pancake filters on a V8

ButterFingers

Active Member
hi there,
I have seen pictures of pancake air filters used on the Buick /rover v8 engine.
The original large air filter removed and the much smaller pancake used.
Are the pancake filters more efficient? Is there any performance gained from using these type of filter.
Peter
 
According to Des Hamill's Rover V8 engine book, the best set-up was the standard adapters, cast elbows with large diameter K&N filters and a metal plate between them.
On a 3.9 engine universal cone filters on the carb adapters gave 242bhp, removing the filters from the adapters gave about the same but with the adapters, elbows, K&N's and airflow separation plate it gave 256bhp. It doesn't give any figures for a standard setup retaining the big round filter canister though so you can't tell how much of an improvement these figures are over standard.
I'm using the biggest cone filters I could fit inside the standard filter box, but no separation plate yet - that's a job for another day.
 
the separation plate avoids interference between vacuum of filter 1 and filter 2 (says Des Hamill....) which are very close when they are installed with the ellbows.
If you try to speed up your engine a little bit or more seriously, the books ratwing mentioned, are a standard to go. I know, one of them (do not know, which) you can also get for your Ipad.
But, do not even dream of 242 bhp. This is a modified 3.9 engine, it was used to show the differences in output between various filter options. Direct pancakes are cheap, but no good solution.
Bhp of your engine ? Rolling road test, that´s the only way. But I would save that money, if you have a standard 3.5 engine and it´s not opened yet. You may find a lot of threads, what´s recommended as an overhauling work after xyz miles, i.e. replacing the worn camshaft as first priority. Do you know the internal condition of your engine ?
 
If you put big enough cone filters on the standard elbows they'll be very close or even touching each other - a plate placed between them stops interference between the airflows into the filters.
You'll find typical bhp figures for standard engines on the internet but if yours is modified or if you want the actual bhp of your engine then its dyno time.
Edit - you beat me to it!
 
The 3.9 litre engine as well as being bigger will certainly have the later heads with bigger valves. I wouldn't expect so much with the P6 3.5 as there are breathing restrictions further down the line. Breathing has always been one of the RV8s limits. Not just in terms of power but also willingness to rev. It can however be helpful to fatten the lower torque curve which is what you want with an auto.

A good cam and later heads are tuning 101 for the V8. 30 bhp for not much money, I see absolutely no reason to do this under any circumstances because of course it looks utterly standard. Let's face it if your car has more than 50,000 miles on the cam and timing gear, you need a new one anyway.
 
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