Which air filter.
Discussion
Yeah but K&N are cleanable and reusable, so apart from the flow rate......yeah ideally you'd have to have your car dynoed to make use of the improved flow if it has adjustable fuelling kit installed......and the inner core won't go rusty coz there isn't one.
Having said that, I bought the std replacement from tvrparts, but then my pre cat hasn't got adj fuelling kit onboard.
Having said that, I bought the std replacement from tvrparts, but then my pre cat hasn't got adj fuelling kit onboard.
The Piper one is washable but the foam degrades and crumbles. I guess mine was maybe original so 20 years old so not too bad in the great scheme of things. I'd be interested in if the filter is thought to being a bottleneck and if this improves airflow. Isn't the AFM the point of greatest restriction do you need to upgrade that too to make use of increased volume on from the filters?
indigochim said:
The Piper one is washable but the foam degrades and crumbles. I guess mine was maybe original so 20 years old so not too bad in the great scheme of things. I'd be interested in if the filter is thought to being a bottleneck and if this improves airflow. Isn't the AFM the point of greatest restriction do you need to upgrade that too to make use of increased volume on from the filters?
Ignore the AFM for now. As it is not relevant in my case. The K&N in the picture has done About 10,000 miles and in that time my car has been service by specialists twice and looks pretty shagged.
I wonder if anyone has any back to back Dino runs on both type or perhaps some type of date sheet for the two.
pipercross for £30 or K&N for £60 life span and quality an unknown (I think).
Zener said:
Using twin you wont overwhelm either (flow wise) no way 
but Piper-cross filter more efficiently and thats a fact 
they get dirty quicker too because of that fact also
^^^^ this. but Piper-cross filter more efficiently and thats a fact they get dirty quicker too because of that fact also I’d actually go for the K&N on the twin intake. As it will clearly pull about the same air as when it hits the single tube anyway so the K&N’s will not need cleaning so often which is a right aggro to do regularly especially with two surely.
Remember they can get wet and more susceptible to collapsing under hard acceleration which is why I personally like the K&N as they are strong and keep there shape.
Based on the size of filter and intake pipe I seem to remember both brands can handle the amount of suction pulling through them ok.
Chuggaboom said:
Yeah but K&N are cleanable and reusable, so apart from the flow rate......yeah ideally you'd have to have your car dynoed to make use of the improved flow if it has adjustable fuelling kit installed......and the inner core won't go rusty coz there isn't one.
Having said that, I bought the std replacement from tvrparts, but then my pre cat hasn't got adj fuelling kit onboard.
What is an "adjustable fuelling kit?? " If by chance to can get the odd extra cubic foot of air in at peak RPM, then you might have to remap the engine? - but stop--- the TVR RV8 fuel map reaches peak fuelling at around 5400 rpm, and this is the top of the map so you cant make adjustments above this without an aftermarket chip. The result is the engine actually runs richer above 5400 rpm as the engines volumetric efficiency drops so less air is drawn in per engine cycle. This causes the power to drop off faster than needed, but as you are pushing the RV8 limits at 6200 rpm is no bad thing anyway and it helps cool the piston crown. The bottom line here is the engine is unlikely to run lean at peak RPM. Any area below 5400 RPM is metered in the map against airflow anyway, just like opening and closing the throttle plate.Having said that, I bought the std replacement from tvrparts, but then my pre cat hasn't got adj fuelling kit onboard.
sapper said:
Ignore the AFM for now. As it is not relevant in my case.
The K&N in the picture has done About 10,000 miles and in that time my car has been service by specialists twice and looks pretty shagged.
I wonder if anyone has any back to back Dino runs on both type or perhaps some type of date sheet for the two.
pipercross for £30 or K&N for £60 life span and quality an unknown (I think).
I don't have anything to reference. But many years ago I did do a lot of reading and research. And there is good info out there.The K&N in the picture has done About 10,000 miles and in that time my car has been service by specialists twice and looks pretty shagged.
I wonder if anyone has any back to back Dino runs on both type or perhaps some type of date sheet for the two.
pipercross for £30 or K&N for £60 life span and quality an unknown (I think).
The cotton weave filters such as K & N do flow well and can give more power over a paper filter. Although ultimately the filter element only contributes a tiny amount. Max of 5hp, but more like 2-3hp or less. The rest of the intake design will generally have much more bearing.
However the additional flow over paper is generally down to slightly worse filtering, although the cotton weave is still fairly good. The issue comes however that a cotton weave filter will become dirty and clogged much sooner than a paper filter. And once dirty the cotton weave generally flows less than paper. Therefore you need to clean a K&N far more often than you'd change a paper element.
And here is one of the issues. The proper cleaning and re-oiling kits for K&N are very expensive. It is also very easy to over oil a cotton weave filter, which not only will make it flow far worse than it should, if you have a MAF you can end up with oil on it and lots of issues.
Foam filters from my research in the past generally flow better than cotton weave filters, but this is 100% down to far worse filtering ability. In a dusty environment I don't think these would be the choice of filter at all. Due to the lesser filtering ability they don't clog up as quickly as a cotton weave filter. But still require cleaning and re-oiling. Which is generally cheaper than K&N and less frequent, but if in dusty environments the oil will get dirty very quickly. And without the oil it just won't be filtering fine particles.
The best filter type I came across was a synthetic weave filter. A company called Donaldson makes such filters. These tend to have the same filtering ability as paper, but flow rates akin to the foam filters and have none of the drawbacks of foam or cotton weave.
https://www.donaldson.com/en-us/engine/filters/pro...
A correctly sized / shaped filter of any type will not reduce airflow.
A larger than required size of filter will extend the service life before clogging restricts flow.
It takes a lot of dirt build up to restrict flow significantly, and extra dirt on an oiled filter soaks the oil and becomes part of the filtering medium itself.
The std foam filters on griffs/chims whether round or flat are good for in excess of 300hp. The restriction is the pipework not the filter for most owners. I've run a Griff to 350hp on the flat version of the filter but had modified the fibreglass box to have two exit pipes not just one. See note below about smoothbore pipes.
On a Chim the ACT smoothbore intake is unrestrictive to at least 350hp (dyno tested) and is therefore a very good thing. Not sure on the Griff but the sharp bend under headlight would be the most restrictive part so make sure you get that bit right.
Edited by spitfire4v8 on Wednesday 26th August 10:34
Foam filter oiled correctly do not filter worse than cotton its why OE manufacturers (the big 4) use them for Moto X and off road motorcycles (certainly did back in the day) even used on the road I found (new pre-oiled) K&N's let a fine dusty/gritty paste accumulate on the bell-mouths of my Weber side-draughts post filter media back in the day 
I went over to Piper X and never looked back the oily film remained from fuel stand off but the gritty feel gone , I was not ecstatic about this time as this was a new build and not a particularly cheap one as I remember so that was me and K&N done I prefer real world results than sponsored magazine articles which I'm sure K&N are use too
I went over to Piper X and never looked back the oily film remained from fuel stand off but the gritty feel gone , I was not ecstatic about this time as this was a new build and not a particularly cheap one as I remember so that was me and K&N done I prefer real world results than sponsored magazine articles which I'm sure K&N are use too spitfire4v8 said:
On a Chim the ACT smoothbore intake is unrestrictive to at least 350hp (dyno tested) and is therefore a very good thing. Not sure on the Griff but the sharp bend under headlight would be the most restrictive part so make sure you get that bit right.
Having just fitted one of the ACT smoothbore kits - I knackered the standard tube after taking it out to swap the radiator - I can confirm that fitting the bit that runs from the air filter to the bulkhead is a right pita. You need arms like an orangutan, and preferably three of them. The problem is that it's an awful lot stiffer than the original pipe which is quite bendy, so manoevering it about in the space it's in is really hard.Forums | Chimaera | Top of Page | What's New | My Stuff