Gernby

Let me try explaining this again. My logic has nothing to do with a Lexus TSB. I only mentioned the TSB to explain why I switched to 5W-20 in my Lexus in the first place. The reason why I am considering switching to 5W-20 in the S2000 is because I believe there would be a performance benefit similar to what I saw in my Lexus. I think this is very sound logic, but I'm not sure if 5W-20 would shorten the life of the motor. So the point of the thread was really ONLY to discuss the safety of using 5W-20 in an F2XC.

psychoazn

Have you considered Motul 300V 0W20?

I've had terrific results with the 5W30. It is a group V based oil

zeroptzero

well the maximum power and fuel economy gain might be in the range of 2%, most estimates put it at 1%, but lets consider 2 percent as a max. point for argument's sake. That is basically a 5 hp difference max. The average person can't detect a gain or loss of 5hp on the butt dyno so it really isn't a big consideration in my opinion. Like mentioned above I run 5w40, I can't detect any power loss but it could be losing a bit, it just isn't noticeable , and 5 hp isn't going to do much in the 1/4 mile either, it wouldn't get you a 1/10th of a sec. I don't think.

If you could gain 5 hp and not risk increased wear, then I'd say go for it. If you did get increased wear then it wouldn't be worthwhile IMO. A used oil analysis is somewhat helpful after the fact of using it for say 5,000 miles, but I'm not sure that it is the definitive word on engine wear as most testing doesn't give you particle counts.

Run it for 4000-5000 miles and do some testing, kind of like being a guinea pig but that's what you're up against as we don't have alot of data to consider at this point.

In the past Honda used to always spec different weight oil for their high performance (higher revving) VTEC egines, as comapared to the more mainstream variants. I've been trying to find out what they spec for the new 09/10 Civic SI, but I'm not sure what oil they are running. In the past the K series 8000 rpm engines were spec'd with different oil than the lower performing K series engines. There must be a reason for that. I'm wondering if the new Civic Si specs a different oil than the base Civic engines ?, that would be good to know.

Gernby

People spend thousands of dollars on intakes and exhausts that yeild 5 rwhp. If a simple change from 10W-30 to 5W-20 results in 5 rwhp with minimal increase in wear, then it would be the biggest bang for the buck mod around.

I just placed an order for 6 quarts of Redline 5W-20. If there's ever a good time to try it, it's NOW! I'll send in a sample for UOA after about 1K miles, then again soon after depending on the UOA results.

Would there be much benefit in a before / after leak down test?

marcucci

Hahaha, it's not good bang for the buck if you need a new motor in 50k mi.

I can't see that there would be any benefit in a leakdown test. I would only do them on a regular basis to see if you can identify if sealing improves with age and if/when it starts to deteriorate. I would expect that even if the oil did cause an issue, you'd get a good 50k of operation before you could even tell a difference on a leakdown.

I think the oil analysis is your best bet. I would do one after the oil has been in a few thousand, then again at the next few changes, and compare those results to other S2's with similar mileage on 10W30.

Gernby

Why the "Hahaha"? Did you not read the middle of the sentence that qualified the "bang for the buck" status?

Gernby

I haven't considered any brand of 0W-20. I'm also not aware of Motul being any better than Amsoil or Redline. If there is a clear front runner in quality, then I'd be up for that brand for the first trial.

marcucci

The "hahaha" is for the outlier in your analysis that you're ignoring called Engine Failure. The probability is low but I think it exists, that the wear will not be "minimal" but more than minimal.

I think it's a low probability but, well, do you think Honda didn't change the oil weight on the S2 just b/c of the additional testing required? Don't you suppose they tested it with different weights when they designed it? Without knowing for sure I know I am not keen on testing it on my car.

With the oil analysis, especially if you do it between changes, I would expect you'd notice any increase in wear right away and certainly be able to abort the experiment before doing enough damage to matter. So I suppose you can mitigate the potential for disaster (or I suppose eliminate?).

zeroptzero

Redline would be my choice as they give you a lot of anti-wear additives, in excess of API approved over the counter oils. If the boundary layer protection of a thinner oil fails you might be protected by the AW's that are in the oil. It's a great group 5 oil.

Take a sample of the oil you dump during the new oil change, and then you will have something to compare it to after the 20 weight is done.

Leakdown tests are always great to have, if you don't mind the added expense of doing more than one. I don't know if you'd see much change after one oil change interval, perhaps after a couple of them or so. I guess it all depends on how much you're willing to throw at this experiment.

Yeah 1hp gain typically costs you $100 on average for a Honda, so I can see how the prospects of 5 hp can be tempting. That gain might be at the crank rather than the wheels though, not sure, I haven't thought about it enough.

I'm not negative on this as long as the vehicle owner knows what their getting into, and it seems that you do. I''m very curious to see the results, sounds like a cool experiment , keep us posted if you go ahead with this.

psychoazn

I don't buy into this video 100%, but this is the first video on youtube that pops up if you search 300V.

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Take it with a grain of salt, but keep in mind MANY publications have shown dyno gains using 300V on both cars and motorcycles.

It doesn't hurt that the UOA on my engine with 300V is steller. I'm sure Amsoil and Redline have a great product as well; they show great UOA as well. My decision to use Motul is that it is readily available to me.