T25 Turbo Map for 3B. (2 Viewers)

[Dougal]

Rang up a turbo shop today getting pricing on the GT2056, he just about fell over when I told him what it was for and said to small. He recommended a GT2554R, but the only reason he could give me was that "yeah I've done heaps of diesels" Didnt fill me with confidence.

The GT2056 actually has a bigger compressor capable of more flow and higher pressure than the GT2554R. The 2056 also has a smaller turbine for faster spool.

The GT2554R is more suited to petrols in the 1.8-2 litre range, Nissan use it on their 4wd turbo Avenir GTZ. It's a good turbo but turbine is bigger than you are looking for. The 2056 is more suited to diesels this size, a GT2560R is the next step IMO. Same turbine as the GT2554R but bigger compressor.

 

[Hulsty]

Well there you go a better explanation than the turbo shop bloke could muster up thanks. Plain bearing unit should be cheaper too

 

[Hulsty]

Anyone have thoughts on how a T25 with
Turbine A/R .54
Compressor A/R .48


specs would perform on a 13BT? I have come across one at a reasonable price.


With how my setup is currently I am getting ~14psi boost at 2600rpm (when the turbo overboost light comes on) I want to get this level of boost in earlier as I am having trouble holding low 2nd with the 35'' tyres on in step conditions, I need more torque, already have reduction gears to compensate for the larger tyres.

 

[Dougal]

Anyone have thoughts on how a T25 with
Turbine A/R .54
Compressor A/R .48


specs would perform on a 13BT? I have come across one at a reasonable price.


With how my setup is currently I am getting ~14psi boost at 2600rpm (when the turbo overboost light comes on) I want to get this level of boost in earlier as I am having trouble holding low 2nd with the 35'' tyres on in step conditions, I need more torque, already have reduction gears to compensate for the larger tyres.

I haven't come across the 0.54 turbine housing before. Some of the T25's with the 0.64 A/R housing have a 54mm compressor wheel. Do you have the numbers off the tag in the middle?

Either way, it's a suitable turbo that will deliver boost sooner than what you have. But knowing a little more about it can give certainty.

 

[Hulsty]

PM sent.

 

[Hulsty]

Thanks Dougal, I'll give it a go and see what its like, should at least be better having a rebuilt turbo

cheers

 

[Hulsty]

Turns out the turbo is a Garret T25 / TB02/22 from a Nissan 300ZX VG30DETT

From this web site Turbo Size Comparison

Map http://cherrypicker.tripod.com/images/14411_40P_Z32.gif

I get
The stock turbo on the vg30dett is a TB02/22

Compressor

* Wheel: T2
* Inducer Diameter: 1.57"/40mm
* Exducer Diameter: 2.02"/51mm
* Housing: TB22
* CFM: 304 max

Turbine

* Wheel: T22 69trim
* Exducer Diameter: 1.53"/38.9mm
* Inducer Diameter: 1.85"/47mm
* Housing Flange: T25

 

[Dougal]

This one is actually a T2/T25, it has a smaller exhaust turbine and housing than a normal T25.
It will spool pretty quick, but it will choke sooner than most.

What is your rev limit?

 

[Hulsty]

3000rpm normal driving

I hold it on the governer (4000rpm ish) for short bursts to get up hills etc off road maybe 30sec mainly to maintain speed, not for lack of power

I want to hold a nice 15psi ish across a useable range.

The specs I just posted do they conincide with the advertised specs in the ad I posted yesterday

 

[Dougal]

3000rpm normal driving

I hold it on the governer (4000rpm ish) for short bursts to get up hills etc off road maybe 30sec mainly to maintain speed, not for lack of power

I want to hold a nice 15psi ish across a useable range.

The specs I just posted do they conincide with the advertised specs in the ad I posted yesterday

The information he gave in the ad was correct, just a shame he didn't list the tag numbers.

For reference my Isuzu is 3.9 litres (so about 15% bigger than your 13BT) and with a T25 at 15psi would rev fine to the 3,600rpm rev limit. Increasing boost to 20psi bought a noticable reduction in power over 3000rpm as the exhaust pressure built up.

I think you're probably going to be okay with this one, but it is the smallest turbo any sane person would run on this engine. It's also interchangable with T25 parts so you can simply get it rebuilt with a T25 turbine and the housing bored out or swap it for a whole T25 that will bolt in place.

It would be a great turbo for a 2.8 hilux.

 

[Hulsty]

I wouldn't need to rev beyond 3000rpm if I had enough torque to get a higher gear. Sound like it will build 15psi pretty quick then, along as it should hold that to a tick over 3000rpm I will be a happy camper, more fuel down low and it should be good

 

[Hulsty]

I find my biggest problems when driving is I struggle to pull past 2000rpm after a gear change will my big tyres on or up hill and get stuff grinding along at 1800rpm and 5psi

 

[Dougal]

I find my biggest problems when driving is I struggle to pull past 2000rpm after a gear change will my big tyres on or up hill and get stuff grinding along at 1800rpm and 5psi

This turbo will fix that.

 

[derelict]

Need advice on turbo ASAP

I just finished reading through this thread on the T25 and have a question that can hopefully be answered pretty handily (Dougal, your message box is full). I am new to the whole turbo thing but my 3B is destined to take me on trips through the mountains and although it is quite healthy (480-480-470-465) and is able to haul the truck up 3000 foot climbs, a turbo would help keep me from having to literally go foot to the floor, not to mention that it is going to help "fill in" the gaps in the gearing of the H55F I have. There are times where 3rd is revving too high and 4th is too low when doing climbs. I am looking at making up a kit using a 13BT manifold, CT to T3 adapter and a T3 with a .42 compressor and .48 turbine spec. Is this a good sized turbo for the 3B? It spends most of its time below 2600 rpm. What do you think?

I have a chance to pick this turbo up, brand new NOS for about $350 but I need to make sure it will work so hopefully an answer can come pretty quickly! Thanks.

 

[Dougal]

I don't know anyone who's run that specific T3, but I'd expect it to be a shade bigger than the T25 air-flow wise.

 

[gerg]

The t3 that I have liked for the 3B has been a stage 1 turbine (smallest of the T3s) with a 50 trim compressor. Its efficient at low boost all the way up to 20. The only down side is its an old school design so best efficiency is 75%, but it has a nice big island for the sweet spot. Even with a .48 housing it will spool noticeably slower than the other turbos mentioned here because of its greater rotating mass. I think others on the board have reported 10lbs before 2000rpm with bagged out motors running bagged out old turbos. That was with waste gate welded shut. I doubt that turbo would pull much past 3000rpm at any pressure. One nice thing with this one is that at 23psi its on the map up to 2700 or so.
g

 

[gerg]

The 60 trim can take it to redline with 16psi
g

 

[derelict]

The 60 trim can take it to redline with 16psi
g

Not looking to go that high so I guess I will pass. Looking for something with 10 to 12 psi maximum that will spool up to boost pressure quickly and hold it to 2600 rpm or so. I am very rarely over that. Im looking to make more power than stock but not create a rocket. My experience with turbos is that higher you go in boost on a stock motor, the more you are taking away from it in longevity and reliability. Personally, I wouldnt mind a supercharger option. I know that there are drawbacks to them, just like there are to turbo applications, but for me, living in the lower rev ranges, boost right off the bat would be fantastic (like what a supercharger can offer).

That being said, there isnt, or at least I havent seen, a supercharged 3B so what turbo would suit what I am looking for? As quick to spool as possible building boost around 1500 and then peaking around before 3000. On the highway, Im cruising at 2500 rpm (65-67 mph) and around town Im usually revving around 2000.

 

[Dougal]

Not looking to go that high so I guess I will pass. Looking for something with 10 to 12 psi maximum that will spool up to boost pressure quickly and hold it to 2600 rpm or so. I am very rarely over that. Im looking to make more power than stock but not create a rocket. My experience with turbos is that higher you go in boost on a stock motor, the more you are taking away from it in longevity and reliability. Personally, I wouldnt mind a supercharger option. I know that there are drawbacks to them, just like there are to turbo applications, but for me, living in the lower rev ranges, boost right off the bat would be fantastic (like what a supercharger can offer).

That being said, there isnt, or at least I havent seen, a supercharged 3B so what turbo would suit what I am looking for? As quick to spool as possible building boost around 1500 and then peaking around before 3000. On the highway, Im cruising at 2500 rpm (65-67 mph) and around town Im usually revving around 2000.

GT2052 if you can buy new, T25 if you're junk yard diving.

 

[derelict]

GT2052 if you can buy new, T25 if you're junk yard diving.

Im looking at these and noticing that T25 is a very generic turbo as they come in a variety of different specs. I looked at GT2052, which everyone is saying is great, and its looking like the stock GT2052 is a GT2052 - 727264 - 2 which is a .51 (50 trim) compressor and .52 (72 trim) turbine. So, these are the ideal numbers for a 3B to start delivering power lower down and holding it up to 3000 rpm? So, what is the desired exhaust side trim and the desired compressor side trim for the T25, or any turbo for the 3B? There are a few kits available but I am weighing whether to build up my own "kit" or just buy one, whether it be a kit or Keiths set up (which I am leaning towards).