Ah ok, thanks. There are 2 aluminium tubes and I wasn’t sure what they were for so I blocked them off. I was having issues with hesitation at 5k rpm under load but today I diagnosed the problem to be the engine running lean due to a high flow air filter I was using, I put the stock filter and air box on and problem solved. I thought maybe those tubes were vacuum hoses that needed to be connected to something and they were the reason for the hesitation.

I believe the engine is a 98-99 F3 engine based on pictures. The engine was given to me but I don’t have any information on it. I am actually using it in a Fiat 126 race car. I have only just got the engine running and my first race coming up so really needed to get the hesitation fixed ASAP I couldn’t find any info on those tubes in manuals etc. Here is a picture of the car it weighs around 500kg, it’s a flying machine now. From what I have read on the forum I gather I would need to Increase the main jet size in order to use a high flow air filter, is that right? Thanks again for the help


https://cimg0.ibsrv.net/gimg/cbrforu...6fd118af3.jpeg