3 replies to this topic

[Boing Ball]

I just noticed that the B186 did not have a diffuser while it was a race winning car (see https://www.reddit.c..._powerful_cars/). So, when did diffusers became common place?

[Nathan]

When the 'flat bottom' rules weren't in place.

[PayasYouRace]

That Reddit photo isn’t of a Benetton B186. It’s one of the Alfa Romeos (can’t be sure, but most likely the 183T). The B186 had the four cylinder BMW engine which gave it an asymmetric engine cover. It also had a white engine cover with multi-coloured streaks. It actually had a massive rear wing with a floor level plane. The aero department at Benetton back then were very much the aero pioneers in the mid-80s, especially regarding underbody aero.

The typical diffuser of the “flat bottom” F1 car (1983-2021) was born out of of flat floor regulations which ended at the rear axle. It’s why in those early days cars had to have little floor extensions under mirrors and such, but not under the wings.

I’m not sure which was the first car to use a diffuser at the end of the floor, but they were definitely springing up in the 1983-1986 period. Cars like the FW11 were already blowing exhaust gasses into the diffusers.

[Nathan]

This got me thinking and looking.  I don't think they ever really went away, they just re-located from sidepod to behind the rear axle and thus became much smaller.  It looks like when they went to atmos 3.5 litres in '89 rear diffusers became bigger.  I distinctly remember building the Jordan 191 model and that diffuser being quite large.  However, that also never became a design trend.

 

Here is someone else's model to demonstrate...