Sam's build thread

[sambb]

So I've done a bit of testing of temps now that the oil cooler is fitted. I have an OE spec Tridon 90 degree thermostat. The mocal sandwich plate uses an 82 degree oil thermostat I believe. Temps taken from instruments grp 003 in vcds = coolant temp sensor for water and sump sensor for oil.

Previously on a 10 degree morning wth the original gear all in the car, just doing a local small street commute, with water at 10 degrees and oil at 9 degrees, after the below times the temps were as follows:

10 mins - water 80 - oil 61
13 mins - water 88 - oil 71
15 mins - water 90 - oil 76
17 mins - water 95 - oil 84
18 mins - water 93 - oil 88
21 mins - water 95 - oil 91 thereafter the water oscillated around 94 degrees and the oil trended up to 99 degrees and stayed there.


Today with separated water and oil systems (no heat exchanger) and with the oil cooler installed I decided to test the worst case winter commuter scenario for the cooler. The fog lamp facia was taped off so that zero airflow could get to it. It was 10 degrees ambient too:
from cold start:

8 mins - water 93 - oil 50
10 mins - water 95 - oil 64
12 mins - water 94 - oil 71
14 mins - water 92 - oil 80
17 mins - water 91 - oil 85
19 mins - oil 88
20 mins - oil 90

Then going home from work this afternoon from cold in ambient 18 degree air (oil cooler still blanked off to any airflow):

0 mins - water 19 - oil 16
6 mins - water 80
7 mins - water 85
8 mins - water 88
9 mins - water 90.....
14 mins - water 95 ish - oil 80
16 mins - - oil 85
18 mins - - oil 90
22 mins- - oil 95

It seems that post oil cooler/sandwich plate that the water temps are coming up to 90 degrees 5 minutes faster. My guess is that this is because the heat exchanger has been removed. On warm up previously the water temps were loaded down by the slower to heat oil possibly putting a latency into how quickly the water could get up to temp. So the water heats to operating temp sooner now. However once up to urban temp I've noticed it will oscillate more. Previously with the heat exchanger, the oil and water temps would lock onto each other anywhere between 95 -100 degrees and then hold each other very frimly in that windown. Now without the oil in the heat exchanger to dampen the changes in water temp you can see it move around more eg at the end of a down hill coast the water temp will drop to 87 degrees and then get back up to 95 once you get back onto the throttle. Its like you can see the different temperature water bursts that the thermostat is providing. This is less so in traffic on the fans though where it still locks itself to one temperature though.

Thankfully on both 10 degree ambient days, it took basically 16 mins for the oil temps to get to 80 degrees. A little bit quicker on the 18 degree afternoon. Pre and post mod it took the same 20 odd minutes for the oil to reach 90 degrees. That was my biggest fear as under temp oil is bad news, so the fact that in normal driving that the oil temp was coming up just as fast with cooler + sandwich plate as standard is great. It must be remembered though that this is with a 6 row oil cooler, blanked off to any air flow and eventually heatsoaking too. Also, pre and post mod, the oil temperature eventually set itself on 100 degrees. At one time in bumper to bumper on the way home on the 18 degree afternoon after 45 minutes in Sydney turd traffic the oil temp got to 103 degrees which is a function of zero airflow and total heat soak. It cooled back to 99 once I got moving again.
So basically I think the numbers show that you can run an oil cooler and sandwich plate without the heat exchanger and get OEM type temps from water and oil (water coming up 50% quicker though). Once up to temp the water will have slightly bigger oscillations - seems to be 'on' the thermostat more than when its temp was held stable by the oil. And the oil once up to temp seems to want to exist in the 95-100 degree band that it had previously.
What I'll do next is the exact same test with all the blanking removed so that the oil cooler is seeing airflow throughout the warm up process and see if it retards the rate of temp increase of the oil. I expect the water will be unchanged from above though since it is completely independent of oil temps now. Longer term i'll build some nice ducting for the cooler and then i'll settle on the right amount of blanking for street driving, and open her up for max flow to the brake ducts and oil cooler ducts when I'm on the circuit.
That's the low down so far anyway.

[seangti]

Great share Sam. I'd been curious about those stats too.

I bought a new daily driver this week (VW Jetta), so will have the opportunity to take the car of the road to fiddle with these sorts of things.

[seangti]

Great share Sam. I'd been curious about those stats too.

I bought a new daily driver this week (VW Jetta), so will have the opportunity to take the car of the road to fiddle with these sorts of things.

[sambb]

Oh that will be so sweet to have a garaged track car again. To be honest I was surprised too that the temps came up the same as standard. I don't think that'd be the case if you had it mounted out the front though. You couldn't blank it off then and always getting airflow I don't know if oil temps would come up in the same way. Could be wrong though and I guess we'll see once I can test it again without its airflow being blanked off.
Honestly if I was to do it again, I'd just invite an Enzed guy around to make up hydraulic fittings (only one nut to tighten rather than 3 per fitting) swaged to the hose. Costly but virtually fail safe. I can tell already that these AN fittings are going to be something that i'll have to routinely check to make sure they are always in order.

[sambb]

Just went for another little commute drive this arvo in 18 degree ambient. suburban streets onto 60kph rd with traffic lights every couple of minutes. The entire fog light facia was removed to let some airflow in - no ducting concentrating air through the core but some mass airflow getting into the fender area.

0 mins - water 16- oil 15
8 mins - water 80 - oil 43
9 mins - water 85 - oil 47
11 mins - water 90 - oil 55...

18 mins - - oil 80
21 mins - - oil 85
23 mins - - oil 88
25 mins - - oil 90

so luckily I was able to go back to back on an 18 degree day with and without the facia. With the airflow running through it, it took roughly 4 minutes longer for the oil to reach its temp. That probably mirrors what a cooler out in the front air flow would see eg one that cant be blanked off and that gets mass airflow rather than concentrated air via a duct.

[metalhead]

Interesting... I got an oil temp gauge in the Vette for the first time last week - all new gauges actually, I've had them waiting to be installed for a while, got sick of the unreliable and inaccurate factory gauges. I have no oil cooler but a large sump, and run my water temps relatively low. My oil temps follow a similar trend of rising slower than water temp (to be expected) then roughly following water temps though with less variance and a little higher. Generally I'm seeing ~20F (~11C) higher than water temp in manifold next to thermostat, or ~10-15F (5-8C) higher than water temp in the head.

[sambb]

Yeah its surprised me actually just how long the oil takes to get up to temp. Makes you realise that you have to wait at least 15 mins before tearing around at all. You're dead right, dash gauges are next to useless. Our water temp gauge shows 90 when the temp isn't even 70 degrees and stays there when the water temps are up over 100 degrees. I think my thermostat is a 90 degree one. I assume that means it cracks at 90 degrees. Given that the water temps coming out of the head are 95-100c it doesnt seem bad that the engine is only adding 10 degrees to the water in normal driving. The real test will be on the circuit. Without the oil trying to drag up the water temps via the heat exchanger and the cooling system able to work on its own, it'll be interseting to see what temps result from radiator versus engine (assuming the thermostat will be wide open). Ideal world will be for the oil cooler versus engine battle to result in 100 degree oil rather than it heading up to 130 degrees. If not then the only option is to go to more rows in the cooler or get Adrian Newey to design the ducting to it.
Actually have a weeping AN fitting at the sandwich plate. Its so tight in there that i'll have to take both fittings off to get to it but its not the end of the world. Given that it hasn't pissed oil everywhere, I'll enter the last hillclimb round at Huntley tonight. Are you going Andrew?

[metalhead]

Yep, I'm entered. They were only accepting entries by mail on the website, but do you want me to ask for an email address for you? I have the secretary on fb.

[sambb]

yeah that'd be great thanks.

[sambb]

Fastest I've been up there is 28.63. I honestly can't remember what tyres I was on - could actually have just been a front pair of AD08R's. One place I don't like it to be wet so fingers crossed for the weather. I've paid up but will get the entry off today.