Interesting Filter Mods

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Active Member
Oct 3, 2008
Hello All,

I have been trawling around for new ideas for air filters. I have a 450SLC and ideally I would like to fit a large pancake airfilter, one like the Holley carbs.

But that has its flaw, for example the heat soak problem due to the small engine bay and large engine.

But this one seems very interesting:

Obviously I would need to take away the internal circular type filter in the round airbox.

I happen to have a good airfiler, like the one in the photo but with a carbon fibre heatshield and a induction hose.

Would anyone know the problem with fitting it this way?

Thanks for all your help in advance.

The only problem I can see is carb icing in our lovely, wet winters!!! This would lead to stalling when you stop, lack of power at constant throttle etc.
If it's fuel injected it should be ok - maybe someone else knows better??
Before degrading the filtering performance with one of those abominations, do you know that the air filter is being restrictive? Have you measured the pressure drop across the filter?

I suspect that the original filter has a huge active area, and I would be really surprised if it's causing any real restriction, and I would also be quite confident that it's protecting your engine from injesting damaging particles, unlike the mickey mouse bolt on job.
Hello All,

Thanks for the reply. I am actually very happy with the design at the moment, the only mod I am thinking about doing is to add an induction pipe from the airbox to fresh air source.

The 450SLC runds quite hot and the compartment is quite hot and although it doesn't suffer from any performance defect, it seems quite slow in motoway speed. It can do high speed but I also need to push the throttle quite hard.

I am not sure what is causing the hesitant of the engine or whether it is built like this (the car is 1.7 tons!) I might need to change the gear box oil and new engine oil and may be bearing needs some grease. Any ideas?

Yes, making sure that the car is really well serviced is the obvious starting point - for example, making sure that no brakes are dragging, the tyres are in good condition, and correctly inflated, and checking that the engine is running correctly will repay you both in terms of performance, and in mpg improvement.

As an example, some years ago I spent quite a while sorting out a Porsche 928. It's v8 engine sounded smooth enough, but it wasn't really performing. I gave it a good service, and when I connected up the oscilloscope, I saw that the burn times for a couple of the cylinders weren't right - the spark was occaisonally shorting to the power steering reservoir from those plug leads. With that fixed, the car flew!

The point of my ramble is that a v8 has enough cylinders to always sound smooth to the ear, but, can actually be running like a dog.

Incidentally, the spark plug HT leads shorting out could also have been found by the simple method of lifting the bonnet at night with the engine running - the sparks would have been obvious. If you, or anyone does this, take very special care not to touch the moving and rotating parts at the front of the engine - just because you can't see them in the dark....
i used a holley & filter on my old scimitar with the 3ltr for v6 & it ran well did nothing for the mpg thou
Thanks all,

I am planning to have it service, ie oil change, new spark plugs, new oil filter, I actually think the brakes are dragging a bit, and will have that sorted, bleed the brakes again. new pads. The air filter seems very clean.

Thanks for all the tips. Coincidentally, do you know how well should these engines perform, the performance can be very good from 60 mph to more than that, but it is when the throttle is hard push.


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