Gernby

I had an '02 AP1 for 4 years, and put 75K miles on it using 5W-30 Mobil 1. It was consistently strong at club dyno days, and I never had any issues with wear, so I think 5W-30 was a good choice for it. I traded that S2000 in on an '06 Lexus IS350, which was supposed to use 5W-30. However, Lexus issued a technical bulliten stating that 5W-20 was preferred, so I started using that. I sent in several samples to Blackstone Labs for UOA, and the reports always came back good. I also found that my IS350 was dynoing significantly better than the "normal" IS350 (13.24 @ 105 1/4 mile on street tires), and my fuel economy on the highway was friggin' awesome. I think the lighter oil must have contributed some to this, but I have no idea how much.

I talked about this with another knowledgeable S2KI member who does a lot of Honda work (I'll let him chime in if he wants). He said that the clearances in the S2000 are not significantly different from the other Hondas that use 5W-20, and his only concern would be the difference in oil temps and the fact that the S2000 is the only honda other than the NSX that uses FRM.

If I switch to 5W-20, I would start with Amsoil or Red Line, and do a UOA after 1K miles, or so. Thoughts?

[Flame suit on]

I did make the switch to 5W-20, and have posted UOA's later in the thread.

zeroptzero

I'm a fan of 5w-20 in the right engine, I run it in my Ford Escape without any worries, but I would not use it in the S2000.

The s2000 is a higher compression motor and it creates some heat under hard driving, the 5w-20 will thin and shear a bit too much for my liking. The hp and mileage benefits will be very small, around 1%, which no person could distinguish on the butt dyno. I run Amsoil 5w-40 and I can't feel any hp loss over 10w-30 though I'm sure it could be occurring.

I read in the past that during Honda's testing of 5w-20 they observed higher rates of wear on the camshafts but the amount of wear was within their acceptable standards. They added lots of moly to their 5w-20 oils to help reduce the wear issue. That might be fine to the average person but any extra wear isn't my cup of tea despite it being acceptable to some people. Maybe over 100,000 miles it is still considered insignificant, but why take the chance. The camshafts are a huge part of the performance package of this vehicle, not like your average Honda Civic.

I don't have a problem with 5w-30 or 0w-30 on this engine, but I would never run 5w-20 in my s2000. I like the Amsoil line of products, if I did run a 5w-20 I'd run something with boatloads of additives like Redline as added protection. Good luck with your choice.

slalom44

I think this is a good idea, since you plan on checking your UOA. There's plenty of documentation that film thickness is proportional to RPM, so using Amsoil 5W-20 should work fine. From what I have been able to find on a VOA posted on BITOG, the cSt viscosity for Amsoil 5W-20 at 100c is about 9.2 which is a little on the high end of the range for this grade. And since Amsoil 5W-20 probably doesn't contain any Viscosity Index Improvers to shear, you will likely not thin out unless you get some fuel dilution. I've seen many Mobil 1 XW-30 UOAs that have had viscosities close to this with no adverse effects.

I'd be hesitant to use a 5W-20 from some manufacturers such as Mobil 1, since they tend to be on the thin side in the first place. And since some other brands have a reputation of shearing out of grade, I wouldn't want to take the chance.

If you plan on doing a lot of heavy accelerating, you might want to get a UOA early as you suggested. But if you're not, you could easily go to 5,000 miles before testing. Of course, there will be some that will disagree with me. I use Amsoil 0W-30 and I have had nothing but excellent results on all my UOAs.

I don't buy the statement that Honda made public any testing results using 5W-20. I work with Honda (supplier to HAM) and they absolutely do not make internal test results available to the public. Just because someone read it in the past doesn't make it true - especially if it's on the Internet.

SpitfireS

Amsoil ASM 0W-20 is 9.0 cSt / HTHS of 2.8
Amsoil XLM 5W-20 is 8.5 cSt / HTHS of 2.7
Redline 0W-20 is 8.2 cSt / HTHS of 2.7
Redline 5W-20 is 9.1 cSt / HTHS of 3.3

IMO the Redline 5W-20 is the one to go with IF one wants to try out a 20 weight.
Mostly based on HTHS.
The Redline 5W-20 also has the lowest Viscosity Index of 145.

Amsoil SSO 0W-30 is 10.3 cSt / HTHS of 3.2

Now that I look at those numbers all on one page.. that Redline 5W-20 is pretty good.


With it you'll be doing a lot better than the 10W-30 dino crowd, they are quickly driving around with thinner oil thinking they use what you SHOULD use just because the manual says so.
Yes, UOAs of dino 10W-30 show it shears quickly into 20 weight numbers like 8.5-9.0 cSt, HTHS is not tested in UOA's though but HTHS of dino 10W-30 will not be much higher (if at all) than the oils mentioned.

Hmm.... Redline 5W-20.... hmmmm....

marcucci

I'd be interested to see comparative data between 5W20 grades... or 5W30 for that matter.

I share JFUSION's concern, otherwise... the clearances in the F2xC are the same as for the H22A, the "other" FRM 4 cylinder in Honda's family. Granted it revs a little lower, but I would think the extra 1k in revs wouldn't make a huge difference. It also has the same oil cooler setup from the factory, and generates similar oil temps on the street and track.

The H22A was spec'd at 5W30 from Honda.

I'd guess the S2 would do fine, maybe suffer some minimal additional well, probably well within what's acceptable within 100k mi for Honda. But... for an engine that already has a tendency to glaze cylinder walls badly... I am not sure I would want to risk any additional wear.

So- I'll be interested to see what you find in doing this but I'm not sure I want to volunteer.

SpitfireS

Oil temps on the track can get pretty high.
I would not track it with a 20 weight and no oil cooler.
https://www.s2ki.com/forums/index.ph...ic=705376&st=0

Gernby

I would definitely want to have an oil cooler if I were to try a track event with 5W-20, but I had no idea a cooler would cost so much.

If I can find a decently priced oil temp guage, I think I will give the Red Line 5W-20 a try.

Any suggestions for a cheap temp guage? I probably wouldn't even do a permanent installation..

zeroptzero

I would love to see a UOA of this, whatever brand and visc. you choose. Keep us posted.

I got the Honda 5w20 wear information from a post on BITOG, someone posted a link to the data document that looked like a legitimate Honda engineering document. I'll try and search it next time I log into the forum.

marcucci

If you want a cheap install on the gauge, you could drill and tap a stock drain plug. I think it will fit. Just tuck the gauge under the dash or seat or temp mount it somewhere.

JFUSION, I would imagine that the oil data changes annually, which seems about as often as mfrs change their blends or the API comes out with some new spec. This is what drove me away from Amsoil and back to M1, I couldn't find enough data on a regular basis to justify the price difference and availability.

gernby, if you want a cheap oil temp gauge, I have one or maybe even two autometers I'll sell cheap.

zeroptzero

yeah you're right. I think Redline is looking better and better as they don't care about API standards and don't need the starburst symbol on their oils. Amsoil could be dragged down by that in the long term. I'm still going to run Amsoil for the near future with a small bit of additive boost and I'll see how it goes. I'm running their 5w-40 viscosity and I'll work my way downwards if warranted and it doesn't work as well as I want it to.