Substitute For 20W-50 engine oil?

Comptech specified that 20W-50 engine oil must be used for the autorotor supercharger. I have difficulty getting hold of this engine oil in Malaysia.

Can I use engine oil with other specification for the supercharger? Please note that it is hot and humid in Malaysia all year round - Tropical weather without winter.

Thanks everyone.

Normally people having trouble finding 20W50 end up putting in 5W50. Its much easier to get ahold of, especially in time sensitive circumstances, and AFAIK is essentially the same thing. Only difference is that it has a wider operating range, peaking out at the same very high temp as 20W50. It is less viscous when cold.

If you're in a bind and need oil, Id put some 5W50 in it while you keep looking for what CT recommends.

5w50, 15w50 and 10w60 tend to be the alternatives. The last being sold by Castrol and available at BMW Dealers.

Make sure it's full group 4 synthetic

Kenne Bell recommends 50 weight Redline oil for an autorotor SC in our Yukon.

On this topic.. what's a good 20W-50 oil that is recommended for the SC?

Want 20w-50 synthetic oil?
Here's where I get mine. They have Redline, Royal Purple and Lucas brands of 20w-50 full synthetic oils.
http://store.summitracing.com/egnse...DDS=1&Ntt=20w-50&searchinresults=false&N=+115

I use Royal Purple. It's easier to see on the dip stick.
At 3.5-4 oz per fill in the CTSC, that's about 8 changes per quart.
Buy two quarts and you'll be set for some time.

RP has a reputation of being too thin/wearing down fast. Is this not a concern for their 20W-50?

Given the low requirements - I may just go with Amsoil..

slownsxt said:

RP has a reputation of being too thin/wearing down fast. Is this not a concern for their 20W-50?

Click to expand...

Reputation? Where did you get that? You have some reliable data in regards to thermal breakdown of the stated viscosities of Royal Purple?
If you do, please share.
Comptech recommends Redline but I believe that has more to do with how easy it is for them to get, at least thats' the impression I got when I called them to ask. They said ANY quality synthetic 20w-50 would be fine.

The SC will never see high enough temps to worry about thermal break down. The loads are not high enough on the gears and bearing which are in the oil bath to worry about protection from oil sheer break down. Any synthetic oil should work and tend to give better oxidation protection than a mineral based oil.

If the oil gets changed once a year on the SC, any brand of full group 4 synthetic, like zahntech says, will work great.

pbassjo said:

Reputation? Where did you get that? You have some reliable data in regards to thermal breakdown of the stated viscosities of Royal Purple?
If you do, please share.
Comptech recommends Redline but I believe that has more to do with how easy it is for them to get, at least thats' the impression I got when I called them to ask. They said ANY quality synthetic 20w-50 would be fine.

Click to expand...

I haven't quite yet finished my doctorate's dissertation on the subject but my own experience their Synthetic Oil (5W-30) was that it break down significantly faster than say Mobil 1.. There are a few other posts/forums that echo this feeling though I’m too lazy to find them..

As has been mentioned, since the SC does not experience significant thermal stress, Comptech recommends it and MIT has denied my application for their PHD program in Mechanical Engineering …I will have to assume that it will be ok

slownsxt said:

I haven't quite yet finished my doctorate's dissertation on the subject but my own experience their Synthetic Oil (5W-30) was that it break down significantly faster than say Mobil 1.. There are a few other posts/forums that echo this feeling though I’m too lazy to find them..

As has been mentioned, since the SC does not experience significant thermal stress, Comptech recommends it and MIT has denied my application for their PHD program in Mechanical Engineering …I will have to assume that it will be ok

Click to expand...

I thought that if you had something to share that was concrete and fact based, not your or someone else's "feelings" I and others would be interested to know. This is a technical forum after all.:wink:

slownsxt said:

I haven't quite yet finished my doctorate's dissertation on the subject but my own experience their Synthetic Oil (5W-30) was that it break down significantly faster than say Mobil 1.. There are a few other posts/forums that echo this feeling though I’m too lazy to find them..

As has been mentioned, since the SC does not experience significant thermal stress, Comptech recommends it and MIT has denied my application for their PHD program in Mechanical Engineering …I will have to assume that it will be ok

Click to expand...

What's your criteria for determining breakdown? Are you basing your opinion on look/smell/feel?

I'm no engineer but I would venture to say that the equipment needed for truly and consistently measuring oil breakdown are not readily available to the general public. I would also venture to say that appearance and smell are not reliable methods for measuring oil breakdown at all.

I'd be interested in some actual empirical data. There are plenty of people who swear by RP and based on it's price it seems demand is fairly high. I don't see how it could be so inferior to a run-of-the-mill product like Mobil 1 but I could be wrong. It does warrant some research.

NSXGMS said:

What's your criteria for determining breakdown? Are you basing your opinion on look/smell/feel?

I'm no engineer but I would venture to say that the equipment needed for truly and consistently measuring oil breakdown are not readily available to the general public. I would also venture to say that appearance and smell are not reliable methods for measuring oil breakdown at all.

I'd be interested in some actual empirical data. There are plenty of people who swear by RP and based on it's price it seems demand is fairly high. I don't see how it could be so inferior to a run-of-the-mill product like Mobil 1 but I could be wrong. It does warrant some research.

Click to expand...

I used RP extensively on one of my cars (b/c I bought a whole bunch online and had to use them..) and they thinned out too quickly compared to Mobil1. This may not be empirical data but it is data.

Another piece of data where the consensus is that the general syn oil is not that great is at: is: http://theoildrop.server101.com/for...ds=Royal+Purple&topic=&Search=true#Post810567

They do say their race oils are good, which I haven't tried/contest with.
I'm not saying RP 20W-50 is not good or good enough, I'm just saying that it might not be one of the best, and we only want to best for the NSX <sarcasm>

A Blackstone Analysis would provide some light on this controversy....

SLownsx, buying a "whole bunch on line" and just looking at how it flows when you change it and what they chat about at "Bob is the Oil Guy"forums,:smile: (the root name of the link you provided) is not data.
An example of data would be results from tests of independent, dis-interested laboratories.


I can't find much except findings of seemingly biased sites that are owned by or feature the product that comes out on top of their "test".

I really would like to know more.
There was a link to a comparison test in a past Prime thread but if I recall there was some question to it's authenticity and bias.

Slownsx if you use Amsoil I'm sure you'll be just fine.
As I said before, I use Royal Purple primarily because of it's color. For me, it is easier than Redline to see on the dipstick for the CTSC.