[Roadsters] Roadster air filter question ...

[Graeme]

"How do you compensate for the loss of the venturi stacks that are built
into the stock air cleaner?"

Good point, they would have to be replaced possibly with some conventional
straight ram tubes/velocity stacks. An alternative to expensive ram tubes is
four monumental vases. These are made of spun aluminium and have a full
radiused edge on the throat. I bought 4 of these to build some ram tubes for
a set of individual throttle bodies I am making for an FJ20. 


"Has anyone stuck a temp probe under the hood against (or inside) the air
cleaner to determine if the existing air is really that hot (at speed, not
at idle)?"

Haven't with a Roadster but years ago when I got my FJ20 engine conversion
running in my 510, I started off with a simple underbonnet intake for the
plastic box air cleaner. The Haltec ECU has an inlet air temp sensor which I
was monitoring on a laptop. The inlet temps. were through the roof! I then
built a 75mm plastic duct to run from the base of the aircleaner box to the
radiator panel. It was then taking air from outside the engine bay. Can't
remember the actual numbers but the intake temp dropped from 60+deg C to
ambient, just like that. The reason I used a 75mm duct was that I had a
selection of stormwater fittings in the garage doing nothing :)
I could feel the engine was a LOT stronger when accellerating and was really
potent on a cool morning!!

Once you route the intake air through an air cleaner, panel or round, any
ram air affect is largely lost in my opinion.




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