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2CV racing with car #48: round the clock again...


chaseracer

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2 hours ago, DSdriver said:

How does the carb get iced up when you have been running for over twelve hours?

Drivers reported freezing* fog on the long back straight, in the early hours. The front grille's upper section points pretty much straight into the air filter so the cold and moist air is being force-fed straight into the carb with nothing to warm it on its way through. 

We all initially thought it was crap in the fuel but once some drivers reported the fog, it all made sense - sadly too late for us, we'd already lost all the time we'd made up. 

If the weather had been any different overnight, it'd probably have been fine. 

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1 minute ago, Crackers said:

Drivers reported freezing* fog on the long back straight, in the early hours. The front grille's upper section points pretty much straight into the air filter so the cold and moist air is being force-fed straight into the carb with nothing to warm it on its way through. 

We all initially thought it was crap in the fuel but once some drivers reported the fog, it all made sense - sadly too late for us, we'd already lost all the time we'd made up. 

If the weather had been any different overnight, it'd probably have been fine. 

Yes, freezing fog is the only things that’s ever caused me problems on the motorway- just had to slow down to reduce the cold damp airflow over the carb.

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14 minutes ago, DSdriver said:

erm... its August, what happens in winter?

Freezing fog as well. I think it’s more to do with the sudden temperature and humidity change. I went out cycling this morning and it was 10 degrees and could see my breath - august in Hampshire!

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image.png

I have slept for many hours now, and don't look quite so worried as when Laurence was guiding a slick-shod Toaster around in a hailstorm in the last hour with no tow-back available!

George is supremely relaxed because he's out of his romper suit and knows I can't plug him back into the car... 😁

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4 hours ago, chaseracer said:

image.png

I have slept for many hours now, and don't look quite so worried as when Laurence was guiding a slick-shod Toaster around in a hailstorm in the last hour with no tow-back available!

George is supremely relaxed because he's out of his romper suit and knows I can't plug him back into the car... 😁

It is quite scary how much you look like your AS avatar... :-)

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On 8/27/2023 at 4:18 PM, DSdriver said:

How does the carb get iced up when you have been running for over twelve hours?

it has nothing to do with the engine temperature and everything to do with the temperature and humidity of the air being drawn in.  A raceing engine suffers from this more than a road engine as it operates at WOT for a lot of the time.

https://en.wikipedia.org/wiki/Carburetor_icing

As we were driving through fog at 2AM, it's likely that the incoming air was at 10-ish-degrees C, and 100% humidity, which puts us in the "very high likelyhood of carburettor ice" zone.  This is exasperated by the air cleaner getting a very good cold air feed from the front grille.  Absolutely no inlet air heating at all.

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On 8/27/2023 at 6:48 PM, DSdriver said:

erm... its August, what happens in winter?

You put the supplied 'grill muff' on below 10 deg C (or you do if you want it to run right and actually have an effective heater)

Or to paraphrase an old 2CVGB saying...

Mufff On below 10. Muff Off above 10

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The solution for some cars seemed to be a couple of rows of duct tape over the top half of the grille, blocking the path into the filter. Presumably once the air was diverted over the top of the engine / oil cooler area it was warm enough to stop the icing problem.

You live and learn!

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19 hours ago, 500tops said:

Great to see a car rocking the square lights...

Dummy round lights for the sprint races, always full-LED squares (with round LED spots) for the 24hour, all mounted a bit squiff to illuminate the bits the driver needs to see.

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