[bobpr]

Hi guys
I have this manifold which fits a 4HF/G/E1 engines and I was wondering what turbo to fit to it I can get a GT25 for the 4HE1 but it doesn't have the T3 mount.
The 4HF1 is 4.2 ltr so I need to know what your suggestions may be.
Bob

 

[Dougal]

I can't read the numbers in the photo, can you post them up?

 

[bobpr]

The mount is a T3 type I have altered the sizes to larger type

 

[Dougal]

The "official from Garrett" T3 stud measurements are 86x44.5mm, each stud being M10 with an 11.2mm clearance hole.

So yeah, that's a T3.

 

[bobpr]

Thanks, Any sugestions as to what turbo that I should use or what would suit bearing mind that it is a 4HF1- 4.2 ltr. I have had the pump set up to start fueling at 1850 RPM.
Bob

 

[Dougal]

Thanks, Any sugestions as to what turbo that I should use or what would suit bearing mind that it is a 4HF1- 4.2 ltr. I have had the pump set up to start fueling at 1850 RPM.
Bob

How much boost do you want?
Up to around 20psi a garrett GT2860R would be a good match with the 0.64 A/R turbine housing. Of course that's a T25/T28 flange so you could use an adapter. Aftermarket T28 housings appear to be available with T3 flanges.

 

[bobpr]

Thanks,
what engine uses that turbo and the boost of around 18to 20 psi would be OK
I'm not looking for neck breaking power.
Bob

 

[Dougal]

If you're looking for a used one, then a nissan skyline or silvia etc would make a possible donor.
The silvia turbo is bigger (0.86 A/R exh housing) but is also ball-bearing. Isuzurover runs one on his 4BD1.

 

[bobpr]

That's great
How much difference is the GT28 to the GT25
The GT25 is used on the 4HE1 but the manifold mounting is not T3. Is there an exhaust turbine housing that can be swapped, to get the T3 mount configeration and who would possibly be the supplier
Bob

 

[bobpr]

Dougal,
What is the equivelant in the Holset turbos? and I Think most of them come with the
T3 Mount
Bob

 

[Dougal]

Dougal,
What is the equivelant in the Holset turbos? and I Think most of them come with the
T3 Mount
Bob

To be honest I have no idea about the holsets and their naming system confuses me. Carcrafter is probably your best source of info there.

The GT25 is a tiny fraction smaller exhaust wheel than the GT28. The old T28 is now called the GT2560.
Some aftermarket turbine housings exist for GT28 turbos, but I also have designed a T3-T25 adapter system which Isuzurover uses.
There's a guy on outerlimits4x4 called Matt McInnes who has recently come up with a very clever T3-T25 adapter design which can be used either way around (also fits T25-T3). But I don't know if he's selling them yet.

 

[carcrafter22]

For a holset I would look for something with a 9cm housing, with 4.2 liters the he341 would be a great turbo and with a little more fuel I feel you could get away with an he351 if you were looking to build a healthy motor.

whats the max rpm on your motor? Whats it in?

 

[bush65]

You might also consider a Garrett GT3071 (can be had with T3 flange) or one of the Mitsubishi TD05 turbos (don't know flange details).

I was talking recently to a Land Rover owner having a problem with the late wastegated Garrett turbo on his 4BD1T. His experience makes me think you need to be careful your turbine and housing are not too small.

He had a compressor failure and the shop he took it to damaged the turbine impeller while repairing it. They could not source a replacement turbine impeller (Garrett make the turbo for Isuzu and don't sell to others). So the shop fitted an impeller from a turbo used in a Nissan engine. The impeller size was close to the original - the housing had to be machined out a little, but it had an extra blade.

Now the engine has more boost at low revs, but chokes at higher revs where boost and performance have suffered. He is not happy with the outcome.

 

[Dougal]

You might also consider a Garrett GT3071 (can be had with T3 flange) or one of the Mitsubishi TD05 turbos (don't know flange details).

I was talking recently to a Land Rover owner having a problem with the late wastegated Garrett turbo on his 4BD1T. His experience makes me think you need to be careful your turbine and housing are not too small.

He had a compressor failure and the shop he took it to damaged the turbine impeller while repairing it. They could not source a replacement turbine impeller (Garrett make the turbo for Isuzu and don't sell to others). So the shop fitted an impeller from a turbo used in a Nissan engine. The impeller size was close to the original - the housing had to be machined out a little, but it had an extra blade.

Now the engine has more boost at low revs, but chokes at higher revs where boost and performance have suffered. He is not happy with the outcome.

I'd be hesitant about running a turbo as large as the GT3071. One aussie who has put a GT2876R (0.64 A/R turbine housing) on his 4.2 toyota diesel isn't getting 10psi boost until 2300rpm.

Small turbines certainly do limit topend, I also spent some time talking to the person John mentioned above. I run an even smaller turbo on my 4BD1T and have the same behaviour but 1-200rpm sooner than he does. The turbo I currently run (T25 with a 0.49 A/R exhaust housing) is several sizes smaller than I usually recommend to others.

Sizing a single turbo is all about compromise, low end torque vs high end power.

 

[bush65]

I had the GT3071 in mind from back when I had compared Garrett turbos to the Holset HE341, which is a preferred choice for those wanting better performance from the Cummins 4BT.

Although the GT3071 is considerably larger than the stock 4BD1T turbo, it is still smaller than than the HE341.

Compared to a 4BD1T, the larger displacement, 4.2 litre 4HF1 will need approximately the same air flow at lower boost pressure, for the same power.

The HE341 has a 56/76mm compressor and 58/65mm turbine.

The GT3071 has 53.1/71mm compressor and 51.8/56.5mm, 0.64 A/R, or 53.6/56.5mm, 0.86 A/R wastegated, or 55/60mm, 0.63, 0.82 or 1.06 A/R, non-wastegate.

IIRC the stock turbo for the 4BD2T has a 40/51.3mm compressor and 42/55mm, 0.67 A/R turbine.

When I looked up Garrett specs to enter the above GT3071 info, I noticed that only the non-wastegate GT3071 is available with a T3 flange turbine housing.

Edit: From memory, when Randy had a HE341 on his 4BD1T with the stock fuel injection pump, he couldn't get much more than 20psi boost pressure

 

[bobpr]

Thanks fellas now I have some thinking to do. I just received the GT25 that is used on the 4HE1 engine but the compressor seems to appear slightly too small for what I would like to achieve.
Idealy it would be great to have max boost at around the 1850 to 2000 RPM range and then I can gear the drive train to maximise the torque produced.I am waiting on another turbo which has these specs

MGP-4003, T3/T4 TOP TURBO WITH INTERNAL WASTEGATE
Trim-T 73
A/R -T 0.63,
Trim-C 70,
A/R- C 0.6
Flange-T Inlet T3
oil cooling

How would you think this would work


I can get a HE341 or the GT2860 but will these give me the boost at the disired RPM
Or what changes to the compressor and turbine should I do
Bob

 

[bobpr]

For a holset I would look for something with a 9cm housing, with 4.2 liters the he341 would be a great turbo and with a little more fuel I feel you could get away with an he351 if you were looking to build a healthy motor.

whats the max rpm on your motor? Whats it in?

The prefered working range would possibly be from about the 1700 range to 2700 or 2800 RPM with mostly reving in 1850 to 2000 cruising.That is where I have set the max fuel so max boost would be needed here.I have looked at the HE341 and it does seem to have the specs that may suit.
The engine is in a NPR 4x4 so good torque would be handy
Bob

 

[Dougal]

Thanks fellas now I have some thinking to do. I just received the GT25 that is used on the 4HE1 engine but the compressor seems to appear slightly too small for what I would like to achieve.
Idealy it would be great to have max boost at around the 1850 to 2000 RPM range and then I can gear the drive train to maximise the torque produced.I am waiting on another turbo which has these specs

MGP-4003, T3/T4 TOP TURBO WITH INTERNAL WASTEGATE
Trim-T 73
A/R -T 0.63,
Trim-C 70,
A/R- C 0.6
Flange-T Inlet T3
oil cooling

How would you think this would work


I can get a HE341 or the GT2860 but will these give me the boost at the disired RPM
Or what changes to the compressor and turbine should I do
Bob

That T3/T4 is much bigger both physically and airflow wise than a GT2860, I don't know exactly how it will compare to the holset.

Garrett's GT turbos are using smaller compressor and turbine wheels than the likes of Holset for the same airflow. This lets them accelerate to working speed a little quicker but makes them a whole lot more compact.
A Holset HX25 has the same airflow as an old T25 garrett, but the HX25 has a 56mm compressor wheel and the T25 has a 51mm.
From there the HX30 holsets step straight up to an 83mm compressor wheel.

Randy originally used an HY35 which I found these maps for (attached below), It looks like our engines will never stretch the limits of those turbos.
The HE351 is supposed to have the same compressor. Maybe it's just me, but I consider these massive overkill unless you're looking for 300hp on a single turbo. The green map (the smallest one) is capable of 45 lb/min (600cfm) at 45psi boost, that's going to give a 3.9 Isuzu about 300hp.

 

[bobpr]

Thanks '
So if I want the max boost to occur at around 1850 RPM then the smaller compressor will do it or is it the smaller turbine
Bob

 

[Dougal]

Thanks '
So if I want the max boost to occur at around 1850 RPM then the smaller compressor will do it or is it the smaller turbine
Bob

You need a combination of a turbine that can spin the compressor fast enough at that rpm and a compressor that can deliver boost without surging.
Do you know the specs on the original turbo? That's a good place to start.

How fast does your 4H turn? I remember some of them hit the governor at 2800rpm.