water fed turbo, oil and coolant considerations
Turbo Mini Forums

For those of you who dont know my wee story, I fitted a turbo to my nat-asp engine, turbo was mint on installation.after not many miles the turbo started smoking, if you pulle dthe sparkplugs they wee all squeaky clean and fine, BUT shitloads of blue smoke out the exhaust. this got worse and worse to the point where i notice dhte compressor wheel was now fouling the housing! knackered bearings.

Fitted antoehr turbo to the car a few weeks ago, and after some very spirited driving it to ohas started on this downward spiral over teh last few days.

Teh turbo is a T25 from a rover coupe (second unit was sourced from a S13 200sx) getting fed with filtered oil btu i omitted the water lines. Engien is a little 1.4 k-series.

at first i thought this turbo died from surge, i was running no dump valve, for the second turbo i fitted one!. Then started thinking that i was mayb running the turbo(s) to the left of the surge lien under full chat , which raises a question, how the hell do you find out if this is happening!? .. would love to know!

anyways i started thinkign about if i was cooking the oil or not, this engien doesnt have an oil cooler! I know i have a thermocouple somewhere so will get some readings ASAP but thought i'd post up a pic from the post-mortem of the furst tubo for you gents to cast your eyes over.


camera doesnt capture it that well but the closer you get to the "hot" side, the darker the discoloration. the bearign on this side is MUCH worse than the bearign on the cold side. looking at the general condition and oil saturation of both housings its obvious alot mroe oil is comeign out the turbine end than the compressor end.
so is it surge , lack of water cooling to the core, or overheated oil

i guess this is more a statement than a quesiton as i'll be testing to try find the answer but should be interesting and if anyones seen similar /. can answer teh surge Q please pipe in :)

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

That looks pretty normal for the 'colour' but the scoring shows it is in poor health clearly...

You know surge when it happens - and in your engine (It's a 1600cc isn't it?) it's not going to ever happen with the tomcat T25. As i understand, it is akin to a cross between a growl and a bark of a dog ; but having never experienced it myself I can't honestly explain in more detail. All I do know is that is you're listening out for the above kind of sound, then you'll instantly recognise the noise above the normal engine/turbo noise...

Edited by turbodave16v on 2nd Jan, 2007.

ahwell. im cool in that respect then, i jstu get the magic "whooooooooooosh" and away i go :) .. its a 1.4!

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

finally got some decent weather so got soem figures. a k-type thermocouple lowered down the dipstick tube into the sump recorded an oil temp of 105 degrees after a reasonably hard run and an infra-red thermometer made the core of the turbo at 146 degrees.

this is on a very cold VERY windy night, drove for aprox 2 hours on the motorway to make sure that everything was nic eand hot periodically useing full throttle then pulled over and measured the temps.

am i right in thinking 100deg is around the uppe rlimit of where the oil should be? if so its no doubt getting nudged a good bit over that inside the core of the turbo

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

I'd say that about 90deg is the lower limit and around 125-130 the upper limit. After talking with a couple of major oil suppliers these figures seem to the accepted design targets and what we tell our customers (who are vehicle manufactures) we have rated our components for.

Every day is a school day ...........

How fast and how expensive ...... the same question...

Are you actually getting an adequate flow of oil to the turbo?

Some of these oil feed pipes with only 1/8 bsp connections look a bit small in my opinion, compared to the large banjo and pipe used on the metro.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

I assumed i was, as there is no "blueing" ofthe shaft and the wear is predominantly at the turbine end, the ID of the hose and fittings is at no point smaller than the origional rover oil feed hose the first turbo came with :( if it was oil starvation i'd expect discoloration of the shaft from heat, and relatively equal wear on both bearings tbo.

cheers roger, i guess the next thin gto do is to measure the temp of the oil as it actually exit's the turbo! but going bywhat ypur saying i shouldnt have an issue in that regard :S stumped!

should add, boost is at 15psi.

Edited by evolotion on 13th Jan, 2007.

turbo 16v k-series 11.9@118.9 :)

Denis O'Brien.

think id stick a guage take off at the turbo inlet to make sure there is oil pressure at that point all the time ,especially when wizzing round sharp bends .!
regards robert

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM