alternating track day oils

[bmchi]

Hi all,

have done about 1000km's including a track day on castrol edge 5w40. I changed to the 5w40 just for the track day however this grade is not what i want to be running on the street. the viscocity is a a bit of a overkill, on the street i usually run 5w30.

would it be ok to change to a 5w30 and drain the 5w40 and keep it in a bottle to be used for the next track day?

i dont plan to mess around with the filter which was also put on just before the track day.

 

[skyship]

There is very little difference between Castrol Edge 5/40 and 5/30. If the engine manufacturer recommends 5/40 for racing to offer better protection when hot it will be perfectly OK to use 5/40 for normal use.
If you were using something like a 20/60 race oil it would be different as the W rating would be bad news for cold starts and the 60 would increase fuel consumption when warm.

 

[supercity]

There is no reason you cant use the 5w30 at a track day. What are your oil temps like?

I'd leave the 5w40 in and just change to 5w30 next time if thats what you want to use. Its not practical to swap it out for a track day.

 

[[RT] ProjUltraZ]

Whoa?? two Aussies who want 5W-30? so its not everyone there that uses 40 or 60W.

Originally Posted By: supercity
There is no reason you cant use the 5w30 at a track day. What are your oil temps like?
Its not practical to swap it out for a track day.


i don't know about that, i don't even know what car but oil temps would be a deciding factor. I do agree it's better to run 40 all time than 30 all the time on a track car. just drive easy for the first 20 min

 

[CATERHAM]

I have the same dilemma with my track car that can see 20C hotter oil temp's at the track than I will ever see on the street.
I've found the solution is to first not run an oil at the track that is any heavier than necessary based on oil pressure.
There is a good chance that the 5W-30 does provide sufficient hot OP and therefore operational viscosity.
Secondly, choose a track oil with as high a viscosity index as possible. Not only does have advantages all round but it will provide you with the lightest oil on start-up on the street.

If you choose to optimize your viscosity for the maximum oil temp's you'll see on the street instead, leave some room in the sump prior to going to the track so that you can add some very heavy oil to bump up the viscosity should it prove necessary.

Having said the above, if you have relatively fresh heavy oil from the track, I'd live with it on the street until it's time to change do an oil change. It's not like it's overly heavy for street use, just not optimum.

 

[HTSS_TR]

Or have 1/2 quart less than full of heavy oil on track day, then top off to full mark with thin oil after track.

 

[rslifkin]

Originally Posted By: HTSS_TR
Or have 1/2 quart less than full of heavy oil on track day, then top off to full mark with thin oil after track.


I wouldn't want to run anything less than at the full line on the track, due to sustained high revs and high cornering loads.

 

[supercity]

Originally Posted By: [RT
ProjUltraZ] Whoa?? two Aussies who want 5W-30? so its not everyone there that uses 40 or 60W.

Originally Posted By: supercity
There is no reason you cant use the 5w30 at a track day. What are your oil temps like?
Its not practical to swap it out for a track day.


i don't know about that, i don't even know what car but oil temps would be a deciding factor. I do agree it's better to run 40 all time than 30 all the time on a track car. just drive easy for the first 20 min


To carry over from the other thread we were discussing using a heavy 30 (or light 40). The Castrol Edge 5w30 that we get here is SL/A3 rated with HTHS 3.6. This is a high revving 1.6L N/A engine.

The Castrol Edge 0w40 is another option but expensive (PAO) HTHS 3.6. Still cheaper than M1 0w40 by quite a margin.


BTW with reference to 40 and 60 grades in Australia, this is what Castrol has to say

Originally Posted By: Castrol

Castrol EDGE 5W-40 SN provides outstanding wear protection in high performance engines designed to run at their optimum level on lower viscosity oils

Castrol EDGE 10W-60 SN gives you the confidence to demand maximum engine performance
from today’s competition and high performance engines requiring lower viscosity higher
performance oils. Castrol EDGE 10W-60 SN is proven in tests to deliver outstanding oil
strength.


Yes they are saying 10w60 is a "lower viscosity oil"

 

[bmchi]

the reason why i wanted to go back to the 30 for the street was because of the noticable difference to performance (butt dyno).its quite significant although it could be all in my head (however doubt it)

the engine is a 4age BT 20v so its a 1.6L that sees a redline of 8k on the track. im not running a oil temp or pressure gauge but ive heard from other owners that it can get hot very fairly quickly. normally looking at anywhere around 120 C temps during spirited driving on the street.track temps have been known to get higher.

reason why i ask if a lightly used oil would be ok stored in a bottle (saving it to be used again) is so i dont always have to run a thicker oil after a doing a track day.OR running a thinner oil on track so i can continue running the oil on the street as im happy with the 30 for street and the 40 for track. I then also have oils for two different duties, i dont want/have to waste the oil.

I will also be installing an oil cooler on the next change and am eager to do it soon ....getting itchy. summer is coming up in oz and i would normally run a 40 but with the oil cooler im convinced i dont need to take the extra precaution and can go back to a 30.

thoughts?

 

[supercity]

Sure you can do that if you want but it's a waste of effort if you ask me. Keep in mind you can't totally replace the oil so if you are changing it back and forword just for track days the 40 will end up diluted a little bit further with the 30 every time you change it. If it were me and for the arguements sake it required a 40, I would use the 40 all the time.

Another option is to run an ester based 5w30 like Motul or Redline which has the same HTHS as the Castrol 5w40.

 

[bmchi]

aah i didnt think about that supercity, thanks for pointing it out.
i think i will look for a nce stout 5w-30 and thn run that for both street and track.

I will most likely invest in a oil temp/pressure gauges for track days anyway so i can keep everything in check.

 

[CATERHAM]

Originally Posted By: supercity

Another option is to run an ester based 5w30 like Motul or Redline which has the same HTHS as the Castrol 5w40.

A common misconception.
If a 30wt oil has the HTHS viscosity more typical of a 40wt oil then for all intents and purposes it is a 40wt oil and your oil pressure will reflect that.
That why Red Line advises that it is often best to drop a grade when switching to their oils.

The only way to get the benefit of a lighter oil on start-up is to go with a higher VI oil.
Foe example M1 SN 0W-40 has the same HTHSV (3.8cP) as RL 5W-30 but due to it's higher 185 VI vs 162 for RL it is noticeably lighter on start-up.

 

[supercity]

OK thanks for clearing that up. It would seem the SAE grades are somewhat misleading!

 

[fdcg27]

You live in Australia and think that a 5W-40 is too thick for daily street use?
Seriously, I doubt that you'd see much difference between a 5W-40 and a 5W-30 in typical daily driver use.
If you're installing an oil cooler, then a thirty might be suited to track use.
As Caterham is fond of pointing out, unless you have a real OP gauge, you're only guessing as to what the engine needs.
Without a gauge, I'd be inclined to simply use the forty.
Way too much trouble to drain and refill on a regular basis, and it's very difficult to drain and decant oil while keeping it as free of debris as I know you'd like it to be.
Best bet would be to put an OP gauge in.
This would tell you everything you need to know, including maybe some things you'd just as soon have remained blissfully ignorant of.