Oil cooler for 500
Discussion
I have been looking back over peoples views on oil coolers ,and all the expert opinions seem to say its a waste of money but like some other owners on hot days my oil pressure drops by about 5 PSI and it bothers me ,it normaly runs at 40ish and ticks over at 30 the cars done 10,000 miles and every thing is spot on with the cooling ,the fans cut in at 80 on my gauge and on a hot day when moving the car runs a couple of degrees below that. Am i correct in thinking that the advice that the oil pressure should be a maximum of 40 PSI means just that and a 5 or even 10 PSI below that is still good allso i have never seen an oil cooler fitted and i cannot see any where to fit one except a tight fit in front of the radiator and finaly would it be worth fitting a fan over ride switch to bring the fans in earlyer on hot days because it gets on my wick when the pressure drops, or am i being daft thanks for any advice given regards Steve.
steve290353 said:
on hot days my oil pressure drops by about 5 PSI and it bothers me ,it normaly runs at 40ish and ticks over at 30
Lots of RV8 owners would kill for those pressures. A 500 running Mobil 1 can give as little as 30psi cold, 15 hot and 5-10 tickover in a traffic-jam. They're famous for it.
I've improved things significantly by using a thicker oil, Castrol RS 10/60, but the pressure hot is always less than when warm.
Enjoy it!
steve290353 said:
I have been looking back over peoples views on oil coolers, and all the expert opinions seem to say its a waste of money.
I wouldn't say that. Most opinion would agree that they can be very usefull esp on a track day with a very hot ambient temp but as above you haven't got any problems so won't benefit much.
As for max pressures 4 to 5 bar is ok (60psi) enjoy
IMO oil manufacturers strive to develop oil that retains its performance under stress (heat & pressure). It only seems logical that an oil cooler can only help keep your oil & hence engine in better condition.
I seem to remember reading that even modern synthetics with long string polymers will break down if subjected to extended heat cycles. Dont know what it means but it sounded good!
Dave
I seem to remember reading that even modern synthetics with long string polymers will break down if subjected to extended heat cycles. Dont know what it means but it sounded good!
Dave
markh said:
As long as the oil cooler has an in line thermostat to stop it over cooling the oil, what harm can it do on a day to day basis, and extra protection on track days and continental trip.
Mark
The issue is where do you put the cooler without restricting the air flow to the rad so that the cooling gained is then set against a less efficient rad.
The problem is that there is not much room.
shpub said:
The issue is where do you put the cooler without restricting the air flow to the rad so that the cooling gained is then set against a less efficient rad.
Sorry to disagree, but I can only see this argument being valid if you have air con - which of course has the condenser in fron of the rad. As for reducing cooling, adding oil cooler is surely similar to having extra cores in your radiator - and since oil is cooled directly the water coolant is not working so hard. If you have no oil cooler the water coolant still has to dissipate heat from the oil via conduction thru engine block - increased heat soak.
Essentially if the cars cooling system can cope with air conditioning, then on a non ac car the addition of an oil cooler in a similar location will be far less impact on the cooling system.
Dave
Using the car's air con raises the engine temp by about 5-10 degrees. Does it on all the 4 TVRs I have had that have had air con fitted. The air that passes through enters the main rad at a higher temp and the cooling efficiency is reduced. If that reduction is less than that gained from the oil cooler, the end result is a deficit. So fitting an oil cooler means having to work this out to ensure the overall benefit.
The problem with the oil cooler is that while it will cool the oil it also restricts and heats the air flow going into the rad. There is one big balancing act going on here. The Griff air flow is not the biggest known to man and the potential for this balance to work against you is higher. Not really black and white and it does depend on the engine and how much heat stress the engine is generated.
Fitting a cooler to try and prevent a 5psi oil pressure drop is probably not a good way of spending a couple of hundred pounds, especially as the sensor is not that accurate at the best of times.
The problem with the oil cooler is that while it will cool the oil it also restricts and heats the air flow going into the rad. There is one big balancing act going on here. The Griff air flow is not the biggest known to man and the potential for this balance to work against you is higher. Not really black and white and it does depend on the engine and how much heat stress the engine is generated.
Fitting a cooler to try and prevent a 5psi oil pressure drop is probably not a good way of spending a couple of hundred pounds, especially as the sensor is not that accurate at the best of times.
Posted a similar thread on the Chim forum the other day, as I was seeing little oil presure when at idle in traffic. The car was goiing in to RT racing anyway so I asked Richard for his thoughts. Apart from the comment they all do that! He effectivly echoed Steve's view that an oil cooler wasn't the best answer and in some cases when they had been fitted had made things worse. I assume due to the positioning radiator issue.
He did however report doing something to my oil pump and I now see a good 10psi at hot idle and 45psi when. running at 3k revs as opposed to the 30 psi previous. Cost only 1hr labour.
He did however report doing something to my oil pump and I now see a good 10psi at hot idle and 45psi when. running at 3k revs as opposed to the 30 psi previous. Cost only 1hr labour.
Oil runs hotter than water, so if you're fitting an oil radiator overlapping with the water radiator, you need to make sure the oil radiator is downstream of the water radiator not upstream. In other words, put the oil cooler in behind the main rad not in front. Air con coolers go in front because they run at much lower temperatures.
If your water cooling system is not overloaded and you don't need to extract a massive amount of heat from the oil, fitting an oil-to-water cooler can be a very effective solution. It has the added benefit of acting as an oil *heater* during the critical warmup cycle, bringing the oil up to temperature much more quickly.
If your water cooling system is not overloaded and you don't need to extract a massive amount of heat from the oil, fitting an oil-to-water cooler can be a very effective solution. It has the added benefit of acting as an oil *heater* during the critical warmup cycle, bringing the oil up to temperature much more quickly.
All well & good when not moving Peter, but my reasoning is more like: Thrash motor moving quickly so good air flow which is when the oil is getting hot & will be cooled. Come to a halt all temps go up, no airflow, pumps circulating least flow, so temps start rising. Oil is not getting hotter at this point, but if it is previously cooled (when running fast) there is likely to be less load on the cooling system.
This is why I suspect that even mounting oil cooler in front of rad is not such a problem. The rad suffers from lack of airflow, but oil cooling is required when there is plentiful airflow, unless of course you thrash the engine in your drive!
Dave
This is why I suspect that even mounting oil cooler in front of rad is not such a problem. The rad suffers from lack of airflow, but oil cooling is required when there is plentiful airflow, unless of course you thrash the engine in your drive!
Dave
Spend, the problem isn't that the oil cooler restricts air flow through the water rad, it is that it heats the air massively, so the part of the water rad that receives the air after it has been through the oil cooler is either ineffective, or in extreme cases, actually heats the water up rather than cool it down. The general rule is to put the cooler components (air con cooler, intercooler) nearer the cold air supply, and the hotter components (oil cooler, EGR cooler etc) further back. In the Griffith the oil cooler is the hottest component you will have in that air flow so it should be last in line.
In other words, the right answer is to put the oil cooler behind the water rad not in front.
In other words, the right answer is to put the oil cooler behind the water rad not in front.
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