I am about to do a fluid overhaul on my Z. It has 75,400 or so on the clock. I was going to buy "synthetic" fluid for my engine, M6 tranny, and my stock rear end. Are these fluids really worth the extra $$?? Do they add any horespower to the motor, or make up for some of the parasitic loss in the drivetrain?? Just curious about this. Also, should I run 10W30 synthetic oil instead of 5W30 in my engine with my mileage? Any feedback is greatly appreciated. Thanks guys.

 

i just switched to syn oil here last week at 47,000 miles.

synthetic doesnt add any power. it runs cooler and cleaner. it will look dirty when you change it for a while because it is breaking down the dyno-goo that it has been running on and clean up your engine.

also something to watch out for is oil leaks.......if you have any this will simply continue until fixed, but if you dont and the only thing keeping it from leaking is the dyno-goo built up over the leak and then the synthetic cleans it out.....you may start to leak oil. i have heard this to be a common thin in higher mileage engines.

however i switched and all is good. i have only heard great things about syn oil and that it will greatly increase the life of your engine

 

This is just my 2 cents, but I tore my motor apart and rebuit it about 4 months ago. This was due to having smoke coming from my valve cover breather(I knew I had broken a ringland or my rings were toast). Well as I tore the motor apart I found out that #1&7 ringland were broke. I was sure I had to bore the motor .30 over and do the 355 thing. Well I checked all the bores, and looking very closely to #1 & 7, and they were still within factory new specs. This is after 114000+ miles and 95000+ of those miles being supercharged. So I just went with standard bores and slapped the motor together and its been running great. I have used Mob 1 every oilchange at 3000 miles. So in my case I would have to say the stuff works. To add, the bearings also looked great, and the motor was very clean with no sludge. Just my two cents again.

 

Someone recommend this page once to discuss oil.

http://theoildrop.server101.com/cgi/ultimatebb.cgi

I can't get it to work right now but maybe it'll be running later. The general consensus there seemed to be that Redline was the best oil made. The drawback is that it's more expensive and harder to find than Mobile 1.

 

It's clear that synthetic (engine) oil is superior for almost all applications. Ignoring exotica like alcohol or nitro burning motors, about the only street car you wouldn't want to use synth on is, perhaps, a very high mileage vehicle or a brand new engine. Less friction, which not only decreases wear but produces more hp and even cooler engine temps under extreme circumstances.

It gets more complicated with the tranny and the rear end. For one thing, except for perhaps road racing, these parts really aren't very taxing on lubricants. The stresses just aren't nearly as high as in the engine. And they depend upon having a certain amount of friction to operate properly, especially the synchros in the tranny and the posi in the rear end. OTOH, any time you lower friction you will gain hp.

Here's what I do: run non-synth in a new motor for the first 500 miles or so and then switch to synthetic. Synth has so little friction that it may interfere with break in. In the tranny and rear end I run the old dino juice.

Rich Krause