bgoetz

So I guess is there any downside to the 140 then? I can wait and buy the 110 and do it later if it is better than the 140. The old fluid is 110 installed by the previous owner.

bgoetz

Found 110!

iDomN8U

Were talking about oil. The thickness will differ at 100C but the consensus is that its safe. When using dissimilar brands you might have one manufacture use zinc and another use idk moly for anti wear. This combination might not be ideal. I'm not a expert.. But personally I won't be concerned mixing the 140w with 90 if I only had half a bottle of each. Otherwise I'd use the 90 until the summer season then go with a 110 or 140. Really splitting hairs here.

zeroptzero

The old gear oil classification within the fluid industry in 1999 had the 90 viscosity leading up to the 140 viscosity. Honda originally specified an SAE90 fluid for the S2000 diff. The industry later revised the gear oil classification to include 110 , and they squeezed it in between the old 90 and 140 viscosity range. The new 90 viscosity was on the thinner side of the earlier viscosity range. The new 110 ended up being closer to the middle of the old SAE90 spec, a better match than the new 90 viscosity would be. So the new 90 is on the thin side of the old SAE90 spec circa 1999. Not the best description but it is the best way I can describe it, without referring to charts.

So basically when Honda first engineered the S2000 they intended to have a fluid in the diff that was closer to todays 110, and not as thin as todays 90 spec.

Emil St-Hilaire

Running 4.56 Richmond gears,I use Amsoil 75-140; helps reduce the whinning noise.

bgoetz

Did you notice any difference between the 110 and 140, which one did you prefer? I have acess to both now and am not sure which one to go with.

zeroptzero

Well I had some used fluid analysis completed of my run with Amsoil 75w140 and LE1605 (SAE110), and running my LE1605 sample twice as long as my Amsoil 75w140 resulted in one-half as much wear. The viscosity of my LE1605 sample tested thicker than my Amsoil 75w140 sample oddly enough. The wear levels of my Amsoil 75w140 sample were still very good and within universal average range, but the wear levels of my LE1605 were really low.

Unfortunately when I sent in my used fluid sample of Amsoil 75w110 it got lost in the mail and I never got the results of that run Going by the paste that was visible on the magnetic drain plug I would say the 75w110 had the largest amount, 75w140 had less, and LE1605 had the lowest amount. I never noticed anything different between 75w110 or 75w140, they both felt good to me, fuel economy seemed to be the same as well. You would be safe running either viscosity, if you don't track the car then 75w110 would be fine for street use, if you do track the vehicle or run it in really hot temps then 75w140 would be a safe bet. You cant go wrong with either.

One caveat with LE1605, it gets really thick in cold temps, I would not want to run it in any winter driving conditions, for cold temp operation the multi-grade fluid like 75w110 is a better choice.

bgoetz

Think I will give the 140 a try, it seems more protective than the 110 and you still had 2x the wear as LE, not sure I want to go less. The car will hopefully see some track time and certainly autox time. Plus I have the 110 now, so if I notice any big differences I can put 110 back in the next time around.

zeroptzero

I think 75w140 will work well for you in those driving conditions, and you still get some decent protection from low temps if you get any in your region. The 75w140 wear numbers in my used fluid analysis were still very good, it was just that the performance of LE1605 was outstanding, so nothing wrong with the Amsoil in how it performed when I used it and I would still recommend their diff fluids.

jkelley

Where do you live in the states? I would take JFUSION's advice over my own (he's very knowledgeable and objective about oil-related topics, among other topics). But the one thing that just sits funny with me is that cold start with 140. Have you seen this stuff at room temp? It's practically a solid. You pretty much have to warm it up in the microwave to be able to even pump it. So for the first however long into your drive (street or track) that stuff is a solid I would think. My advice is not in research or experience, just observation, so you can definitely take it with a grain of salt.