M50 B25 Turbo will a T04E T3/T4 work ?

[toadster987]

Hi Im planning a M50 NV turbo project at some point in the future. I have read alot about Holset turbos being the recommend choice which was my plan as its tried & tested but a mate has a brand new T04E T3/T4 which was for his Skyline but decided to sell car. The exhaust side is .63 A/R and the cold is .50 A/R. Just wondered what some of you turbo guys thoughts are on this turbo?

[Gunni]

Without any dimensions it´s hard to give an answer, but the short is that it will work.

[baptie0]

Hi toadster,

i have a t04e on my m50 & it seems to be ok so far....

but to be honest i dont have much faith in it, i only got it as a temporary turbo to get me up and running.

its covered about 6000 miles since i did my conversion.

[GeoffBob]

I have read alot about Holset turbos being the recommend choice which was my plan as its tried & tested but a mate has a brand new T04E T3/T4 which was for his Skyline but decided to sell car. The exhaust side is .63 A/R and the cold is .50 A/R. Just wondered what some of you turbo guys thoughts are on this turbo?

I think maybe you are referring to a T3/T04E, compressor map below:



At 5400 rpm engine speed at a boost pressure of 1-bar and intake temperature of 25'C your 2.5litre M50B25 engine will induct (from basic calculations) roughly 0.23 kg/second (30.4 lbs/minute) of air flow. Assuming an ambient barometric pressure of 1-bar (at sea level) then this equates (looking at the above the grapgh) to roughly 30 lbs/minute of air at a pressure ratio of 2. That puts you slap bang in the middle of the maximum effciency island, so I'd say the T3/T04E is a fairly decent proposal for your engine (so long as it isn't one of those cheap chinese jobs that falls apart if you sneeze to close to it).

30.4 lbs/minute of air mixed with fuel in a ratio of 12:1 should deliver around 308hp at the flywheel.

But be warned, despite the cheap T3/T04E from your mate you will need to fork out a fair bit for the rest of the bits you'll need to make this work. Don't forget to fit correctly sized injectors and a fuel pump that can deliver the required fuel. An aftermarket ECU would also be a good idea.

EDIT: Have corrected above airflow units to lbs/minute (not lbs/seconds as originally posted)

[baptie0]

I have read alot about Holset turbos being the recommend choice which was my plan as its tried & tested but a mate has a brand new T04E T3/T4 which was for his Skyline but decided to sell car. The exhaust side is .63 A/R and the cold is .50 A/R. Just wondered what some of you turbo guys thoughts are on this turbo?

I think maybe you are referring to a T3/T04E, compressor map below:



At 5400 rpm engine speed at a boost pressure of 1-bar and intake temperature of 25'C your 2.5litre M50B25 engine will induct (from basic calculations) roughly 0.23 kg/second (30.4 lbs/second) of air flow. Assuming an ambient barometric pressure of 1-bar (at sea level) then this equates (looking at the above the grapgh) to roughly 30 lbs/second of air at a pressure ratio of 2. That puts you slap bang in the middle of the maximum effciency island, so I'd say the T3/T04E is a fairly decent proposal for your engine (so long as it isn't one of those cheap chinese jobs that falls apart if you sneeze to close to it).

30.4 lbs/second of air mixed with fuel in a ratio of 12:1 should deliver around 308hp at the flywheel.

But be warned, despite the cheap T3/T04E from your mate you will need to fork out a fair bit for the rest of the bits you'll need to make this work. Don't forget to fit correctly sized injectors and a fuel pump that can deliver the required fuel. An aftermarket ECU would also be a good idea.

The turbo on my m50 is a chinese garrett copy

I had it looked at by cr turbos and they thought it was good quality.

Is there anything that can be done to make it last or should I just get a proper turbo?

[GeoffBob]

The turbo on my m50 is a chinese garrett copy

I had it looked at by cr turbos and they thought it was good quality.

Is there anything that can be done to make it last or should I just get a proper turbo?

If it works fine for you then keep it. My biggest complaint is that the performance isn't as indicated by the map (the maps tend to be a little over ambitious). I don't like the Chinese copies much, but whether they are as bad as their reputation I wouldn't know since I avoid them. May very well last you for years and years without problem. I wouldn't want to push the turbine temperature too high on one though.

[baptie0]

thanks for the reply Geoff, do you think it would be a benefit to fit a 360 degree bearing to it?

[toadster987]

Thanks for your replies guys, yes I suspect it could be a chinese turbo as there are no brand markings on it. thanks for the map Geoff I think it is a T3/T04E. I was hoping for higher than 308bhp to be honest after reading about other M50's with good results. I was planning a thick MLS gasket , MS2 and injectors and fuel pump. I am a long way from this as Im busy fighting the usual rust nightmares at the moment but may do a deal on the turbo and add it to the parts box.

[MarkT]

Don't forget the head studs too mate, and a clutch kit. Fair bit of money there in the cutch itself.

[GeoffBob]

I was hoping for higher than 308bhp to be honest after reading about other M50's with good results.

At 1.5-bar boost you'll be making closer to 385hp at the flywheel, so long as your charge cooler (air-air or water-air, which ever you choose) can keep the temperature of the air inducted into your engine down to 300 Kelvin (27'C), and so long as the turbo, engine, drive-train etc can withstand the rigours. I would however suggest that 1.5bar boost (P2/P1=2.5) from a Chinese T3/T04E is a touch on the high side due to the fact that the shaft speed will exceed 100,000 RPM at 38lbs/min air flow. I think that by 1.5bar boost you might want to look at a larger turbo.

Regardless of the above, whatever you do, don't underestimate the importance of a good charge-cooler. Keeping the temperature of the inducted air down is not (as so many seem to think) just a "nice" thing to do for your engine, the temperature of the inducted air dictates the density (and hence mass) of the air inducted into your engine! Hot air means reduced power - so budget for a goodly sized cooler as well!

thanks for the reply Geoff, do you think it would be a benefit to fit a 360 degree bearing to it?

Sorry baptie0, I almost missed your question.

This all depends on how much boost you are currently running or planning to run since it is usually the turbo thrust bearing that suffers under high boost. Under high boost a 360' bearing would certainly be a good idea, at the expense of an ever-so-slightly higher bearing drag, and thus a slightly longer spool up time. Of course, replacing a standard 270' thrust bearing with a 360' bearing requires that the thrust collar be assembled from two pieces (since there is no way to get a 360' thrust bearing over a one piece collar). Whether these bits and pieces are available for the Chinese knock-off turbos I do not know. And likewise, I do not know what constitutes "high boost" for a Chinese turbo as I avoid these turbos as much as possile. I suspect that they are easily good for 1.5 to 1.8 bar boost, but I stand corrected on this.

BTW, my main complaint (from the little experience that I do have) with regard to the Chinese knock-offs is that their performance (the volume of air flowed at a given pressure ratio) is not as indicated by the maps posted on the net that are "claimed" to apply to the Chinese product. This is, I suspect, due to fact that the Chinese copies are literally that - copies. The turbine and compressor wheels have been duplicated as a function of 3D scans of the original Garrett wheels, and are not exact copies. Hence they are aerodynamically not the same. Neither are the housings. Strength wise they could well be very good and never give you any trouble (only time will tell)

Be warned however - Change your oil regularly (at least every 5000 to 6000 miles) as journal bearing turbos are particularly sensitive to oil quality. A coked turbo is ultimately a dead turbo. I would personally suggest a fully synthetic oil with not too wide a viscosity rating. I use Mobil-1 0W-40 with journal bearing turbos. It is extremely important to use a fully synthetic oil with a journal bearing turbo due to the higher temperature at which the oil will fail and coke. So long as you aren’t running ridiculously high boost (whatever that is by the Chinese definition?) I would suggest that you would do better to change your oil regularly (for a fully synthetic oil) rather than adapt the turbo for a 360’ thrust bearing.

Hope this helps,

Regards
Geoff

[toadster987]

Thanks Geoff for your advice Im gona return this china turbo to my mate its not worth the trouble going with a cheap turbo, I will using a Holset when I get there as there tried and tested with good results. Cheers!

[MarkT]

I'm going to be using a TD05 16G off of an Evo8 on my M50 build. As they are will flow enough for 360bhp and about 2 bar at full chat. Cost me £90 and I can upgrade to one with a larger hot side pretty cheaply too.