Thread: Another 120 project begins

Revising my estimated T25 compressor map with calculated values assuming 60% effective intercooling gives the following map:



Compressor efficiency looks even more reasonable between 2000 and 3000 RPM.

Next step is to work out how much fuel the 4BD2TC fuel pump can deliver at low RPM

- 132cc/1000 strokes @ 1000rpm produces 57 kW / 540Nm of torque
- 143cc/1000 strokes @ 2000rpm produces 140kW / 660Nm of torque
- 123cc/1000 strokes @ 3000rpm produces 150kW / 470Nm of torque

pumping more fuel at 3000 rpm pushes the shaft speed off the compressor map, which I take is somewhat bad for turbo longevity.

The 4BD2T pump full load map looks somewhat different to the 4BD1T pump in that it can deliver more fuel at low pump speed, and has a longer boost compensator stroke (0.7mm compared with 0.5mm for the 4BD1T)

The first adjustment point is A, rack position R1 (11.9mm) @ 950RPM pump speed.



Full load map at the top



Differences between 4BD1T and 4BD2T covered in this post:
http://www.aulro.com/afvb/isuzu-land...ump-4bd1t.html

I can confirm both pumps have the same mount BTW.

Cheers

Bojan

Originally Posted by Offender90

Revising my estimated T25 compressor map with calculated values assuming 60% effective intercooling gives the following map:

Compressor efficiency looks even more reasonable between 2000 and 3000 RPM.

Next step is to work out how much fuel the 4BD2TC fuel pump can deliver at low RPM

- 132cc/1000 strokes @ 1000rpm produces 57 kW / 540Nm of torque
- 143cc/1000 strokes @ 2000rpm produces 140kW / 660Nm of torque
- 123cc/1000 strokes @ 3000rpm produces 150kW / 470Nm of torque

pumping more fuel at 3000 rpm pushes the shaft speed off the compressor map, which I take is somewhat bad for turbo longevity.

You'll struggle with vibration at the 1000rpm point. With my t25 I have 10psi boost from ~1200rpm. That's on the limit of usable. 1600rpm is the point where I can begin to smoothly apply full throttle in higher gears. I plan some flywheel inertia additions to help.

I've been using 140cc as the fuelling limit until we get better information. I'd like to build a test-stand for my spare pump, but don't hold your breath. That gives about 132kw and 19lb/min at 2000rpm with my figures. It's nicely on my map too.
Coincidence, I've also had 3000rpm at 122cc, 154kw, 24.7lb/min. It's just off the map but I reckon it'll be fine.

Here are my graphs from 24psi intercooled. Cap the boost to 20psi and that's what I'm currently looking at.

Dougal,

How do you determine how much fuel the pump delivers at full load at each pump speed. Rack position doesn't correlate to pumped volume as I understand it, as pumping efficiency increases at higher pump speeds.

From the pump calibration data I posted earlier - Point A (rack position R1, or 11.9mm) supplies 77mm^3 / stroke (or 77cc/1000 strokes). Point B on the other hand (rack position R1-0.15, or 11.75mm) supplies 79cc/1000 strokes. Is there a way to convert rack position and pump speed data into a volume of fuel delivered at full load?

My pump has a big red 180cc written on it, although the text in Katakana next to it I understand says something about engine oil (my better half didn't understand the Kanji characters).



Anyone know what this refers to? Oil flow required for initial lubrication or max fuel flow?

Also with regard to the turbo, does exceeding maximum shaft speed (i.e. moving off the compressor map upwards) have significant consequences for turbo longevity? I assume the interrupted efficiency islands generally follow the shape of the ones that fit on the graph.

I think 180cc is lube oil quantity for pumps that aren't on the pumped engine oil circuit.

The only figure I have to base this off was Randy (Carcrafter22)'s measurement of max pump flow before he got his one modded. John has his own measurements and right now I'm trying to nudge a Canadian who's getting his pump rebuilt to get us some figures from across the speed range.

A test bench would be reasonably simple to setup. Variable speed electric drive, measuring pots for each injector line and that's about it. If you've got ideas on how much power it takes to turn a pump under test, then I'm all ears. I'm limited to single phase power at the moment, about 3kw max.

Exceeding turbo shaft speed all depends which map you beleive. Some maps run to higher rpm than others for damn near identical turbos. I'm fine with running them a little off the top of the map. But you can't go far before hitting flow limits anyway.

Originally Posted by Offender90

Dougal,

How do you determine how much fuel the pump delivers at full load at each pump speed. Rack position doesn't correlate to pumped volume as I understand it, as pumping efficiency increases at higher pump speeds.

From the pump calibration data I posted earlier - Point A (rack position R1, or 11.9mm) supplies 77mm^3 / stroke (or 77cc/1000 strokes). Point B on the other hand (rack position R1-0.15, or 11.75mm) supplies 79cc/1000 strokes. Is there a way to convert rack position and pump speed data into a volume of fuel delivered at full load?

My pump has a big red 180cc written on it, although the text in Katakana next to it I understand says something about engine oil (my better half didn't understand the Kanji characters).



Anyone know what this refers to? Oil flow required for initial lubrication or max fuel flow?

Also with regard to the turbo, does exceeding maximum shaft speed (i.e. moving off the compressor map upwards) have significant consequences for turbo longevity? I assume the interrupted efficiency islands generally follow the shape of the ones that fit on the graph.

Translation from my colleague:

~= When installing pump engine
Oil injection volume

Originally Posted by Offender90

Dougal,

How do you determine how much fuel the pump delivers at full load at each pump speed. Rack position doesn't correlate to pumped volume as I understand it, as pumping efficiency increases at higher pump speeds.

From the pump calibration data I posted earlier - Point A (rack position R1, or 11.9mm) supplies 77mm^3 / stroke (or 77cc/1000 strokes). Point B on the other hand (rack position R1-0.15, or 11.75mm) supplies 79cc/1000 strokes. Is there a way to convert rack position and pump speed data into a volume of fuel delivered at full load?

My pump has a big red 180cc written on it, although the text in Katakana next to it I understand says something about engine oil (my better half didn't understand the Kanji characters).



Anyone know what this refers to? Oil flow required for initial lubrication or max fuel flow?

Also with regard to the turbo, does exceeding maximum shaft speed (i.e. moving off the compressor map upwards) have significant consequences for turbo longevity? I assume the interrupted efficiency islands generally follow the shape of the ones that fit on the graph.

From my colleague:

~= When installing pump engine
Oil injection volume

To me it sounds like the volume of oil to add to lubricate the pump on install???

Originally Posted by isuzurover

From my colleague:


To me it sounds like the volume of oil to add to lubricate the pump on install???

It's handy having a japanese speaking colleague... or in my case colleague of a japanese speaking colleague

Originally Posted by Offender90

It's handy having a japanese speaking colleague... or in my case colleague of a japanese speaking colleague

He is a native French speaker who is fluent in English and Japanese. Makes our education system look sub standard...
(His girlfriend is native Japanese for any hard translations...)