The Lotus Grand Tourers

I have a nice new very shiny alloy radiator to fit to my car, the good news is that my radiator fans both work.. the bad news is my fan shroud is broken so when its fitted the left hand fan fouls the radiator, part of the top section is missing about 1/3rd of the left hand side. This is the post '89 fan shroud that is either ABS or fiberglass and is screwed to the top and bottom of the radiator and not the 5 screw holes for the earlier setup. Should I try and keep the original setup or are there better options?

You may find it easier to repair the existing set up. The shroud is obviously essential for correct airflow. Look at Neil's Excel SA thread for fibreglass work

- if it's just a repair required and it is fiberglass, it should be doable, otherwise I think they are listed for sale on the SJS website.

Is this the one? https://www.sjsportscars.com/parts-and- ... K0141K.htm - a lot easier to buy than manufacture form scratch

Neil

That is it! however there is a good third of the top of it missing it may be easier to buy it.. irritating though it may be. If I had the missing section i would without a doubt fix it

If we´re still talking about this Ford Fiesta Fans, I´m pretty sure, too, that the Air will need some kind of "Guidance". Just a thought... if Repairing the Shroud is too complicated and a new One is too expensive: I´ve just installed some new Aftermarket-Fans. Works great and because of the rather modern Design you don´t need a Shroud anymore. I spent 70 Euros for both, so I´m pretty sure they are Chinese... didn´t come with a Xi-Jin-Ping-Autograph-Card, though

Oldtimer_Basis wrote: ↑

Thu Nov 18, 2021 20:35

If we´re still talking about this Ford Fiesta Fans, I´m pretty sure, too, that the Air will need some kind of "Guidance". Just a thought... if Repairing the Shroud is too complicated and a new One is too expensive: I´ve just installed some new Aftermarket-Fans. Works great and because of the rather modern Design you don´t need a Shroud anymore. I spent 70 Euros for both, so I´m pretty sure they are Chinese... didn´t come with a Xi-Jin-Ping-Autograph-Card, though

Agree that modern fans are much more efficient but I've found that ram air efficiency is compromised if they are mounted directly on the matrix. The ideal stand off is about 2 inches or more to not inhibit ram air (the centres of the modern fan motor are often a very large diameter) but then you need to mount them in a shroud to restore the fan efficiency if held too far off the matrix.
Of course if ram air is inhibited the fans will switch-on (early) and you won't overheat - I'm just referring to ram air efficiency at low speeds (traffic). I did a lot of development making various cowls with different stand-off's on the Clan's rear radiator where ram air is diffcult to achieve at low road speeds.

"...but I've found that ram air efficiency is compromised..."
Right... that could become a Problem especially, when we are talking about the Engines with higher Output and Compression than the Standard one. Problem insofar, as the Fans might keep running permanently until you turn off the Engine, at least in hot Weather Conditions...

Oldtimer_Basis wrote: ↑

Fri Nov 19, 2021 19:30

"...but I've found that ram air efficiency is compromised..."
Right... that could become a Problem especially, when we are talking about the Engines with higher Output and Compression than the Standard one. Problem insofar, as the Fans might keep running permanently until you turn off the Engine, at least in hot Weather Conditions...

Not quite what I'm referring to. A good tell-tale test of ram air efficiency occurs at low roads speed, and regardless of engine output.

One of the things I like/admire about the Lotus Elite /Excel radiator cowl design is the speed at which the temperature drops once on the move in free air after a heat soak session in traffic that causes the fans to cut in and out (stop-start crawls). The ambient temps can be high but you still get good ram air cooling.

The rad nose/bumper aperture into the front cowl is small relative to the volume of air infront of the rad. This allows the air to decompress and cool as it fills the large void in the cowl before it enters the rad matrix, adding to cooling efficiency ..and the faster you go the more extreme the effect. But even at low road speeds (below 40 mph is key) the Lotus rad cowling is working for you. The design is negated somewhat if you place anything too close behind the matrix which might baffle the exit air, including the fans being too close/directly attached to the matrix.

Not saying you will overheat per se, just that you've compromised Lotus' very efficient design.

Great Info, Peter! I never spent Time thinking about that. My Answer to Cooling-Problems always was: Take a bigger Fan.
Or: Punch more Holes into the Front LOL
Using Low-Pressure to cool the Air before it enters the Radiator is brilliant!

In my TVR owning days ( well before I had the excel) my first 350 used to get a bit hot from time to time but the rad wasnt ducted at all so the the air could just spill around the sides instead of going thro it so I designed a duct not dissimilar to the excel and never had an issue afterwards. Peters right, the rad ducting on the excel is superb.
Bash

Hi Bash I had overheating problem with my TVR S1 but it was ducted, got round it by fitting fan with more blades out of a Renault Laguna ..
http://tvrserenity.blogspot.co.uk/