Engine Cover - Yes or No

[Roger 912]

On my red Turbo Esprit I have been running the car for the last 4 odd years without an engine cover as when I purchased the car it was not there. My green Turbo Esprit has one however and I have thought about making one for the red job.

At the Cape Town car show, one of the other Esprit owners berated me for not having an engine cover as he says it was there to aid engine cooling. I, however tended to disagree as my thoughts were that it was more of a cover for the engine to stop ingress of rain from causing problems with the plugs, plug leads and distributor.

Any thoughts on this one?

[CharlieCroker]

It was definitely designed to aid engine cooling but my S2 was missing the cooling air filter box and hoses when I bought it and I have run my car for the past year without the cover and have not over heated once. It's your call, if you like looking at your engine or working on it regularly then leave it off. I'm sure others will say "Keep it on" but I've had no issues not using mine.

[910Esprit]

Yuk - The cover keeps all the traffic road film out of the 'boot' Yours must be unuseable for anything clean?

[Roger 912]

Amazingly enough, after travelling possibly 10 000 kilometres without the engine cover there is no ingress of dirt at all. Occasionally I dust off a layer of fine dust. Perhaps it is due to our climate as my car does not go out in the rain, if at all possible, and never on a dirt road. What I have done to keep heat out of the rear boot and that is to mount a half inch wide rubber strip about 3 to 4 inches high across the back of the boot. This makes contact with the boot/engine lid and things remain very cool in the back.

Yes, it is nice for people to look through the rear quarter light windows and see the engine in all its glory.

Surely it is better for the louvres to cause a vacuum inside the engine compartment over a wide area, rather than suck out the heat in one hot spot area?

Edited November 14, 2011 by Roger 912

[Bibs]

I don't use the engine cover, I like seeing the engine behind me and it's protected from above by the glass back on the SE. More tenuously, it's heavy and high up so removing anything like that can only help handling.

[skiing]

I have a glass engine cover, this allows me to see the engine (which I discovered was useful when it slightly caught fire a few weeks ago) - I would not have seen this otherwise and the car could have been in serious trouble...

[Paul Coleman]

I have a glass engine cover, this allows me to see the engine (which I discovered was useful when it slightly caught fire a few weeks ago) - I would not have seen this otherwise and the car could have been in serious trouble...

Perhaps we should start fitting 'Fire Exit' signs above the doors on these cars, like they have on planes?

Paul.

Edited November 15, 2011 by Paul Coleman

[skiing]

heheh - I think I should certainly run a fire safety drill with all passengers - "If I turn white, and say quite casually that we appear to be on fire, release your seat belt (noting different button design to other cars) and pull door handle (shove with shoulder maybe necessary in some weather conditions) - wait for car to come to 'power-stop' and then bail out and stand back as your until-this-point-cool driver fumbles for fire extinguisher tab whilst getting boot open"... ah the glamour...

[Mike6]

Why not remove the boot floor and save even more weight. That way you also get to see the gearbox and other bits and pieces.

[Bibs]

Sounds about as sensible as removing the bodyshell... what a funny idea Mike, bit early to be on the sauce isn't it

[Mike6]

Never to early when you are my age. Seem to remember someone driving around with a quick release boot floor for ages. Just cannot think who it was!

[dodge1979]

Thats not a daft idea really...ive been thinking about adapting my floor to remove separate from the boot wall, but to have a quicker releasr on it whilst still enabling it to remain sealed and waterproof..easy access to gearbox etc and it would save spreading my weight about carefully like spidermam when im tinkering on the engine...and it gives me something to think about whilst at work :-D

[robington]

_{Somebody, (who I consider knows about these things), told me that the whole undertray/engine cover/louvre set up is a crude, but effective part of the aerodynamics of the car.}

_{The air is fed via the undertray and sills and forced up through the engine and out the top of the engine cover into the mating part fitted to the tailgate. The air is then forced over the louvres creating downforce.}

_{I have no idea how true this is or at what speed the benefits are supposed to kick in, but it looks plausable to me!}

_Rob

[Bibs]

Tosh mate I'm afraid. Any air that been through such a packed area will just add a small amount of turbulence and drag, not an iota of downforce.

[simonb]

And I thought I read that they put a gurney flap above the louvres to negate the unwanted downforce at the back (but wanted to keep the pretty louvres)

[molemot]

Thats not a daft idea really...ive been thinking about adapting my floor to remove separate from the boot wall, but to have a quicker releasr on it whilst still enabling it to remain sealed and waterproof..easy access to gearbox etc and it would save spreading my weight about carefully like spidermam when im tinkering on the engine...and it gives me something to think about whilst at work :-D

No need to worry about spreading your weight carefully on the boot floor...I haven't broken mine yet, even when I was 24 1/2 stone...

[red vtec]

Never to early when you are my age. Seem to remember someone driving around with a quick release boot floor for ages. Just cannot think who it was!

My floor comes out seperate, A jig saw did the job

[dodge1979]

Oh breaking isnt an issue..so far its withstood weekly visits from my lumbar..to view, work and stay warm....bur ive noticed though that whenever im in there, naturally im puttin more weight on the left, and so the right side has come loose..despite being screwe and sealed down all round...so a seperate removable floor to bulkhead type set up is required

[Roger 912]

I always thought that at speed the louvres created a vacuum and sucked air out of the engine bay. I know that the Nascar ducts are forcing air into the engine bay at speed so it would make sense for the louvres to suck the hot air out.

I am not saying louvres suck. I think they look great and very 70s and 80s.

I know that some cars had fans fitted to the top engine cover. Was this to try and keep the plenum cooler and did the fan suck or blow?

[Bibs]

NACA duct - http://en.wikipedia.org/wiki/NACA_duct

The fans are for when the car is stationary and in traffic to help remove heat...

[Roger 912]

Thanks Bibs, yes that makes sense as the engine does not have the benefit of the air being rammed in to cool it.

[B33 ENN]

On the old turbo cars with the louvres, and on the later cars with glass-back or flat-deck vents, there is a low pressure area created as fast air moves over the roof and off the back. This low pressure assists in "sucking" the hot air in the engine bay out.

It doesn't create any intended downforce effect, that I'm aware of, especially as there is no skirt or shaped undertray below the car. However, using the Lotus engine cover is useful because of the seal it creates between the boot space and engine bay when the tailgate is closed. That seal helps ensure the air is only drawn from the engine bay and not the boot, maximising efficiency

From what I know of Lotus, certainly in the older cars, they never added something unless it really had to be there. Also, the mass of the cover in proportion to the rest of the rear body/drive-train is negligable to have much effect on the rear roll centre to really improve handling in any noticeable way, at least on a road spec car.

So, in my opinion, it should be used.

Edited January 20, 2012 by B33 ENN

[B33 ENN]

A couple of years ago a few owners on here said although that was the theory when looking at small water droplets when it was raining they could not see any suck out around the louvres.

I'm not sure about water droplets giving a good indication, partly due to the mass of water versus a gas, and part due to turbulent effects corrupting uniform flow patterns. I can only go by a wind tunnel smoke tests on similar vehicle body profiles I've seen, and the effect it is there. It would work better on the glass back or louvred versions for much the same reasons those designs naturally produce less drag than the open butressed version of later cars.

There is a shaped under tray at the front and under the engine. I don't know if having the engine cover has any effect on handling though!! I would always use it though as I'm sure it will separate the engine from anything you want to keep in your boot.

That tray isn't actually meant as an aerodynamic improvement, and from what I last saw of mine, it isn't shaped as such. It would need to extend all the way to the back to the rear bumper and have a basic volume diffuser to function as such. I believe it's primary function is protective, against water splash up, and general debris.

Nice avatar by the way I used to love elite can you get it for any of the play stations etc?

Thanks. I don't believe Elite was ever ported to the consoles. I believe it was only released on home gaming computers and PC versions. I also don't think Elite 2: Frontier made it further than the PC. Just checked and Wikipedia article says there was a Nintendo ES version way back, but mentions nothing else console wise.

If you have a PC, there is a good share/freeware homage called Oolite you could try, or better yet, play EgoSoft's X series games. (If you are new to them, best start at X3: Terran Conflict.)

Edited January 20, 2012 by B33 ENN