Turbo oil seals - a solution?

[Chris Wilson]

I'm not aware of any hybrid setup that successfully managed to offer larger exh A/R ratios and keep the sequential operation.

 

The only one that came close was by a SF member.

 

And that is PRECISELY why I don't like hybrids. Stuffing a bigger compressor wheel on without balancing up the exhaust side is a real mess. And the exhaust side is VERY small to give the low RPM boost and fast spool that makes the stock J-Spec Supra such a great road car.

[JohnA]

And that is PRECISELY why I don't like hybrids. Stuffing a bigger compressor wheel on without balancing up the exhaust side is a real mess. And the exhaust side is VERY small to give the low RPM boost and fast spool that makes the stock J-Spec Supra such a great road car.

 

 

Exactly

Simply machining a larger compressor in the existing housing doesn't make a hybrid, but an unbalanced contraption that is much easier to stall. (I've done it:innocent: )

And don't get me started on cut-back turbine blades, what a hack...

[Thorin]

Simply machining a larger compressor in the existing housing doesn't make a hybrid

 

 

But that's all the "hybrid" turbo's fitted to supra's are, machined out housing with a larger compressor wheel. I've not heard of any available with a larger A/R. I personally wouldn't bother with hybrids either for precisely those points

[Stevie Boy]

Looks like this turned into a dispute as to why Single turbo's are the "only" option forwards, which i really didn't want.

 

Ok so appears from what has been said that trying to get more from stockers by just "slapping" an unbalanced compressor wheel on is a waste of time fair enough, i'm sure DanDan didn't appreciate his TurboTechincs rebuilt "hybrid" turbo's being rubbished, he might not have his A/R's to hand but perhaps this does not bother him and maybe to him the proof in the pudding of having 30,000m+ of what he feels is improved performance is enough.

 

Personallly i don't wanna make the mistake of turning my car into a saga of trying to get my car running right on a budget single kit. Also thanks to Jamie who demonstrated a tasty

GT4088 hammered on 2 stage rev limit may only last 5,000miles or so, I would have imagined this was an "un-butchered" turbo to start with.

 

If we forget about grafting a larger compressor wheel onto stock turbine for a sec, would it still not be possible to simply replace ceramic without aim to surpass original output but simply do away with the ceramic assembly and provide something which is maybe a little more reliable?

 

i.e. Recondition stock twins as an alternative to waiting for the inevatible of "when" the original ceramic assembly will let go, but by the sound of things this is obviously a waste of time, would a reconditioned set of UK turbos also be a waste of time? I didn't realise TurboTechnics operate their business from a shed and thought purhaps as they specialize in reconditioning turbo's of all makes and models they might be ok and there balancing equipment was up to the job.

 

I therefore assume from whats been "discussed" so far in this thread about prolonging the life of turbo oil seals that there are no possible preventative measures other than usual stuff (like regular oil changes, use of decent oil and suitable grade, allowing turbos and oil cool, etc) , that can be made to improve/extend their life in away, far enough.

[JohnA]

.. .. prolonging the life of turbo oil seals that there are no possible preventative measures other than usual stuff (like regular oil changes, use of decent oil and suitable grade, allowing turbos and oil cool, etc) , that can be made to improve/extend their life in away, far enough.

I can't say how much JSpec turbos overspin compared to UKSpec units, not without fitting a rev counter on each one first.

What I know is that I've pushed my UKSpec turbos very-very hard, perhaps harder than anyone around here on in the States. Silly hard.

The seals are fine despite the age of the turbos (130K miles now:blink: ).

I guess for reliability you can't go wrong with good air filtration (stock box and paper filter) and obsessive oil changes (fresh synthetic every 1500-2000miles max)

 

From what I know the seals go from lack of lubrication.

This can be due to the tiny amounts of oil being available at the shaft at any moment at full boost not being up to scratch (if I only have a few drops of oil for that millisecond, I'd want them to be fresh, not tired and full of sludge)

It can also be due to the hacked 're-design' of the turbo with a larger compressor fitted in. The forces involved at full boost are pretty considerable, and if the whole rotating assembly is being pulled to one side under duress, it would be easy to 'squeeze' the oil out at the time when it's most needed.

This creates scoring as metal touches metal, and it all adds up pretty quickly.

 

OEM turbos have been properly tested and simulated to be perfectly stable under prolonged stress. The manufacturers cannot afford to lose their good name or have hordes of angry customers and recalls.

Remanufactured turbos don't have such stringent constraints, so what you get is pot luck.

[Stevie Boy]

OEM turbos have been properly tested and simulated to be perfectly stable under prolonged stress. The manufacturers cannot afford to lose their good name or have hordes of angry customers and recalls.

Remanufactured turbos don't have such stringent constraints, so what you get is pot luck.

 

Surely once you've gone BPU and running higher than stock boost levels you've already deviated from the original manufacturers stringent constraints and criterion for what the turbo's were intended for, therefore ending up in a pot-luck situation also?

 

Well done on 130k of hard miles on original turbo's, testament to obsessive oil changes being worthwhile.

[JohnA]

Surely once you've gone BPU and running higher than stock boost levels you've already deviated from the original manufacturers stringent constraints and criterion for what the turbo's were intended for, therefore ending up in a pot-luck situation also?...

In a way yes. Once you are forcing them to operate outside their design parameters you can only blame yourself when they fail

The difference is that you are occassionally overspeeding something that was a balanced design to start with.

With the 'hybrids' this is supposedly not the case, since you are paying good money for an assembly that provides more airflow at less shaft rpm. But that's not exactly what you get, and the distinct lack of specs/documentation doesn't help either. Has anyone ever seen a compressor map for any of the hybrids?

That's a bad start right there.

Unreliability comes as an optional bonus.

 

I once had a 'hybrid' go back and forth the so-called specialists FOUR times and it still kept smoking like a sailor. Once I made my saga public, lots of people flooded me with emails, victims of similar hacks. And it wasn't company-specific either, all major UK turbocharger remanufacturers have displayed their fair share of incompetence. Hence my reluctance to accept anything but a 'no-quibble replacement' guarantee. (Look at their small print and see if anyone is confident enough to give you that)

[Stevie Boy]

In a way yes. Once you are forcing them to operate outside their design parameters you can only blame yourself when they fail

The difference is that you are occassionally overspeeding something that was a balanced design to start with.

With the 'hybrids' this is supposedly not the case, since you are paying good money for an assembly that provides more airflow at less shaft rpm. But that's not exactly what you get, and the distinct lack of specs/documentation doesn't help either. Has anyone ever seen a compressor map for any of the hybrids?

That's a bad start right there.

Unreliability comes as an optional bonus.

 

I once had a 'hybrid' go back and forth the so-called specialists FOUR times and it still kept smoking like a sailor. Once I made my saga public, lots of people flooded me with emails, victims of similar hacks. And it wasn't company-specific either, all major UK turbocharger remanufacturers have displayed their fair share of incompetence. Hence my reluctance to accept anything but a 'no-quibble replacement' guarantee. (Look at their small print and see if anyone is confident enough to give you that)

 

Cheers John, I appreciate what your saying. Makes a difference hearing a justification for not having stock j-specs turbo's rebuilt other than "waste of time, T61 gives you loads more hp and torque and low egt's, etc" Even if your not necessarily after that, just seems a shame there's no alterative for those wishing to keep a BPU+ j-spec factory set-up for the long run and have confidence they won't fail in the near future.

[JohnA]

...Makes a difference hearing a justification for not having stock j-specs turbo's rebuilt other than "waste of time, T61 gives you loads more hp and torque and low egt's, etc"

There is a lot of truth in that statement though. The single will (potentially) give you loads more hp and lower EGTs in the process.

Of course in order to harness that potential you will have to create a new balance, making new compromises that were not made by the original designers of the car.

It is up to you whether the resulting car's character suits your needs.

It is not a straight part swap as you know, far from it...

...just seems a shame there's no alterative for those wishing to keep a BPU+ j-spec factory set-up for the long run and have confidence they won't fail in the near future.

It is extremely difficult to refurbish the ceramic wheels, the way they are fixed to the metal shaft is almost a factory secret.

That's why all the aftermarket offerings are steel 'upgrades'

[Kranz]

It is extremely difficult to refurbish the ceramic wheels, the way they are fixed to the metal shaft is almost a factory secret.

That's why all the aftermarket offerings are steel 'upgrades'

 

The steel 'upgrade' is just a Toyota Landcruiser 2.4L LJ70 1984-1990 turbine that is identical other than its inconel and not ceramic!!

 

And the standard compressor upgrade is a Garrett T04E 60 trim compressor wheel (Part Number 409096-0013) with a re-machined compressor housing to suit.

 

Oops! Have I just given the trade secrets away? Oh well

[Thorin]

The steel 'upgrade' is just a Toyota Landcruiser 2.4L LJ70 1984-1990 turbine that is identical other than its inconel and not ceramic!!

 

And the standard compressor upgrade is a Garrett T04E 60 trim compressor wheel (Part Number 409096-0013) with a re-machined compressor housing to suit.

 

Oops! Have I just given the trade secrets away? Oh well

 

Very interesting, thanks

[Stevie Boy]

There is a lot of truth in that statement though. The single will (potentially) give you loads more hp and lower EGTs in the process.

Of course in order to harness that potential you will have to create a new balance, making new compromises that were not made by the original designers of the car.

It is up to you whether the resulting car's character suits your needs.

It is not a straight part swap as you know, far from it...

 

It is extremely difficult to refurbish the ceramic wheels, the way they are fixed to the metal shaft is almost a factory secret.

That's why all the aftermarket offerings are steel 'upgrades'

 

I still think you misunderstand me, in that I don't doubt for a second the conversion to single would provide significant gains in hp, torque and the lowering of egt's etc.

If not just for the sheer basics of the removal of the complex TT set-up for a simple single, before even getting involved in the wide choice of aftermarket turbo's with greater compressor wheel designs and DBB alternatives in comparison to stockers.

 

I am a little disappointed, as I didn't really wanna go single unless/until I replaced my Auto with a manual, so at least if i started down that route progressing to larger turbos would less of an issue than having at some point doing a manual conversion, which has seemed to become quite fashionable.

 

I know there are options out there to go for only a modest single conversion suited to an Auto for the time being, but when you weigh up ALL the costs, seems this money would be better spent on goin towards getting a manual than throwing at a reletively unmolested Auto @BPU+, if you see what I mean.

 

The "Hybrid/Recon" theory was merely a short term plan I had set, with a rough figure just over £1k for turbo recon which I initially thought would do no harm, whereas now sounds like more harm than good, so prob best left as is, that's fine saves me a short term £1k, as long as i don't fubar my j-spec's in the meantime!

 

Looks like hold fire on "minor" investments and concentrate on next project.

[Stevie Boy]

The steel 'upgrade' is just a Toyota Landcruiser 2.4L LJ70 1984-1990 turbine that is identical other than its inconel and not ceramic!!

 

And the standard compressor upgrade is a Garrett T04E 60 trim compressor wheel (Part Number 409096-0013) with a re-machined compressor housing to suit.

 

Oops! Have I just given the trade secrets away? Oh well

 

Agreed, does sound interesting, but is that still a trade secret for an unbalanced turbine and compressor "marriage made in hell" or does is it work well, AR's to quote etc?

[Kranz]

Agreed, does sound interesting, but is that still a trade secret for an unbalanced turbine and compressor "marriage made in hell" or does is it work well, AR's to quote etc?

 

Turbine A/R is the same and TBH that will be the biggest problem as its small (not as small as the UK spec though) and will ultimately limit the power the engine can produce as it will overspeed if extreme boost is called for.

 

Sadly there isn't a replacement turbine housing or wheel that is either a bigger A/R ratio or more efficient, and so cut back turbine blades are sometimes used to reduce the area of the turbine blades to therefore reduce the force of the exhaust on them and allow more exhaust gas flow past without overspeeding the wheel.

 

This may reduce overspeed but it kills low down performance, and probably unsettles the balance of the turbo (by balance I don't mean the spinning inertias but the turbine to compressor operational characteristics).

 

There is a good substitute for the standard T04E compressor wheel but I don't know if its been done. The 'disco potato' is the same size, and flows well.... but the problem will still be the turbine.

 

For the ultimate hybrid I'd consider an extrude honed turbine housing (allows it to flow about 15% more IIRC) with a steel turbine from the Landcruiser, double piston rings on the turbine end oil seals, the 'Disco potato' compressor wheel and a Turbo Technics 360 degree thrust bearing. All new hydrodynamic bearings & seals and probaly new turbo centre housings as the turbine piston rings run in these and cause wear to the housing, and we don't want any leaks!

I'd have the lot balanced to a very high tolerance up to 200k rpm to ensure it stays together as the new parts will no doubt put more than normal forces on the shaft.

 

All in I'd expect it to cost £300 in parts alone for each turbo.

[JohnA]

On top of that, for a proper job, the sequential will have to be re-adjusted so that the changeover routines fit the personalities of the new turbos.

 

(That's why I chose a totally different route, that doesn't compromise low-down pull at all. But that's a different story.)

[Kranz]

On top of that, for a proper job, the sequential will have to be re-adjusted so that the changeover routines fit the personalities of the new turbos.

 

(That's why I chose a totally different route, that doesn't compromise low-down pull at all. But that's a different story.)

 

I'm guessing that'd be pretty difficult on the stock ECU?

 

Personally I'd do away with the sequential system (on a manual) and fit a second wastegate on No2 turbo (by using a No1 or Landcruiser turbine housing). No problems with the second kick or boost control.

[JohnA]

I'm guessing that'd be pretty difficult on the stock ECU?

Yes, especially on the auto.

I guess one could hack an easier half-way path by adding springs to the wastegates (mechanical intervention rather than electronic)

It wouldn't be perfect (as Toyota would have done it, not even as a good AEM would do it) but it would be passable I guess.

 

Personally I'd do away with the sequential system (on a manual) and fit a second wastegate on No2 turbo (by using a No1 or Landcruiser turbine housing). No problems with the second kick or boost control.

You're right, on a manual you don't need much of this hanky-panky, you just keep the revs higher and get on with your life.

 

If I had a manual I'd probably have fitted a large single already.

[Thorin]

It is possible to increase the amount of boost the first turbo will make alone before changeover point. A few people have done this to smooth out the transition, but it's not easy to change the actual transition point.

 

I'm struggling to find a thread on controlling the 1st turbo boost, I believe Ian C may have done it with his hybrids though.

[Kranz]

I'm struggling to find a thread on controlling the 1st turbo boost, I believe Ian C may have done it with his hybrids though.

 

Try from here onwards http://www.max-boost.co.uk/max-boost/supra/boosting_the_beast.htm

 

Was under John's signature

[Thorin]

Try from here onwards http://www.max-boost.co.uk/max-boost/supra/boosting_the_beast.htm

 

Was under John's signature

 

 

 

Ah yes, thought John would know but I didn't bother looking on his site

[Stevie Boy]

Turbine A/R is the same and TBH that will be the biggest problem as its small (not as small as the UK spec though) and will ultimately limit the power the engine can produce as it will overspeed if extreme boost is called for.

 

Sadly there isn't a replacement turbine housing or wheel that is either a bigger A/R ratio or more efficient, and so cut back turbine blades are sometimes used to reduce the area of the turbine blades to therefore reduce the force of the exhaust on them and allow more exhaust gas flow past without overspeeding the wheel.

 

This may reduce overspeed but it kills low down performance, and probably unsettles the balance of the turbo (by balance I don't mean the spinning inertias but the turbine to compressor operational characteristics).

 

 

Did you mention the UK steel turbos have a greater A/R than J-Spec?

 

Trying to get my head round this, guess i should search for some stats but as you guys know already, is this purely because the J-Specs have a larger radius of exh turbine housing than UK, but have the same size entrance orifice as a UK or does the UK exh turbine housing have a larger entrance orfice as well as smaller housing radius than J-Spec?

 

I wondering if the fast spooling of the J-Spec was pure influenced by it's A/R or does having a ceramic turbine give lower ineria than steel.

 

i.e. Does having the lower inertia ceramic turbine increase it's chances of overspeeding when trying to get more than stock boost from them or is it all down to the A/R?

 

Also is it correct that if this ceramic turbine is replaced with steel the turbo becomes laggier? If this is the case is this down to an increase or decrease of inertia and does it's characteristic to overspeed reduce which i would have thought would reinstate some form of balance in the turbine shaft or is the force/friction applied along the shaft changed so drastically the the original lubrication can't cope and chances of turbo failure on J-Spec with steel exh turbine marriage.

 

Hope that makes sense, I've confused myself now

[JohnA]

...Was under John's signature

John needs to re-write these pages, because they are getting a bit long in the tooth.

But John can't be arshed, he's currently finishing his loft conversion...

[Stevie Boy]

On top of that, for a proper job, the sequential will have to be re-adjusted so that the changeover routines fit the personalities of the new turbos.

 

(That's why I chose a totally different route, that doesn't compromise low-down pull at all. But that's a different story.)

 

As mentioned on a manual car it's a much easier story, keeping ontop of the power and keeping "on boost" is a far easier when you start talking large singles, i was just looking for a way of (as i'm sure you have done yourself) "reliably as possible" getting the most of the stockish set-up.

 

Mines a Auto also (J-Spec), I never know from one day to the next whether i wanna keep it, sell-up and replace with a Manual version, or maybe even something different who knows. What I do know, having recently got mortgaged-up for the first time, is money is pretty scarce these days.

 

So spend way too much time deciding what to do so my Supe next, but at the same time trying not to turn it into the money-pit most of my past cars have been. Ok so it has a Blitz LM-V SpecFMIC (original was totally shot and price I got on this new was probly half a stock Mr-T job), Blitz NUR Spec R (came with the car, does the job- all be it a tad too loudly), oth cat's removed with restrictor, EMB (so I have some degree of control over stock ECU) and some additional cooling measures i added in hope they would help prevent any probs that could arise from the abuse a number of drag runs and general driving Tom-foolery in the past 4years i've owned it. I've no atmospheric "Put-tshhh" dump valve (though I do have an aftermarket adjustable recirc, as I assume OE recirc was rated for stock boost pressures).

 

I feel my pretty much last weak link in the chain of "peace of mind" is the ceramic turbo element.

 

Not wanting to fork out a small fortune for a decent small single setup, which I feel costwise would weigh in not too far off a reasonably large single set-up (without the additional fuel system costs), I would really like to know if something can be done with the stock twins!

 

John hope you don't mind me asking but which company made the original mess of your turbo's so i'll try and avoid them and who did you end-up using to sort out the previous mess made by turbo reconditioner, I can understand if you can say on forum post but i would appreciate if you could PM who I should avoid and who you recommend if any, thanks.

[JohnA]

...John hope you don't mind me asking but which company made the original mess of your turbo's so i'll try and avoid them ....

We reached an out-of-court settlement and my part of the deal was not to mention their name.

 

The final job was done successfully (well, 90%) by Turbo Dynamics. That was 4 years ago, mind you.

A couple of years before that, TD had themselves a bout of very bad publicity after fookups with rebuilds, so there ya go.

Tread carefully, it's a minefield.

[Stevie Boy]

We reached an out-of-court settlement and my part of the deal was not to mention their name.

 

The final job was done successfully (well, 90%) by Turbo Dynamics. That was 4 years ago, mind you.

A couple of years before that, TD had themselves a bout of very bad publicity after fookups with rebuilds, so there ya go.

Tread carefully, it's a minefield.

 

Cheers John much appreciated.

 

Oh and when your done you can get cracking on my loft conversion!