Rb Engine And Oil Cooling Idea .

[discopotato03]

Started this yesterday and Wi Fi dropped out right at the Post New Topic Point ... @#&^($%#@ !

I'm interested in anything that can allow me to use a bit more low/medium speed on load ignition advance and avoid the detonation . People who've been developing engines for ages seem to agree that running a coolant temp of ~ 70C is the sweet spot for maximum power output . This would not be hard to achieve (with the right thermostat) but the sorts of viscosity oils some people run may have problems .

I'm wondering what people think about running lightish oils like for example the Mobil 1 10W30 so that the oil does not need to get real hot before it flows easily . I do realise that it needs to get hot enough to boil off any condensation and combustion products if its to have a reasonable life ie 5000 K's .

So what do you think of water at 70C and oil at say 85C to bring down combustion chamber temps ?

Thermostats . I only know of the std I think 76 deg and 62 deg Nismo thermostats for RB's , is there anything in between .

Cheers A .

I remember Gary saying they use a Davies Craig electric water pump (race car) with speed controlled by the Motec to regulate temperature without a thermostat . If Davies Craigs "intelligent" speed control box could be relied upon and the pump body made of aluminium I'd go that way too . I still don't have faith in the composite pump body because its engine damage time if it cracks/leaks .

[StockyMcStock]

i am interested in the answer to this too, particularly if people have any experience with sub-80 degree temps causing bore/bearing wear at an accelerated rate. i know my vehicle has a fair whack more power when it's at 75 degrees than when it is at 80.

[godzl1975]

maybe using an oil cooler?..on really hot days ie 35deg mine just hits 80deg....on normal temps (25-30) it sits on 70 or so deg.

[discopotato03]

Any theories on why the bores or bearings would suffer any more wear with the engine coolant temp at 70C . Someone I know swears that the bores won't be round at lower temperatures but I fail to see how 5-10 deg C would make very much if any difference .

An oil cooler and bypass thermostat may be needed to get oil temp up from cold in winter and reasonable in summer .

Cheers A .

[T04GTR]

ok.. for a start. from working with ron toronack (sp?) he sugested that on his race cars (brabam's)they achieved maximum power and efecancy at a coolant temp of 75 and oil at 110.

and this was provan on the v8 supercar we worked on.

the whole reason for the oil to be 100+was so that from any blowby and therefor moisture getting into the oil it would boil off. the oil would last longer and you would get much less sludge build up.

anyway. my two cents.

[T04GTR]

maybe using an oil cooler?..on really hot days ie 35deg mine just hits 80deg....on normal temps (25-30) it sits on 70 or so deg.

really? is that of your factory guage?

[Dobz]

the bores arent out of round at lower water temp. they just wouldnt have expanded enough to give the piston adequate clearance.

the piston/bore clearance is setup according to the water temp. being run

[T04GTR]

also oil. most engine oils dont really become efecant to over 80deg.

refer to the gay castrol magnatec add.

[Sydneykid]

On the engine dyno an RB produces more power with water temperature at 85 degress than it does at 70 degrees. I don't think it is feasible for a road going RB to have the oil temp higher than the necessary 100 degrees and the water temp below 80 degrees. The intercooler/radiator/oil cooler size ratios would be impossible to achieve within the packaging.

Keeping in mind that the fan/fans do nothing to improve engine cooling over 60 kph.

cheers

[Dobz]

your best just to put a good oil cooler on it.

it's not the bores that cause detonation it's the pistons when they get too hot, hence the reason most of the RB engines have oil squirters spraying the backs of the pistons to soak up the heat.

you can lower the water temp if you want, it just means you'll need to downsize the piston diameter to keep the clearances right because the bore isn't going to expand enough for stock clearances at 70 degrees

[khunjeng]

If ur going a thin oil use the GC 5W30...GC= Germal Castrol. Not our local stuff. Can buy it form a few suppliers here. Good stuff.

I use a 5W30 Redline blend with a 40wt in mine...the film strength og my 30wt is higher than the 0w40 M1.

The only time I would go a bit thicker is for track work where the op temps will be higher. I would also use a oil temp and pressure guage and determine what thickness is fine.

[Scooby]

guys you need to consider the other stuff that goes on in your engne that you can't see. temp measured at one point can be a misleading indicator. most engines have awful cooling systems even though they don't overheat and puke coolant - they're awful because they allow hot spots, localised boiling and a number of other sins usually due to air in the water jacket and poor pump pressure.

ideally the thing should run at the highest EVEN temp ie even throughout the block temp it can stand without boiling as this improves effciency and therefore hp/qty fuel(BEMP?). i suspect that is the basis for SK's comments re getting more power at 85 deg than 70. the trick is to have a cooling system that is well engineered enough to do that and that includes a deaeration tank, air bleeds if required and a really, really good water pump.

[blk180]

ARC and Sard sell thermostats that open at 68c

Hi Brad

Nismo 68 Degree thermostat is also available.

Model Number : 21200-RSZ30

Low Temp Thermostat at 68c with standard being 76.5 Degree's.

$215 Delivered with NISMO radiator cap.

also that from slide

[carl h]

ive found that since i've redone my cooling system in my s14 (modded 20) and refitted the cooling fan that my coolant temps are a stable 82*c while cruising at gets as high as 84* when in traffic.

according to the power fc knock rarely goes above 15 on 14psi and scrapes 20 at 18psi.

it seems to me that the cooler the engine runs (compared to the 85-95 it used to with my efan setup) that it generaly feels better overall, im quite happy with my current setup as it has proven to work well for me.

next mod tho is to add an oil cooler because after i do a few good hard pulls i can see on the pressure gauge that it has dropped a few psi indicating to me that the oil is starting to thin out...will be fitting a setrab unit to the car and using a mocal plate to keep it some what regulated.

[RB30-POWER]

They already run cooler then most new engines on the market or engines running in late models cars.

Like fords I6 and ecotechs v6 run around 90-110.

RB are at 76-90.

Look at the Neo engines, they run hotter again, better emmisions and efficiency.

You don't want any cooler then 76deg IMHO.

[WazR32GTSt]

our 86 corvette runs aound 100deg, hell the thermo fan doesn't even come on until temp reaches 110deg!

[aDrew_C]

Thats always been my understanding too. Right now my water temp doesn't seem to get higher than 86, and usually sits on 80C when cruising. I always thought an engine will run better at higher temps to a reasonable extent, provided it's a good even temperature.

What people would be experiencing with their cars running worse at higher temps would more than likely be due to the fact that the a/f ratio should richen up at higher temps.

[gtst25]

They already run cooler then most new engines on the market or engines running in late models cars.

Like fords I6 and ecotechs v6 run around 90-110.

RB are at 76-90.

Look at the Neo engines, they run hotter again, better emmisions and efficiency.

You don't want any cooler then 76deg IMHO.

Yep - that's why they had all those problems with the old holden red motors when they turned blue and tried to increase the running temps to get better fuel economy and effeciency. Lots of boiling and engines running on was the result. A pitiful attempt for an engine in the late 80's from holden - thank goodness they went onto the rb30 in the vl but shortlived - disaster again when they went back to the rotton gm pushrod v6 in the vn's.

Cheers

[dontfeelcold]

They still managed to botch up the rb30 in the VL by putting the radiator to low in comparison to the head.

[gtst25]

They still managed to botch up the rb30 in the VL by putting the radiator to low in comparison to the head.

Definately - and I bet that was holden not nissan.

Cheers