MX-3.com

delete me

I'd ask Ryan or one of the other engineer types...

There is no one answer. Too many variables too many moving parts/ condition. There is a blanacer for a reason.

That is not true. We may all just not be privy to the info. The engineers know what it is who tested the car because they tweak minor things to suppress the resonance for warranty reasons and customer appeal. I'll give an example the '94 metro I drive is 67 mph. One can test a car live on the road by using a device similar to what is used in a aircraft ground power unit (GPU) to set the 400hz for the aircraft power match. The older manual units have a knob you twist to increase the engine RPM via the throttle and lock in at the right hz that is independent of the automatic start governor. The guage is basically a set of plastic beads on individual springs at slightly different tensions that start moving (vibrating) and become a blur at the current hz of the engine.

You could find out through experimentation, but I'm 99.9% sure no one on here cares.

specialtyneed wrote:That is not true. We may all just not be privy to the info. The engineers know what it is who tested the car because they tweak minor things to suppress the resonance for warranty reasons and customer appeal. I'll give an example the '94 metro I drive is 67 mph. One can test a car live on the road by using a device similar to what is used in a aircraft ground power unit (GPU) to set the 400hz for the aircraft power match. The older manual units have a knob you twist to increase the engine RPM via the throttle and lock in at the right hz that is independent of the automatic start governor. The guage is basically a set of plastic beads on individual springs at slightly different tensions that start moving (vibrating) and become a blur at the current hz of the engine.

I'm really lost here, how does one relate to the other? Yes the older Stewart Stevens had a throttle that allowed you to fine tune the hz to 400. How would that system help you zero in on the destructive freqs. in your engine? There are ways to check for and measure vibration but I've never heard of a system like your talking about being used. Pick ups (accelerometers) are usually employed and some kind of reference baseline is needed. I would think if your looking to find an elevated resonance you'd want the vehicle stationary so as not to induce any input not related to the engine like drive line imbalance's, etc. Anyway, I'm sure you know what your doing I just never heard of it being done in the manner you suggested.