Race Engine Forum UK

Hello Guy/all,

Do you always knife edge the divider between the inlet ports on a 16v head? Or are there any instances where you wouldn't do this and just leave a smooth radiused edge? How much in the way of gains (if any) are there to be made from this mod or is it just a case of splitting the air cleanly and evenly?

Thanks,
Martin.

That section, which I call the splitter, varies in shape from head to head - some like Integrale and Vauxhall XE have a long splitter, dividing the airstream almost at entry, while others like Toyota 16v are very short.

On the longer ones the gain in knife-edging varies from 2-3 cfm to way more than that, but the best gains come only with full reshaping and sometimes shortening (not always at top and bottom), because simply putting a blade-like form on the nose of the splitter can result in an aerofoil 'hump' on the splitter further into the port, so you see there's a lot more involved than just sharpening the thing.


GC

Thanks for the reply, lovely clear shot down the integrale inlet port btw!