Chaz
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| posted on 25/6/05 at 10:56 AM |
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Whats with a dry sump?
Its probably a very noddy question to lots here. Whats the difference between a dry and wet sump? Well i know how a wet sump works, so whats with a
dry sump? What are its adv and disadv?
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flak monkey
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| posted on 25/6/05 at 11:01 AM |
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Dry sump lets you mount the engine lower to get the COG down. Not sure about any other advantages though...
Sera
http://www.motosera.com
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dmottaway
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| posted on 25/6/05 at 11:18 AM |
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dry sump has at least one pump that evacuates the oil from the sump to a remote tank and a pressure pump to take it from the tank to the engine.
advantages are larger oil capacity, oil-air separation, lower engine mounting.
high RPM engines enjoy a small HP increase by not having the crank churn the oil in the sump.
disadvantages are cost and complexity, need to mount tank somewhere nearby, and they nearly always leak.
mounting the tank will offset a portion of the CG movement gained by lowering the engine.
or so I have heard.
dave
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MikeRJ
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| posted on 25/6/05 at 12:14 PM |
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Probably the most important use of dry sumping is to eliminate oil surge.
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Surrey Dave
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| posted on 25/6/05 at 12:45 PM |
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Thats what I thought MikeRJ....
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James
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| posted on 25/6/05 at 01:45 PM |
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Me too!
Chaz,
Hi speed cornering will mean the oil can all slop (for want of a better word) to one side of the sump and therefore not get picked up by the pump-
eventual result engine goes bang!
Hicost recently fitted one to his Cossie engine. The tank sits in the boot area.
Cheers,
James
------------------------------------------------------------------------------------------------------------
"The fight is won or lost far away from witnesses, behind the lines, in the gym and out there on the road, long before I dance under those lights."
- Muhammad Ali
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Chaz
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| posted on 25/6/05 at 07:10 PM |
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Thats got to increase weight, with his oil tank right at the back with all the wiring for both pumps and the oil lines!?
Where do most people put them/ rig them up?
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Simon
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| posted on 25/6/05 at 09:01 PM |
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quote:
Originally posted by Chaz
Thats got to increase weight, with his oil tank right at the back with all the wiring for both pumps and the oil lines!?
Where do most people put them/ rig them up?
Chaz,
There is no wiring - the pump is "usually" mounted very near the sump and driven by a crank pulley. Oil is fed by usual oil hoses. So
discard heavy steel sump and replace with lightweight ally one, and lose weight saved on extra hosing. Gain huge benefits from surge protection and
churning (which in itseld should release the odd horse or two )
ATB
Simon
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andylancaster3000
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| posted on 25/6/05 at 10:07 PM |
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IMHO the main purpose of a dry sump is to prevent oil surge and the eventual oil starvation and expensive clean operations! Any other advantage is
only second to that. Therefore it is not hugely cost worthy for a road based car but any serious track car does usually require one.
They can be built at a very reasonable cost with a bit of thought. The original pump can be re-plumbed as a pressure pump, a seperate pump can is then
used as a scavenge pump (this is generally the bit requiring the most thought!) A sump can be made from an original sump re-worked into a shallow
trough with a length of RHS as the collector tube.
Or.... you could just go and buy a bolt on kit from Pace for a couple of thousand!
Andy
[Edited on 25/6/05 by andylancaster3000]
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phelpsa
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| posted on 25/6/05 at 10:30 PM |
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Remember that not all engines react well with a dry sump! For example GSXR 1100 engines don't react too well to a difference in oil level in the
sump.
Adam
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gazza285
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| posted on 25/6/05 at 11:22 PM |
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quote:
Originally posted by dmottaway
and they nearly always leak.
or so I have heard.
dave
Who told you that? Why should they leak "nearly always"?
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gazza285
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| posted on 25/6/05 at 11:24 PM |
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quote:
Originally posted by phelpsa
Remember that not all engines react well with a dry sump! For example GSXR 1100 engines don't react too well to a difference in oil level in the
sump.
Adam
Why? Dry sump systems don't have a sump.
Explain why a GSXR 1100 needs a sump filled with oil instead of a dry sump system.
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ned
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| posted on 26/6/05 at 09:50 AM |
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i will be bold and say that people don't know what they're talking about re the above gazza 
It's a simple enough concept, how can people be getting it that wrong!
Ned.
beware, I've got yellow skin
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Bart Vangampelaere
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| posted on 26/6/05 at 06:31 PM |
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If a GSX-R engine is anywhere near the type of motorcycle-engine I know, it is not comparable with a car engine. Sumps of motorcycle engines are not
like car engines. They are a part of the engine block casting (usually split somewhere in the midle) and therefor can't be removed.
Since all that cast metal stays in place, drysumping seems useless.
As for car engines, dry sumpsetups are indeed mainly there to eliminate surge, but the lowering of the engine can be a very important factor too.
There's no more reason for a dry-sump setup to leak then any other oilline to leak.
I'd say: for track cars: go dry sump. For road cars: depends on how much money you want to spend.
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JoelP
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| posted on 26/6/05 at 07:06 PM |
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in my limited understanding, its done in some cases to prevent oil starvation, and in some to reduce the sump. I had no idea how it worked until i
read this thread, i always wondered how you collect all the oil as it drops back out the bottom - i guess a couple of pumps would do that nicely.
Bike engines are more likely to need dry sumping as, when used in cars, they will suffer more sloshing of the oil in the sump - as bikes lean through
corners, the engine feels a lot less sideways forces than it would in a car being held level. Some engines are dry sumped cos they need it for
reliability, and some because its to valuable an engine to risk without one. Hence zx9s and blades are rarely dry sumped, cos they are cheap, but
zx12s and busas will often be, as they are damned expensive.
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Dale
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| posted on 26/6/05 at 07:10 PM |
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What about something like this-
http://www.accusump.com/acc_products/acc_units.html
It was sugested to me by the guys at the turboford site when I inquired about drysumping the 2.3 or if it was nessesary for oil surg on that
particular engine.
Dale
Thanks
Dale
my 14 and11 year old boys 22
and 19 now want to drive but have to be 25 before insurance will allow. Finally on the road
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Rorty
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| posted on 28/6/05 at 06:24 AM |
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Blimey! What an eye-opener!
Anyway, I've had several engines that were dry sumped and none of them leaked. I've seen some that do, but it's usually a reflection
on the car's owner.
Bart, have you actually seen a bike engine since you got out?
I don't think there has been a vertically split sports bike engine for 20 or 30 years, though throwing down a gauntlet like that, someone will
no doubt rush forward with an example or two.
All the bike engines I've seen and worked on in recent years have all had detachable sumps, like car engines.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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Peteff
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| posted on 28/6/05 at 09:08 AM |
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Blimey! What an eye-opener!
Time warp 
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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gazza285
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| posted on 28/6/05 at 09:57 AM |
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I thought that everybody talked like that in Australia?
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Bart Vangampelaere
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| posted on 28/6/05 at 05:29 PM |
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quote:
Originally posted by Rorty
Blimey! What an eye-opener!
Anyway, I've had several engines that were dry sumped and none of them leaked. I've seen some that do, but it's usually a reflection
on the car's owner.
Bart, have you actually seen a bike engine since you got out?
I don't think there has been a vertically split sports bike engine for 20 or 30 years, though throwing down a gauntlet like that, someone will
no doubt rush forward with an example or two.
All the bike engines I've seen and worked on in recent years have all had detachable sumps, like car engines.
 got me there...
Well, I've been out of bike-stuff for not that long, like 8 years ago I had my final year of car-mechanics, and we had traing for two days a
week, full school year. I did mine in a bike shop, and can tell most engines had split casings, but not vertically. The castings were horizontally
split, if I remember right. Then again, it's been a while since I looked at a bike engine up close...
Bike engines could indeed use a external pump, and tank, but then again, if the system works on a bike, where cornering speeds are way higher, and the
engines are almost tilted to the side, why should they have a problem in a car??? Show me the car that has that much body roll!
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gazza285
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| posted on 28/6/05 at 06:06 PM |
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That's the problem with putting bike engines in a car. In a bike you lean into the corner and the centripital force keeps the oil on the centre
of the sump. In a BEC the oil is thrown to the side of the sump as the engine does not lean into the corner like it does on a bike and oil starvation
is the result.
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Liam
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| posted on 28/6/05 at 06:15 PM |
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And cornering speeds (or forces at least) are certainly not way higher on a bike!
Liam
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Bart Vangampelaere
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| posted on 28/6/05 at 08:30 PM |
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http://www.mcnews.com.au/NewBikeCatalogue/2001/Suzuki/GSXRimages/6_donk_600p.jpg
just have a look... oil is kept in the housings, not in a seperate sump as in a car engine.
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The Shootist
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| posted on 28/6/05 at 08:38 PM |
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Want some Ketchup for that foot!
Take a gander at the bottom of the engine. It's got a sump pan bolted on.
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stevebubs
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| posted on 28/6/05 at 08:40 PM |
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quote:
Originally posted by Bart Vangampelaere
http://www.mcnews.com.au/NewBikeCatalogue/2001/Suzuki/GSXRimages/6_donk_600p.jpg
just have a look... oil is kept in the housings, not in a seperate sump as in a car engine.
Not meaning to be rude, but what's the sump-like plate at the bottom of the engine? A typical car engine has the sump integral to the engine,
too.
When running a bike engine may well (as standard) keep a lot less oil in the sump than a car engine, but the oil *will* eventually drain back down.
As mentioned before, this low capacity isn't usually an issue in a bike because cornering forces etc hold it in the right location.
In a car, this isn't the case because
a) the engine doesn't lean like it does in a bike
b) more often than not, the BEC has the engine N-S rather than E-W as in a bike.
Both these mean the precision bike engineering in the shallow oil sump dept stops working and the pickup is often in danger of being uncovered and air
being sucked up into the whirry bits instead of oil.
3 answers to this
1) Overfilling is popular with the more robust engines (R1, Blade, ZX9) etc. Not enough to cause churn on the crank, but enough to ensure a constant
supply
2) Baffling to prevent oil moving away from the pickup
3) Dry Sump. Suck all oil out of the bottom of the engine into the top of a separate tall (and 99% of the time larger capacity) tank using scavenge
pumps. Take a feed from the bottom of that tank (which should never have the pickup uncovered) and use that feed to supply the oil pressure to the
whirry bits
Does that help or confuse?
[Edited on 28/6/05 by stevebubs]
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