OOOHHH seeing as we now have an engine specific home for Techy questions I thought I'd post this one here instead

Reading through the recent mails about melting pistons in Sti's, I've been wondering whether an oils cooler would help prevent the engine temperature form getting high enough, and the viscosity of the oil low enough for this to occur.

Has anyone fitted an oil cooler to an Impreza Turbo (of any type), and found if it helps, particularly on a track day, where the car will run at higher engine speeds for prolonged periods.

Also are there any suitable oil cooler kits available, and is a secondary pump required on a Turbo engine for a cooler?

Tim,
Apparently, HKS have just launched a new oil-cooler kit, specifically designed for the STi IV and V although it can be adapted for other models.That's the only one I've come across to date though there may well be others available.There's also a transmission oil-cooler just come out.

I've no idea about how much it costs but I received the info. via TDI (who appear to be unsurprisingly off just about everybodys christmas-card lists at the moment due to the unfounded and unprofessional, disparaging remarks made regarding Pete,David,and Grahams respective tuning organisations.)
As they are the main uk franchise for HKS however, they nonetheless have the relevant info. to hand, and also have an interesting new website which is worth investigating if only for product info.+ pics. and there's also a linked HKS web-site;( www.tdi-plc.com)

You could also/alternatively try www.dpmotorsport.com/accesories.htm for HKS stuff.

We are working on an oil cooler kit for the Impreza, all types.

In Japan it is the first thing they do before even changing exhaust. However we have not done detailed oil temp testing yet and we have learned not to assume that because the Japs do something it is gospel.

It is one of these nice and rare things in the tuning business in that it cannot possibly do any harm and can only work to improve engine temps/life etc.

All Imprezas have an oil cooler fitted as standard but it is run through the water coolant system and therefore runs at 100+Celcius so will only drop temps at best to 100+. A decent air/oil coller should drop the temperature to 75-90 depending in driving.

Japanese oil coolers are very expensive.It's a good thing to have as they cools the oil to a safe operating temperature but I don't think it will help to prevent piston melting on STi.We in Brunei did suffer several STi and a few WRX with holed and melted pistons mainly no.2 or 3.A tech guru from Jun(Jap Tuning Company) came to Brunei for commercial reasons was asked why all these blown pistons.His answer was hot climate(30 deg C)and low fuel RON(97 RON).He recommended installing a cooler setting thermostat and use octane booster to start with.

I read somewhere that fitting an oil cooler is the only change that Nissan are making to the official imports of the new Skyline.

July's EVO magazine states that Nissan is adding oil coolers for the engine, the gearbox and the rear differential on the UK R34 Skyline to prevent possible overheating problems that may otherwise occur at prolonged autobahn type speeds.

When going above normal boost levels ie 14 psi and above depending on which version you are looking at, this excess boost level will cause the engine to blow by and thus build up pressure in the engine. This combined with the standard oil breather setup tends to ENABLE oil to be drawn back into the engine via the inlet track . The reason behind the oil breather tank kit is to prevent this and when exceeding regular boost levels ie 15 and above , any oil that is blown out of the engine will be caught in the oil breather tank and only air is allowed to exit the tank back into the engine.

Greg Nikolettos
BPM/AVO

BPM,

Interesting context switch from oil cooler systems to oil breather systems, it couldn't possibly be something to do with a BPM breather system being available, could it?

Moray
\\Sceptical mode off\\

Currently I'm building an engine running with low temp. water thermostat and 13 row oil cooler kit.

The oil cooler kit comes with adaptor, oil temp. by pass, oil filter adaptor,13 row oil cooler and steel braided hose... very expencive.

I reckon this would get the temp. down to <95C . I will post the results after doing some testing with the engine...should be by end of next week.

Anyway it is good to have oil cooler for turbocharge engine. Impreza original oil cooler are to small.

Would be better if you have oil cooler for the gearbox....and oil spray to the gearing. This will prolong the gearbox life.

Weekend track day is not cheap huh!!!!!