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84 Turbo Esprit Undertray - A picture - Interior/Exterior/Lights/Glass/Alarms/ICE/HVAC - The Lotus Forums #ForTheOwners Jump to content


84 Turbo Esprit Undertray - A picture


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You'd need to seal up the small holes in the tray if you want to stop all the oil drips, LOL.

 

Of course, on later cars Lotus cut out some largish areas to provide airflow to the exhaust side of the engine (see the picture of my '88's). I installed some rubber gaskets on the edges of mine, after driving through a 12 hour rainstorm in 2005. The carpet jute under the gas tanks was a bit soggy! :blush:

 

The lead edge goo on my car was only applied to the catch-bracket, to keep airflow from blowing the pan off at triple-digit speeds I'm sure. There was nothing on the bolt holes (which will resist moisture fine, if packed with anti-seize).

 

 

I wish I was the RTV supplier to Lotus Cars back then.  I'd be a millionaire by now. :P

The M100s I've worked on seem to be totally assembled with RTV!

 

 

 

P9030017.JPG

Atwell Haines

'88 Esprit

Succasunna, NJ USA

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I am not too fussed that mine is missing. I had one on my S4 years ago and I seemed to be taking it off every other weekend! My days of 3 figure speeds in the Esprit are over anyway....well almost B-)

cheers

C43

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If this is not fitted the sill ducts are not going to do anything, they will just eject onto the road rather than air being deflected upwards by the trailing edge of the undertray. Not sure what the implications of this are on cooling.

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I've seen some very persuasive post that say the only purpose of this tray was to reduce noise in some drive by noise test? Mine has never had one since 1988 when I got it, and no ill effects as far as i can tell.

Scientists investigate that which already is; Engineers create that which has never been." - Albert Einstein

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8 minutes ago, CarBuff said:

A deep air dam in front makes the airflow argument unimportant.  But then, you need to watch out for 'sleeping policemen' (speed bumps) :sofa:

But a deep air dam at the front would not render the sill NACA ducts unimportant. These ducts were added by Lotus and were not part of the Guigiaro Turbo design upgrade (according to the Walton book) in order for air to be ducted into the engine bay and flow out through the slats. 

 

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I suspect people's view of the importance of the undertray will be directly proportional to their ownership of one.....    Like a lot of other stuff, imaybe ts not essential, but as far as I'm concerned its part of the original package, like a handbook, a toolkit or whatever.

Edited by 910Esprit
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24 minutes ago, Andyww said:

But a deep air dam at the front would not render the sill NACA ducts unimportant.

Sorry, My SARCASM emoji didn't load properly. 

24 minutes ago, Andyww said:

 

Atwell Haines

'88 Esprit

Succasunna, NJ USA

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http://www.motorsportmagazine.com/archive/article/june-1980/112/lotus-esprit-turbo

Quote from Roger Becker:

Aerodynamic changes include a deep front spoiler, side skirts incorporating NACA ducts to provide cooling airflow to the engine compartment, directed by an undertray beneath the engine and finally exiting through ducting louvres in the rear hatch, which replace the standard Esprit's rear windows.

 

Not sure why some people here dont agree with the guy who designed it.

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5 hours ago, C43 said:

would be interesting to CFD the car and see if the actuality matched the design intent...

 

What I do know is that they hacked a car around the Hethel test track with temperature sensors all over the engine bay. I spoke to the person who bought this car (Bernard White) many years ago. I would guess they used a testing approach rather than theory.

They seemed to be paying particular attention to engine bay airflow and temps, for good reason.

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Ah yes the real life approach! Kind of surprised they had a data logger in the early 80s but they would have needed it for the active car development. I bet it was the size of the passenger compartment! 

 

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  • Gold FFM

The post is on here somewhere, I think Bibs asked the question about the purpose of the undertray, and according to Brian Angus, it was solely to cut down on noise.

As for aiding cooling, I took my undertray off when I bought the car, and with the amount of accumulated greasy crap on it, I felt it was more likely to be a fire hazard, so I left it off, and I've never out it back since then. I've never noticed any cooling problems with it removed, and as the effing rear crank seal has started to leak again five minutes after I changed it, it'll remain leaning up against the wall in the garage for the foreseeable future!

  • Like 1

Margate Exotics.

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Stringent noise regs were not introduced until 1996. Why would the Turbo esprit be noisier than the S3 NA which does not have the undertray? If anything the undertray would reflect engine noise up through the vents and increase it.

The airflow design is obvious when you look under the car with the undertray fitted and see where the side dusts exhaust to.

If Roger Becker said the vents and undertray were added for cooling I dont see any reason to doubt it. I would think at high speed the engine bay temp would get extremely hot with reduced airflow, under turbo boost conditions. Not hot enough to cause any immediate and obvious problem but hot enough to cook everything and shorten life of components such as hoses, seals, engine mounts and other rubber parts, clutch slave, alternator, ignition module etc.

Extreme condition of no air flow at all and this happens. Not suggesting it would reach this condition in reality.

 

 

 

esprit_engine_test.jpg

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  • Gold FFM
3 hours ago, ian29gte said:

, and as the effing rear crank seal has started to leak again five minutes after I changed it, it'll remain leaning up against the wall in the garage for the foreseeable future!

Should have fitted it properly then 

Only here once

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  • Gold FFM

It's telling that the S4 onwards panels have about 25% of them cut away, which makes me think that was  to dissipate heat. But by doing that, they would probably let out more noise. And if there was any aero effect, they had presumably weighed up whether the benefit of that outweighed the potential for overheating! Or it could be they decided to cut the holes out to lighten the car!

Margate Exotics.

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@brian_gt4 Would you be able to clarify please mate? Thanks! :)

88 Esprit NA, 89 Esprit Turbo SE, Evora, Evora S, Evora IPS, Evora S IPS, Evora S IPS SR, Evora 400, Elise S1, Elise S1 111s, Evora GT410 Sport

Evora NA

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