620R cooling

[Doctor]

Well done Mark, it is behaving well - especially encouraging as your S3 is tighter packaging compared to my SV. 

[7 wonders of the world]

Well worth the effort to get them functioning correctly, cooling circuit is now as it should have been,

Next thing is to add one of these....

https://www.ebay.co.uk/itm/MOCAL-OT-2H-OIL-COOLER-REMOTE-THERMOSTAT-WITH-12JIC-FITTINGS-PORSCHE-911-BCU/122638806161?hash=item1c8dd7ac91:g:-58AAOSwd0tdvEbf

you can also get a 92 degree stat as the stock one is only 80 degrees

 

[Doctor]

Neil, why not use Laminova oil/coolant heat exchange instead?

We use the racing stat that is 82 degrees. 

[7 wonders of the world]

Laminova are great for warming the oil on a cool day however they dump excess heat into the cooling system and peg the oil temp accordingly, the oil is designed to run at a higher temp circa 90-120 degrees.

 

[Doctor]

My plan is to install the oil temp gauge (not standard on any 620 (!)) and see what is what. What I'm also planning to do is to cool the gearbox oil. 

[Mark w]

Finally got my re-calibrated gauge back .Now reading within 2 degrees of what easimap says .

The new normal 

  

 

Sorry about the rotation !!

[Doctor]

Have they changed the iteration sticker at the back of the gauge to C?

[Mark w]

No , my original case ( which has the B sticker ) so it was either a re flash or new internal circuit board .

 

[CtrMint]

Hi Mark, 

Do you consider your cooling revisions complete.

Thanks

[Mark w]

Hi Mark 

Yes I think so , I guess some more driving in different conditions will be beneficial to highlight any potential issues but at the moment all seems fine .

[Doctor]

I'm working on some more temperature measurement options and perhaps more extraction of the hot air from the nosecone when stationary. 

[CtrMint]

I know the thread has moved on.... but I think this is important.

So I went out in my 620 last night for a lap around the course, it was a social run with a mate and his Westie.

Since the ambient temps felt cooler I decided to go to town on the front grill with some clear plastic film I'd bought, slightly thinner than the stuff used on the door screens etc.  We also both fueled up.  I brimmed the car as I have previously, something I hate doing due spillage risk over the rear exhaust!

Anyway, after a fun anticlockwise lap, to say the fuel usage was different is an understatement.  Typically without the covering, I'd see the fuel gauge read around the quarter mark once home, basically 50 miles for 3/4 tank at less than 60c.  Comical right, but acceptable in CCs book!

The car ran over the mountain and round the west side of the island at about ~80c!  Coming back through Douglas and Onchan the temps did rise to near fan on temps even at 25 to 30mph.  Lets just say I kept the speed up to prevent the fan!

She's used under a quarter of a tank according to the gauge!  A staggering difference! Fuel use is comparable to the 420.

I still don't find the covering acceptable and clearly the airflow wasn't quite right for 30mph.  I suspect reducing the covering so that ~30mph will see the correct temps will result in <60c @ >50mph etc.

I've txt Simon Lambert this morning to see if I can get this sorted properly.  The evidence is clear, CC needs to sit up and listen.

[Mark w]

Keep us posted .

 

[7 wonders of the world]

Nice night for a rub over the mountain Mark

The film you refer to.... are you still blanking off the radiator... or just the oil cooler..?

 

[CtrMint]

Yeah, it was pretty good, though we drove quick and sensible, some moron in a dirty diesel Golf decided to overtake myself the westie and the car in front of me going into Windy!  complete t8ss pot.  He couldn't wait for Hailwood rise!   We were out a little late, had too much of a natter in Ramsey, and ended up in the dark beyond Kirk Michael, so not ideal.   

I used the film to blank the radiator grill, and my oil cooler has always covered by the reg plate.

I would estimate I covered 75% of the radiator grill with the film.  So I didn't forget I cut it down when I got back, though I'm sure the offcut is still knocking about. After 5 I'll try and get some images up, 

 

[7 wonders of the world]

Why are you still blanking the grill...?

 ISTR you had put a remote bypass stat (PRT) in yours now.... or have you removed that now...?

With the coolant stat functioning correctly there is no need to blank the grill at all, the water in the rad will only be allowed to circulate once the stat permits it to do so.

Oil circuit needs a stat and permenant airflow though, stopping to remove the number plate is not a realistic solution, especially on the TT circuit

[elie boone]

Back to the future then, Saab in the 50's and amongst others had curtains before the radiator to control aiflow and with doing so the tempurature these curtains where adjusted from inside the cockpit. 

[7 wonders of the world]

Land Rover's had roller blinds too.......

[aerobod - near CYYC]

One suggestion for cars from the past decade or so is to have on-demand cooling with automated shutters / blinds on the grille to remove the need for a thermostat, but improve the aerodynamics when cooling wasn't needed. Not sure if Opel implemented it yet, but I know other manufacturers have looked at it: https://www.car-engineer.com/radiator-shutter-reduced-aerodynamic-drag/

BMW I know has removed the conventional thermostat, using on-demand electric cooling pumps in many current models, as I'm sure other manufacturers have, too.

With the very well defined and compact air intake on a Caterham, it would be fairly straight forward to engineer a servo driven shutter system to open and close the air intake based on water temperature from the existing sensor.

[ScottR400D]

The evidence suggests CC haven’t yet quite mastered the old thermostat/radiator/pump idea, James. 

Servo driven blinds and sensors might be a step too far......... 

[Mark w]

IMPORTANT UPDATE 

GOOD NEWS FOR 620 OWNERS .

Ive been in contact with one of the directors at Caterham and shared the details of the Mark W / Doctor  modifications . 

It wouldnt be right of me to share the full written response i got but its fair to say it was positively received and has initiated Caterham to look at modifying what they are currently doing . I quote " your solution is essentially exactly what we have in mind although achieved in a subtly different way" - My guess its that they will be looking at a remote stat in lieu of the modified housing but that is only a guess .

Other relevant info , Marks cries for help will be acknowledged and he and another customers cars will be modified .Additionally " [ after fully testing ] further down the line when we have a productionised product I think we’ll look to make it an aggressively priced update for cars in the field"

The down side of the exchange is that there was no offer to pay for my R and D 

Anyway , i hope thats of interest , please dont follow this post up with cries of "not soon enough" , " should have been right in the first place " etc ,  Previous posts like that on this thread almost put me off sharing our work with the wider community .

[Shortshift]

Well done Mark and Igor (and Neil) - that is a great outcome and it's terrific to know that CC are also following-up and on the case with a number of potential actions.  For me, as a potential 620 owner (at some point!) this really helps to address what was a worrying weakness in the car's configuration and paves the way for a safer ownership experience.

Now, all that you (both of you) need to do is get your R&D project properly written up for Lowflying!

James

[Mark w]

Yep , noted James .

[7 wonders of the world]

There's and easier way using the OE Ford stat but this was the most straight forward solution for most people.

Wonder is CC will retro fit these FOC or be like Morgan with the steering arms and charge customers....

[7 wonders of the world]

Next step, albeit a much simpler one, is to look at a stat in the lubrication circuit....  then all will be happy