANY COMMENTS GREATLY APPRECIATED 

[Rosco 76]

Standard

[Gedi]

Yep, stick with the paper one if you value your engine.

It's good for over 500bhp anyway, so no need to change it

[Nev]

Yep, stick with the paper one if you value your engine.

It's good for over 500bhp anyway, so no need to change it

 

1 OEM paper filter is not good for 500 BHP, I know as I designed my own new dual panel filter and upgraded to 4" inlet pipe and got an extra 55 BHP. I know 3 other guys on here who had similar experiences by improving the airbox on cars with > 350 BHP, Simon, Duncan and Carsten.

 

Even at 300 BHP it's worth having twin paper filters BTW.  

Edited by Nev, 16 June 2014 - 06:12 PM.

[slindborg]

Maybe replace "the" with "a" in gedis post and its ok

[chris]

I read this somewhere :

 

"Don't waste your money on an expensive overhyped inlet air filter. OEM is sufficient to 400 BHP (and probably better quality)."

[Nev]

I read this somewhere :   "Don't waste your money on an expensive overhyped inlet air filter. OEM is sufficient to 400 BHP (and probably better quality)."

Yep that was me, the OEM filters can be relied on to actually filter. However they do create a pressure loss, as I explained I got a massive power increase by doubling the surface area of the filter. Any engine running over 300 BHP will get mild gains at a guess if they do this, up to massive gains if you are already running 500 BHP.

[Jester666]

Thanks for all your responses, seeing as I'm looking at 245-250 bhp I think I'll stick with the standard one. However the discussion about the twin paper filters is interesting. Are they available commercially ?

[Duncan VXR]

Oem is the best option for filtration and restriction higher up the range is more linked to oem airbox setup which was proved with Dave on the rr and removed It has a good surface area, itg panel rated to high 400's if I remember correctly speaking with Andy DG

[Jester666]

Cheers Duncan VXR and all those who responded. For my purposes I am going to stick with the OEM filter. I was just checking that a re-map to stage 2 would not be benefited by a different filter 

[Gedi]

 

Yep, stick with the paper one if you value your engine.

It's good for over 500bhp anyway, so no need to change it

 

1 OEM paper filter is not good for 500 BHP, I know as I designed my own new dual panel filter and upgraded to 4" inlet pipe and got an extra 55 BHP. I know 3 other guys on here who had similar experiences by improving the airbox on cars with > 350 BHP, Simon, Duncan and Carsten.

 

Even at 300 BHP it's worth having twin paper filters BTW.  

 

 

Yes but that's linked to the airbox design and not the actual filter itself.

I've read many times that a standard paper filter will provide enough airflow for over 500bhp.

 

I seem to remember someone (maybe Simon/Dave) doing some tests using the OEM airbox, and finding no difference between an paper filter and aftermarket ones. I realise he was 'only' running ~400bhp though

[Bumblebee]

Apexi filter if you don't mind a loudish noise

[wowzer]

I use a k&n panel filter with no problems the air box is modified for air flow . It's a noisier set up than standard

[slindborg]

Apexi filter if you don't mind a loudish noise

And a shortened engine life...

[Nev]

Yep, stick with the paper one if you value your engine. It's good for over 500bhp anyway, so no need to change it

  1 OEM paper filter is not good for 500 BHP, I know as I designed my own new dual panel filter and upgraded to 4" inlet pipe and got an extra 55 BHP. I know 3 other guys on here who had similar experiences by improving the airbox on cars with > 350 BHP, Simon, Duncan and Carsten.   Even at 300 BHP it's worth having twin paper filters BTW.

  Yes but that's linked to the airbox design and not the actual filter itself. I've read many times that a standard paper filter will provide enough airflow for over 500bhp.   I seem to remember someone (maybe Simon/Dave) doing some tests using the OEM airbox, and finding no difference between an paper filter and aftermarket ones. I realise he was 'only' running ~400bhp though

I'm sorry, but saying that 1 OEM paper filter is sufficient to allow good flow for 500 BHP is not correct. 500 BHP consumes something like 750 cubic/feet of air per minute - just think about that for a moment, that's the volume of a small room in 1 minute! A single paper filter will cause a large pressure drop with that much suction, which in turn means the turbo has to work harder, which in turn means you lose power. Both the theory and actual implementation of a dual panel box (with dyno figures) demonstrate my point. When I installed my new airbox the power increase was quite astonishing when I drove it. One must be careful about reading things off the internet and assuming its correct, there is an awful lot of dis-information out there I'm afraid.

Edited by Nev, 17 June 2014 - 09:31 AM.

[siztenboots]

your compressor wheel blades will thank you for having the best filtration you can get

[Nev]

your compressor wheel blades will thank you for having the best filtration you can get

This is dead true, I had a shitty mushroom filter on my car for only 1500 miles and when I inspected my turbo the compressor blades were pitted and the leading edges were eroded so I had to send it off for a £400 grind and balance. You can see some pics in my write up about it here: https://sites.google.../07---update-26

Edited by Nev, 17 June 2014 - 09:37 AM.

[Gedi]

One must be careful about reading things off the internet and assuming its correct, there is an awful lot of dis-information out there I'm afraid.

 

 

I was just about to respond with the same line 

I can't even find the data anymore, so it's entirely possible that I got it from an even more reliable source than the internet ..... my local pub on a Friday night 

[siztenboots]

I bought a turbo described as "Turbo Dynamics Stage 2 Astra Vxr Turbo 3,000 Miles" , and had it serviced by TD. The engineers report stated pitting and wear on the comp wheel , which they remachined.

[denno]

Apexi filter if you don't mind a loudish noise

And a shortened engine life...

Out of curiosity how many engines lives have been shortened through the use of an apexi filter?