Does anyone know the resonant frequency of the drive-train and engine in various states, like 1st gear, 2nd gear, clutch up vs clutch down in them all, or at intermediate points, vs the torque flipping frequency of the on/off fuel limiter?
Given every car has different weight wheels, different clutches, and can be driven in a range of ways, I wouldn't like the idea of having a customer get a gearbox spitting out it's bits under certain rare but possibly attainable conditions.
You could probably work it out with some decent maths, but I haven't. This is why most diesels will stall by design rather than struggle and resonate under certain low frequency conditions (generally under 600rpm or so), and have DMF to avoid resonant frequencies destroying the engine/gearbox/drive-train etc.
Also just the rapid and variable frequency at which the fudge operates is gonna add weird loads through the crank, into the camshaft and so on... all at high engine speeds and so on.
Lets put it this way, I wouldn't want a solid lower engine pulley, 4800rpm and a hard cut rev limiter fudge doing it's thing
Maybe I'm worrying too much.
I've always talked my customers out of doing this because I just think it's silly hehe.
I know people fit dump valves because they think they are cool, and they kinda are. But they do NOTHING useful on a diesel, so it's actually a bit silly.
Hard cut rev limiters on a diesel just seem like they have never been done probably because it's not good for the diesel engine. Maybe if you had uprated rods/bearings/bolts and a good crank (HDi110 one perhaps?) then I'd be ok with it, but doesn't anyone else cringe at the idea of throwing ALL that extra stress on a HDi90 crank/rods/bolts at high rpm, likely already running torque way beyond the OEM design specs?
Dave
Given every car has different weight wheels, different clutches, and can be driven in a range of ways, I wouldn't like the idea of having a customer get a gearbox spitting out it's bits under certain rare but possibly attainable conditions.
You could probably work it out with some decent maths, but I haven't. This is why most diesels will stall by design rather than struggle and resonate under certain low frequency conditions (generally under 600rpm or so), and have DMF to avoid resonant frequencies destroying the engine/gearbox/drive-train etc.
Also just the rapid and variable frequency at which the fudge operates is gonna add weird loads through the crank, into the camshaft and so on... all at high engine speeds and so on.
Lets put it this way, I wouldn't want a solid lower engine pulley, 4800rpm and a hard cut rev limiter fudge doing it's thing
Maybe I'm worrying too much.
I've always talked my customers out of doing this because I just think it's silly hehe.
I know people fit dump valves because they think they are cool, and they kinda are. But they do NOTHING useful on a diesel, so it's actually a bit silly.
Hard cut rev limiters on a diesel just seem like they have never been done probably because it's not good for the diesel engine. Maybe if you had uprated rods/bearings/bolts and a good crank (HDi110 one perhaps?) then I'd be ok with it, but doesn't anyone else cringe at the idea of throwing ALL that extra stress on a HDi90 crank/rods/bolts at high rpm, likely already running torque way beyond the OEM design specs?
Dave