Well, I was at 5000 miles and had been putting off changing my oil...and decided to change the tranny oil at the same time because I was getting a lot of notchy shifts. So I changed the oil first and my first surprise was how black the oil was...man guess I should have changed it at 3750...anyway...I put in Mobil 1 Synth 10W-30. Then I changed the tranny oil with Honda MTF...I was gonna put in Synthetic and hope it got better but because I have had my clutch slipping recently and didn't want to run into problems in trying to get them to cover the clutch under warranty since it's going out so soon. Anyway, I got everything changed and went on a drive. Engine seemed to rev a lot more free but acceleration seemed a lot more sluggish...I have heard a few people on this board complain of this before and they said it got better in time so hopefully mine will to. As far as the notchy shifting it made no difference. I wasn't to upset cause it only cost me $10 to change the tranny oil but, I still have the notchy shifting. Haven't had the 1-2 grind problem now though for about 1000 miles so at least that problem is gone. So anyway the point of this post is to ask those people that have had synthetic oil in there engine for a while if it tends to loose that sluggishness and as far as the tranny goes...has anyone experienced any lasting good luck with changing the tranny oil to synthetic...It has been stated on the board before that people thought it made a good differenece right away but, I'm curious how it is after a few thousand miles...

 

I changed my tranny fluid to Redline oil at 7000 miles. It was good until I took it to the track a few days after (I clicked off 1000 miles getting there and back and 100 miles on the track). At 9000-10000 miles it started getting really notchy when cold. It's way notchier now at 13000 miles than before the fluid change. I'm planning to change it back to Honda MTF in a few days and see what happens.

 

Well that makes me feel a little better!

 

This is a totally non-scientific observation but so is 99 percent of the observations on this board.

I think putting off the move to Mobil One or any other 100 percent synthetic engine oil should be put off until at least 10k miles or two, maybe three oil changes.
After the third day of driving after my change to Mobil One 10w-30 after having used Castrol GTX from the get-go (14K miles), the car feels just the same, if not a little bit smoother. Initially, my impression was that VTEC transition was smoother, but now that I've driven around and VTECed some more, it's the same ol' S2000 action (a good thing).

Don't rush to change to synthetic. Let your engine fully break-in first. I'm glad I waited.

 

I agree. American Honda Motors warns not change to synthetic oil due to the FRM Cylinders (Fiber Reinforced) in this aluminum block for at LEAST 5000 miles. Honda claims that synthetic oil is to slippery to seat the rings properly (seating the rings refers to the rings shaping themselves to the precise size of the bore). Honda went on to say synthetic oil is perfectly safe to use after 5000 miles. The response from the Service Engineer for NSX, and S2000 automobiles said the original oil should be left in for a MINIMUM of 5000 miles. Use conventional motor oils due to the FRM cylinders until that time. And, as you've said several members on the board indicated they wished they had waited until 10000 due to performance loss.

 

www.blackstone-labs.com can evaluate oil and tell you about wear patterns. Your notchy shift could be a damaged gear which could be picked up by particle count.

Utah