Green cotton or pipercross?

[james.g]

Re: no.1, point taken, although i was trying to get across the fact that people often make a decision on a component (the filter) based upon the performance of the (induction) system, which can be misleading.

The standard max airflow for a cupra would be about 442cfm / 0.209 cu m/s - that equates to 256g sec, although this assumes ideal conditions. I'd be making sure my induction system was rated for this flow!

Also, when you consider the max pipe flow speed of 23.94 m/s, that gives a min pipe diameter of 10.5 cm for anything feeding fresh air to the filter, or from the filter to the turbo.

BTW, the minimum required filter area for this flow is 74 square inches - not actually that much!


What diameter pipework do you have?

Also, it's worth bearing in mid you're increasing your inlet temp by not using a CAI so the speed of sound will reduce accordingly - sq.root (1.4 x 287 x Temp[kelvin]) - and necessitate a larger pipe.

An isolated cold air feed will give you a noticeable increase in power - as long as it's done properly!

 

[J0N]

Re: no.1, point taken, although i was trying to get across the fact that people often make a decision on a component (the filter) based upon the performance of the (induction) system, which can be misleading.

The standard max airflow for a cupra would be about 442cfm / 0.209 cu m/s - that equates to 256g sec, although this assumes ideal conditions. I'd be making sure my induction system was rated for this flow!

Also, when you consider the max pipe flow speed of 23.94 m/s, that gives a min pipe diameter of 10.5 cm for anything feeding fresh air to the filter, or from the filter to the turbo.

BTW, the minimum required filter area for this flow is 74 square inches - not actually that much!


What diameter pipework do you have?

Also, it's worth bearing in mid you're increasing your inlet temp by not using a CAI so the speed of sound will reduce accordingly - sq.root (1.4 x 287 x Temp[kelvin]) - and necessitate a larger pipe.

An isolated cold air feed will give you a noticeable increase in power - as long as it's done properly!

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The standard max airflow for a Leon Cupra would be closer to 137g/s. The standard max airflow for a Leon Cupra R 210 and 225 would be closer to 160g/s and 169g/s respectively. If it were 256g/s then these cars would develop power within the regeon of 335BHP.

Its also worth bearing in mind that turbo charged cars are forced induction by definition.

As far as the pipework goes I am using 80mm from the airfilter, through the MAF to a Forge tip which at no point has a smaller inside diametre than the turbo inlet. (A K04)

Since changing to my current setup my inlet temp has actually decreased by 8 degrees although I have no proof of the ambient temperatures at the time the logs were taken but they wont have differed by a significant enough amount to really effect the intake air density in the real world, nothing that the intercoolers can't take care of. My airfilter is situated as close to the wing as I can get it so is in the line of the OEM intake funnel and as far away from heat source as possible. I will, however be fitting a CAI in due course.

Dont get me wrong, your points are valid and very interesting and you clearly know your stuff but as we have well and truly hi-jacked this thread for which I must apologise to epts2008 I feel I have to ask, which do you prefer, Green Cotton or Pipercross?

 

[james.g]

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but as we have well and truly hi-jacked this thread for which I must apologise to epts2008 I feel I have to ask, which do you prefer, Green Cotton or Pipercross?

lol

Given the choice i'd go for the pipercross as i had quality issues with a green filter before. Generally i would use K&N as they are good quality and still flow well with a surprising ammount of dust and rubbish caked on the surface.

BTW, the flow rate is a function of the capacity, volumetric efficiency and any boost. A half decent (eg Alfa twin spark) normally aspirated 2 litre will require up to 205cfm which works out to about 119g per sec! The number i quoted was for the 240bhp Cupra, full boost @ 7000rpm.

Even with a turbo engine it's worth eliminating any pipe losses you can, and it's also worth bearing in mind the intercooler will reduce the charge temperature by a set ammout, so if your charge temp going into the intercooler is 3C cooler, so will the charge leaving the cooler. Every little helps! (Christ, i sound like an Asda advert...)

 

[J0N]

Lol. Ok mate, fair enough. We'll have to get together some time and discuss world peace. Oh, and that's off the Tesco ad.

 

[wild willy]

And that matters because?
Its a valid reply to a valid question,
I speak from experience of doing literally hundreds of logs using both a Green and Jetex Filter. Most enthusiasts on this site want a high quality filter that both protects thier pride and joy and gives best performance. I was just offering my humble opinion, but bow down to your superior Knowledge.

 

[james.g]

Hey up Willy. Must seem like i've been having a go at you! Random coincidence i assure you..!

I suppose what i'm trying to do - probably badly - is give people a bit of fact / science to counter the endless sales jargon, pap and blather you get from industry. You would not believe the ammount of misinformation i see used to try to sell products, which i suppose isn't surprising given the money involved in the tuning market.

As for filters, i've found that K&N, Pipercross, ITG & Jetex filters are fine and will do a perfectly good job. All will flow at least 4cfm if you clean them annually, so you can easily work out what filter size you need. All filters benefit from running in an isolated cold air environment, either through being in an airbox, or baffling a cone. You will always benefit from reducing the restriction from the inlet piping (details i posted before).

To be honest that's about it! It does eliminate a lot of 'which is best' arguements and turns it into 'both are good enough'.

Of course there is the aesthetics factor. Some of the CAI kits are works of art and look fantastic under the bonnet - and if it does the job, why shouldn't your preference come down to which looks nicest?

Me, i tend to be a bit tight (need the cash for replacing tyres after 'enthusiastc driving') so i'd probably fit a panel filter to the OEM airbox and replace all the pipework to and from, which you can get to look surprisingly standard...