Lucky Breathes Easy

I guess so, and in theory the best filter upgrade would be just a much bigger paper filter, so you get the same filtering quality with higher flow capabilities. I just assume it wouldn't fit in the housing ! :LOL:
 
Richard, that's spot on! That really is the point of the conical design over the standard Rover offering - it presents a much larger area of filter mefium to the airflow. If I could buy that shape in plain paper filter material, I would. The nearest I've got to it is the filters I'm using. But note that they are a happy accident, I went looking for K & N's and was offered these instead. I was fortunate that they played to my prejudices on oiled filters, but can't claim any credit for having sought them out! And they were much cheaper - you pay for the K & N name!

Chris
 
Now that Lucky, my '70 S1 3500 is nearly ready for his trp to the rolling road, I thought I'd see if there were any quick and neat mods to help his breathing. This on the principle that changing the induction side after a rolling road set up will definitely generate another visit, whereas if I change the exhaust I will probably get away with it without resetting the engine.

Now the obvious thing to do is to throw away the Rover air cleaner cylinder and elbows and substitute a pair of K&N's mounted direst to the carbs. But in the first place I think it looks very chav and also I don't like having to sit and listen to induction roar. So I had a look round to see if I could do anything with the existing air cleaner box. Eventually I found this nice pair of K&N look alikes which bolt directly in place of the existing circular element with the addition of one extra rubber sealing ring against the end cap. The extent of the mods is to drill a hole in the end of the new filter and then find a longer screw to locate into the existing bridge piece.

The filter is an MPUAF9 from http://www.streetwizeaccessories.com/index.php which you are likely to find in local accessory shops. Advantage is a huge increase in the area of filter medium available for air to get through and elimination of the right angle turns inherent in the old circular filter. And nobody can tell from the outside! I may well go on to increase the diameter of the inlet trumpet to the filter box as well.





Chris
Hey mate, can I confirm this is the filter: https://www.amazon.co.uk/Streetwize-MPUAF9-Chrome-Sports-Filter/dp/B002C2QFEE
 
An interesting subject - on ‘Wheeler Dealers’ they usually argue that ‘K&N’ type filters don’t help power because they take warm air in which is less dense than cold, so lower in oxygen content.

They say a good inlet pipe near the front of the car is better.

Just a question
 
Hi, That's right, even better if there is mist in the air or rain because the water vapour helps again. Have you ever noticed the engine runs better on cold misty mornings?

Colin
 
Years ago I experimented with water injecton, but the kit I really needed was not generally available back then. You need a very specific water droplet size in the vapour to work, and this is only possible with a very high pressure pump and tiny nozzle.
After my trials I spoke at length with Aquamist who specialise in systems for boosted applications, they said that water injecting a normally aspirated engine although not a total waste of time would not see any massive gains. They did say that spraying a mist over a cold air intake filter would not do any harm though.
 
Hi, I had a kit for it when I was running a 3 litre Essex V6 in a Cortina Which essentially ran the water in a pipe through two of the exhaust manifold branches which was boiled and the steam was piped into the air filter. It was never commissioned and used because the engine was moved to another car.

Colin
 
All this talk is great, especially about getting cold air into the air cleaner. Below is a pic of the 928 front engine bay, showing the air intakes on top of the radiator, feeding into tubes that run into the air cleaner casing. Note the rubber seal on top of the inlet housing that seals onto the bonnet, and forces the air into the radiator or the air cleaner feeds. The actual element is 500x140mm, feeding initially a 4.5L 220hp engine, and still used all the way up to 5.4L and 350 hp.
My 2.5L turbo Subaru, producing 250hp has a similar air inlet over the radiator feeding directly into the air cleaner casing behind the RH headlight.
3ly2Cd4.jpg

I am thinking of finding a neat way to run a tube from the air cleaner casing to a source of clean ambient air in the P6 - have a length of 2.5" flexible hosing handy.
 
Hi jp928,

Good to see an old thread again.
Years ago I used a cold air snorkel (sucking air from an outlet in the NSF inner wing) on my 3.9 P6.

In latter years, I swapped the P6 Air cannister for the SD1 version with the much larger intake pipe (also used by SydneyP6) and also put an air scoop on with the appropriate hole in the bonnet to allow hot air out when idling.

I presume you have seen Beastie. It looks like it has air intake pipes mounted at Radiator level (rather than above the rad as in the 928 bay above). I would have thought that wasn't the more efficient location as it would draw in warm air through the radiator (I'm probably mistaken as to where the pipe inlets are).

Simonrocker2.jpgscoop.jpgscoop2.jpgP6_Beastie.jpg
 
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Simon, what size filter elements fit inside that SD1 housing? It looks much narrower than the original P6B housing..? Wish I could have got one in your colour!
thanks
 
Jp928,

There have been some really interesting contributions to this thread and similar from the seasoned members SydneyRoverP6B, Rockdemon,Chris York, Testrider and others. So have summarised a few points below, cribbed from their posts, hopefully in the right context.

From my understanding, the air cannister is in fact a smaller diameter when compared to the P6B issue, but the inlet issignificantly larger thereby allowing almost 3 times the volume of air to enter per minute.

With a 3.9 litre engine (like mine), the OEM P6B air canister inlet is perhaps borderline at best, but on a hot day with hot air, the inlet would prove to be too small. The OEM P6B filters are too small right from the off to pass the volume of air that the 3.9 would require.

The SD1 elbows have an outer diameter of 66 mm, vs 72 mm for the original P6 3500 elbows.

From my own experience, I used the original 3.5 elbows with the SD1 box. It's a bit of a squeeze and I had to remove the rubber vibration mounts on the cleaner canister to inlet manifold studs and elongate the bracket holes (simply file a slot) to make the canister legs fit the studs. Its sits tight and so doesn't' rattle

A previous member referenced these filters with the SD1 box, I think mine were identical.
https://www.amazon.co.uk/Streetwize-MPUAF9-Chrome-Sports-Filter/dp/B002C2QFEE

Of course it goes without saying that new filters and increased inlet flow etc may require an upgrade of the carb needles, and that is where the funs starts....
Simon
 
Just a note on the above - I used the original P6 elbows with the replacement SD1 Air filter canister, hence the mods for fitting required.
 
Previous set up, now on 4 bbl.
Enlarged inlet into P6 filter can, extended P6 elbows, Montego paper element air filters, 2.5" flexible routed to near side air duct in front valance.
Carbs were latterly 2" HS8.

1592232320949.png
 
I'm too lazy to backtrack through your posts, Cobraboy! Please clarify what you mean by 'extended P6 elbows' !? Did you have to increase the bore because the HS8s have larger intakes?
Have you still got that filter can with the bigger intake snout? Does it fit on the standard P6 elbows and HS6s? If "yes and yes!", is it now surplus to your requirements? I'd give it a good home.
 
I'm too lazy to backtrack through your posts, Cobraboy! Please clarify what you mean by 'extended P6 elbows' !? Did you have to increase the bore because the HS8s have larger intakes?
Have you still got that filter can with the bigger intake snout? Does it fit on the standard P6 elbows and HS6s? If "yes and yes!", is it now surplus to your requirements? I'd give it a good home.

Well honestly, I type all this drivel and you cannot be bothered to read it. I am cut to the quick sir.

The HS8 when fitted to the intake and with the stock elbows fitted came out wider, so in order to get the elbows to reach the filter case I had to add about 30mm to the elbow in the form of a band of aloominum. The filter can inlets are unmodified.
I do still have the filter can with the bigger snout, and it still has the new Montego filters in it. I like to hang on to stuff with successful mods until the next mod down the line is proven. But as its you and also a Monday I would be prepared to sell it.

Perhaps we can discuss after I have had Smithers check the cocktail cabinet stock levels.
 
I do humbly apologise for my lackadaisical approach towards repeat reading of your well written research papers. Please let me know what Smithers deems necessary for the resupply of your liquor stocks, and I'll have Jeeves take care of everything.
 
This is interesting. 1970's Rolls Royce engine with the cold air feed going forward into the front valance region.
Presumably the Air Filter arrangement is local to the intake which may / may not have air flow improvements.

On that basis and given the Rolls engines were > 4 L, for the P6, how about removing the x2 Air Filters in the canister and replace with a single filter located forward or in the side panel regions (like most modern vehicles).

Rolls_engine.jpg
 

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Hi, That's where the filter is, that long length of trunking to the carbs is far from ideal. The filter should be as close to the carb as possible.

Colin
 
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