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I've heard guys say that when you reach a certain HP level you need to change to a different damper or when you add a blower. I thought it was just High RPM's that destroyed dampers. For example: If I have a stock 94 cobra and rev it to 5500-5800, chances are the damper will last as long as the motor. Now I take that same motor and do a H/C/I and add some boost to it- I still run it up to 5500-5800 but making a lot more power. If I am running the same rpm's, why would my stock damper be more likely to fail? What am I missing here? Thanks
 

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SFI Dampers are designed differently. They are generally 1 solid piece thats balanced for the counter balance weight.

Stock units have a inner and outer ring, the two are separated by a rubber spacer. On a high horse motor, you can spin the outer ring off, or the outer ring can shift due to the torque of the motor or the higher rpms.
 

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Dac said:
On a high horse motor, you can spin the outer ring off, or the outer ring can shift due to the torque of the motor or the higher rpms.

It can happen with a totally stock motor, too.
 

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SFI dampners are still 2 piece units, BUT the outer is positivly retained. The ROMAC and others use a monster C clip. Others use a crimped bent aluminum or steel piece that will positivly retain it.

The reason the upgrade is requirred when you do much more than anything than put to the grocery store...

The build design used in the stock stuff is designed around a 4800 RPM HP peak, and a very Non-agressive driving style.

The torque of the engine causes a stress load against on the rubber between the inner and outer ring. A harmonic dampner is really only functional at a semi-constant RPM such as highway driving.... BUT we also use them as counter balances.... so saving the bearings is involved at all RPM.

During hard acceleration all balancers suffer from outer ring mass shift. The inner spins faster and gets ahead of the outer..... SFI rated balancers will use a better (thinner) rubber segment and reduce this shift. THis prevents the balancer from tearing itself apart as quickly......

All balancers have a life span.... and should be replaced. If your rebuilding an engine.... if the internals have given up, odds are you should get a new balancer. If its only a anual freshen-up, well maybe press. I wouldn't use a balancer older than 5 years old on any rebuild.... SFI or not.
 
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