A question for all you guys out there running custom turbo setups. . .
What oil flow and/or pressure are you running to your turbo?
I have a car at the moment with the setup:



The turbo is a newly reconditioned T25 (new bearings, seals and shaft).
The oil feed is taken directly off the oil pressure light feed via a T-piece and the drain is about 5/8" and runs into a fitting in the back of the block where the mechanical fuel pump used to be. Initially, we tried the feed unrestricted and the turbo poured oil into the exhaust and stank the place out. . .
Since then, I've tried a 1mm restrictor in the line (still smoked like a bastard) and have now fitted a stainless needle valve into the turbo oil feed line so that I can adjust the flow.
Does anyone have any idea what sort of oil flow a turbo should receive at idle?

whats the oil return like?, i was told that the oil return should be as downhill as possible othe wise can slow up and let oil past the seals

Hmmm. . .there might be a level-ish section along the back of the block - certainly not uphill, though. The return pipe is pretty big diameter compared to the feed as well (about heater hose size) so I would have thought it should draining pretty well.
What I will check though, is the fitting I made to attach the return hose to the block (where the old fuel pump was). . .that might be a bit tight. . .hope so, my garage is really starting to stink of burned oil. . .

yeh i would possibly try to make that as downhill as possible

is your T25 useable in a "suck-trough" (charger behind carb) set up? if not the vacuum that builds up within the turbine housing with the throttle closed will draw oil out of the bearing, especialy with the turbine turning high and the throttle closed

from memory the phrase is "positive oil seals' i think the t25 is ok, its usually a problem with turbos off desils(yes spelt very wrong). nice looking setup you have there. what sort of boost are you running, any problems with pinging? how hot does your inlet get?

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speed costs....how fast do you want to go...

As far as I'm aware, you're correct on the oil seal thing. . .I've had the turbo modified by a specialist so that it can be used in a suck through setup. . .
At the moment, its running about 12psi and it seems to be coping fine on 98 octane - no pinging even with the oil contamination that's everywhere.
It's currently using a standard dissy, but I have an electronic one from an EA82T Subaru engine (same as the Pulsar ones, essentially but with a boost-retard facility) that I just need to find an igniter for. Hopefully, once that's in, we might be able to screw in a bit more pressure. . .
Inlet temps are actually quite reasonable with the fuel running through the compressor. While I haven't measured them, the inlet manifold never gets much above warm to the touch. The big problem is going to be carb icing, I think. I'm planning on running a coiled copper tube around the dashpot and running the turbo cooling water through it if icing turns out to be a problem.

Off Topic, but where did you get the EA82T ?

Very, very interested..... been looking for boost retard for a while.....

(Grant may be interested too ....)

Cheers
J

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Got it from an import wrecking yard here in Perth. . .only the dissy, not the whole motor.
I could remember reading that guys who turbocharge pinto motors in Escorts and Cortinas tend to use the EA82T dissy because it has boost retard, so I though it would be worth giving it a go.
For what it's worth, I'm sure I can remember a place somewhere (may have been back when I lived in Adelaide) that you could buy vac cannisters for distributors. . .surely it wouldn't be too hard to fit a advance/retard cannister (assuming you can buy them) to an advance only dissy?
As I said, the Subaru dissy is essentially the same as the Pulsar ones (cant remember the number of it off hand, and I haven't got it here with me) but for the fact that it has four wires coming out of it instead of two. . . .I'm assuming this means it needs an external igniter .

if carb icing becomes a problem there is/was a nice part fitted to scandinavian minis
http://www.minimotorsport.de/etk_detail ... er=LZX1623
sorry, german only, means its an electrical carb heater, original Rover, fits the carb bowl.

and to answer your oil pressure question: my MG Metro Turbo engine (fitted to a 86 Mini Mayfair ) has 1,5 bar at idle and 5 bar max (warm engine), nothing special, just higher volume (don't know how much, turbo oil pump)

you say "oil contamination everywhere". is your engine bay oil sprayed? where does it come from? i'm asking as my turbo does not "share" it's oil with the engine bay
any way you can check the crank case pressure?

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Rover 214 atm ....

I guess what I meant by 'oil everywhere' was that a lot of oil is getting into the exhaust (from the turbo oil feed and past the turbo oil seals) and spraying out the back, through the tail pipe (at least what doesn't get burned and turned into smoke!). There is only a small amount in the engine bay that drips out around the wastegate rod in the exhaust housing of the turbo.
Your engine gets around 1.5 to 5 bar of oil pressure (about 20 to 70psi - about the same as my motor) but does the turbo see this full pressure, or is there a restrictor in the oil feed line somewhere?
If a slightly 'uphill' oil drain on the turbo is enough to let oil past the seals, I would have thought 70psi through a 3mm feed line would have had oil sraying in all directions!
Thanks for your help!

I`d say your turbo has a problem,

sounds to me like the mod to make it "Fuel compatable", well,,,er,,,isn`t!!!

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

i use the factory steel oil feed line
have never seen any restrictor, it's just a steel line with banyos both ends and the banyo bolts are looking very normal
i know some other use the braided line Mini Spares sell, without any restrictor, and no problems, maybe a restrictor is build in somwhere/somehow

just looked through "maximum boost" from corky bell for "blue smoke":
dirty air cleaner, plugged crank case breather, collapsed/restricted air tube before charger, foreign object between air cleaner - charger, charger flanges, clamps, or bolts loose, inlet manifold cracked, gaskets loose or missing, connections loose, restrikted oil drain line, charger seal leakage, worn journal bearings, excessiv dirt buildup in compressor housing/behind turbine wheel, excessiv engine pre-oil/engine idle, coked or sludged center housing, leaking valve guide seals
much to check, i think
BTW, did your engine run before?

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Rover 214 atm ....

Thanks for everyones help on this subject - from the replies I've had, it looks as though the problem is the oil drain from the turbo. . .it's probably not as 'downhill' as it should be.
The blow by from the motor is also probably causing it's own problems - the turbo gear is on a 'consumable' motor at this stage - I didn't want to blow a good motor to bits before I'd got things sorted. So it's pretty worn out and there's quite a bit of blow by - I think this might also be slowing the oil draining from the turbo by blowing it back up the pipe - the result? Lots of smoke and stink.
I think I'll redesign the oil drain slightly, and increase it's diameter. . .hopefully that'll sort things out!!

Pete, my turbo oil drain is about an inch below the block deck (head surface) and the hose goes along the firewall and drops into the fuel pump boss the same as yours....

I'm running a blow-though system, and I've never had any oil contamination issues like you are having...

I'm using a piece of 1/4" EFI fuel hose for my oil feed, in through the factory Mazda Oil Banjo (IHI RHF-5) - the banjo has two smaller holes, rather than one big one, and they are about 2mm ea ... I'm also running a ball bearing core... so oil pressure is less important than flow...

I'm not running a restrictor, and oil flow is "pretty good" (had a hose come off once in the garage and spurted oil a good few feet !!)

I'd be looking twice and again at the turbo housings, especially the exhaust housing.... he may not have replaced the bush there .....

Good luck
J

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