April Fastrack--Oil Sumps

[Matt King]

Anybody else find it ironic that in the same issue the CRB rejects a letter requesting a rule change to open up the oil sump, saying "there is no demonstrated need," they are asking for input on allowing dry sumps for FVs?

http://www.scca.com/documents/Fastrack/ ... l-club.pdf

[jpetillo]

Yes, very ironic. SCCA's an organization run by many people. To me that means that the reason can vary from the left hand not know what the right hand is doing, to the timing of when different information was received by the CRB and was drafted into the newsletter, to perhaps SCCA reviewers believing that there was not a sufficiently demonstrated need in the letter for them to act on it, but then deciding that perhaps the subject should be open for recommendations from the community because it was such a good idea.

I have two questions...
1) What could be the reason that rule for sumps and oiling systems in any SCCA class is anything other than free and open?
2) What's the cost of a dry sump system?

[dd46637]

A dry sump system for a FV should cost pretty much the same as FST.
The pump is 100, then approx. 50-100 for fittings and hose.
You will probably have to make a tank or have one built, I am having one done for 125.
Last year I bought one off e-bay very reasonable (75 I think).
It can be done for under 400.

Now for the opinion part,
I don't think it will fly. There are to many that prefer to see FV stay just like it is.

Dave

[Matt King]

I'd like to see the sump rule opened up to at least allow the larger wet sumps that have been discussed in other threads. As for dry sumps, I'd be open to that too as long as they are not able to create a power advantage. The effect of pulling significant crankcase vacuum (10-15 in/Hg) on ring seal can be very significant on high-HP engines. On a Vee engine it could possibly be worth a HP or two. If the replacement-type internal dry sump pumps don't scavenge strongly enough to pull any significant vacuum, it might be OK to allow them.

[brian]

The main difference in a dry sump versus the sump extension is that the dry sump system changes the way the engine works and provides opportunities for other upgrades. Sump evacuation, oil shearing and negative crankcase pressure are a few of the more common upgrades that can prove expensive. I have never had an oiling problem with a well designed windage system. If a car has an inclined motor like the XTC, Lazer or Cambell then there may be issues. The FST cars have nearly double the torque as a vee and maintaining the oil film on the crank is more challenging so their issues are unique to them. I would not recommend a dry sump system for vees because it will raise the bar and some folks will find hp advantages.

It shouldn't come as a surprise to anyone that the rule process and the CRB are prone to politics.

[dd46637]

FST horsepower gain was 1-1.5 IIRC.
The 2 stage pump that we use does not provide enough vacum to give a serious negative crankcase pressure.

The real benifit IMHO is longivity.
It is really nice to prepare for a new season with only a head freshen and an oil and filter change. As opposed to having to have a rebuild every year.
I have to agree that it seems curious that the request to modify the sump rule seems to have been flatly denied and in the same publication comes a request for member comment on dry sump.

And just for the record I have no dog in this fight. Just offering some information.

Dave

[hardingfv32-1]

I would say the quality of the sump modification request was not as good as the request for a dry sump. You are trying to convince a committee with limit FV knowledge. At least we will have plenty of time for input.

How about establishing some FACTS......

Can we spec a two stage pump that does not provide serious negative crankcase pressure? From my own development work (using a front seal), I can state that a 3 hp shop vac will not budge the torque needle on the dyno at 5000 rpm.

IF there is limited HP gain, say 1/2 hp and the cost is about $400, then this could be a good upgrade from a engine longevity point of view.

Brian

[jpetillo]

Can someone give an indication of the difference in wear and tear as compared with what we run now or a baffled, but larger, sump? Dave mentioned a head freshen would all that would be needed with a dry sump. That sounds like a $400 savings alone as compared with a seasonal rebuild. Am I off?

[SR Racing]

Dave is correct. Every FST engine we get for refresh has shown zero bearing wear. The engines also run much cooler due to a dry sump. This helps longevity with pistons and rings. HP gains on the track aree under 2 HP (FST). FST rules stipulate a 2 stage pump that fits in the existing VW case oil pump position. (No belt driven pumps). The internal scavage pump is typical 23mm gearing and the external pressure side is 21mm. This will not be an easy rule to pass in FV. Costs will be in the $400+ area. (If done at rebuild time) You also need a 4-5 quart resevoir. A dry sump will save a few engines and give them longer life. We implemented in FST when there were only 10-12 cars built so the impact wasn't as great. The positives are oil pressure that never drops below 30lbs., 20+ degrees cooler operating temps, a bit of HP, no critical oil levels (we don't even have a dip stick since there is no oil in the case when running),. and maybe best of all.....NO OIL in the engine compartment, on the valve covers, or out the front pulley, etc.

Case pressures never drop into the negative range, but blowby measurements are less than 1.5 CFM in the FST and would probably be under 1cfm in the FV.

[hardingfv32-1]

The most common failure from oil pressure fluctuations is damaged/spun rod bearings. If you do much racing, you probably have had this type of failure. If we can get agreement that a dry sump would end such failures then this would be an easy decision.

The HP gain will be an issue as this will make the change necessary to keep up. Jim, any first hand HP numbers for a FV with a dry sump? Are the HP gains seen on the dyno?

Brian

[SOseth]

A request came into the club to allow an alternate means of fastening the oil sump the the engine. The means was not specified. My comment was that I didn't see the need. I stated my belief that if we were to change that part of the rules with regard to oil sumps, that I would just as well see FV adopt dry sumps as the first guys have done. This really was an off hand comment at the time but I do believe that it would benefit the class long term. It was then suggested by another member of the F/SR committee that it be put out for member input.

Let's not get ahead of ourselves here...There is no request into the club to change the rules to allow dry sumps in FV. This is a request for input only. I personally think there is much more upside to this than there is downside. Frankly the First guys have this figured out. It works. I probably costs no more than a set of tires and will, I think, allow more time between rebuilds, and should elevate FV out of the oil polluting ranks.

SteveO

[jpetillo]

It works. It probably costs no more than a set of tires and will, I think, allow more time between rebuilds, and should elevate FV out of the oil polluting ranks.
SteveO

All good. Would it impact the amount of oil on the track toward the end of an FV race? If so, would it result in a significant difference in traction?
John

[problemchild]

While I respect and see Steve O's view that "if we are going to change the oiling rules, then lets go all the way and go dry-sump", I really don't think that 75% of the FV community want the expense and logistical challenges of dry-sumps any more than they want $2K intake manifolds. I would suggest the opposite.

What would be the most realistic solution, would be to determine what is required to fix the wet-sump system. I am talking about changes not currently allowed in the rules. Perhaps machining new ports, moving relief valves, changing by-pass ports, etc. Think outside the box ..... and fix what is wrong with the current system so that HP would not be affected but reliability would. Then change the rules to allow those mods. The current pumps produce more volume and more pressure than we are using. Somebody needs to find a way to use what we are already making. There are lots of smart people out there. Surely someone can figure this out! It may be as simple has a 10 minute machining operation, a $.50 spring, or a $5 piece of hose. For example, some Pinto engines (FC and S2) have external hoses that return oil from the head directly to the pick-up area in the sump.

The most difficult thing about dry-sump systems for FV, will be finding room for tanks. Some of the FST cars ended up with tanks hung up behind the driver's head on the firewall. It would be a breeze for some and a nightmare for others! It is not the magical solution that some would suggest.

[SR Racing]

All good. Would it impact the amount of oil on the track toward the end of an FV race? If so, would it result in a significant difference in traction?
John

Yes, you will no longer leak on the track.. (assuming all other things done correctly. )

Re: problemchild's comments. If I were only interested in our Vee racing, it would be a no brainer. I would go dry sump... However, this is not a simple solution in many current Vees. If I were the one that makes the rules in FV, I would probably say no to dry sump. It would force $400+ at MINIMUM down everyones throats. And that assumes YOU are doing the work. Some cars won't lend themselves well to dry sump locations. There clearly is a HP advantage, thus forcing everyone to go to the dry sump to be competitive. Many Vee drivers only want to race, they don't want to spend lots of time and $ designing or paying others to upgrade. So think about it... <g>

At the time we suggested the rule in FST, problemchild was opposed to it. (For several valid reasons.) I had my concerns also, but knew that it would resolve the problems. After the implementation, I was VERY happy we bit the bullet. Pressures always stable, temps 20+ degrees cooler, bearings with long lives and CLEAN engines.

We have not built a 1200 engine with a dry sump, so I can't swear to a HP gain number, but it will clearly be there. I suspect in the 1+ range. (Which is a lot in a Vee.) (Of course when you add up the gains from Split Fire spark plugs, Nology wires and coils, "Version 2, 3, and 4" heads, carbs and manifolds we are pushing 85 HP already. )

Due to the low torque output of a Vee, most can certainly get by without a dry sump system at current failure rates and rebuild timings. FV's are developing only 60+ lbs of torque. (High torque is the worst case issue for engine bearings.) FST's are developing close to 100lbs. They will not live at 10 to 12 lbs of pressure for long.

In regards to a simple non-dry sump fix via plumbing, etc. I don't think it is forthcoming. (With the possible exception of bigger sumps.) Plus the forward tilted engines mentioned above, (XTC, Lazer and others) exagerate the problem. This has been an issue for 20+ years and I don't think there is a simple fix for blowby, other leaks, etc.
It is (dry sump) definately a proper way to address a racing engine with a Vee's design, (All real road racing cars use dry sumps). But at this point in the FV life cycle I am not sure it is good for the class overall.

[hardingfv32-1]

Ask any engine builder and they will say 75% of the FV community can't take care of their present oil system. This is the main cause of the rod bearing failures. While the dry sump is harder to install initially, in the long run it reduces costs. I bet the engine builders would offer a discount for those using dry sumps just to reduce the arguments over who's responsible for a bearing failure.

This is an oil starvation problem. You need to get the oil back to the pickup tube entrance. There is no simple fix that will fit under most chassis. We are seeing record high cornering forces from the latest tires which has aggravated the issue. How about smaller and harder tires.... slow speeds ??

Brian

[brian]

God, I hate to get into this. Oil on the track is caused by 4 things: too much oil, often done to prevent starvation, poorly assembled engines, blowby and mechanic failures. Adding a dry sump engine would help solve the first issue but would not help the others. Maybe pulling a little vacuum might help in crankcase pressure, but would not eliminate the cause of the pressure. So if you think the track will be cleaner, just remember that the dry systems have more external components and are a lot more complex.

A well designed oil system, sump, windage tray and return system will prevent engine starvation. Eric Oseth has designed a fantastic sump extension and coupled with a good pickup, it will eliminate starvation if you get the oil back to the sump. The major challenge with a wet system is getting the oil to return to the sump where it can be picked up. At BRM enginering, we have been building off road engines for many years, and if you think cornering is tough, try wheel standing hill climbs.

The engines we prepare last a very long time and,while Brian's right about the variabilty of skills among the competitors, there are some basic things we teach our customers. One is to check the oil while idling. If you have any external components oil can be trapped and mislead the dipstick. Second, if you are not running a well designed return system, go easy until the oil is warm. Oil will stick, bridge and stop returning if it's cold and thick.

Regarding HP, in a interview in F1 engine magazine, one of the three major contributors to hp growth in the past ten years came from oil evacuation. As a vendor, this is an opportunity, as a competitor, it's just another trick I don't want to buy.

[hardingfv32-1]

With regard to real race engines dry sump systems, they use multi stage pumps that draw a serious crankcase vacuum. As Jim said, with a single stage suction side pump (with say a restricted rotor size), we can assume this is not where the extra power is coming from. Is windage control that much improved? Jim, I assume you saw the FST dry sump power gains on the dyno not some kind of track measurement.

No HP gain would make this an easier sell.

Brian

[brian]

Once you've eliminated the wet sump, many things are possible; including an electric vacuum pump.

[hardingfv32-1]

The big rule rewrite/update restricted the use of electricity to ignition, starter, radio, DA, and instruments. No fans or pumps.

I wonder if we can restrict the size of the dry sump tank to keep the oil level high in the engine. This could negate the HP gain from reduced oil windage.

Brian

[SR Racing]

Oil on the track is caused by 4 things: too much oil, often done to prevent starvation, poorly assembled engines, blowby and mechanic failures. Adding a dry sump engine would help solve the first issue but would not help the others. Maybe pulling a little vacuum might help in crankcase pressure, but would not eliminate the cause of the pressure. So if you think the track will be cleaner, just remember that the dry systems have more external components and are a lot more complex.

With a single stage scavenge pump you won't pull any case vacuums. (F1 and others actually use a vacuum regulation system since they can pull enough to suck in birds <g>) However you will literally dry the engine up. You will not blowby through the seals, pulley etc. Even valve covers won't leak, since there is no/very little oil in the case when racing.

Actually there isn't any more "complexity" in a dry sump system than a full flow external cooler system that most people use now.

As I said, I am not for it in FV, but it IS clearly in every way an advantage over a wet sump system. We can be oppposed to it, but let's be honest about the pros cons.

[SR Racing]

Jim, I assume you saw the FST dry sump power gains on the dyno not some kind of track measurement.

HP gains were all on the dyno. It would be easy for me to accept that on track gains MIGHT be even greater since windage losses would be more with on track dynamics.

[SR Racing]

...One is to check the oil while idling. If you have any external components oil can be trapped and mislead the dipstick....

I also hate to be seen as supporting dry sumps in FV, 'cause I don't, but.... I had raced and built engines for other venues for many years. When I first bought a FV 20 years ago, I remember the owner taking 10 minutes to explain to me how critical it was to check the oil properly and not to have 1/2 quart to much and worse, 1/2 to little. At the time I was thinking to myself what a weird system and how I would fix that. (Of course after reading the GCR, I found that you couldn't fix it legally.) Certainly all engine types should have their oil levels checked before each session, but the babying and criticalness of oil levels in an FV is pretty ridiculous. Running low on oil in a real race engine or leaking all over the track is something others don't worry about. In our FF, FCs, FST's or most any race engine we just spin open the tank and look in there. If it looks full of oil, it's fine. <g> Again, just trying to keep it honest.<g>

[smsazzy]

If we could find a way to make it not be a significant HP gain, I would be all for it. I love the idea of a dry sump for all the reason's listed. I also, can't think of a single reason not to go this route, except that if a HP gain is realized, then everyone will have to do it. That isn't going to fly.

For what it is worth though, aren't we the only lass with real race cars running a wet sump system? If you want to promote the class to a younger generation of racers, eventually we're going to have to move in this direction. Why not now?

[brian]

In all "'honesty" most vees have a simple oil block on the case and that approach is a lot less complicated than a dry sump system. Jim is right in saying that an external cooling and filtering system is close to complexity of the dry approach. One issue that we've had with remote oil storage is warming the oil. Some engines, like ours, can't idle long enough to heat the oil and require tank heaters. Having an horizonally opposed engine with a very shallow sump does make the VW unique in the engine world so it's not surprising or ridiculous to see that oil levels are critical.

Smsazzy, not sure what a "real" race car is, but SCCA has several classes that still have wet sumps. American sedan comes to mind.

One final point, if you are having oiling problems, it is currrently legal to put an Accusump or accumulator on your vee.
(9.1.1.C5.D.29 PAGE 199) Not only will it eliminate oil starvation and a need to overfill the motor, it will do it for a fraction of the cost associated with a dry sump system.

[sabre1]

It has been mentioned a couple of times here and I would like to reinforce the concern of where do you put the dry sump tank - it isn't small and it will not be a trivial issue to place one of appropriate size (probably 5 or 6 quart volume) in our cars! In most cases it will require a custom tank to fit. Take some 1 quart oil bottles and see how many will fit conveniently in one location...

Another point to mention, the $100 two stage pump isn't the only one out there. I bought a used 2 stage pump for $200 that normally cost around $600; The vacuum stage is HUGE; pressure stage is pretty big as well. Does it make a difference, don't know yet as I haven't done any dyno testing - but at some point I will. It may not fit in all Vees due to it's length, but....

I will say that the $100 two stage pump is a nice piece and seems to work well, though you may also need to change your crank pulley to accommodate the slightly longer pump.

-Jim