Engine oil, why do NSX owners seem to want 10W30??

[rsevo6]

I see that lots of the people here seem to use 10W30 engine oil in their NSX.
I am wondering WHY?

I have been driving Turboed cars for over a decade now, most of them tuned for extra power (more than a NSX and from smaller engines, so more stressed) and have always been using fullsynth oils (10W50 and for the last few years 5W50) without ever having an engine or turbo fail on me, even with heavy track use.

I am about to change the engine oil on my newly bought '98 NSX and even though my feeling is to stay with a 5W50 fullsynth, perhaps experienced NSX owners can explain why 10W30 is better on specifically the NSX? so tell my why I should use that too.

I fail to see why to use 10W30 oil when a 10W50 or 5W50 has much higher specs regarding it's temp range use.
A 5W50 covers the same properties as a 10W30 oil AND more!
It does the same but over a much wider temp range.
Can someone give me a tech explanation why NSX owners seem to stick to 10W30??
Any serious info (so not: it feels good, everyone does, so must be best:redface: :tongue: ) much appreciated

 

[Hal_396]

The first thing that comes to mind is........ Its what Acura recommends!

 

[Hugh]

I am about to change the engine oil on my newly bought '98 NSX and even though my feeling is to stay with a 5W50 fullsynth, perhaps experienced NSX owners can explain why 10W30 is better on specifically the NSX? so tell my why I should use that too.

The larger the spread between base number and top number in a multi-viscosity oil, the more polymers needed to maintain viscosity over that range are required. I can see using a 5W30 but definitely NOT a 5W50. A 50 weight oil is way too thick for an NSX engine. You might as well squat over your motor and take a dump in the oil fill hole.

In any case, there is now a rule on Prime that requires anyone starting an oil viscosity thread to read this thread first.

 

[ChopsJazz]

I see that lots of the people here seem to use 10W30 engine oil in their NSX.
I am wondering WHY?

RTFM :wink:

 

[rowr]

LMAO!:biggrin: At least I would be if I didn't keep burning my butt cheeks every time I did an oil change:smile:

 

[nsxtasy]

I am wondering WHY?
.
.
.
perhaps experienced NSX owners can explain why 10W30 is better on specifically the NSX? so tell my why I should use that too.
.
.
.
Can someone give me a tech explanation why NSX owners seem to stick to 10W30??
Any serious info (so not: it feels good, everyone does, so must be best:redface: :tongue: ) much appreciated

The Honda engineers who designed and built the NSX also wrote the owner's manual and the service manual for the NSX, both of which are excellent documents with a lot of useful information. Apparently you've never opened either one. Check them out; you might learn something...

 

[OLDE GUY]

.....my feeling is to stay with a 5W50 fullsynth.....

Hey, why not; feelings are everything.

....let us know how it turns out :wink:

 

[rsevo6]

The Honda engineers who designed and built the NSX also wrote the owner's manual and the service manual for the NSX, both of which are excellent documents with a lot of useful information. Apparently you've never opened either one. Check them out; you might learn something...

A bit negative remarks don't you think?

Following your way of thinking, you shouldn't change anything on the car as the engineers have thought of the best possible for you, so drive it the way it is!!
I wonder why so many people choose to change shocks/brakes/exhausts etc??? Because these preform better than the OE parts

During the 28 years that I have owned numorous cars and motorcycles (I have owned about 60 in total I think), I have learned not to blindly follow guidelines in manuals and "advice" given by uninterested "professionals" at workshops!

Guidelines given in owners manuals/shop manuals are intended to cover "normal" use at the most economical rate, ensuring reliability of the product (car).
This however doesn't mean that there aren't any better but more expensive products available with higher specs.

Also, the oil quality specs have changed a lot since the years when the lubricants advice for the NSX was decided by Honda engineers.

Not at least considering this is plain ignorant.

As I WILL sometimes be pushing the NSX to the limits of it's capabilities(track use), I want to make sure I am using the best possible protection with lubricants.

Over the last 15 years, I have been tuning and driving my privatly owned Turbo and supercharged cars, incidentally using them to their full potention during trackdays, so I have made it a point of interest to research the best engine and transmission oils possible for the use I am making off them.

I have done the same now during the last 2 weeks for the NSX, consulting a few oil specialists at Valvoline and Castrol.

General conclusion is that it is better NOT to use a high temp viscosity of 50 as this might restrict fast oilflow at higher revs. Low temp viscosity choice between 5 or 10 really is not a very important issue, both will be OK.
So the choice came to a 10W40 semi synthetic oil and a wider range full synthetic 5W40 oil.
Considering the fact that a full synthetic offers much higher surface pressure resistance and is better capable to withstand extreme high oiltemps (possible track use) much longer before breaking down, the choice was made that the 5W40 full synthetic oil will be the best choice for the by my intended use of the car offering highest possible protection against breaking oilfilm under high surface pressure and long break down protection at high temps, with at the same time offering a good viscosity index for the NSX engine, so I will be using this.
Just thought I might share this with any interested people here.

 

[Hugh]

Regarding multi-viscosity oils: (I previously posted this in another thread)

For the NSX I would not recommend going higher than a 30 weight multi viscosity oil because of the very fine oil passages required by the VTEC. Using a lower viscosity lower (W) designation is perfectly safe such as a 5W30.

To help anyone who cares to offer an explanation, I'll help you along with a little information about multi-weight oils.

Multi-weight oils (such as 10W-30) are an invention made possible by adding polymers to oil. The polymers allow the oil to have different weights at different temperatures. The first number indicates the viscosity of the oil at a cold temperature, while the second number indicates the viscosity at operating temperature.

At cold temperatures, the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up, the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C, the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 5W-30 as a 5 weight oil that will not thin more than a 30 weight would when hot.

The following is important

One point that no one brought up however is the difference between synthetics and conventional motor oils. Conventional oils require a lot of polymers. This really isn't a problem for gasoline engines but has caused problems in diesels. Polymers can shear and burn forming deposits that can cause ring sticking and other problems. Generally the higher base multi-viscosity oils require fewer polymers than the lower ones.
(20W50 requires fewer polymers than 10W40 even though they both have a 30 point spread.

This all becomes moot with synthetics

Synthetics require far fewer polymers to achieve their rated temperature range. In fact Mobil 1 5W30 does not use any viscosity index improvers (polymers) in their 5W-30 formulation.

 

[rsevo6]

Thanks Hugh, but I am missing the point (perhaps lack of understanding of english) on the difference between the polymer amount in conventional and synthetic oils, can you clarify?

 

[Hugh]

Thanks Hugh, but I am missing the point (perhaps lack of understanding of english) on the difference between the polymer amount in conventional and synthetic oils, can you clarify?

Conventional oils require a much larger amount of polymers than synthetics. Polymers are the problem with multi-viscosity oils. The wider the viscosity range, the more polymers are needed. Not only that but the lower the base viscosity, even more polymers are added to acheive a given viscosity range than an oil with a higher base number.
Example: 10W30 requires more polymers than a 20W40

Synthetics are constantly being improved to lessen or completely remove the amounts of polymers necessary to acheive their multi-viscosity number. Some synthetics have no polymers at all.

In any case, however you came to your decision to use a semi 10W40 or full synth 5W40 was flawed. Stick to a 10W30 or 5W30. It's ok to lower the "winter" number. Not ok to raise the operating temp number.

 

[MiamieNeSeX]

You might as well squat over your motor and take a dump in the oil fill hole.

[/URL] first.

Easy for you to say. Param pum


Armando

 

[KooLaid]

I go by what Dali Racing says...with a twist, "Father Honda knows whats best for the car and Father knows best."

 

[nsxtasy]

A bit negative remarks don't you think?

Hey, you're the one who never mentioned the fact that the proper viscosity is specified in the manuals, but nevertheless asked why people use 10W30. The obvious conclusion from those two facts is that you've never read the manuals.

yourself. :tongue:

Following your way of thinking, you shouldn't change anything on the car as the engineers have thought of the best possible for you, so drive it the way it is!!
I wonder why so many people choose to change shocks/brakes/exhausts etc??? Because these preform better than the OE parts

Now you're changing the subject. You weren't asking about shocks or brakes or exhausts. You were asking about oil. The answer is simple: the engineers DO know what they're doing, and what is best for the car's engine.

The other fact that you're ignoring (you seem to like ignoring facts) is that most of the specifications in the NSX are made under the assumption that the car will be driven hard, such as on a racetrack. Just to cite one example, that's why the original alignment settings were specified in a way that led to greater tire wear - because they also improved the handling. The NSX was not designed solely for sedate daily driving, and the advice given in the owner documentation isn't based on that assumption at all.

As for aftermarket parts - the tangent that you inserted to distract from the ignorance displayed in your original question - those parts don't always perform better than the OEM parts in every way; there are usually trade-offs in getting one kind of part vs another, trade-offs like ride comfort vs cornering capability, dusting vs resistance to heat, etc. There are no such trade-offs with engine oil.

During the 28 years that I have owned numorous cars and motorcycles (I have owned about 60 in total I think), I have learned not to blindly follow guidelines in manuals and "advice" given by uninterested "professionals" at workshops!

And I have learned that people who do things differently, thinking that they know better than the engineers that designed the car, rarely do, and often encounter technical problems that would have been avoided had they followed the conventional wisdom. That's why I avoid buying cars driven by such ignorant folks, like the NSXs out there with 15-year-old timing belts driven by people who think they know how to maintain the car better than what the manual specifies.

Not at least considering this is plain ignorant.

I haven't seen anything as ignorant in this topic as wondering why people use the viscosity engine oil specified by the people who designed and built the engine.