R500D Cabin Temperature Reduction

[john milner]

If a heater is fitted it is worth checking that off really does mean off. Not a cure for excessive over heating but every little helps.

 

[Rogercsr7]

Hi Chris,

Sorry, must have dozed off for a couple of weeks! Not been able to do a back to back comparison of Zircotec v wrap for instance, but subjective assessment tells me the Zircotech was a success in heat reduction. Costly I know, but happy to recommend. As Neil says anything to reduce heat going down the transmission tunnel (chimney) is a good thing, especially in a summer traffic jam.

Roger

[chrisbeddoe]

Thanks for the feedback Roger & Neil. Think I am going to take the plunge and send the headers off to Zircotech.

Interesting point around the heater too John. I find that it does still push quiet a lot of heat through the vents even when off. So much so that I have blocked the foot well vents up. Will investigate this a little further to see if its not quite off. 

Chris

[john milner]

The heater problem is usually caused by the cable being incorrectly adjusted at the control valve. I thought a hot cabin was normal until I corrected it.

Apparently it is a quite common factory fault.

I have a SV with a VVC engine and no heat problems.

[Rogercsr7]

Have a look at the seal between the the heater intake plenum and the bonnet. You might be getting hot air from the engine bay into the heater instead of fresh air

[chrisbeddoe]

Interesting, I will try and get some tinker time in the garage this weekend and investigate futher

Chris

[Dartmoor7]

Further to the heater comments above, if you ensure the heater valve is fully closed you can use the heater fan to blow ambient temperature air into the footwells. I always do this on really hot days, and I don't have a massive heat soak problem in the first place.

[chrisbeddoe]

Sadly didn't get time to get in the garage this weekend but it definitely sounds like the heater is contributing to the issue. There is absolutely no way I would put the fan on in warm weather atm, as it just blasts me with hot air no matter what setting it is on. Will investigate this further :-) 

[anthonym]

R500K here, hoping we are not excluded by "specifically R500D"

My solution, developed over many years now, is two fold:

Half doors. Half hood and ski jacket to hand.

Squirty bottle of water.

With the half doors I now rarely need the water, but that water instantly and massively reduces temperature (basic science someone else will explain). In extremis remove the squirty lid and tip over your head. Squirty part is for feet and legs and tunnel - especially the tunnel. Alike for passengers (ours suffer like drivers in the Duratec).

About the tunnel, I have always worn shorts, the tunnel top forms a "side knee rest". Come to think of it my shorts are ALWAYS longer than my knees.

I have tried wrapping the primaries and bulhead insulation.

What I never did try was insulation on the inside of the cockpit and/or something much more substantial between the primaries and the bulkhead. If you see the fridge door pic in Low flying (this or last month) shows my primaries on the dyno. THAT is what we are up against. Explains a lot I think. Granted the D revs a bit lower for a given power, but power is power and that means heat.

The bulk buy mentioned above has my attention.

(If your starter is same side as primaries that's another story waiting.)

Hope something in here is useful - for me half doors changed my experience.

p.s. about the squirty water, drying time is ... not long :-)

[Jonathan Kay]

Interesting comment on the need to close the heater valve completely. Hope that helps.

By the time I was relying on evaporative cooling (see Spitfires and the predecessors) I'd be looking at getting more ambient air flowing onto the hot bits of the cockpit.

Jonathan

[NeilCSR]

Zircotech treatment on headers has made a big difference.

First proper day out yesterday, couple of hundred miles covered with a representative range of driving (slow traffic to fast cruising with plenty in between).

The tubes on the tunnel never got beyond warm (comfortably so).  Previously, even on a cold day they would have been far too hot to touch when the car was warmed up properly.

Neil

[Titanium7]

Has anybody tried removing the vinyl ducting sheet in the nose cone to get more air moving past the engine and exhaust primaries?

[John Vine]

Has anybody tried removing the vinyl ducting sheet in the nose cone

Oh yes, that was one of the first things I tried on my R400D.  It seemed to help, but I didn't do a proper before/after/before test.  The most noticeable improvement resulted from wrapping the primaries.

JV

[chrisbeddoe]

So it appears the heater valve was stuck open as suggested. Has made a huge difference to the foot well temperature (thank goodness). Will have to see how it fairs in the summer but for now the zircotec is on hold.

Thanks for the top tip :-) 

[chrisbeddoe]

Update!

Heater cable fixed the foot well was still swelteringly hot last summer so this spring I sent off the exhaust primaries to get ceramic coated by Zirocotec. I have to say they look incredible:

I can report that the engine bay is definitely cooler and this is demonstrated by the engine running at lower temperatures (still within the operating window obviously), which will come in handy with the odd summers day track day. The car now holds a steady 87 degrees on motorway runs and around town, but more importantly in traffic rarely hits 108 degrees at which point the fan comes on (a temperature i was never overly happy about). 

The bad news is that the food well is still uncomfortably hot :(

So my remaining options are:

1. Remove the plastic air ducting around the radiators to increase airflow through the engine bay.

2. Additional heat insulation in the foot well panels

 

Not sure which order I will do them in, but will update on any progress

[Ian B]

Oooh those look nice 

I had wondered about adding a rear facing "scoop" under the tunnel to suck air out of the tunnel under the car, as I believe it effectively gets trapped there. Unfortunately I don't know enough about how the air flows under the car, or how such a scoop would perform.

Something like this (upside down and facing the back)

[Ian B]

Another thought was to vent the sides of the tunnel at the back into the passenger compartment behind the seats.

That area seems to be under negative pressure and so might suck air out of the tunnel.

I realise this would be into the passenger space but I think that it would be drawn out of the car by the negative pressure behind the seats.

Something like this, vertically in the sides of the tunnel

[Jonathan Kay]

Did that academic who did the CFD study the underside?

How about starting with a pressure probe?

Jonathan

PS: Meredith effect! :-)

[NeilCSR]

Those headers do look beautiful....

I've removed the alloy plate underneath the prop shaft - not a stressed piece (confirmed by Arch) but should help air get out at the back and reduce the temperature of the transmission tunnel.  

Considering adding a bonnet scoop for the air filter, partly to reduce charge temperature but mainly to create airflow through the engine bay, albeit on the opposite side to the headers.

All different 'tweaks' have helped reduce the underbonnet temp but still too hot.  Don't want to remove the plastic deflector behind the rad - which is the obvious solution - as that would probably add lift to the front at speed.

Neil

[Croc]

 

I did the bonnet scoop into the intake.   I added one to my CSR and it lowered the intake temperatures substantially.  I was running before and after data off the CAN J1962 connection under the dash and an AIM solo (which works just great with the Caterham ECU) to prove my theory.   However, solving one problem created another.  Now I get venting hot air out the bonnet louvres right into my face if I am running the aeroscreen and relatively low speeds (i.e. road usage).  Higher speeds on track and it is not noticeable.  Don't notice it with a windscreen.  

I need to drop the alloy plate under the prop shaft like you (Neil) did to allow the air to flow through better which will minimize the new louvre effect.  

I did not wrap or coat the primaries on my CSR - will do it next time engine comes out.  

[Mike Biddle]

Chris, here are my experiences with footwell temps, which was a big issue for me when I first got the car new in 1996, ambient temps in Dubai being rarely less than 20C, and I was often driving the car in 35C.

Needless to say the footwells were getting really hot and I experimented a lot to get that under control as far as possible.

Wrapping or coating the primaries will help.

Insulating the transmission tunnel internally is a big help if done well. A lot of hot air from the engine bay goes down there.

While you are doing that, try to seal all joints around the tunnel and footwells, whether you run a standard or aeroscreen there is a lot of negative pressure in the cockpit and if you get someone else to drive you can run your hand around under the dash and feel hot air coming in almost everywhere.

I took the heater out and threw it away,then covered the hole making sure it was sealed up well. You don't need it anyway, just wear motorcycle clothing if you want to drive in cold weather.

Finally, I fitted air scoops to the footwells, and that really helps, the negative cockpit pressure ensures a good blast of cooling air on your feet.

You can see the passenger side scoop in the picture below. Of course not everyone wants to cut holes in the side of their car, but I use mine for touring and comfort is paramount.

 

 

[Jonathan Kay]

I can report that the engine bay is definitely cooler and this is demonstrated by the engine running at lower temperatures (still within the operating window obviously), which will come in handy with the odd summers day track day.

I understand the effect on the engine bay but why does the engine run cooler?

Thanks

Jonathan

[Jonathan Kay]

Finally, I fitted air scoops to the footwells, and that really helps, the negative cockpit pressure ensures a good blast of cooling air on your feet.

Those scoops take ambient air from outside and push it into the footwells? No connection to the engine bay?

Thanks

Jonathan

[NeilCSR]

Don't know the exact logical explanation but in my experience coating the headers did make the engine run cooler - or maybe this is a function of where the sensor is in the system?

Even runs cooler than before when using Evans waterless, which should have the opposite effect as the heat absorbing capacity of the glycol mix is less than that of water (70% or so?).

That's experience.

Neil

[NeilCSR]

Finally, I fitted air scoops to the footwells, and that really helps, the negative cockpit pressure ensures a good blast of cooling air on your feet.

Those scoops take ambient air from outside and push it into the footwells? No connection to the engine bay?

Don't think that Mike Biddle's post was about the engine bay, although that is the obvious source of the heat.  His issue was footwell temp, which is the reason for fitting the scoops.  

A pretty stunning vehicle with a unique badge: