KnifeySpoony

I know many people would say there's nothing wrong with those oil temps with modern good oils. But having some headroom is surely a good idea. You can always block it off for cooler days. Unfortunately with my pusher fan, it's not easy to block my cooler, so i just block the lower air inlet on my race style nosecone, which only helps a little to keep temps up while street driving. Cold morning drives to the track on the freeway have me fearing for my engine. 

Wow that's a big cooler. I'm curious to see how your temps respond. Also maybe I missed it, but do you drive it on the street as well? With my little stock cooler on my newer 420R, temps in the tank are scary low on the street, but that's without a Tstat. Will be interesting to see how you get on. 

To add some data points to the thread - my oil temps on track usually run about 80C after fully up to temp. Highest I've seen was 88C. Water temp around 95C peak. Oil pressure never drops below about 4.2bar even at its hottest. I'm running the Motul 5/50.

I'm very happy with my Antigravity ATX12HD. Weighs almost nothing and no issues starting.

Well, hopefully the softer hose is enough to preserve my radiator. The first one only lasted about 3k miles and maybe 10 trackdays. Mind you the leak was miniscule, but I changed it out as soon as I noticed it. Current one has about 1000miles and 4 days on it. Time will tell.

Ah Ok, I thought you were criticizing my solution. You can the see OEM routing is bad and the hose is under some tension to make the bend back to radiator inlet. The inlet pipe is angled coming out of the rad, presumably to address this, but didn't work well. That combined with the super stiff hose and vibrations must be contributing to failures. Hence my silicone hose.

Here is the standard setup with original hose.

It looks like you have a totally different radiator and different mounting setup. Also is your car an SV? 

Because of the bend in the hose, it does ride up over the catch can a bit. I thought that might make it harder to bleed but I had no issue. And because the hose is so much more flexible, I can actually just move it over to remove the catch can. Previously I had to suck out the oil, because the old hose trapped it.

sorry for upside down pic

FWIW here's what my grafted 620R hose looks like. Looks slightly bent but it's so flexible there isn't any load on the radiator.

My vote is for TPS.

Just hand sanded with whatever I had lying around.

I had to sand mine to get them to fit as well. Caterham gonna Caterham. 

I and some others have changed out the top (super rigid hard rubber) rad hose for the much more flexible silicone hose from the 620R, which is available from Caterham parts. You just need a coupler, very easy install. Too soon to report on effectiveness but no issues yet on my second rad. And btw, your can get a new water rad alone from Caterham parts (ie without oil cooler) if desired. 

I have a "race" nosecone which allows more airflow to the oil cooler, although i block the lower opening on cool mornings. I suppose it could still cool more than the standard nose though. Blocking it bumps temps up about 5C on the freeway vs having it open. The highest I've ever seen on track is about 83C. 

I can tell you that on my 420R driving to the track on cool fall mornings (in California) - steady state on freeway at 70mph, I'm seeing as low as 41C in the tank. Yep.

The delta between oil temp in tank vs sump will change a lot actually. It will certainly vary with the delta between oil temp in the cooler vs ambient temp, as well as airflow. 

Apparently de-aerated oil is easier to measure the temperature of accurately which is one reason that most dry-sump systems have the temp probe near the bottom of the oil tank. It would be nice to have another sensor in the sump to see the oil at its hottest I suppose. 

There's already a bung on your dry sump tank ready to accept a temp sender. On my 420R I got a dual temp gauge (oil/water). It came with senders for both oil and water. Just put one into the dry sump tank, and the other replaced the the sender in the "submarine" for water temp. Very simple install. The oil in the tank is the coldest in the system, as the cooler is before the tank, and the oil cools further within the tank, so be ready for some scary low oil temps...

I have a newer 420R and I use the same method as you and get about 6.4L out during a change. Just for another data point. But I'm not sure if my sump design is any different.

I mean, a second+ is a lot when you are at a plateau and chasing tenths. Depends what your goals are. 

ZZR about a second quicker in my experience. In terms of durability, the ZZR surprisingly don't seem to wear much quicker. The ZZS developed "chunking" on the edge of tread blocks up front, while the ZZR are not at all so the ZZR holding up better up front actually. ZZS is definitely no slouch on track though, I was surprised how well it performed. 

Re: Top radiator hose - I followed in the footsteps of a member here and fitted the top hose from a 620R to my 420R. It replaces just the forward section of the standard stiff hose - I just got a coupler and swapped it in. It's been working well so far. My first rad started leaking after less than 3k miles. I didn't have any bleeding issues and the flexibility of the hose lets me take out my oil catch bottle to empty it instead of having to suction it out.

6 hours ago, aerobod - near CYYC said:

It is certainly common, if not standard, on all R400D and R500Ds.

I mean on current model cars. I think all the superlight series cars came with watts.

AFAIK only the 420R race cars and the 620R come with watts linkage. Maybe the new 420cup does too.  My 420R has watts linkage installed from new so I've never experienced the radius arms. Car seems plennnnty lively for me with the watts on - wouldn't want it anymore so.