Full boost at ? RPM

[Dr H]

Having just fitted a boost gauge and reading some recent posts re boost and RPM can anyone answer me this question -

At what RPM should I see max boost on a standard S2 engine?

Paul, Minhea, anyone

Cheers

Leigh

[Mihnea]

Ummm, depends on the car m8, should be something like 2700 RPM at the latest.....

[S2central.net]

Yeah it depends on LOAD primarily - go find a hill and attempt to climb it in 6th from about 30mph, then you'll put the maximum load on the engine such that the ECU will pemit a temporary burst of 'overboost' - typically 1.1 - 1.2 bar on a stock healthy ABY depending on temperature etc. The ECU allows this for about 15 seconds, then drops back to max sustained boost at approx 0.8bar.

The homefries are obviously more aggressive than that - allowing overboost to 1.4-1.5bar which is where the fun factor comes in to play

I shall graph the stock and chipped maximum boost profiles very soon. There's not enough hours in the day really..

Paul

[Dr H]

Cheers guys

I figured it must be related to load, but didn't realise just how much until I did a few tests. It seems almost impossible to get the 0.8 boost at lower revs on a straight flat road unless you accelerate from low speed in a high gear getting the boost at higher revs is easy. I guess this is the 'load' issue.

My overboost seems a bit strange though. About three times today I managed to get the gauge up to 1.4bar and once it just about hit 1.5 bar. This only happens momentarily. I can get about 1.1 bar constant doing the up hill low revs foot to the floor trick. any ideas?

Leigh

BTW I wouldn't recommend watching a boost gauge that isn't actually installed (holding it in your hand) gets a bit hairy