If my FD burns through its oil every 2-3 weeks (which means I have to pour more oil into it after buying some at a gas station), what's the point of even changing the oil? Aren't I changing it by refilling it?

 

I thought about that myself a couple of times...but I figure better safe than sorry..

 

well any dirty oil and crap in there will not get burnt and you need to drain it out and refill. How much are you putting in there? Mine burns oil but it is like 1/4 quart every 1000miles so I just fill it up alittle at 1000 and then change it at 2000.

 

Remember only a small amount gets consumed, so you should still replace youre oil.I replace mine every 2K or less so I never add any oil in between changes.Another good reason not to use expensive synthetic oil in the FD.

 

If you are consuming ALL your oil (4 quarts) in 2-3 weeks you need to be worrying about other issues - like how much does an engine rebuild cost.......

 

a quart every 1k? mine doesn't go through that every 2k. You've got an oil leak buddy.
Fine metallic settlement and carbon deposits will slowly drop to the bottom of the oil pan and continue to do so until the oil is changed. The same particles will eventually clog up the filter and slow down oil flow.
Now for the fun part, the turbos spin @ a rate of >100k rpms which is more than 10 times the speed of your engine, which means that any kind of wear will be accelerated 10 time. The only thing that keep the turbo spinning is a thin film of oil, if contaminated enough, the particles will literally eat through the spindle and create play, it then turns into a cascading effect, with enough play, the turbine and the compressor will rub against the turbo housing and start to break apart faster than you can say "twin turbo".
So do your self a big favor change your oil.

 

The OMP should be injecting 1qt/800-1500 miles depending on how hard you drive. The TURBOS can easily leak 1qt/400miles into the intake (my case) with out excessive smoking, I can't see mine smoking from the drivers seat but people following me have told me they can see some smoke when I get on the throttle.

 

That's about what I do. I just change it at the 2000-2200 mark.

 

No, combustion by-products are still building up in your oil filter and they're also contaminating the remaining oil and the inside of your engine. At one time I had the same theory you do, but I learned the hard way. It was a piston engine car. I kept adding oil frequently, thinking the engine was getting a fresh supply, then one day it just snapped. It was the worst sound I had ever heard. It sounded like 100 nuts and bolts in a metal garbage can being shaken violently.

 

Having a small burn rate is not necessarily something to be happy about. It may mean that your OMP isn't metering enough oil, or more likely that you are burning the right amount of oil, and that you are getting a lot of fuel in the oil which makes it seem like you are burning less. Or it might mean that you aren't enjoying the effects of the gas pedal very much.

As has been pointed out already, you still need to change the oil. Refilling does not replace enough of it (it shouldn't anyway), draining gets the junk out (including the fuel that dilutes your oil), etc...

Also, choose a brand of oil and stick with it. Mixing different oil formulations in the same engine is a bad idea -- they won't always work well together. Buying whatever is available at the gas station is expensive and bad for your car. Buy some oil and keep a quart in one of your storage bins -- use the same oil that is in the engine.

-Max

 

Max is 100% right here. I change my oil in my FD every 1800-2200 miles. I've sent a sample from the last 5 oil changes to Southwest Spectro Chemical for analysis. Every time I've got 10% fuel dilution in the oil. Nothing else is alarming, I run 20W-50 because of the fuel dilution. I never have to add oil between changes.

The car is a 93 R1 with 56K miles currently, original motor and turbos, been testing the oil since about 46K miles. DP, CB and Efini y-pipe are the only engine mods. Recently I hooked up a FJO wideband to it and found that under WOT a/f ratio is lower than 10:1 (limit of wideband). The overly rich tuning of the stock ECU is causing some fuel to get into the oil and I'm sure causing a power loss.

Jeff

 

Why replace tires when the steel belts are showing?

 

I consume about 1 litre in between oil changes with 10w30 Rotella T with 5w30 it rises to a litre and a half. I would suspect 20w50 the consumption would drop a bit. I change oil when I see my oil pressure drop from a normal 4kg/sq.cm. (meter is metric) to about 3, that signals fuel dillusion and breakdown have started. It will vary depending on how hard, how hot, or how short the trips are. So it would work out between 3000km and 6000km. I am trying to keep a daily log of pressure, level, air temp etc. to get a pattern but the drop in oil pressure seems to be the best way to tell.

Has anyone else noticed this effect?

For you non-metric boys: a litre is a US quart, 4kg/sq.cm is about 60psi and 1600km is a 1000mi. And my speedo goes to 280!

 

mine burns 1 quart of oil every 1500 miles.
I wait to do an oil change when it is time to add another quart,
kills 2 birds with 1 stone

 

Wow that's some serious stuff there...Here's what I'm wondering? How is fuel get into your oil? The only way fuel and oil should be meeting each other is via the OMP when it injects the oil into the engine.

 

OK here is an oil question:

My car has normal oil consumption as far as I can tell. I always baby it, so it doesn't burn much, but when I get on it I have to add 1/2 quart sometimes. I use 20/50.

Now here is the thing. When my car idles, oil press. is way way low. Just above 0 I mean under 30. The first time I saw this I damn near messed my pants. But as soon *** you touch the throttle it shoots up to 60 even before 4000 RPM. Seems to be very responsive, just very low at idle.
Is this normal? How is your oil pressures at idle?

 

My car just burned 2 quarts in 2 days in only about 300 miles.........but it was at MADS
(it doesn't smoke and normally doesn't burn anywhere near that much, but running around at 7k for extended periods will use it in a hurry!)

The interesting thing is that since my last oil change 2500 miles ago, I have added a total of 3 quarts now, but the oil is still black, so it definitely still needs to be changed.

 

The oil injection system has its own injectors, so it doesn't even really meet with the fuel there. What does happen is that unburnt fuel slips past the side seals (and maybe other places, too) and thus gets into the oil. All cars get some dilution, but it is pretty extreme on the FD (and perhaps other rotaries as well).

-Max

 

I've never had to add oil. I change my oil every 1500 miles or so, and it is rarely, if ever, even down at all on the dipstick.

 

The "0" pressure at idle is a symptom of a dirty connector on the oil pressure sender and/or the sender itself going bad. clean the connector (the sender is under the filter mount) and see if it improves - if not take off the sender and clean it, if still no change then get a new sender.

 

You guys with no oil consumption may have problems of your own. The FD is supposed to burn oil by design. 1qt per 1700 miles.

Someone posted this awhile back, I can't remember who, but I pasted it into a txt file so I'd remember.

"Oil metering system is about 400 parts gas to 1 part oil.

1 gallon = 4 quarts

So, you use 0.01 quarts of oil/gallon of gas. Or another way of looking at it, you use 1 quart of oil/100 gallons of gas.

Assume 17mpg. (100 gallons of gas)*(17mpg)=
1700 miles. "