ShaunB
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| posted on 16/5/11 at 02:50 PM |
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Engine mounts
Finally got round to watching the in-car video from my Locost heat at Cadwell (forgot to turn it on for the final - d'oh!). It's the
first time I've used the camera and one thing I noticed was how much my engine is moving side to side when cornering  . I could see that the
exhaust manifold was moving probably 3/4" left and right and that cannot be good for handling! I have 50mm tall rubber mounts (same design as
"RD Link") on the chassis rails and then a solid mount up to the
block. I have no idea if the rubber mounts I have are heavy duty or not.
What designs do other racers have?
Matt G - what do you fit to your Procomp cars? Got any pics you're happy to show me?
Matt C - have you had any feedback from the design I saw in the TMC workshop?
Mine is a Stuart Taylor chassis, and I want to move the engine up a few mm anyway so I can lower the whole car and still have the required 50mm sump
clearance. At the very least I could make longer copies of the ones I've got and drop to 35mm HD rubber mounts, but I'm sure I've
seen mounts where the rubber is angled up at 45 degrees which would mean the cornering force would trying more to compress the rubber than push it
sideways.
Acceleration/Braking must be similar but that would be assisted by the gearbox mounting.
Cheers,
Shaun.
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tomgregory2000
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| posted on 16/5/11 at 03:04 PM |
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you want the mountings at 45 degree so as you say the rubber is in compression rather than shear
mine is like this and i have some very stiff rubbers fitted and the engine doesnt really move at all
 
Description
 
Description
[Edited on 16/5/11 by tomgregory2000]
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A1
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| posted on 16/5/11 at 04:53 PM |
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these burton ones are really good, pretty much no movement at all. might have to modify them slightly though...
http://www.burtonpower.com/rd352.html
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jacko
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| posted on 16/5/11 at 06:45 PM |
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engine mounting
 
Description
This is how i made my stabilizer not race but could be used on a race car
Jacko
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procomp
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| posted on 17/5/11 at 06:51 PM |
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Hi
The actual mounts we make are just custom made to suit the engine position in height and offset to suit the kit as we manufacture it with the dummy
engine box fitted. But that's all down to getting the offset and weight positioned to suit the application.
The rubber mounts are just the HD rally design items which are mounted flat. don't worry about being at a 45deg angle its not necessary.
What is of concern is that you are not able to get the engine height right by using the STD Stuart Taylor mounts and rally design rubber. I have a
very strong feeling that you are being led down the route of raising the engine to achieve the min ride height. If this is the case IT'S WRONG.
The suspension geometry will be way way out.
If you want to know what works best on the ST/Aires chassis give a ring with the details of your current ride heights front and rear and ill advise
from there over the phone as it's easier than a million messages Etc
Cheers Matt
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TMC
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| posted on 18/5/11 at 10:38 AM |
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Shaun,
We have now tried a few different designs of mount, and the solid wishbone type that you saw works very well to stabilise the engine, but over time
the vibrations do seem to wear the metal. I think more work is needed to make them a long term solution. When I have more time I'm hoping to run
some FEA tests on the designs and find out where the weak points are, but its just not something I can fit in at the moment!
For the time being we've gone back to a similar design to yours, albeit made to measure in each car as Matt suggests above.
Cheers,
Matt
http://www.tmcmotorsport.co.uk
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ShaunB
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| posted on 18/5/11 at 11:45 AM |
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Matt C - That would have been my expectation with the wishbone design, the vibration energy has to go somewhere. In the event of an accident,
I'd rather there was at least something to flex.
Matt G - I'll need to take some measurements tonight and give you a call. From memory I've 100mm at the front, 115mm at the rear, 55mm
under the sump. The engine mounts are currently sitting on 6mm spacers to enable those heights, so perhaps I do not have the ST mounts. The lower
wishbones are parallel to the ground with me aboard, which is what I suspect you are worried about if I manage to lower the chassis another 20mm.
When I bought the car (it came from Aaron Bailey) it had a standard xflow sump. It's now running one that is 10mm shorter, and I'm in the
process of creating another which will be 22mm shorter than standard, whilst maintaining oil capacity.
My assumption is that running the car down near the minimum ride heights takes the CoG as low as possible which is good thing, but obviously not at
the expense of wrecking the suspension geometry.
Cheers,
Shaun.
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