Tugz_S2K

I was going thru the owners manual and i realized somthing simiar to my GTI VR6. The S2000 can use 5W40 oil...Currently my VR6 has 24,000kms and I have been using Texaco Havoline formula 3 5W40 Synthetic.....It runs flawless and no trouble to date..

VW actually reccomends the use of 5W40 if the car is ever driven above 80mph for extended peropds of time. Looks like ill be switching to Havoline 5W40 in the s2k when the time comes...

Anyone currently use 5W40??

xviper

Hadn't really given it much thought till this thread. I currently use Mobil 1 5W30 synthetic and plan to go with 10W30 when winter is over but 5W40 sounds intriguing.

jguerdat

There's a concern over the amount of additive required to make the oil respond over a wider range (e.g. 5 -30 vs. 5-40). If the oil base does this naturally (dino oil won't, dunno about whether a synthetic can be built this way), it should be fine. However, if you need to force it to do this via additives, how long will it take before the additive breaks down, leaving you with less protection than you started with (how much less depends on how much breakdown has occured).

Try to keep the spread as low as possible (single-weight oil is NOT recommended for street cars). Don't forget that the higher the viscosity, even at high temperature, creates more viscous drag, leading to less power and acceleratrion...

naishou

[QUOTE]Originally posted by jguerdat
[B]There's a concern over the amount of additive required to make the oil respond over a wider range (e.g. 5 -30 vs. 5-40).

Tugz_S2K

Other than Power loss and fuel economy, no......

But in some new motors a thick oil like a 40weight is not reccomended, due to the fact that the internals are not designed to flow as thick of an oil. Thats why I was surprised to see Honda reccomend 5W40 in the S2000 all year around....That weight oil, I thought, only the German manuf. reccomended(Used in my VR6). Since mostly in all Honda motors, Honda reccomends 5W30 and more recently 5W20....5W20 because it helps the motor meet LEV-ULEV standards.

I think if Honda reccomends 10W30 and 5W40......I would definately go for the 5W40. Its much better protection especially when its churned to 9k rpms...

naishou

That occured to me too, but then I realised that 10W-60 oil is thinner (absolute viscosity) at operating temperature (especially when racing) than 10W-30 (or 5W-30 for that matter) is at startup, especially in cold weather. Now the oil pump and oil journals all have to be able to handle the thicker absolute viscosity at low temps, so they should easily handle an SAE 60 oil at over 100 degrees C. We're talking absolute viscosity differences of over 2 to 3 times here, so I can't see a 10W-60 for example causing problems with circulation, but it will offer better protection (won't it?).

StwoK

If you are using a synthetic oil in the winter time, why are you worried about a 5w-xx oil ? If it was petro based I would look for a 5w-xx because at 10 degrees it still pours like honey. But since you mentioned synthetic oil, all 10w-30 or 10w-40 oils pour freely till about -40 degrees and start-up time is when the most engine damage occurs. When comparing most company's 5w-xx to their 10w-xx synthetic oil, the 10w-xx has the greater shear strength. Shear strength is the oil's ability to maintain a protective film between two metal surface. At 9 grand keeping my crank and bearings seperated is important me. And the shear strength of synthetic oils is about twice that of petro oils! I'ld stay with a 10w-30 synthetic.

Honda recommends only 10w-30 for the F20C. Goto the FAQ page and read Service Update.

naishou

That's not true. The 5W oil specs are stated at -25 degrees C (-13F) for cranking viscosity and -35 degrees C (-31F) for pumping viscosity. It's exactly the same spec whether the oil is synthetic or not. If it's called 5W, it has the same viscosity at those temperatures regardless of whether it's made from dead marine animals or unobtainium. Now synthetic oils may go even lower than that without turning to treacle, but that's only of interest to those living in Canada or Siberia. Between -31F and 212F, any 5W-30 oil will have very nearly the same viscosity as any other.

StwoK

[QUOTE]

naishou

[QUOTE]Originally posted by StwoK
[B]