BirdShot

I changed the fluids for a new season of autocross last week. I sampled the engine, transmission and diff. These fluids had been in the car for over a year and about 4000 miles. At least 150 autocross runs in that time including hard launches, 9K shifts and aggressive throttle. In the reports I have the previous history since I have owned the car except for the transmission, that is a first time sample. This is a 2003 AP1 with 50k miles

First up is the engine.


I am still surprised in how well these engines wear even with hard use. Very low wear metals and no contamination. The TBN and OX/NT show I could have used this fluid for much longer (synthetics of this type start around 40 for oxidation) The fuel dilution was on the higher side. High fuel dilution in track and autocross cars is fairly common and I'm not really concerned with it. The viscosity looks like it may have been reduced slightly as a result but still within spec. I re-ran a few of these tests for confirmation.

The previous history is with a Kendall 5w-20 that was in the car when I first got it. Overall I was very happy with this report considering the type of use it has seen.

Next post will be the transmission.

BirdShot

Next up is the transmission. I had changed this fluid once already but I forgot to take a sample so this is the first time I have seen it in a UOA. The fluid is Amsoil MTF 5w-30 with standard testing along with an Analytical Ferrography slide I made.



The standard testing shows low wear metals and no contamination issues. The viscosity was lower than it should have been, possibly from shearing. Otherwise not much to talk about here.





The ferro slide shows more about it's current condition. Again, nothing major to talk about. Wear was fairly low and was mostly standard rubbing wear. A few laminer wear particles, some cutting wear and small amounts of copper and aluminum.


Next up will be the diff. I am still waiting on one final test before I can post the report but I looked at the slide this morning. Not pretty . Here is a link to my first sample and you can see it was pretty nasty back then as well.

zeroptzero

Wow, those are very low wear numbers for one year OCI's, and aggressive driving / auto-x, that is very impressive.

I was wondering where the titanium additive came from, I never knew Amsoil to use Titanium in their forumlas, I wonder if that is something new with their oils ?. That 5w30 has a killer additive package based on those numbers.

You have the same fuel dilution numbers I have with my engine, I'm hoping I can get mine to drop a bit, I've recently gone with new coils, injectors, and increased plug gaps , I will see what the next UOA tells me.

Nice reports , thanks for posting.

INDYMAC

Everything looks great so far BirdShot. I had a 3.4 GC fuel on my AP2 last time. I'm hoping the new O2 sensors corrected the problem. The Titanium is an additive left over from the Kendall GT-1. The Kendall actually has more Ti than Castrol FST. Looking forward to the differential report. Thanks for posting.

BirdShot

Now for the differential. Keep in mind, autocross use mostly. Were talking repeated 7-8K launches.


Like I say, not pretty. I had suspected the first sample a year ago was actually the OEM fluid or at least it had been in there for a long time. The biggest issue from the last ferro I looked at was high amounts of corrosive wear. The particles on that slide were mostly very small but there were TONS of them. The ICP reflected that with very high PPM of gear material.


Here is the latest report along with the previous history.



This time the ICP looks good, additives are a little out for what we have on SVT, the VIS100 is in range and overall the report looks good.


The slide is a little scary. I knew it before I even looked at it under the scope, the oil line on the slide was obviously heavy with ferrous material. Looking up close you can see a heavy amount of medium sized, fresh laminar wear particles along with a heavy amount of rubbing wear. A small amount of Aluminum and Copper could also be seen.





The last two images show roughly the same spots as the first two, but this was after I heat treated the slide. Heat treating revealed that most of the wear is actually from low alloy steel such as the gears themselves. Better perhaps than a medium to high alloy that would indicate a bearing issue, although some of the wear is medium to high alloy.


So what's going on and what can I do about it? My thoughts-


It could be a viscosity issue-

This is the 75w-110 weight and is thicker than the previous fluid by a significant amount. Perhaps the fluid is not THIN enough to actually get between surfaces or it is not able to get there quick enough.


Perhaps its not THICK enough? By comparison, I had much more autocross on this fluid than the previous slide and now I have much more fresh wear particles than before. It could be it is not thick enough to actually provide an adequate film between surfaces for the increased amount of launches.


Note: This is a fair weather car and rarely sees cold temps.


It could be an additive issue-

Anyone else think the EP package for this fluid seems a little light? Shockproof fluid for example has double the phosphorous compared to this severe gear fluid.


Perhaps there is not enough anti-wear (sacrificial layer) to handle this type of extreme use.


It could be a fact of life-

This is pretty much the hardest type of use a street car diff can ever see. Standing starts getting up to speed as quickly as possible, not to mention the accel and decel hard throughout the run.


One thing I want to look into is increasing the magnetization inside to try and pick up more of these particles before they are allowed to circulate, compounding the wear. Also this reinforces that I need to pick up a spare diff to have with me at events!


Your thoughts and experiences are welcome.

zeroptzero

Anychance the new fluid was doing some cleaning. I know the first run of Amsoil 75w-110 in my car brought out a lot of sludge like material, despite being used for a very short inteval of light street driving use.

My gut feeling for your application is that you should go thicker given your fair weather driving conditions, and your type of driving. I would recommmend LE1605, while being thicker overall it is supposed to have better metal clinging/climbing properties. Phosphorous is an important additive in that regard. A low P formula probably isn't the best for your type of use.

BirdShot

It's possible there is a cleaning effect from switching to this type of fluid but I really didn't see much evidence of that in this example. Those wear particles are fresh and likely have been generated recenty.

A co-worker of mine is also leaning this way. I'm not 100% sure though, the first sample had a thinner fluid and did see some autocross. I was not seeing anything like the size/severity of these particles on that slide.

I absolutely agree I should get something in there with a heavier EP.

starchland

Any chance you have a pic of the drain plug magnet? Or how much was on there? Thanks for the new reports.

BirdShot

I should remember to take a quick shot of the magnet next time.

It was well coated with ferrous shavings, but I honestly didn't look at it closely enough.

zeroptzero

LE 1605 is an SAE 110, not overly thick. Indymac has some UOA"s posted of the LE1605 in this thread link listed below, however, the addtive pack doesn't look any better than the Amsoil. Shockproof sounds like it is designed for your type of use, it might be worth a try.

https://www.s2ki.com/s2000/topic/706...#entry21947369


When you see wear metals that high is it a sign that the diff. is nearing the end of it's life ?, or do you think it can take a hit like that can keep running properly ?. Have you noticed any added noise or different operating characteristics lately ?.