yet another oil tank thread, vellios vs oe Options

[blabla914]

I'm purely interested in the oil control of these two tanks under high cornering loads.

I have a vellios tank purchased from patrick motorsports about 3 years ago. I understand some of the EARLY vellios aluminum tanks had oil control problems, but it was fixed quite some time before I bought mine.

However, at the last autocross I caught my oil pressure gauge jumping around. As I came off a medium speed (about 4000rpm in second) corner I saw the oil pressure gauge make a BIG wiggle. I took it a bit easier the rest of the run and I didn't see it do it again. The car had been idling for at least 15-20 min and had roughly 170F oil temp. I also ran the motor at like 2000rpm in staging a bit to make sure the scavenge pump had a chance to empty the case. I verified the level after the run and it was overfull. I can't get the hang of adding oil to this thing to save my life. It's usually a little low when I show up at autocrosses (it's generally the only time I check it, but I autocross quite a bit) and I always add too much. I'm worried it's doing this when I'm not looking, which is normally the case when I'm trying to look where I'm going. I've been trying to keep an eye on it, but it can be tough to push the car real hard when you're looking at the dash, and it seems it doesn't do if unless I push real hard. Know what I mean?

I am further worried by a tech response I saw a while back in the panorama where a guy wrote in saying he had popped his -6 at the glen. The first question the tech guy asked was if his car had the factory -6 tank. He didn't necessarily ask if the tank was a vellios, but he say that the factory -6 tank should be adequate for what he was doing.

My car has a pretty standard setup with an aluminum tank, no front cooler and -12 aeroquip lines. It's hooked up to a '69 2.0L motor that is mostly E spec. and I use a 7k rpm rev limiter, but shift at 6500 rpm.

I'd be interested to hear from you guys who are running on the track or autocross with the aluminum tank that fits in the stock location. Any pickup problems? Any tricks I should know?

Thanks for your help.

Kelly

[blabla914]

I have some info for you guys, or as the Dude said "new s**t has come to light, man"

Luke,

Thanks for posting that pict of your tank and the fitting. However, since that fitting appears to measure 1" at the tapered end means it is 3/4" NPT, not 1". Carrol Smith reminded me that NPT refers to the INSIDE diameter of the piece of pipe that accepts the thread.

Some interesting dimensions:
-12AN ID is 0.69"
The ID of the S-line from my engine when it was in a 911 is .743".
-12 is a little small, but not terrible.
Here's where things get ugly. The ID of a -12AN fitting is only 0.583"
The ID of the tube on the bottom of the oil cooler where it meets the case is 0.707"

I did a little searching on some other forums, most notably an off road racing forum where they seem to all be running dry sump setups. An undersize supply line was listed one of the reasons people lose oil pressure at high revs. Another was not using an anti-collapse spring in the supply line.

Seeing that I've only noticed a problem after I started running 30 mm chokes and a 7k rev limiter (stock is 7100+/- 100) I'm thinking starvation at high revs is my problem. I'm glad I sorted this car at autocrosses before going to the track. Seems to me sustained high revs at the track would have had a rod sticking out of the block quick.

Smart Racing Products recommends -16 supply AND the spring for rear mounted tanks and -20 also with the spring for front mounted tanks. These guys seem to drive their cars like I drive mine. When it runs.

Smart also makes a big deal out of the fact that their anti collapse is flat instead of round. I don't know if this is really as big a deal as they do, but it's about the same price so what the heck.

Bottom line, I'm going to switch the supply line to -16AN and run a smart anti collapse. I also found bakerprecision.com which was the only place I could find an aluminum weld on male -16AN fitting.

Joe,

I know your setup has quite a few miles on it and some track time, but if I were you I might consider atleast getting an anti-collapse and maybe switching the supply to -20. I know it's expensive, but it's cheap compared to a motor.

Rich,

Thanks for posting the spring. Not easy to find them for sale though. Oh and an OC54 is definately 72+.

Kelly