anybody fitted an accusump?
Discussion
I take it with a baffled sump it is just as it sounds ? Sorry for being a complete Non-techie on this.
Where can you get them, can you get them at dealers?
Thanks for your advice!
Where can you get them, can you get them at dealers?
Thanks for your advice!
bogie said:
why do you think you need one? its only the Toyota engined cars that have issues...and a baffled sump is good enough for most owners that are not racing them
For the yota engined cars you can get a Moroso baffled sump:
http://www.hangar111.com/ckshop.php?item=751&r...
http://www.hangar111.com/ckshop.php?item=751&r...
Why? Well I have a 111R toyota engine in my car, and it strikes me that the accusump is a better first mod than a loud exhaust or an odd 10 bhp from a new ECU. It was noticeable at the 60th just how many new cars were having them fitted.
Had a long chat with a senior Lotus engineer at the 60th (name withheld for obvious reasons)and FWIW he explained the toyota engine oil issue as follows.
The block used was originally designed for a smaller engine (I think he said 1400)and the passage ways for oil return from the head is sized accordingly. Get the engine up to 8k revs with the oil pump working hard and quite a lot of oil ends up in the head rather than in the sump. Combine this with a prolonged left hand corner on sticky tyres and if also the oil level is low to start off with, then its possible for the oil pick up in the sump to suck up air. Thats where the accusump comes in. Baffling the sump is still marginal. the ideal solution would be a dry sump system with a greater oil capacity, and Lotus have also experimented with additional external oil returns on race cars.
He was adamant that the problem doesnt arise on the normal tyres and with plenty of oil in the sump.Its strictly a track day / sticky tyres / low oil level issue. But then thats whay I intend to use my Elise for.
Interestingly, he also said that valve float doesnt occurr until 10k so there is safety margin in the rev limiter set at 8.5k for (I think) 15 dec and 8k continuous. In other words you cant over rev under acceleration, only under engine braking
Anyway accusumps are cheap in the US so it seemed to me that this was a good winter project.
Had a long chat with a senior Lotus engineer at the 60th (name withheld for obvious reasons)and FWIW he explained the toyota engine oil issue as follows.
The block used was originally designed for a smaller engine (I think he said 1400)and the passage ways for oil return from the head is sized accordingly. Get the engine up to 8k revs with the oil pump working hard and quite a lot of oil ends up in the head rather than in the sump. Combine this with a prolonged left hand corner on sticky tyres and if also the oil level is low to start off with, then its possible for the oil pick up in the sump to suck up air. Thats where the accusump comes in. Baffling the sump is still marginal. the ideal solution would be a dry sump system with a greater oil capacity, and Lotus have also experimented with additional external oil returns on race cars.
He was adamant that the problem doesnt arise on the normal tyres and with plenty of oil in the sump.Its strictly a track day / sticky tyres / low oil level issue. But then thats whay I intend to use my Elise for.
Interestingly, he also said that valve float doesnt occurr until 10k so there is safety margin in the rev limiter set at 8.5k for (I think) 15 dec and 8k continuous. In other words you cant over rev under acceleration, only under engine braking
Anyway accusumps are cheap in the US so it seemed to me that this was a good winter project.
bordseye said:
He was adamant that the problem doesnt arise on the normal tyres and with plenty of oil in the sump.Its strictly a track day / sticky tyres / low oil level issue. But then thats whay I intend to use my Elise for.
Which begs the question why did Lotus sell the S2 Exige without an accusump when its fitted with A048s?errr...yeah, I know all that, and have spent many hours, in fact days up at Lotus chatting to various people ....getting the 'official' line on things 
1) why dont all cars from Lotus with A048s come with them?
2) why hasnt every Yota car without one blown up on track (there are many Exiges being raced without them)?
keep the oil topped up on a trackday and you will be fine...of course unless you can corner as hard on the limit as a Lotus test driver
therein lies another explanation - I think theres only 2 or 3 corners on UK tracks where it *could* be an issue for prolongged cornering at the limit, if you are Gav Kershaw
most people on track days wouldnt even get an Exige loaded up like that on road tyres, let alone A048s ...they are just being careful and justifying an expensive option item on the car that may be needed by 0.1% of the people that buy an Exige
IMO a baffled sump is a much easier option to go for the amateur.
1) why dont all cars from Lotus with A048s come with them?
2) why hasnt every Yota car without one blown up on track (there are many Exiges being raced without them)?
keep the oil topped up on a trackday and you will be fine...of course unless you can corner as hard on the limit as a Lotus test driver
therein lies another explanation - I think theres only 2 or 3 corners on UK tracks where it *could* be an issue for prolongged cornering at the limit, if you are Gav Kershaw
most people on track days wouldnt even get an Exige loaded up like that on road tyres, let alone A048s ...they are just being careful and justifying an expensive option item on the car that may be needed by 0.1% of the people that buy an Exige
IMO a baffled sump is a much easier option to go for the amateur.
bordseye said:
Had a long chat with a senior Lotus engineer at the 60th (name withheld for obvious reasons)and FWIW he explained the toyota engine oil issue as follows.
The block used was originally designed for a smaller engine (I think he said 1400)and the passage ways for oil return from the head is sized accordingly. Get the engine up to 8k revs with the oil pump working hard and quite a lot of oil ends up in the head rather than in the sump. Combine this with a prolonged left hand corner on sticky tyres and if also the oil level is low to start off with, then its possible for the oil pick up in the sump to suck up air. Thats where the accusump comes in. Baffling the sump is still marginal. the ideal solution would be a dry sump system with a greater oil capacity, and Lotus have also experimented with additional external oil returns on race cars.
He was adamant that the problem doesnt arise on the normal tyres and with plenty of oil in the sump.Its strictly a track day / sticky tyres / low oil level issue. But then thats whay I intend to use my Elise for.
Interestingly, he also said that valve float doesnt occurr until 10k so there is safety margin in the rev limiter set at 8.5k for (I think) 15 dec and 8k continuous. In other words you cant over rev under acceleration, only under engine braking
that's somewhat subjective to put it mildly...The block used was originally designed for a smaller engine (I think he said 1400)and the passage ways for oil return from the head is sized accordingly. Get the engine up to 8k revs with the oil pump working hard and quite a lot of oil ends up in the head rather than in the sump. Combine this with a prolonged left hand corner on sticky tyres and if also the oil level is low to start off with, then its possible for the oil pick up in the sump to suck up air. Thats where the accusump comes in. Baffling the sump is still marginal. the ideal solution would be a dry sump system with a greater oil capacity, and Lotus have also experimented with additional external oil returns on race cars.
He was adamant that the problem doesnt arise on the normal tyres and with plenty of oil in the sump.Its strictly a track day / sticky tyres / low oil level issue. But then thats whay I intend to use my Elise for.
Interestingly, he also said that valve float doesnt occurr until 10k so there is safety margin in the rev limiter set at 8.5k for (I think) 15 dec and 8k continuous. In other words you cant over rev under acceleration, only under engine braking
Accusump is a bodge, period. That's not to say they don't work, or have no place on a car, however, the fact remains they are a bodge.
At the end of the day, the first port of call for oil starvation should be a baffled sump along with increasing the oil capacity of the sump (at this point I should mention that there are good and bad sump baffle solutions).
If you actually think about it, an Accusump can only work with the oil the pump is pumping, and if the pickup is on fresh air, then it's only a matter of time before the accusump runs out of oil.. not sure on the spec of the oil pump, typically though they are running at some 40-60 litres a min, so how long do you think a 2L accusump is going to last?
Yota engine suffers because it has a very small sump, perfectly adiquate for it's intended purpose (adding a big sump to an engine increases the oil warm up time, and has an effect on emmissions).
As for the over-rev comment, that's somewhat wide of the mark, at 10K rpm the valvetrain is far from safe, the Yota valvetrain is not renound for being strong.
Also, if you ever get to 10K rpm, the chances are the oil pump gear will shatter, if you ever tune the 2ZZ, fitting a steel gear is mandatory..
Edited by Scuffers on Tuesday 23 September 12:54
I dont think there can be any argument Scuffers that a bigger baffled sump would help (or better still a dry sump system) but it was interesting that some of the cars that Lotus prepared for racing had had extra external oil drainage fitted. Nor would I disagree that the accusump is a bodge but if it works its better than stripping down the engine etc to do things the "pure" way, why not?
Clearly the accusump works which suggest to me (using your logic) that the flow figures you quote for the oil pump cant be right. Except of course that much of that flow at 8k revs will be going through the pressure relief valve and straight back into the sump. Only a minor part will be going through what are fairly tight bearing clearances, but enough nevertheless to accumulate oil in the top of the engine. Now I'm not sure where the accusump is plumbed in but assuming that its on the output side of the oil pump, then as soon as pressure starts to drop it will feed oil into the bearings. Accusump themselves talk of a 15 to 60 secs release time foir the accusump once the pressure drops below the threshold. There arent many corners that last that long.
As for the rev limit I did report what he said that valve float was reached around 10k. In other words thats the point when valves will hit pistons. So all I was reporting really was his insistence that there is no valve problem with the engine limited to 8.5k and indeed there is still some safety margin.
I did say FWIW before quoting the guy but having interviewed and employed dozens of mech engineers in my life (and I mean engineers not spanner wielders) this chap quite impressed me. On that basis I will believe what he said until I meet someone even more convincing or see some hard evidence to the contrary.
Clearly the accusump works which suggest to me (using your logic) that the flow figures you quote for the oil pump cant be right. Except of course that much of that flow at 8k revs will be going through the pressure relief valve and straight back into the sump. Only a minor part will be going through what are fairly tight bearing clearances, but enough nevertheless to accumulate oil in the top of the engine. Now I'm not sure where the accusump is plumbed in but assuming that its on the output side of the oil pump, then as soon as pressure starts to drop it will feed oil into the bearings. Accusump themselves talk of a 15 to 60 secs release time foir the accusump once the pressure drops below the threshold. There arent many corners that last that long.
As for the rev limit I did report what he said that valve float was reached around 10k. In other words thats the point when valves will hit pistons. So all I was reporting really was his insistence that there is no valve problem with the engine limited to 8.5k and indeed there is still some safety margin.
I did say FWIW before quoting the guy but having interviewed and employed dozens of mech engineers in my life (and I mean engineers not spanner wielders) this chap quite impressed me. On that basis I will believe what he said until I meet someone even more convincing or see some hard evidence to the contrary.
bogie said:
therein lies another explanation - I think theres only 2 or 3 corners on UK tracks where it *could* be an issue for prolongged cornering at the limit, if you are Gav Kershaw
Wow - I must be far better that I think. I did mine on the road! with 25% oil.The big problem with accusump is that you lose the boot. Storage space is minimal at best - can you afford to lose the boot?
bordseye said:
As for the rev limit I did report what he said that valve float was reached around 10k. In other words thats the point when valves will hit pistons. So all I was reporting really was his insistence that there is no valve problem with the engine limited to 8.5k and indeed there is still some safety margin.
Engine buzz does not make valves hit pistons. It causes oil starvation of #1 main engine bearing then across the big end bearings .Accusump is a proven engine saver. I know of an engine buzzed to 14k and survived. It was fitted with an accusump. I know of an engine Buzzed to 9260 and subsequently died. (BANG!)
I dont want to lose my boot so there is a set of precautions;
1) check oil regularly (every week)
2) DONT buzz the engine
3) fit a baffled sump
[quote=Gooby
Engine buzz does not make valves hit pistons.
[/quote]
Wrong. If you take the engine revs above the point where valve float ocurrs by buzzing, then the pistons will hit the valves, valves will bend and possibly break, then the pistons may well hit the bent valves etc etc
And that applies to any engine except the few old designs where it isnt possible for the valves ever to touch the pistons
Engine buzz does not make valves hit pistons.
[/quote]
Wrong. If you take the engine revs above the point where valve float ocurrs by buzzing, then the pistons will hit the valves, valves will bend and possibly break, then the pistons may well hit the bent valves etc etc
And that applies to any engine except the few old designs where it isnt possible for the valves ever to touch the pistons
Edited by bordseye on Wednesday 24th September 08:13
bordseye said:
Gooby said:
Engine buzz does not make valves hit pistons.
Wrong. If you take the engine revs above the point where valve float ocurrs by buzzing, then the pistons will hit the valves, valves will bend and possibly break, then the pistons may well hit the bent valves etc etcAnd that applies to any engine except the few old designs where it isnt possible for the valves ever to touch the pistons
Edited by Gooby on Wednesday 24th September 09:12
Gooby said:
bordseye said:
Gooby said:
Engine buzz does not make valves hit pistons.
Wrong. If you take the engine revs above the point where valve float ocurrs by buzzing, then the pistons will hit the valves, valves will bend and possibly break, then the pistons may well hit the bent valves etc etcAnd that applies to any engine except the few old designs where it isnt possible for the valves ever to touch the pistons
Edited by Gooby on Wednesday 24th September 09:12
the 2zz cannot do 14K rpm without consequences, in fact, going to 9+ is not without real risk.
I actually can't think of a single (car) engine that can rev to 14K without phnematic valve springs....
Scuffers said:
Gooby said:
bordseye said:
Gooby said:
Engine buzz does not make valves hit pistons.
Wrong. If you take the engine revs above the point where valve float ocurrs by buzzing, then the pistons will hit the valves, valves will bend and possibly break, then the pistons may well hit the bent valves etc etcAnd that applies to any engine except the few old designs where it isnt possible for the valves ever to touch the pistons
Edited by Gooby on Wednesday 24th September 09:12
the 2zz cannot do 14K rpm without consequences, in fact, going to 9+ is not without real risk.
I actually can't think of a single (car) engine that can rev to 14K without phnematic valve springs....
I have seen the read out on an engine that has revved to 14k. I saw him drive it for 2 weeks until he sold it. It WAS accusumped.
So I do know - first hand.
Gooby said:
With respect - I HAVE seen it. 9260 was all my non accusumped engine needed to let go. New bottom end.
I have seen the read out on an engine that has revved to 14k. I saw him drive it for 2 weeks until he sold it. It WAS accusumped.
So I do know - first hand.
lolI have seen the read out on an engine that has revved to 14k. I saw him drive it for 2 weeks until he sold it. It WAS accusumped.
So I do know - first hand.
with respect, that's b
ks.how can you say you saw it doing 14K? if the ECU had that then it down to a dodgy crank sensor signal, no way could an engnien do this without several parts failing, starting with the valvetrain, the rods, the oil pump etc.
at the end of the day, an Accusump does nothing for any of this....
I strongly suggest you might want to take some lessons in engines, cause you cleary do not have a clue...
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