E9 Under engine plate/wall

RTHLSS1

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Hi guys,

was there originally ever plate or splash wall mounted under engine? If it was where to source it.

Thanks
 

Gransin

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John was faster, but I'll add the link:
 

CTD

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I have one on my coupe. Looks very clean when you look at the car from the front but they are not very solid. They are very fragile.
 

HB Chris

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The e3 one we bought is pretty sturdy, you just need to bend it around the frame and such to attach so we left it off. Maybe Mike will install it as he has the 2800.
 

Stevehose

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Usually discarded back in the day from absorbing oil etc as well as a pita when working from below.
 

stphers

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The original ones were made out of that compressed cardboard stuff and did not stand up well against the environment or old/grease from the engine Old ones were a real PIA to take off or put back on Most were discarded because they were only half there left on most of the cars that saw normal driving
 

Drew20

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My CSL, which has the cowcatcher front splitter, has lost its under engine tray. I have been told that the undertray improves stability at high speed, by reducing lift at the front I assume.
Do you think my car would benefit from the undertray, given it has the splitter, which is also designed to reduce front lift?
At high motorway speeds the steering is lighter than I would ideally like, not that I spend much (any) time thrashing around the M25 at 120mph
 

aearch

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i bought a new one and imediately sealed it with a flat clear coat then
i added two and three light coats of undercoating
on both sides
it looks really great and is now protected from the elements and debris and easily cleanable.
 

dbower

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I bought one from the dealer about 2 years ago and also coated it with several layers of undercoat. It has held up well so far. Biggest difference that I have noted is that the engine runs significantly cooler.
 

Honolulu

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Inquiring minds crave to know: dBower, how can it happen that the engine runs cooler with the undertray than not?

With the undertray in place the engine compartment is more sealed than without. What happens to air heated by passing through the radiator when the undertray is in place, unless it provides some venting at the rear with enhanced aero/venting capabilities?
 

Simufly

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Probably more efficient airflow extraction, reducing bay turbulence?
In other cars running without the undertray lowers the MPG
 

dbower

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Inquiring minds crave to know: dBower, how can it happen that the engine runs cooler with the undertray than not?

With the undertray in place the engine compartment is more sealed than without. What happens to air heated by passing through the radiator when the undertray is in place, unless it provides some venting at the rear with enhanced aero/venting capabilities?
Honolulu, I wish I could provide a scientific answer, and a sample of one (me) may not be sufficient for a general conclusion. Wouldn't it be interesting to know why BMW put it there anyway, other than to annoy us at oil change time. The turbulence theory seems as good as any.
 

sfdon

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orums.nasioc.com › forums › showthread

Jan 22, 2019 - In regards to coolant temps, I think the undertray helps reduce turbulence from the tires and road surface inside the engine bay and behind the radiator. It's technically making air flow more smoothly through your radiator by preventing turbulence occurring behind the radiator.




 

dave v. in nc

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That makes sense, helping make the engine bay a controlled environment for the radiator... Making it from an absorbent material, not so much sense....I've always called it my car's "diaper".
 
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