Which engine oil do you feed your GT3?

[Fl0pp3r]

Excuse *yet another* engine oil thread

Would like answers to be GT3 specific if poss - 50:50 road:track use let's say.

Personally, I use Mobil Super3000 X1 5W40 (really trips off the tongue that one), but am considering some Millers CFS NT of the appropriate formula.

Interestingly, one respected Indy I know emulate Manthey's choice of Castrol Edge Titanium 10W60 for their customer GT3's, which is actually BMW's approved oil for M models. Apparently this formulation also eliminates the well known (but entirely harmless) 'smoke on start-up', which would be an added bonus.

What do we think? As always it will come down to a cost/benefit compromise - the Millers oils cost noticeably more, but perhaps they are worth it?

[Steve Rance]

I use Motul sport ester 5w 50

[Trev450]

I don't own a GT3 but I would have thought that 10W/60 is too heavy for a car being used on the road where the oil temps don't get up to what they do on track. I personally use Millers 5W/40 in my CS, but know of owners who go as heavy as 5W/50.

[Fl0pp3r]

ok thanks for the feedback chaps. I must admit I thought 10W60 looked on the heavy side. Maybe 5W50 is the sweet spot.

[BertBert]

Fl0pp3r said:

ok thanks for the feedback chaps. I must admit I thought 10W60 looked on the heavy side. Maybe 5W50 is the sweet spot.

What on earth are you all talking about? "heavy side", "sweet spot"? What can that possibly mean with regard to oil performance in your engine? You can't feel it, see it, smell it. That car doesn't drive differently. What criteria are you (all not the OP personally!) using to make this judgement?

[red997]

if you want advice from someone who works on GT3s daily, I suggest you give Fearnsport a call and ask them

[Trev450]

BertBert said:

Fl0pp3r said:

ok thanks for the feedback chaps. I must admit I thought 10W60 looked on the heavy side. Maybe 5W50 is the sweet spot.

What on earth are you all talking about? "heavy side", "sweet spot"? What can that possibly mean with regard to oil performance in your engine? You can't feel it, see it, smell it. That car doesn't drive differently. What criteria are you (all not the OP personally!) using to make this judgement?

The terms 'weight' and 'viscosity' are both widely used and interchangable to describe the thickness of an oil. Maybe you're not familiar with that criteria.

[BertBert]

Trev450 said:

The terms 'weight' and 'viscosity' are both widely used and interchangable to describe the thickness of an oil. Maybe you're not familiar with that criteria.

Well yes I am. But I am intrigued as to how people are judging the best weight for their engine. I don't think people have any more idea than I do into this black art.

For the post I was querying (sorry to pick), what does "a bit on the heavy side" actually mean? What is too heavy for an engine? What do the criteria mean. I'm happy to say that I don't know. What determines the right weight for an engine?

Bert

[Fl0pp3r]

BertBert said:

Trev450 said:

The terms 'weight' and 'viscosity' are both widely used and interchangable to describe the thickness of an oil. Maybe you're not familiar with that criteria.

Well yes I am. But I am intrigued as to how people are judging the best weight for their engine. I don't think people have any more idea than I do into this black art.

For the post I was querying (sorry to pick), what does "a bit on the heavy side" actually mean? What is too heavy for an engine? What do the criteria mean. I'm happy to say that I don't know. What determines the right weight for an engine?

Bert

That's really the reason I started this thread Bert - I don't profess to know either, and I suspect there is no definitive answer as it'll depend on how you use your GT3 predominently, what climate you live in, budget etc etc

I followed Trev's lead in referring to the viscosity of different oils (e.g. 10W40) by their 'weight' - sorry for any confusion caused.

Sticking with the 'weight' metaphor for a minute - i guess part of my question was, are we better off using a slightly heavier/viscous grade of oil (ie one with higher (W)inter and high temperature grades) in our GT3 engines, or do people generally stick with the 0W40 Mobil1 that is one of Porsche's recommended oils? For instance, I've heard that because a 10W50 grade of oil is thicker, it can help prevent smoke on start-up as it tends not to pool as much between use. Of course, the flip side is that the protection offered on very cold start-up is theoretically inferior (a 0W grade being better), so you might not use a 10W grade if you live somewhere with very harsh winters.

The other key factor is of course what the oil actually consists of - full vs semi synthetic, and then within synthetic you have true ester-based vs non-ester based oils. The question for me here would be - is the extra cost of a true ester-based oil (like those from Millers and Motul to name two) really worth it in terms of engine performance and longevity?

Horses for courses as ever but I thought it would be interesting to try and find out what GT3 owners are using, and of course all opinons are welcome!

[Trev450]

BertBert said:

Trev450 said:

The terms 'weight' and 'viscosity' are both widely used and interchangable to describe the thickness of an oil. Maybe you're not familiar with that criteria.

Well yes I am. But I am intrigued as to how people are judging the best weight for their engine. I don't think people have any more idea than I do into this black art.

For the post I was querying (sorry to pick), what does "a bit on the heavy side" actually mean? What is too heavy for an engine? What do the criteria mean. I'm happy to say that I don't know. What determines the right weight for an engine?

Bert

Yes it is a 'black art' indeed, and I certainly don't fully understand it either. As F10pp3r has outlined above, it really is a trade off between the added protection a heavier (sorry thicker oil will give and the risk of premature wear on start up that could occur during cold weather. I've gone for a 'middle ground' viscosity (5W/40) in the hope that it will give me some additional protection when hot, but no be so thick as to be problematic when cold.

Edited by Trev450 on Monday 16th November 08:56

[Pip1968]

I stick to the recommended Mobil 1 - 0w 40. Like most i do not do many miles and it is tracked. I am not an oil scientist but always reads these threads with interest. Presumably if this oil was not used in its early days Porsche would not cover problems with their warranty - ????

Pip

[BSRS]

Pip1968 said:

I stick to the recommended Mobil 1 - 0w 40. Like most i do not do many miles and it is tracked. I am not an oil scientist but always reads these threads with interest. Presumably if this oil was not used in its early days Porsche would not cover problems with their warranty - ????

Pip

Exactly, I also only use Mobil 1. 0w40 as recommended by Porsche.
But they only designed and built the Engine, so what would they know...

[Jim1556]

Trev450 said:

I don't own a GT3 but I would have thought that 10W/60 is too heavy for a car being used on the road where the oil temps don't get up to what they do on track. I personally use Millers 5W/40 in my CS, but know of owners who go as heavy as 5W/50.

FYI, 10W60 is the standard oil for my E46 M3, whether road or track, I've never had any issues with smoky starts or usage even when leathered.

Another high stress, >100hp per litre engine...

[Trev450]

Jim1556 said:

Trev450 said:

I don't own a GT3 but I would have thought that 10W/60 is too heavy for a car being used on the road where the oil temps don't get up to what they do on track. I personally use Millers 5W/40 in my CS, but know of owners who go as heavy as 5W/50.

FYI, 10W60 is the standard oil for my E46 M3, whether road or track, I've never had any issues with smoky starts or usage even when leathered.

Another high stress, >100hp per litre engine...

I appreciate what you're saying, but smoky start ups from a boxer engine are often due to the horizontal attitude of the cylinders which can allow oil to bypass the ring when not running. Using a thicker oil is thought to help prevent this by some.

[Jim1556]

I get that, my point was that a similar high stress engine (>100hp per litre, 8000rpm red line) already uses it. Not too thick in other words.

[Fl0pp3r]

useful comments chaps, thank you.

Like Trev I'm using a 5W40. Both Paragon and my current indy La Rose recommended it. It's also Porsche A40 approved so you guys on warranties should be fine with it:
http://www.opieoils.co.uk/p-805-mobil-super-3000-x...

Jim - I'm tempted to try the Castrol 10W60 for its added protection/thickness at higher temperatures in particular on track and to maybe prevent the smokey startups. As you say its BMW standard issue for M vehicles and its what Manthey apparently use, even though its not Porsche approved.

Question remains are the true ester based oils like Millers worth the extra outlay? I suppose another way to look at it would be to keep the saving made (by buying standard issue Mobil) and change your oil twice annually, particulary if doing more track work.

[Fl0pp3r]

Came across this thread, worth a read on the topic of Millers Nanodrive:
http://www.pistonheads.com/gassing/topic.asp?h=0&a...

Edited by Fl0pp3r on Tuesday 17th November 18:15

[Fl0pp3r]

Excerts from recent 911&Porsche World feature on oil changes...