Hallo,
I was a young child back then at 1988, but I do remember an article in a Greek magazine prior to the F1 start. According to this, Honda (at 1987) had found a clever way to bypass the 4.0 bar restriction, but placing the valve in a clever position. Does anybody knows something about it?
Afaik it wasn't that they worked around it, but rather found a way to reach the 4bar boost. The valve would pop off some part before the 4bar limit and Honda was the first to find a way to fix this problem.
If I remember correctly it was rumoured that Honda had placed the pop-off valve over a Venturi throat, the idea being that the flow rate is increased but as a result the air pressure is reduced, the result being that pressure on either side is higher than that which the pop-off valve experiences, this would again about .2 bar pressure, nothing life changing but every little helps! In qualifying trim in '87 it is quite apparent that some teams ran a sealed wastegate and massive turbos in an effort to overwhelm the pop-off valve, in other words massively overboost the engine, effectively using the pop-off valve to regulate the massive inundation of boost into the plenum chamber and extra boost being achieved by inducting air faster than the pop-off valve could vent it out! A redesign of the valve and stricter regulations regarding pop-off valve placment for '88 made this strategy redundant, in '88 the key was to never pop the valve as it didn't shut totally after being popped!
I was a young child back then at 1988, but I do remember an article in a Greek magazine prior to the F1 start. According to this, Honda (at 1987) had found a clever way to bypass the 4.0 bar restriction,