Airbox, Trumpets & Filters
ITB need trumpets & filters. Well, you need filters most of the time. I have run without them on really nice sunny days, but we don't get much of them. Like shoes, I have a few pairs of both.
Rich at Redline Racing in Brighouse sorted some filters for me, which are loud-ish and look nice
I tried running some carbon fibre trumpets at 60mm (not 40mm) length but lost loads of bottom-end torque. They looked the nicest 😍but did not sound as nice.
I ran 40mm trumpets, which gave the best power and offered the most filter options as they had the most clearance.
While messing with the different setups, I used a Weber Carb Air Volume Synchro-meter to balance the ITBs. I used this YouTube video on how to balance Weber 45 DCOE carburettors to assist, as the ITB videos were pants and did not cover the air bleed screws in the Weber Alpha bodies.
I had a double-ended stainless air box made ages ago and stuck on two massive mushroom HKS foam filters back in the day when they were expensive. There was no real plan to use these on the golf as they were old filters that were fitted to my Mitsubishi FTO and had two for some unknown reason.
The old Mitsi I had back in 2000 is below 😍 she was the best front-wheel drive car I have ever driven.
The airbox takes the edge off the noise the ITB make, and it is suitable for driving in the Autumn months when the roads are a bit dirtier. It also makes motorway driving bearable. Over time, the foam crumbled away, and the outa frame got rusted. I stripped them down and sprayed the metal cages.
I got some new foam elements, covered the air box with black soundproofing, and stuck the lot back in. With the soundproofing, the car sounds quieter and much more musical, and compared to the other filter combinations, it does not rob as much power. It also warms up the engine quicker with the air box, which is a bonus when driving in the Autumn months.
