Thread: Another turbo question-- or 2

Originally Posted by County3.9

Hey Ben, can you tell me how far above the tappet cover your turbo is? (measured from the top of the tappet cover to the upper most point of the turbo). I've got the measurement for a high mount (60mm above, 115mm from edge of tappet cover...thanks rar110) so it'll be interesting to see how yours compares.

My motor was stock LR Isuzu fit same as his. I think there was only one type fitted to NA motors by LR. Although a variation would not surprise me.

Originally Posted by County3.9

Hey Ben, can you tell me how far above the tappet cover your turbo is? (measured from the top of the tappet cover to the upper most point of the turbo). I've got the measurement for a high mount (60mm above, 115mm from edge of tappet cover...thanks rar110) so it'll be interesting to see how yours compares.

Sorry for the wait - just measured.

T28 and Dougal's adaptor.

Highest point of turbine housing is 10mm below tappet cover
Body of compressor housing is 10mm above tappet cover
Outlet flange of compressor housing (could be rotated down) is 30mm above tappet cover

Centreline of top row of manifold bolts to top of outlet flange of compressor is 120mm

maybe a stupid question

Is there a manifold that mounts the turbine lower and on a more horizontal plane or would that create to much heat and effect the starter motor

Originally Posted by dobbo

maybe a stupid question

Is there a manifold that mounts the turbine lower and on a more horizontal plane or would that create to much heat and effect the starter motor

There is no factory low-mount, only top mount and side mount. You'd be best making up a neck to go from the side-mount manifold which reaches around and down to fit a lower turbo position if you wanted this.

I have an old IHI top-mount manifold which the neck was cut off and flipped upside down. Then rewelded.
It's ugly externally, but the flow inside is uglier still. I did as much with a mill, chisel and dremel as I could a few years back to tidy it up internally. Needless to say, I don't recommend this method.

The starter won't have any problems.

Choices, choices, choices....I hate agonizing over which way to go!!!! Someone tell me what I want

Perhaps I am missing something obvious, why would it make that much of a difference which way an exhaust manifold effects the exhaust gasses when the next place the gasses pass through is the turbine where it is all compressed? The factory setup is far from free flowing? Should I look at getting some custom headers built up (anyone done this?)

Originally Posted by Dougal

There is no factory low-mount, only top mount and side mount. You'd be best making up a neck to go from the side-mount manifold which reaches around and down to fit a lower turbo position if you wanted this.

I have an old IHI top-mount manifold which the neck was cut off and flipped upside down. Then rewelded.
It's ugly externally, but the flow inside is uglier still. I did as much with a mill, chisel and dremel as I could a few years back to tidy it up internally. Needless to say, I don't recommend this method.

The starter won't have any problems.

Originally Posted by dobbo

Perhaps I am missing something obvious, why would it make that much of a difference which way an exhaust manifold effects the exhaust gasses when the next place the gasses pass through is the turbine where it is all compressed? The factory setup is far from free flowing? Should I look at getting some custom headers built up (anyone done this?)

The factory manifold is made very compact for three reasons.
1. Faster response.
2. Minimal volume to keep pulse speed high.
3. Keeps the heat in.

It looks to flow quite well for what it is. Sure you can make an equal length header but the amount of work involved and the extra space needed are considerable. In transient operation a header type will probably be worse, but in steady state might give you boost a bit sooner and more top-end.

The turbine doesn't compress the exhaust, rather it funnels it to a higher velocity (creates a free vortex) to get the air speed necessary to spin the blades at 100,000+ rpm.
Delivering the pulses to the turbine with the least disruption and minimal heat loss helps a lot.

A question (or two) for the brains trust!

Background info: I'm running a LT85 and 16Rx70Hx235 tyres. Stock standard ~100 - 105km/hr in 3rd at governer.

In terms of performance goals, I'm after mid to high end improvements. Long term plans include installation of WTA intercooler.

I've had a good sticky about the forum and am now utterly confused What I do know is that I'm one for good quality products (i.e ball bearing internals)

Summarizing what I've read on here (correct me if I'm wrong), I understand that...

> T25 (incl. waste-gate variations) are stock on 4BD1-T's - These however, are not generally recommended (from a performance perspective);

> GT28R - Slightly larger than GT2560R and spools later in rev range (say ~1600 rpm)

> GT2560R (T25/28???) - A good starting point. Spools sooner than GT28R and produces equivalent boost levels;

> VVT turbos (GT2256V etc. Any other noteworthy turbos???) - Best driveability and versatility w.r.t single turbo option.

> Compound setup - BW's / Holset etc ??? - Such setups are suitable for boost levels in excess of ~40psi.

It all boils down to how much $$$ one is prepared to spend. With that said, I'm after a reliable/ good quality setup producing say ~15 to 20 psi comfortably...

Also, what are everyone's thoughts on the suitability of this turbo?

IHI RHF5 VICC VIAN ISUZU TROOPER Turbocharger P/N. 0104-891-090 Item Name IHI RHF5 VICC Turbocharger IHI Part # VE430023 ISUZU P/N 8971480762 Product Situation Brand New Genuine Application 94~99 4JG2T 3.1L Diesel Trooper

Look forward to what peeps have to say