Engine mounting & damping oscillation

[JJW]

Hello all.

Thesedays, I'm dealing with the engine mounting problem. My main concern is that if we mount the engine without any damping system, the mounting points may broke up because of the strong oscillation. So I searched a lot here and there for the information, but got no clear answer.

Is there any special solutions for this on FSAE car?? Or, for someone who knows about general methods for damping oscillation used in motorbikes or cars, I'll appreciate if you tell me them. Thanks.

[JJW]

Hello all.

Thesedays, I'm dealing with the engine mounting problem. My main concern is that if we mount the engine without any damping system, the mounting points may broke up because of the strong oscillation. So I searched a lot here and there for the information, but got no clear answer.

Is there any special solutions for this on FSAE car?? Or, for someone who knows about general methods for damping oscillation used in motorbikes or cars, I'll appreciate if you tell me them. Thanks.

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<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by JJW:
Hello all.

Thesedays, I'm dealing with the engine mounting problem. My main concern is that if we mount the engine without any damping system, the mounting points may broke up because of the strong oscillation. So I searched a lot here and there for the information, but got no clear answer.

Is there any special solutions for this on FSAE car?? Or, for someone who knows about general methods for damping oscillation used in motorbikes or cars, I'll appreciate if you tell me them. Thanks. </div></BLOCKQUOTE>

Simple, its a motorcycle engine, so mount as per motorcycle engine...

[J.R.]

We don't use any damping, just bolt it to the frame, and have never had any problems.

[blister]

No problems with 4cylinder engines. I can imagine that single cylinder are a bit more difficult to mount to your chassis structure

[VFR750R]

racecar...nuff said.

[Chris Lane]

Just hard mount the engine to the chassis. Most race cars do.

If you're that concerned about it, try using some hard rubber washers in the mounts.

[L B0MB]

Yeah, you really can't beat mounting it hard...

Hard mounting and stiffness are inter-related...

If you dont hard mount, you may find the rear end to be a bit sloppy...

Is that enough innuendos for one post?

[Pete M]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by lewis:
Yeah, you really can't beat mounting it hard...

Hard mounting and stiffness are inter-related...

If you dont hard mount, you may find the rear end to be a bit sloppy...

Is that enough innuendos for one post? </div></BLOCKQUOTE>

Umm... Nothing wrong with a bit of vibration as long as you can still see?

[Wesley]

Since most of the judges are OEM guys, I'd imagine they wouldn't mind seeing some NVH data - why you used isolators, how it helped, etc.

We're running some polyurethane bushings on ours, in an attempt to dampen some of the crazy vibration of the Aprilia. Just because it's a racecar doesn't mean you shouldn't consider making it a better and more comfortable experience driving. Plus doing some NVH research never hurt anyone who is going into an OEM job. The same "it's a racecar" could be said about ergonomics, seat comfort, etc. Racecars aren't about being brutal and unforgiving. They're about going fast as easily as possible.

[Steve O]

We hard mounted an engine at one point to find hairline fractures on the block by the mounts. You need to absorb some of the shock to those mounts, not even considering the driver's needs, although I must say that it is nice to not hear our floor pans/teeth rattle now, with the poly bushings.

I should add that we are running a single cylinder...much more vibration that the 4's.

[Ppada]

The 3 things that you have to take into consideration are primarily the chain, anything that has to be used on the bike and the vibrations from the chain.
We used bushes last year but they were rather soft and the vibrations were bigger than mounting it directly on the chassis...
And also you should take care of anything that is mounted on the chassis and is working with the engine....

[overdrive535]

If you haven't already...

It never hurts to take a look at the factory mounts for whatever engine you are using. That said, your forces are not going to be the same as the factory mounts.