Max speed for Pace oil pumps

[reflexdb]

From information I received from Pace, they don't advise running their compact C pumps at speeds higher than 6500 rpm. Pump will be used on an F4i motor. I was planning on driving the pump with the crank shaft (where the stock water pump is), as it seems many teams do. Have any teams had problems running their Pace pumps at higher speeds than 6500 rpm? Or, are you gearing it down to run at a lower speed? If it's geared down, it doesn't seem like it will have a high enough flow rate capacity.

[Maverik]

The stock water pump is not driven by the crankshaft (at least the RR, I'd assume the same on F4i), it is from a chain connected to a smaller gear on the backside of the clutch basket which also drives the stock oil pump (stock oil pump and water pump spin are connected with a shaft). So the long winded explanation is, in the RR, we have not had any issues with pump life or getting the pressures we've wanted with the pace pump... very good pumps. Out of curiosity are you using just a scavenge or fullout three stage pump?

[reflexdb]

Maverik, looks like your right about the pump's drive shaft. Just checked. So, it is geared down from the crank. I'm planning on using a three stage (2 scavenge, 1 pressure). My thought being that we could make the oil pan covering as low profile as possible, for the lowest mounting of the engine. However, I'm rethinking that now.

[Maverik]

There are definite tradeoffs with using a dry sump , but in my experience the benefits far outweigh the negatives. Some benefits:
- Accurate control over oil pressure
- Chop the pan, so much lower engine and much lower CG (this alone can make it worth it)
- Ability to plumb in oil cooler very easy

Negatives:
- Added complexity
- Weight of additional components
- Added draw from electric water pump
- Packaging (though you can make it look good if its well thought out)
- Cost

So why reconsidering?

[jack]

i think the most you could get from a CG drop is a 1/4 inch or so, 3/8 tops. sure seems like a lot of weight and complexity to me. best thing to do would be to ask the lapsim....

[kwancho]

For the record, the other day I was listening to a tape of the 04 Detroit design review overviewing the top 5 teams in design, and I think the 2 or 3 teams that ran a dry sump all did it for the lowering of the CG, which the judges said was the proper reason for a dry sump.

[Beatle]

Lowering the CG is an added benefit but I would argue with any judge who said that is the reason you should do it. You should do it because the oiling system on these engines are not designed for lateral loads. Reliability should be a much larger priority than lowering your CG.
One of the nicest things about the dry sump is that it opens up a lot of possibilities for packaging. Many more components can be remotely located so you can adjust your design around other "more constrained" systems.

[kwancho]

I'm no expert here, but at least in conversations with my engine guy, I think with the proper baffling and pickup modification, we can get 90-100% of the reliability of a dry sump. The packaging is definitely a plus, but not 30lbs worth.
For what it's worth, we're going wet sump this year, but only due to time and money constraints. We'll probably go dry next year.

[Brian Evans]

I wouldn't run a pump like that over 5000 rpm if I could get away with it. When we use those types of pumps, we run a 50% reduction belt drive, and our engines (not motorcycle based) are under 8000 rpm red line.

The traditional reasons for running a dry sump are engine reliability and ground clearance, which of course translates to CoG.

[reflexdb]

Maverik - I'm not reconsidering doing the dry sump. Seems to me that the added reliability and lowering CG are reasons enough alone to add a little complexity and weight. We're dropping enough weight everywhere else anyways. I was reconsidering using the 3 stage pump. May now go with a two stage, and use the internal pressure pump. Only problem may be with the stock oil cooler / filter location on the F4i (interference with exhaust manifold). Looking into it though.

[Ehsan]

Originally posted by Alex Kwan:
I'm no expert here, but at least in conversations with my engine guy, I think with the proper baffling and pickup modification, we can get 90-100% of the reliability of a dry sump. The packaging is definitely a plus, but not 30lbs worth.

Alex, if your dry sump adds 30 lbs to the weight of your car, you are doing something horribly, horribly wrong. Also, I highly doubt you get 90% of the reliability of a dry sump with baffling. The dry sump creates suction inside the engine which is the proper way to bring oil to the inlet. baffles are basically a bandaid. especially since as Beatle mentions, bike engines are not designed to deal with lateral loads, since they are leaned over any time they are cornering. This doesn't mean you NEED A dry sump but claiming you are 90-100% of the functionality could get you some funny looks from design judges.

Reflexdb, I personally feel an external pressure stage is worthless. You already have existing internal plumbing directly to the internal pressure pump. And the internal pump is a gerotor pump, which is a positive displacement pump. These pumps create suction on the inlet side. And if you do the flow calculations, you see that except for very high rpms, you can get enough flow back into the motor from hydrostatic pressure alone if you tank is a reasonable height. At higher rpms, the negative pressure from the internal pump helps you maintain adequate flow. Our team run this setup last year as have many others. Makes for a cheaper pump, a shorter/lighterpump and less plumbing.


And Jack, I think you are a little off on your cg drop numbers. If you have a car that is 600 lbs wet with driver and drop the engine assembly (approx 150 lbs for a 4 cyl with accessories) 3 inches (the max height of the stock pan), that works out to a 3/4" cg drop. I know of many chassis guys who get raging boners thinking of a 3/4" in cg drop. And it also gives you all the lubrication advantages. Yes, it is more complicated, but that just means you need to more than normal development time into it. I think if you have the money, manpower and technical ability, you really should run a dry sump. but its definitely one of those projects that I would recommend first year (and some second year) teams stay away from.

[Ehsan]

And to answer the question that the first post asked, the water pump drive is 1/2 of crank speed, so it'll see no more than 7500 rpm in an F4i.

[VFR750R]

Just for my own curiousness, has anyone ran an external drive for an oil pump off the crank. It might mean a significant amount of work or not much depending on the engine.

I've always had a boner to get a real dry sump (possibly 6 stages+), then use pulleys to change the speed to get the right pressure curve for the application. I'm sure pace makes a nice pump, but there are several companies out there that sell some serious pumps that could be used if dialed in. Benefits are you can keep the stock water pump and possibly drive other accesories like a 50amp alternator, hyraulic pump, ect.

Aside from the weight, how do people feel about it. Do you think it's more money and work then changing to an electric waterpump.

If the alternator side of your motor is dry from the crankcase can you just remove the stock flywheel(or modify it) and alternator, add an accesory drive and new crank trigger(if needed)?

[BeaverGuy]

I know Oregon State and Western Washington have ran belt drive pumps off of the crank. I also believe I have seen other schools that have ran them. The one at Oregon State occured a year before I got involved and I didn't hear anything bad about it. It was however switched to a gear driven version directly off of the crank the following year. The last year I was there the drysump was redesigned to drive off of the water pump instead of the crank so as to simplify the design somewhat. It wasn't made because of a lack on manpower/machining and the drysump from the old car was used. I liked relocating the drysump to the water pump drive as it gave me a reason to use an electric water pump. I do like the idea of a crank driven drysump as it doesn't require changing the cooling system. However, if I was going to do a drysump off of the crank I would probably still do it gear driven as it is a lot less complex than an a belt driven system.

[James Waltman]

Originally posted by VFR750R:
Just for my own curiousness, has anyone ran an external drive for an oil pump off the crank. It might mean a significant amount of work or not much depending on the engine.

Yeah, we did it at WWU in '04 to our F2/F3.
http://dot.etec.wwu.edu/fsae/SharedPictures/Dyno%20Alternator%20and%20Oil%20pump%20%232.jpg
The pump is on the lower left and the new alternator on the upper right.

It was a cool setup but a hell of a lot of work.
We chopped the generator off of the crank and put a pulley in its place. We cut holes in the block and welded on fittings for the plumbing. More pictures and info here (http://fsae.com/eve/forums/a/tpc/f/125607348/m/3446023614?r=3446023614#3446023614) and here (http://fsae.com/eve/forums/a/tpc/f/125607348/m/5026026005?r=5026026005#5026026005).

An oversight in the modification to the old generator cover cost us pretty big during competition. That cover supported a shaft that held an idler gear for the starter motor. Our modification weakened the support for the shaft. When we started the car to run our first dynamic event the cover failed and the shaft moved – it tore a chunk out of the block.
We missed all of the dynamic events on Friday. We borrowed an engine from Idaho, rebuilt it during the storm that stopped the competition, ditched the dry sump, and fit it all in a car that wasn't designed to have an oil pan - in time to start the endurance.

If we had it to do over again we wouldn't bother with the dry sump. It took a ton of work and required massive modifications to the engine (the way we did it). We didn't have time to do it to a second engine so we didn't have a backup. There are easier and better ways to do it though.

As a side note, Milliken was pretty impressed by how low we were able to get the engine. Video (http://dot.etec.wwu.edu/fsae/HostedPics/Movies/Milliken_Impressed_By_DrySump.avi).
The powertrain Judge hammered us for not having any justification (how much horse power does it take to drive the pump and alternator?).

We ran two scavenge stages and the stock pressure stage (including stock oil cooler).

[Welfares]

I highly doubt you get 90% of the reliability of a dry sump with baffling. .

We run a custom wetsump with some serious baffles in it, we also log oil pressure, since we installed the final setup we havn't logged any detrimental pressure drops through high G constant radius corners.

Its run in 3 cars over 4 competitions and something like 30 or 40 hours of testing.

With the custom wet sump we were able to drop the engine about 35mm (i think) and it weighs less than the original.

[VFR750R]

Wow, exactly what I had in mind James. Our YZF's had the starter assembly on the other side, which would have simplified the modifications and reliability problems, but probably still would require the alternator, not that thats bad, the stock one is marginal with fuel injection and FSAE required rad fan.

[Steve Yao]

Ehsan,

While Jack's CG numbers are off if you are moving from the stock oil pan, they are about right for switching from a custom wetsump setup. Dropping the engine height about 1.5" is dead simple for any team with a custom oil pan. Dropping the engine another 1.5" would only gain 1/4 - 3/8" drop in overall CG. So, the dry sump lowered the CG, but the CG is now heavier...has this really made a difference in dynamic weight transfer? Can the change in lateral grip potiential be quantified? Does this give any extra points in Accel, skidpad, autocross, or endurance? Do these points overcome the loss in cost points or team resources?

In my mind, simply lowering the CG is not enough justification. Comparison of cost to benefit has to be considered. Not only of what you actually did, but of the alternatives.

As noted by the UNSW team, and any team who has made their own oilpan and survived competition, wetsumps can and do continue to work with adequate reliability and have data to back it up.

Control of oil pressure is a definately a plus though. Expecially for getting proper oil pressure to a turbo unit.

[Ehsan]

Steve,

You make some valid points and I agree with them. The point about the custom wet sump is very valid and it is a easier alternative to the dry sump.

However, the extra weight issue is not really relevant. Our dry sump added less than 5 lbs to our car. Our tank was paper thin AL and was less than a pound. Using some clever routing, we used very little tubing and the pump itself is not terribly heavy (I don't have my numbers with me). And while I think WWU's method in the picture above is "cool" I think its a terrible and way-overcomplicated way to do it, as demonstrated by their component failure.

The much better way to do it is to use an electric water pump and put the scavenge pump in place of the stock water pump. All it requires is a small bracket, an adapter snout to fit the block and a coupler shaft.

The one thing people are missing as an advantage with the dry sump is the electric water pump. This allows MUCH better temperature control of the engine as you can keep cycling the coolant through the motor even when it is off. FSAE cars have lots of overheating problems and being able to continue effective cooling when the motor is off is a huge benefit (think driver change during endurance).

With the three advantages of lowest possible CG, precise oil control and always availble temperature control, I think its a very justifiable project. Again, its not something a rookie team should tackle cause there are many other places that time is better spent.

But after building one, I would always want one on an FSAE car. If you have one experienced team member who can dedicate himself to it, its really not a very hard project.

But again I will repeat, each team needs to make a judgement on its own manpower and resources before undertaking this type of project. Especially since you are making a very big impact on engine placement and frame design and realizing that its not gonna work 1 month before competition will not give you enough time to fix it if you have squeezed every last mm out of the ground clearance.

[repeatoffender]

Originally posted by Ehsan:
FSAE cars have lots of overheating problems and being able to continue effective cooling when the motor is off is a huge benefit (think driver change during endurance).


An experienced F SAE team would notice however that during the driver change in endurance the car has to be completely off 'electrically'

Most F SAE teams that dont suffer failures due to cooling problems whilst running, only suffer hot start problems, and quite frankly many of those could have been miss interpreted and are infact battery related starter issues.

Cooling systems aren't hard to size, they take effort to optimise however, dry sump systems even help the problem by yes if electrical pumps are used instead of mechanical you have extra control (do most teams even take advantage of this??) and the reduce the cooling load (if you scrap the water-oil circuit)

Id be wary of the number of teams that suggest temperature control as an engine design feature simply because of the use of electrical water pumps also. Unless you use closed loop control and have a small thermal mass (low water volume) you will never be able to keep it within the specified range. At best you can use it for start up (similar to thermostat) and cool down at testing.

[Ehsan]

Originally posted by repeatoffender:
An experienced F SAE team would notice however that during the driver change in endurance the car has to be completely off 'electrically'


touche Repeatoffender. However, if you do have an overheated motor, you could turn on your water pump and fan while trying to restart your car. thats not possible with a mechanical water pump.

And our team had a custom ECU so we had a provision for water control. And for the most part, if you've come off the track, just keep the pump running when you turn the motor off for as long as you are allowed depending on the situation or event you are in.

And I wouldn't suggest temperature control as an engine design feature, I would just claim increased control over stock and the all important ability to cool while the engine is off, which in my experience is a worthwhile feature.

[Steve Yao]

What pumps are people using?
How many are making their own?
How many use the the Pace?

[Boston]

MSU is making their own pump housing using gears from a Kawasaki

[BeaverGuy]

Originally posted by Boston:
MSU is making their own pump housing using gears from a Kawasaki

Oregon State has been doing the same since '02, although there have only been 3 pumps. There was the original belt driven pump from '02 and then the gear driven pumps in '03 and '05. The '03 pump was later used on '04 and on '05 after the '05 pump was transferred to the '06 car. All of these were driven off of the crank; mounting to the crank pickup sensor cover location.

[KU_Racing]

Just pitching in my 2 cents.. I know this topic is probably not going to be debated too heavily. I still think that a dry sump system is overkill for FSAE spec cars because of the complexity and extra cost, even if a simple dry sump is used. We ran a baffled pan last year, and monitored oil pressure. We saw negligible pressure fluctuation from the stock oil pressure curve under extended cornering loads- i think the highest pressure loss was on the order of 5%. All of this from a simple modification made to the oil pan that cost about 5 dollars and took about an hour.

Also, for the 'but a motorcycle doesnt experience lateral g forces in the oil pan' camp, think about how a motorcycle is ridden on the street, not how a race bike corners at a g and a half. Fluids in a bike engine definately move- look and a honda f4i oil pan and pump pickup and you can tell that they were designed to accomodate a certain amount of lateral g loading. The benefits of these small design features can be magnified and exploited with a little creative thinking and fabrication. Also, one more thing to remember: motorcycles are designed not to destroy their power plants if they are running while laying on one side. While it is unlikely that a motorcycle would be laying on its side with anything other than 0 throttle applied, they are still designed to accomodate the extremes of such a situation.

[VFR750R]

Well, riders hanging off the side aside, a motorcycles lean equalizes the lateral g load with a gravitational g load. At 1 g lateral, the bike leans at 45deg. Oil....flat in the pan. Does that mean make a flat pan...absolutely not. You should create a pan that's low at the pickup, no point in making a pan that is 'just enough'. The oil level is probably the most away from the pickup when the bike is transistioning from straight to max lean, as the lateral accel and vertical g's don't match, plus accel and decel which can be more then 1g. Another reason to have a good pan or drysump.

[KU_Racing]

When have you ever seen any sportbike racer that didnt lean off the side of the bike?? consider that a 200 lb rider weighs as much as 40% of the weight of the bike... then think about the lateral loading.

[VFR750R]

Well say a 400lb motorcycle and a 200lb man wrestle. The 200lb man moves his center of gravity 12 inches (probably on the high side) at a height of 36inches above the tire contact point. That's a lean of 18deg from centerline of the bike.

For the motorcycle I choose 400lbs at a height of 18 inches to make it easy, I get....18deg of lean the other way or an equivalent .32g's. Measurable, but seriously...not even close.

Another point I'd like to add about accel and decel. Motorcycles tend to have a high pitching angle for and aft which amplifies the angle of the oil. A hard accelerating wheelie for instance can be over 1 g at a bike angle of 17 deg, which is equivalent to 1.5g's. Luckily our racecars dont pitch much.

[Ehsan]

VFR nailed it with numbers. for a more general explanation, you'll never see the entire 40% of the rider hanging off the bike. Unless he was actually under the bike and hanging on, which would make for an interesting riding style. And you only hang off in more extreme cornering. On the street, you stay on the bike and ANY cornering that occurs at more than 5 mph happens with a lean angle that is perfectly counteracting the g-loading of the oil.

Of course there is some allowance for sideways g-loading, but the majority is taken up by the lean.