Anti cavitation system

[Fred68]

Hi,

 

I have a couple of questions for wich I need an answer before I can definitely order the good Caterham for me, that would be really excellent if someone could help me.

I will buy a Cat 1800 VVC 6 gears in a very soon future, here are my questions:

1. Anti cavitation system:

How is it working: precisely. I would appreciate if someone could send me a description of its way of working, no one could really help us precisely in France.

Wich anti-cavitation do you guys use on track days? I excluded dry sump because of the price.

 

2. Oil cooler or oil radiator: how is it fitted on the car, where exactly?

 

Thank you,

 

Frederic

[John Vine]

Frederic,

 

1. The anti-cavitation system (more correctly called an oil-air separator) works like this:

 

Aerated oil is drawn from the sump and routed (via a sandwich plate next to the oil filter) to the top of a tall aluminium cylindrical tank (called an Apollo because it looks a little like a NASA Apollo rocket) situated in front of the engine. The oil feeds in tangentially and spins round the wall of the tank, and this expels the air. The oil runs to the bottom of the tank, and returns to the sandwich plate and sump. The air is fed via a restrictor and hose to the cam cover. As for which tank to use, I know of only one -- as sold by Caterham (who obtain it, I believe, from Think Automotive in London). Oil capacity increases to about 7 litres, and you're likely to see an oil pressure drop of about 0.25 bar. It's also worth considering fitting a one-way valve in the air bleed hose to prevent oil draining from the Apollo back to the sump when the engine's not running (again, Think Auto can supply what you need).

 

2. I use a Laminova oil/water intercooler (direct from Think Automotive). It sits in the upper water hose, and fits in very well with the Apollo as the input hose is simply the "old" Apollo input. The output hose returns the oil to the top of the Apollo. I find this set-up works really well, especially on trackdays. It warms up the oil quickly, and then controls its temperature much more precisely. I can't help you with other types of oil cooler though (the ones that have a radiator either in front of or behind the main rad).

 

Hope this helps. Try a forum search on "Apollo" and "Laminova". You'll find lots of info.

 

JV

 

PS: I have no commercial connection with Think Auto, other than as a very satisfied customer!

[Bob Corb]

Too slow!! My response that is.

BC

 

Edited by - bob corb on 1 Jul 2002 17:24:02

[Fred68]

Thank you John,

 

Concerning the Apollo if I understand good it really is an anti cavitation system, not only an oil reserve, isn't it. An other stupid question: how does this system react if in a very long curve the sump is quite empty where the oil pump should pum the oil? Would you recommand to get one absolutely if you woud use the Cat mainly on race track?

 

For the Laminova oil/water intercooler is Caterham also selling it directly? If I understand good this system would be ligher as an oil radiator, yes?

Do the Caterham people really fit oil radiator behind the water radiator? What would be the "nomal" way to fit it?

 

Thank you very much, I will try to get infos on the Apollo on the forum.

 

Frederic

 

[John Vine]

Frederic,

 

Well, its main job is to remove air from frothed-up oil, but it's also an oil reserve, as you say. This helps with surge, but the best solution is, of course, dry sump (but I didn't want to spend that much!). I think the Apollo is probably the minimum protection you should consider for a K-series on track.

 

As far as I know, Caterham don't sell the Laminova, but Think Automotive do world-wide mail order. It's certainly very light and compact. Click here for info.

 

I don't know, but I'd guess Caterham would put an oil rad in front of the main rad.

 

JV

[Fred68]

Thank you JV,

 

Frederic

 

[murph7355]

You can't dry sump the VVC anyway. At least not with Caterham's system.

 

I don't know whether this is something intrinsic with the way the VVC works or whether it's simply because the way the VVC engine is installed the Caterham ds pump fouls some other bit of the engine bay too badly.

 

If it's the latter, there may be another solution (alternative dry sump system), but as John said it's much pricier than an Apollo (budget 5-6 times the cost [more like 8-10 times for the Caterham syste]), even if it is the only way to properly protect an engine under strenuous track conditions...

[Bob Corb]

The Caterham Dry sump does not work with the VVC engine for several reasons:-

 

i) The pump is attached in conjunction with the RH engine mount. The VVC has to sit lower in the engine bay (by about 20mm) than std so has a unique engine mount which hasn't got the fitting for the pump.

 

ii) The oil/gas separator tower over the dry sump oil tank gets in the way of the rear timing drive system which is only found on the VVC.

 

iii) The VVC unit has been rumoured to lose control and cause valve clash when ran with a Caterham dry sump system. This is probably because the scavenge pump mixes large amounts of crankcase gas with the oil leaving it frothy. The large amount of entrained air in the oil then confuses the VCT control making it inaccurate leading to mechanical damage. A well designed oil tank and separator should leave the oil with low amounts of air entrainment but the compromised design of the Caterham tank (saddled over the bellhousing) doesn't work too well in this repsect. This is probably one reason R500s are now fitted with Appollo tanks to try and remove some of this entrained air.

 

The Pace system may be better but this also has issues with the RH engine mount being an integral part of the pump bracket.

 

Cheers

 

Bob

 

Edited by - bob corb on 2 Jul 2002 12:04:08

[murph7355]

Pace would look at a slightly revised mount for the VVC if someone wanted to try it, I have no doubt.

 

They're going to do this for the SV, and as all the other bits are the same it would be worth the small amount of effort required.

 

So if anyone with a VVC fancies getting measured up in a month or two I'm sure they'll be up for it smile.gif