xviper

You may recall that I have a diff temp gauge installed on my car. I can monitor the surface temp of the casing between two cooling fins all the time. I have seen temps get up to 90*C. This was during a road trip, immediately after a spirited pass of a slower vehicle. At steady state highway cruising, the diff typically runs around 70*C on a hot summer day. I also have cooling fin extensions made from sheet metal but I'm not sure how effective those are. Shortly after I posted pictures of my cooling fin extensions, Spoon marketed their new S2000 diff housing with elongated cooling fins.

c32b

A bit of an offtopic here

SpitfireS: Regarding the engine oil, I do run an oil cooler and its working well. I run either a 5w40 or 10w-40 weight oil and the temps have consistently been about 210-220 F max even with sustained lapping on a rather hot ambient circuit. It is for this reason that I am wondering if a good 5w-30 like a motul 300v might actually work well without giving up much in terms of wear since my cooling setup seems to keep the oil temps down.

rob-2: I am concerned about the transmission fluid as my previous UOA did show the oils there shearing down quite a bit. I did use Honda MTF previously but it seemed to shear down all too quickly. The known quantity I have was an UOA on Motul Gear 300 75W90 in the transmission and it seemed to do well. I generally change the transmission oils out every 10-15K miles if i get down to the track a bit more often.

c32b

thanks for the clarification. I dont get amsoil much around here but might look into a torco or redline MTF which I could find.

btw, have you had a chance to see how high the diff temps get on the track?

c32b

Thank you, you made good points on the length of my lap runs and the effect of grip levels.

xviper

I don't track my S2000. Honda saw fit to put cooling fins on both the tranny and the diff casings and they also put in a low pressure pump in the tranny. I think they do a pretty good job.

SpitfireS

It's been a while: quoting xviper
Here's a link to my oil temp post: https://www.s2ki.com/...1#entry18847621
Maybe the minutes it took to get the car on jackstands is allready enough to lower oil temps?
Or... it was the SAE 190 keeping it all cool
I remember a post on a 4x4 forum I found through BITOG mentioning lower diff tems running good-ole LE-607.
Less friction = less temp.
Did Spoon ever pay anything?
Ha


Its YOUR thread, you can do whatever you want inhere
Data.... you gotta love it
IMO, yes, your oil temps are very good and no reason to go 40 weight.
You may actually see even lower oil temps with a 30 weight as more oil will flow through the engine - AND heat exchanger - at higher revs.
Redline will have a nice shear stable / good HTHS oil for you no doubt.

rob-2

You're probably better than to shorten the time on the oil than attempt to get an oil of heavier weight to last longer. I'm sure a small increase in weight isn't a huge problem but significant jumps to say a 75w140 might pose a problem. 90 vs 140 hot weight is very different stuff. Buddy of mine ran such weights for a while and the cold performance of this tranny fluid was bad. He quickly switched it out for concerns over wear. The syncros just don't work properly with such a thick oil.

c32b

SpitfireS: reading your thread, I realised I need to update that my final drive is now 4.44 (GT Motoring). Not sure how much of a difference this makes from me using the oils I do.

rob-2: current OCI for diff/trans is about 8-15K miles depending on how frequent I track. Your sharing has led me to get this oil out of my gearbox asap which I will be doing in a few days. I'm really grateful to the community for their open advice.

xviper

I have the J's 4.44 FD gears for the past 11 years. It's also been supercharged (high boost pulley) for the past 10 years. I use fluids that aren't any different from a stock S2000. I started using Mobil 1 75W90 in the diff but as this started to get more and more difficult to find, I began to use various brand name GL-5 multigrade fluids. Some years, it would be 75W90. Other years it would be 75W110. One year, I even put 75W140 in there. I felt no difference and saw no difference in the fluid that came out at each change. Same can be said of the magnetic drain plug.
People can sometimes go nuts when dealing with fluids for their cars. We live in a paranoid and anal retentive world.
Back in the early days of the S2000, it was well documented that "dino" oil of the recommended viscosity analyzed very well. Even after 7500 miles of different kinds of driving conditions, the analysis showed that there was still plenty of life left in that oil. And now, we see owners of S2000s who obsess over what kinds of oils they "must" use in their cars. "Gotta have the best. Money is no object." And still, they blow their cars up. It's not the oils they use. It's the way they use (or abuse) their cars. It's the lack of knowledge and understanding of how the car works that ultimately destroys them. They ask the questions but they don't believe the answers nor do they understand some of the answers.

c32b

thanks for your contribution and it's good to know I can probably use a good 75W90 without potentially increasing wear. I don't know about "money is no object" as I don't earn all that much. My S cost me quite a bit (local car prices are a bit mad) so I am trying to be doubly sure I don't blow anything up or increase wear to lead to additional unnecessary downtime. My family life and work don't allow the luxury to spend all that much time at the shops. To compound that, I dont think there is a local UOA service so it is not very convenient to keep sending my fluids to the US for analysis.

In any case, I take the opinions combined with data points like UOA to make a decision and frankly am very grateful at the generosity of the community with regards to info sharing. I'll be the first to admit that I don't know much (if at all!) about the dynamics of oils but it's nice to know people are willing so water it down to I can at least understand the gist of it.