Turbo for 2H

[Tapage]

It's due to the different exhaust wheel size.

The exhaust scroll creates a vortex, the exhaust wheel interrupts that vortex to create torque on the shaft.
In a free vortex the further you go in, the higher the gas velocity. So bigger wheels interrupt the vortex further out where the gas velocity is lower, that's why you need a smaller A/R ratio with a bigger wheel.

My engine originally came with an IHI turbo which is equivalent to a T3 with a 0.42 A/R exhaust housing.
I'm now using a T25 with a 0.49 A/R housing and they spool up at almost exactly the same point.

Multiply the A/R by the wheel radius and you get what I call the effective flow area. It's a handy number for comparing the spool up point of different turbos.
Remember A/R is usually in inches, so you need to know the wheel radius in inches. A T3 usually has a 60mm (2.36") exhaust wheel.

Thanks Dougal .. I didn't pay much atention to trim numbers in the wheels that I selected .. and actually should be interesting see those numbers for my KKK that it's a .38 AR in the turbine side ..

 

[rchalmers3]

I run a Garrett T25 on my 3.9L Isuzu, but it is governed to 3600rpm and rarely ever sees 3000.
I'm running 20psi boost which is outside what the turbo makers ever intended.

One of these will work for a 2H, but I'd be inclined to go a little larger. A T25 with 0.64 A/R exhaust would work if you're looking for used turbos.

Dougal your Isuzu 3.9L sounds very similar to the 2H. It turns slow and has a similar displacement. Hey, I have an idea and request: Do you have enough info on the 2H to map the T25 .49 A/R and T25 .64 A/R for us?? If you don't, maybe you could map them using your motor.

It would be interesting to see exactly what the margin of saftey is you are refering to.... in a graphical format!

 

[Dougal]

Dougal your Isuzu 3.9L sounds very similar to the 2H. It turns slow and has a similar displacement. Hey, I have an idea and request: Do you have enough info on the 2H to map the T25 .49 A/R and T25 .64 A/R for us?? If you don't, maybe you could map them using your motor.

It would be interesting to see exactly what the margin of saftey is you are refering to.... in a graphical format!

The capacity of the two engines is similar enough, that the main difference comes down to the revs.
The 2H revs about 10% more which gives you another 10% possible air consumption. I'll post up a map later on but it may take a while as I'm currently investing my spare time in some turbo adapters.

The compressor maps of the T25 with the 0.64 A/R exhaust housing aren't any different, but it'll give a little less exhaust restriction so it won't be as likely to blow the exhaust valves open. My Isuzu was a factory turbo and fitted to trucks with exhaust brakes, so it has no problem running up to 40psi exhaust backpressure.
The 2H I wouldn't like to put through the same test.

 

[Tapage]

One detail that I realized in the Tencha turbo process .. I'm not hable to make the IP of Tencha deliver the apropiate amount of diesel that I want for my turbo setup. Should be related to the inline pump ( but the 12H-T have inline pump and looks pretty the same ) or to the factory fuel settings in a NA IDI engine ..

 

[rchalmers3]

The capacity of the two engines is similar enough, that the main difference comes down to the revs.
The 2H revs about 10% more which gives you another 10% possible air consumption.

The revs you refering to are the governed engine speeds, right? What if (as marting indicates in post #8) the driver has lower speed driving characteristics and needs, and is willing to sacrafice a drop off at the high end? Would that change your recommendation or is it your opinion to put the margin in anyway? I'm tuned into this because it sounds like his vehicle and driving needs are very similar to mine, and I'd like to install a system that works as intended the first time. My guess is he would like to experience boost as soon as the throttle is cracked and experience boost at 1k rpm.

 

[Dougal]

The revs you refering to are the governed engine speeds, right? What if (as marting indicates in post #8) the driver has lower speed driving characteristics and needs, and is willing to sacrafice a drop off at the high end? Would that change your recommendation or is it your opinion to put the margin in anyway? I'm tuned into this because it sounds like his vehicle and driving needs are very similar to mine, and I'd like to install a system that works as intended the first time. My guess is he would like to experience boost as soon as the throttle is cracked and experience boost at 1k rpm.

Yes certainly, an intelligent driver watching their gauges can get away with a setup that a meathead could blow their engine with.

Just making sure you realise the risks.

 

[rchalmers3]

It's due to the different exhaust wheel size.

The exhaust scroll creates a vortex, the exhaust wheel interrupts that vortex to create torque on the shaft.
In a free vortex the further you go in, the higher the gas velocity. So bigger wheels interrupt the vortex further out where the gas velocity is lower, that's why you need a smaller A/R ratio with a bigger wheel.

My engine originally came with an IHI turbo which is equivalent to a T3 with a 0.42 A/R exhaust housing.
I'm now using a T25 with a 0.49 A/R housing and they spool up at almost exactly the same point.

Multiply the A/R by the wheel radius and you get what I call the effective flow area. It's a handy number for comparing the spool up point of different turbos.
Remember A/R is usually in inches, so you need to know the wheel radius in inches. A T3 usually has a 60mm (2.36") exhaust wheel.

With all the variables in turbo construction, does your "effective flow area" calculation give you your best fit recommendation of the Garrett GT2560R? Or do you favor a turbo that's close but has a ball bearing?

Would you please demonstrate the calculation on the turbos you recommend? I'd like to see the results and meaning you glean from the results.

Also, Marting will probably not be buying a new turbo. My guess is that these arn't available used??

Rick

 

[rtarh2o]

Just curious what the power would be for a turbo 2H? Would it be possible to install one in an 80 series?
Rusty

 

[Dougal]

With all the variables in turbo construction, does your "effective flow area" calculation give you your best fit recommendation of the Garrett GT2560R? Or do you favor a turbo that's close but has a ball bearing?

Would you please demonstrate the calculation on the turbos you recommend? I'd like to see the results and meaning you glean from the results.

Also, Marting will probably not be buying a new turbo. My guess is that these arn't available used??

Rick

The "effective flow area" isn't something I can use to fit a turbo to an engine, but it allows me to compare two turbos of different sizes without just guessing.
My T25 comes out at 323 square millimetres
The GT2560 comes out at 430 square millimetres so it's roughly 25% bigger in the turbine.

The GT2052 that Diesel42 is using comes out at 298 square millimetres, slightly smaller than the T25 I'm using.

There are several guys in Aussie running the old T28 on 3.9L Isuzus like mine and they're very happy with the results. But I haven't seen or driven their vehicles so I can't offer a comparison with mine.

 

[marting]

WO WO Take it easy guys. This got very technical. lets take it back down a few notches. What is IP ?
What do i have to do with the fuel system? just adjust it? Or add parts?
So from what i have learned:

Oil: from T-piece added to the preassure-feeler thing, return in sump or push-rod cover.

Water: from the drainplug on the block to the hose going out from the termostat.

Exaust: 2,5 or 3" with a "flow-through" silencer

Intercooler: to late, it's already bought. 250x500x76mm 3"in-outlet.

Turbo: To small better than to big?
The easiest to get here i think would be something from a 2-2,5 liter petrol-engine. From Saab or Volvo maybe..What else is there to concider. any small pipes, vacuum, fuel-regulation and so on????

 

[Tapage]

What is IP ?

Injection Pump

What do i have to do with the fuel system? just adjust it? Or add parts?

Ajust if to compensate more air in the system due to the turbo .. means adding more fuel.

Water: from the drainplug on the block to the hose going out from the termostat.

Really the water never worry me to much ..

Turbo: To small better than to big?
The easiest to get here i think would be something from a 2-2,5 liter petrol-engine. From Saab or Volvo maybe..What else is there to concider. any small pipes, vacuum, fuel-regulation and so on????

Are not that simple .. but yes, 2 - 2.5 petrol engine will be the route, but it all depends on the turbo .. smaller turbine, means more backpressure and maybe EGT issue in your engine .. much boost sooner but what to do in the HI range ?

Bigger turbine, means you are dealing with the boost to late in your powerband ..

 

[marting]

Dougal! and you other guys with know-how;

A local guru said i should get a t 25 with a 60 A/R aprx. (i still don't comletely understand what that is)
And that i would be better of with a slightly biggish turbo than a small one. He said that i could limit it's power on top with the fuel adjustment and the wastegate , and a garrett gt would spool up early enough anyway.

Does anyone agree? I will buy a turbo next week...and if i can find a garrett t25 with A/R between 50 and 60 i guess i'll go for it..

 

[Tapage]

He said that i could limit it's power on top with the fuel adjustment and the wastegate , and a garrett gt would spool up early enough anyway..

I'm not Dougal but .. this statement it's complete correct.

The point is, with a bigger compresor, making a bunch of boost .. you can blow your head. or simple waste your money in a huge one that you really don't gonna use complete .. or at least not the 100% of it capabilities.

With a smaller ( more than apropiate ) turbine side, you found your engine with uncontrolable EGT due to the restriction and backpressure in the eshaust manifold .. making much boost sooner and heat probles at higer rpm ... viceversa with a bigger turbine side.

 

[Dougal]

Dougal! and you other guys with know-how;

A local guru said i should get a t 25 with a 60 A/R aprx. (i still don't comletely understand what that is)
And that i would be better of with a slightly biggish turbo than a small one. He said that i could limit it's power on top with the fuel adjustment and the wastegate , and a garrett gt would spool up early enough anyway.

Does anyone agree? I will buy a turbo next week...and if i can find a garrett t25 with A/R between 50 and 60 i guess i'll go for it..

The only A/R choices I'm aware of with the T25 are the 0.49 which I have and the 0.64.
The 0.49 gives you more low end and a wider usable rpm range. the 0.64 will give you more top end power as it's best efficiency point occurs at higher engine rpm.

I am hesitant to recommend a 0.49 A/R T25 for a 2H unless the driver has all the instruments and drives to them. There's a small chance that an ignorant driver could overspeed the turbo, causing it to die prematurely.

Regarding the GT series, being a later generation product they're more refined and may spool earlier than the older turbos of the same size, but the biggest difference is the bearings used in some models.
Garrett use the suffix "R" to show which ones have bearings in them, these will spool up sooner, the ones without have journal bearings.

So in short
GT2560 = journal bearings
GT2560R = roller/ball bearings and faster spool up.

 

[rchalmers3]

Just to reinforce the choice selection: When you recommend a turbo, you are talking about the exhaust turbine A/R, correct?

I keep thinking that if the measurement of the compressor is mistakenly referenced (or assumed), some damaging or disappointing results could happen.

Rick

 

[Dougal]

Just to reinforce the choice selection: When you recommend a turbo, you are talking about the exhaust turbine A/R, correct?

I keep thinking that if the measurement of the compressor is mistakenly referenced (or assumed), some damaging or disappointing results could happen.

Rick

Yes, the exhaust A/R.
Often the same turbo is availble with a few different A/R exhaust housings that can be swapped at will, but the compressor housing doesn't change.

 

[Tapage]

Just to reinforce the choice selection: When you recommend a turbo, you are talking about the exhaust turbine A/R, correct?

It's a mix IMOP ..

You can run a good turbine side, proper fitted and sized for your aplication ( engine ) and a huge compresor that it's way to much for your target .. it means the turbine side can do it properly but the compresor side maybe gotta make boost later than you want and way to much ..

At the end you could find yourself wastegateing ( if this word exist ) the 50% of the real valuable potential of the compresor side due your engine can handle that pressure ..

of coz .. the worst scenario ..

 

[marting]

Ok.. I'm waiting for an offer on a new turbo now.. I'll keep you updated.

 

[marting]

Another thing i thought of; Is it ok to use exaust-hose for part of the exhaust system? It would be easy to make a pipe behind the turbo with the cone-shape mentioned earlier by tapage. And in then use the heavy-duty hose from it, to right in front of the clutch-housing (where it's clamped to a bracket..)
That way i can get a vibration-free system further back and less heat will transfer to the engine-compartement?

Would save me a lot of bending and welding..

I'm talking about hose bespoke for exhaust.. not silicone or anything like that.

 

[Dougal]

It's a mix IMOP ..

You can run a good turbine side, proper fitted and sized for your aplication ( engine ) and a huge compresor that it's way to much for your target .. it means the turbine side can do it properly but the compresor side maybe gotta make boost later than you want and way to much ..

At the end you could find yourself wastegateing ( if this word exist ) the 50% of the real valuable potential of the compresor side due your engine can handle that pressure ..

of coz .. the worst scenario ..

That's only possible if someone has built a turbo from mis-matched pieces.
If you buy a standard turbo, the compressor is matched to the turbine, if they give you two turbine housing options then each of them will work well with that compressor.