Aftermarket / Performance Sealed Airbox Type Air Filters

[V8RX7]

I have supercharged my MX5 and it's making approx 250bhp

I am cutting through the firewall to get cold air from the base of the windscreen, I want to duct that to a sealed airbox type filter

I've seen the various offerings from Ramair, Pipercross etc but they don't appear to be much different to the chinese copies at 10% of the price

Has anyone any experience of the cheap type - I'm happy to swap out the filter for a better one but I do wonder how different they are in reality

I'm more than happy to use a std OEM type if one will fit

The other option is to use a paper element (my preferred option) and build a cold air box around the duct.

Essentially how different are these (most expensive first)

https://www.ebay.co.uk/itm/Pipercross-C7000-Cerami...

https://www.merlinmotorsport.co.uk/p/itg-universal...

https://www.ebay.co.uk/itm/Pipercross-Venom-Univer...

https://www.ebay.co.uk/itm/RAMAIR-Performance-Encl...

https://www.ebay.co.uk/itm/3-Carbon-Fiber-Cold-Air...

[V8RX7]

designforlife said:

but on a car thats already FI i doubt you'll see much of a tangible difference to performance.

That's the thing... it's been dyno proven that superchargers really don't like sucking.

Increasing the TB size alone gave over 10bhp

Some ducted 4" flexi pipe around the engine bay - that cost 15bhp

[V8RX7]

designforlife said:

If you have the budget and want the best gains, this was supposedly one of the best/the best induction kits for the mk1-

Jackson racing CAI -

https://www.ilmotorsport.de/shop/article_detail.ph...

To be fair I spent about that on a carbon fibre CAI for my DC5 and it was worth every penny...and these higher end kits have a very OEM quality fit usually.

I recently sold one - the quality is very poor for the price

As I mentioned mine has to be as short an intake as possible hence it's just a 90 degree bend then one of the mentioned boxes and another elbow through the firewall - total length approx 18"

[V8RX7]

stevieturbo said:

At only 250hp...I'd be using a factory paper filter as a first option.

Even a very small OEM filter will easily offer more than enough flow for that low power.

Yes as stated that's my prefered option

If that were correct then why do manufacturers use such different sizes ?

A sub 200bhp car can have one twice as large as a 1.0 car

Also the inlet / outlet sizes are far too small on many - as stated dyno proven 10bhp gain increasing throttle body size so sucking through two smaller openings will lose that.

Hence looking at the aftermarket