but please explain how the pan will hold enuf oil to last around a long high G sweeper such as the banking at Cal Speedway, Turn 2 at thunderhill or the riverside turn at BW?

My problem w/ trap doors is there is no way to get them to trap more than 1-2qts of oil and keep the oil pump pickup in the oil.

You get 3 qts from an accusump and thats really only good for 20 seconds tops, more likely closer to 10-15 if you've fully starved the pump.

-Ry

 

Correction, you get 2 qts form an accusump and 1 qt of pressurized air.
But your point remains, for cars on slicks, the dry sump is the optimal solution.

 

Look at the big brain on Rylan!

-tony

 

While a dry sump is the ultimate way to go, I think the point that Karner is making is twofold:

1) If you want to go wheel to wheel in any of the current or upcoming series that have spec'd out rules for the S2000, you can't run a dry sump. Furthermore, since none of those series allows slicks, grip is lower as is the attendant risk.

2) Running a baffled pan is legal because it offer no windage advantages like a dry sump (as jzr points out - and they are significant, especially on high rpm engines). A baffled pan in conjunction with an Accusump should provide more than enough protection in any of the current classes.

It would be interesting to see what really happens with a full load of oil on board the stock pan. If you know your average G loading, you could approximate the condition simply by tilting the pan an appropriate amount and seeing where the oil ends up. It may be that transient slosh is more an issue than completely running the pump pickup dry for an extended period. Either will kill a motor, but slosh is far more treatable without a dry sump. I would be wondering if there isn't some oil getting caught up in the head in very high-g corners. Seems unlikely given the large drainbacks into the crank, but nearing 2G of cornering force may find more than a little staying up there. If that's the case, at least one more pickup will be needed up top (probably on the passenger side)

If you do plan on running slicks in a road racing class, the only place to really play on a regular basis is TCRA (you could run NASA SU, but there isn't much competition there). The under 2.2 class in TCRA is well attended, but even a stock motor S2000 on slicks will clean up there easily (ask Karner). To make things really fun you'll need to run in one of the GT classes where you'll start facing Ferraris and Porsches, and you'll need to spend a bit more on the motor to be competitive, dry sump or no.

UL

 

ITE, not on slicks but hooisers. Is where I mainly plan to play next year.

BTW Shawn, I've always been the understanding that in most high reving modern engines (ie: f20c) the crank doesn't hit the oil anyway. So where would the windage gains be from?

 

UL, we've missed you!

 

AFAIK, no modern engine (meaning the last 10-20 years at least) is designed so that the crank actually enters the oil pool in the pan. You'd create way too many problems in doing so, even at relatively low rpms.

However, that doesn't mean there aren't ways for oil to get onto the crank. One way which would be solved by a dry sump is splashing. If you've got a problem with oil starvation in high-g corners, that oil has to be going somewhere, right? You've also got issues like oil drainback from the head. Now, if you don't have a scavenge stage for the head, a dry sump won't eliminate this.

Running a dry sump also means that, depending upon the vacuum you run, you may be running a slight vacuum in the crankcase. This helps eliminate oil vapor issues (the counterweight speed in an S2000 nears 40 m/s at high rpms so the vapor carries some weight) as well as reducing the atmosphere the crank has to move through. Crankcase vacuum can be tricky, but it can free up a fair bit of power when you get it right.

UL

p.s. - Gernby, I'm always around, just don't post much anymore. Occasionally something interesting and new comes up (like this post) that piques my interest and I'll chime in.

 

Are Krank Vents permitted in these classes?

 

The commonly lower crankcase pressures accompanying dry sumping also help rings to seal against the lands that they sit on. Both seal against the land, and seal against the cylinder wall are both essential in keeping combustion pressure.

Besides lower crankcase pressures making it easier for the counterweights to cut through space, pumping losses from mass of gas transferring from from cylinder bottomside to cylinder bottomside as the pistons reciprocate are also reduced. Some racing engines compartmentalize each section of the crankcase across the main to eliminate this gas movement.

Also, with less oil being slung around and up onto the cylinder walls, the ring package tension, particularly on the oil ring, can be reduced and in the process reduce friction losses.

 

Hey, Krazik!

How are you, guy? A dry sump, huh? I'm interested, although for different reasons than y'all. But you understand, I'm sure. I don't need 8 quarts of oil, and I don't need an oil cooler. I'm just looking to make the motor "shorter" so I can build a smaller car.

I took down my motor during the last few passes at the Salt in October. Compression is 196, 186, 165, 155. A leakdown test last night said it "might" be just valves, and I've got my fingers crossed. In any event I'm going to be pulling the head for a "little" work. What's the latest dirt on who makes high RPM cams and on how high you can rev a stock motor (with high performance springs and all)? My salt buddies are thinking we could put up some hot numbers if we can get one of these babies to stay alive to 11,000.

And besides I've now got GM with one of their 2 liter Eco-Tech motors in my class, so it may be time to get a bit serious.

Anyway, hope all is well and you haven't scratched the ole' ride.

later,

Jim