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Hi psii, only the ball bearing core is an issue with rebuilding, some you can. some you can't. You can always rebuild the compressor and turbines. This "not rebuildable" thing is a bit of a furfy anyway. Plain bearing turbos need to be serviced, so they are rebuildable. Ball bearing tubos don't need to be serviced anywhere near as often.

I posted these thoughts a while back, and I have seen no evidence to the contrary...

Plain bearing turbos have oil pressure between the turbo shaft and the bearing surfaces at all times when running. Otherwise the bearings wear instantly. Plus they have to have thrust plates (360 degrees of them in high performance applications) with exactly the same oil pressure issues. This adds up to a substantial amount of friction/drag.

This also has a huge effect on durability, no oil pressure even for a micro second means stuffed bearings. As soon as the turbo shaft touches the bearing surface at 100,000 + rpm , it's all over. This is simply not the case with a ball bearing turbo, which can easily run for several seconds with zero oil pressure.

Water cooling is another feature of ball bearing turbos that adds dramatically to their durability and life. In a plain bearing turbo the oil has to do both, cooling and lubricating. In a ball bearing turbo, the oil lubricates and the water cools, and there is a radiator to remove the heat from the water. Add in the cost of an oil cooler system and suddenly the plain bearing turbo is not so price effective.

The oil pressure required to lubricate a ball bearing turbo is substantially less than that required to lubricate and cool a plain bearing turbo. This means that the seals in the plain bearing turbo have to resist far more pressure to prevent the oil from escaping into the housings. Ever had to clean out an engine and its ancillaries (intercooler, pipes, cat, exhaust etc) after a turbo seal failure? Not a pretty sight I can tell you.

I simply personally can’t see any reason to use a plain bearing turbo, not one.

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question for sydneykid, what is involved for tuning on elf lms? timing and more fuel? also can you tune for elf lms and 98 ron with a way of retrieving mapping for both? are there any aftermarket ecus that can do this? so that you can run both fuels without having to re tune from one to the other? im looking at alternatives to cheap alternatives to getting more power with out upgrading to a larger turbo when the high flow does the job for 95% of my driving. looking at putting on a set of nittos and hitting the drag strip once in a blue moon in the hope of pulling a high twelve, dont care if i pull 12.99, just want to pull a twelve!!!

Isnt the ELF fuel like over $4/Litre, in fact thats for VP fuel, i think the LMS fuel may be something close to $10/Litre (can anyone confirm its price)

Many of the aftermarket ECUs that are laptop programmable can quickly dump down different Maps to the ECU to allow for different fuels/boost etc. Wolf even has memory cards which makes it easier again.

Hi Roy, exotic fuels are not always the answer, LMS is around $5 a litre. So if you buy 20 litres that's $100, compared to $20 for Optimax. For the extra $80 I get a 40 rwkw increase, I don't know any other way to 40 rwkw for $80. Now that works out OK if I only use it a few times a year. But if I need 40 rwkw more often than that or I want it all the time, then there are better ways.

Hi bigcarl, I am not claiming to be an expert on exotic fuels, we have only used LMS in 2 cars and this is my experience from those 2 cars. Only the ignition timing needed to be adjusted, changing the fuel made very little, if any, difference. We have Power FC's with Datalogit software so I can simply upload the more advanced ignition timing maps when we want to run LMS. Only takes a few minutes, total.

A few things to note, our cars don't run high boost, around 1.3 to 1.5 bar is all we use. They have high static compression ratios, over 9 to 1. We run 0.5 richer A/F ratios than would be the case if we were aiming at maximum horsepower. The change in ignition timing is dramatic, between 5 and 8 degrees more advanced and that's a lot.

We get a bit of a bonus from LMS other than power increase. The engine runs cooler, both water & oil, the plugs last longer and the turbo itself also runs cooler as we can see in the exhaust gas temperatures. This is because the LMs fires earlier (remember the advanced ignition) so all of the combustion is finished by the time the exhaust valve is open. This should also mean less wear on the exhaust valves and seats.

As I said at the start, exotic fuels, no matter what type, are not the answer for everyone. But for some applications, they are well worth the cost.

Hope that helps

Hi Ryno, sorry I missed it. As the guys know, I only post stuff that I have experienced. My problem with your question is I have never just taken off a standard RB25 turbo and put a hi flow on. We always do other stuff. Things like split dump, hi flow cat, exhaust, more boost, tuning etc. So I can't answer directly, what I can say is after we have done this stuff, together with the hi flow install, boost starts earlier, builds faster and the engine has more throttle response than it had before.

Consequently my comment would be, if there is any extra lag it is overcome by the usual things you would do anyway. BTW we only use ball bearing high flows, never plain bearing, so I can not comment on them.

Hope that helps

thanx for the info sydneykid. as for spool up time before and after hiflow, with the stock turbo/dump but 3inch exhaust/stock cat, turbo began spooling from 1800rpm and reached fullboost by 2600rpm. with the hi flow, stock dump, 3inch exhaust, stock cat the turbo began spooling at the same rpm as the stock turbo but took until 3200rpm to build to peak boost.adding split dump and 3inch cat has increased rwkws from 204 to 227rwkws without cams or headwork. turbo seems to spool up by the same rpm but boost went from 17.5psi to almost 20psi with out upping boost control!!!

thats correct ben m, the hi flo starts to build boost as low as 1800/2000rpm and peaks at 1.3bar at 3200rpm. i havent been down to the drag strip yet , im looking at buying some decent tyres first because im only running dunlop lemans 245/40s.

Thats pretty low if you ask me, it's only a ~20rwkw upgrade from a stock turbo. If i'm paying $2,000-2,500 for a turbo I want it to produce a heap more than 20rwkw-ish.

Does anyone know what HP the stock R33 GTS-t turbo is rated at ?

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