Accusump

[Gary ZBJ]

Not wishing to take over Austen's thread with a technical discussion.

 

I see that an accusump system is suggested to overcome oil starvation in extreme conditions.

 

A couple of questions, are these easy to fit / remove when selling the car? (I don't mind spending that kind of money to protect my relatively new engine, esp if it can be taken off and put on another car) And secondly, are they enough on their own, or would the car still benefit from a baffled sump?

 

Ps, K series engine if that makes any difference?????

 

EDIT: Just notice on the Hanger111 site, first site up on Google, that the kit is only for the Yota lump, so additional question is can this be fitted to a K?

 

Cheers,

 

Gary.

[Martin R]

A accusump would be complete overkill IMO a lot of people track k series engines and have no trouble. A baffled sump would be enough IMO You have to realise a 220 bhp Honda would be going so much quicker with sticky tyres with Austen driving.

[Gary ZBJ]

Fair enough,

 

Like you say, with Austen driving that machine was going a lot faster than I will be

[Tango190]

A accusump would be complete overkill IMO a lot of people track k series engines and have no trouble. A baffled sump would be enough IMO You have to realise a 220 bhp Honda would be going so much quicker with sticky tyres with Austen driving.

MartinR - do you think Honda convs need a dry sump system - especially Rocky Track ??

[JAO]

Can anyone give advice in respect of the Toyota engine, what would be best. I am only thinking of starting tracking at the moment.

 

FWIW, the Honda S2000 club use Rockingham for trackdays, no reported engine failures or oil problems there, I think maybe one or two of the regulars using Spa and Nurburgring use baffled sumps but not many.

[Steve J]

IIRC engines fitted transversley (e.g. K20a, K-series, Toyota etc) are more affected by oil surge than those fitted longitudinally (S2000).

 

I was under the impression that a baffled sump was recommended for cicuits with long high g corners (Spa, Rockingham) but an accusump system was not required. I haven't noticed any drop in oil pressure round any of the circuits I've driven since the conversion.

[TheRon]

Lotus fit an Accusump as standard to the 240R and 211 and I would have thought they'd have a good reason for it.

[Stumason10]

Would it not be cheaper to fit a dry sump rather than a accusump??

[JAO]

That makes sense, I thought that would be the case, I'd rather be safe than sorry at high revs it doesn't take long to cause serious damage. Is it a case of having one system or the other and are these aviailable for the yota.

 

IIRC engines fitted transversley (e.g. K20a, K-series, Toyota etc) are more affected by oil surge than those fitted longitudinally (S2000).

 

I was under the impression that a baffled sump was recommended for cicuits with long high g corners (Spa, Rockingham) but an accusump system was not required. I haven't noticed any drop in oil pressure round any of the circuits I've driven since the conversion.

[Martin R]

A accusump would be complete overkill IMO a lot of people track k series engines and have no trouble. A baffled sump would be enough IMO You have to realise a 220 bhp Honda would be going so much quicker with sticky tyres with Austen driving.

MartinR - do you think Honda convs need a dry sump system - especially Rocky Track ??

 

Bob, im no expert. If you consider the amount of Hondas now converted and the abuse a lot of them recieve on track days etc they seem very reliable. You also have to consider a lot if not most are second hand engines of known milage but unknown as to their previous use / abuse. Add on also a S / C on a fair few and they seem to last pretty well IMO.

[Tango190]

A accusump would be complete overkill IMO a lot of people track k series engines and have no trouble. A baffled sump would be enough IMO You have to realise a 220 bhp Honda would be going so much quicker with sticky tyres with Austen driving.

MartinR - do you think Honda convs need a dry sump system - especially Rocky Track ??

 

Bob, im no expert. If you consider the amount of Hondas now converted and the abuse a lot of them recieve on track days etc they seem very reliable. You also have to consider a lot if not most are second hand engines of known milage but unknown as to their previous use / abuse. Add on also a S / C on a fair few and they seem to last pretty well IMO.

Reason I ask Martin is a LOT of EVO's seem to get destroyed at Rocky for the same reason, oil surging away from pump.

 

Transverse engines as you know, but, the early EVO engines are the other way round, i.e. cams to n/s later cars cams to o/s

 

Reason I asked about the Honda convs and dry sumps was to see if the scavenge pump system was an absolute cure or if the stad sump needed to change to a rectangle shape with baffles both side and a modded oil pick up or dual pick up pipe.

 

I suspect an easy cure for non broken engines is to fit a dual pickup pipe with non return on a dual baffled sump.

 

But then you tell me they are pretty damn reliable - so I think I may have gone off on one - lol

 

Hey ho

[chorton_1]

You have to be careful with dual pickups because otherwise you just pick up a load of air from one pickup and the airated oil causes bearing trouble anyway. What you normally try to do is trap enough oil in one area (using flap valves and the like) that that there is sufficient resevoir for prolonged cornering. An Accusump is an extension of this, that when paired with a baffled sump works quite well. Alternatively, you can use a pure baffle that just slows the rate of transfer across the sump, but of course this isn't as good (although much better than nothing).

 

Dry sumps are obviously the best because rather than a long flat engine sump, a dry sump usually uses a nice thin and tall tank which limits the effects of high G cornering, however oil starvation is still an issue (e.g. there's a particular crest on a corner at Elkhart Lake in the US that causes a problem, as well as a point in Spa). Ovals aren't a problem because they are steady state and you know the direction of the corner and the likely lateral G.

[bruce]

You have to be careful with dual pickups because otherwise you just pick up a load of air from one pickup and the airated oil causes bearing trouble anyway. What you normally try to do is trap enough oil in one area (using flap valves and the like) that that there is sufficient resevoir for prolonged cornering. An Accusump is an extension of this, that when paired with a baffled sump works quite well. Alternatively, you can use a pure baffle that just slows the rate of transfer across the sump, but of course this isn't as good (although much better than nothing).

 

Dry sumps are obviously the best because rather than a long flat engine sump, a dry sump usually uses a nice thin and tall tank which limits the effects of high G cornering, however oil starvation is still an issue (e.g. there's a particular crest on a corner at Elkhart Lake in the US that causes a problem, as well as a point in Spa). Ovals aren't a problem because they are steady state and you know the direction of the corner and the likely lateral G.

WRONG ( well partly)

An accusump is extra oil stored at oil pump pressure, it is an accumulator filled by the pump so when there are surges it replaces oil that the pump cant supply,they are usually installed straight into the oil gallery at a convenient point, the oil pump pushes a piston back against a precharge air chamber, as soon as the pressure in the engine drops the air pressure pushes the piston back and the oil back into the engine.

Most of my competition cars are dry sumped but i did have a honda blackird powered car that had terrible surge probs that were cured by an accusump.

If you cant dry sump the engine then its the next best alternative

[GCCK]

For a bit of perspective, oil starvation is nothing new! Traditional racing cars have engines in a N-S layout, not transverse. Hence their oil starvation (and surge) issues mostly come under braking and to a lesser extent, under acceleration.

 

Subjecting an engine to not-designed-for loads is bound to throw up oil problems. Those Metros & Maestros never managed a sustained lateral 1.3G, so the K-series was lower engineered. Likewise, type R's aren't low CoG sports cars on ultra-sticky tyres.

 

Conversely, when K-series was released, all Rover's cars were transverse-engined, so when Caterham applied the K to its longitudinal layout, they not only had to sort out a suitable gearbox & bellhousing, but also deal with oil going the "wrong way".

 

For the K, Eliseparts sell a windage plate - sits in the sump and just a metal sheet with some holes in it. The oil can only drain through the holes at a given rate, so can't fully transfer side to side (or end to end of the crank). £40 for the low-tech solution, for anyone who can do their own oil change and owns a torque wrench.

[Gary ZBJ]

The "Low Tech" windage plate sounds a good start for me