engine under tray

[road warrior]

as some may know im plagued with speed bumps where i live and i am forever grounding the under tray, and so .. aside from keeping it clean and upsetting mot men and mechanics alike, what does it actually do and what affect would it have if i removed it ?
Im well aware you will say dont, but.. has anybody removed it ?

 

[skelters]

Apart from protecting the underside of the engine from bumps and stones etc. It'll no doubt be there for aerodynamics too.

 

[ben g]

I haven't had an under tray fitted to my Z4 for about 7 years :lol: no adverse affects as far as I can tell. Some say the mpg decreases, but i don't do massive mileage, so it never bothered me.

 

[GuidoK]

It could also negatively influence the cooling capabilities, as it forms a seal
That could in turn result in higher pressure in the cooling system at certain moments when the engine needs it the most.

If you're hitting speedbumps, you're driving too fast over them/your stance is too low/your springs and dampers are too soft.
Its a low slung sportscar

 

[ben g]

It could also negatively influence the cooling capabilities, as it forms a seal
That could in turn result in higher pressure in the cooling system at certain moments when the engine needs it the most.

If you're hitting speedbumps, you're driving too fast over them/your stance is too low/your springs and dampers are too soft.
Its a low slung sportscar

Clearly never driven on uk roads :lol:

The ramped entrance to my road would cause a problem for any sport spring equipped Z4 with an under tray fitted.

 

[GuidoK]

Clearly never driven on uk roads :lol:

imho its not the speedbumps that are the UK's main road problems but the potholes, dodgy repairs, sunken manhole covers etc, so the general state of it :roll:

 

[road warrior]

i have to drive over speed bumps 3-4 inches high and 4 feet wide and therefore im asking for a reason, my options include removing the cover, converting to standard suspension or selling the bloody car..

 

[Smartbear]

i have to drive over speed bumps 3-4 inches high and 4 feet wide and therefore im asking for a reason, my options include removing the cover, converting to standard suspension or selling the bloody car..

You forgot to add fitting higher profile tyres
Rob

 

[Mr Tidy]

Actually it might be worth removing it - to avoid those b******g stupid advisories MOT testers seem so keen to scatter about these days!

 

[Smartbear]

Actually it might be worth removing it - to avoid those b******g stupid advisories MOT testers seem so keen to scatter about these days!

If it’s removed the MOT guy might see something terrible!
Rob

 

[Mr Tidy]

If it’s removed the MOT guy might see something terrible!
Rob

True, but most of them don't seem too sure what they are looking at these days! (Maybe famous last words - mine is due soon). :roll:

 

[GuidoK]

my options include removing the cover

Better having the undertray as a barrier scraping against the roadsurface than something actually underneath from the engine :roll:

The undertray also keeps water partially out. That prolonges the life of a lot of parts, both moving and electrical.

 

[road warrior]

i have to drive over speed bumps 3-4 inches high and 4 feet wide and therefore im asking for a reason, my options include removing the cover, converting to standard suspension or selling the bloody car..

You forgot to add fitting higher profile tyres
Rob

i tried that and it rubbed on the wheelarch - albeit with the wheels the car came with

 

[road warrior]

as far as cooling is concerned i imagine it would be increased, many years ago i removed the cover from my lexus soarer and fitted a mesh there instead, the engine bay felt soo cool compared to it being very hot before. but as a i say.. thats a by-product my concern is what would be in danger if i removed it.
thr real answer is to go to standard suspension but its all money isnt it

 

[GuidoK]

Why would cooling increase?
The undertray acts like an air dam.
Because the undertray is there, air is force fed through the radiators at higher speeds.
By removing the undertray, you're removing the air dam and air can escape to the underside instead of being force fed trough the radiator, thus less cooling.
You're also feeding extra air to the underside of the car, creating extra pressure under the car, resulting in less grip.

thr real answer is to go to standard suspension but its all money isnt it

You dont have the standard suspension but low slung suspension? :scratchhead:

 

[ben g]

Ffs :lol: this is ridiculous. Forums are full of scare stories.

Like I said, I've had mine removed for 7 years, mostly because when I first bought my Z4 it came as standard on sport suspension and I couldn't drive onto my driveway without scraping the pavement. It was fine ever since I removed it and has been off the car ever since, even after moving house.

I have done almost 70,000 miles in that time and I haven't had any issues with cooling (apart from the expansion tank leaking, which is nothing to do with the undertray removal).

Your car will not blow up as soon as you remove it, so give it a go and see what happens.

The undertray is plastic, so it's not actually there to protect anything from hitting concrete or tarmac :lol:

 

[Migizi]

the large plastic piece is called 'Engine compartment screening' for a reason, it does shield the engine compartment from water, mud, sand, and other debris. Aero dynamics are also engineered into their purpose for cooling and sometimes efficiency.

can you operate your car without it - of course. But intentionally running without it is like simple neglect. :slappy:

 

[ben g]

the large plastic piece is called 'Engine compartment screening' for a reason, it does shield the engine compartment from water, mud, sand, and other debris. Aero dynamics are also engineered into their purpose for cooling and sometimes efficiency.

can you operate your car without it - of course. But intentionally running without it is like simple neglect. :slappy:

One could say the same about driving with the roof down, but we still do it :lol:

 

[Migizi]

...
One could say the same about driving with the roof down, but we still do it :lol:

 

[skelters]

Man buys shoddy German car and the roof comes down. - Daily Mail probably.

Germans force Queen loving Great British, British people from Britishland to buy cars that roof comes off. - The Sun probably.

What would Diana say to the Germans (pages 1 - 64) - The Express probably.