Thread: isuzu & LPG

They're a very common unit. I fitted one in 2007 to my tweaked 200Tdi. It was wired to cancel the cruise control when it blew 700 (which it did quite easily).

Made it very convenient not having to monitor temperatures on the big hills on the Hume.

Just had a look at there web site, lot of interesting stuff at reasonable prices, even better at the moment with the strong AU$.

They even do a unit with 0-20mA or 4-20mA retransmit for data logging, thermocouples, MAP sensors, oh my poor credit card.

www.auberins.com

Lyle.

Originally Posted by Sparkie

Just had a look at there web site, lot of interesting stuff at reasonable prices, even better at the moment with the strong AU$.

They even do a unit with 0-20mA or 4-20mA retransmit for data logging, thermocouples, MAP sensors, oh my poor credit card.

www.auberins.com

Lyle.

Ah, the magical point where coffee and Land Rovers converge.

Originally Posted by abaddonxi

Ah, the magical point where coffee and Land Rovers converge.

LOL, I mainly drive a stage 1 so most of my coffee converges in the bottom of the centre console whenever I drive on our wonderful victorian roads (donkey tracks?)

No current spill proof coffee mug is S3 proof.

Has anyone posted there website in one of the general forums, I'm sure some of the other guys playing with turbo's would be interested.

Lyle.

Originally Posted by Sparkie

LOL, I mainly drive a stage 1 so most of my coffee converges in the bottom of the centre console whenever I drive on our wonderful victorian roads (donkey tracks?)

No current spill proof coffee mug is S3 proof.

Has anyone posted there website in one of the general forums, I'm sure some of the other guys playing with turbo's would be interested.

Lyle.

They are very well known/used by AULRO members and have been mentioned in many threads in other forums here.

e.g a current thread on egt has shown members are using egt + MAP sensors together (single display unit - have to toggle the input code).

since some members are still stuck on the. Adding LPG changes or advances the timing, ( which it cant) and or detonation of the lpg under compression ( which it cant)
To understand what is really going on have a look at or look up "propane decomposition under pressure" that will sort of explain all.

I have dropped of a sample of oil at Cat, it was 1200 klm ago that I changed oil and filters and with 300 klm of running lpg at about 7 ltrs pr 100 klm or about twice the recommended dose with no detonation it will be interesting to see if Dougals claims are correct or not

Some posts above have asked about rack travel during idling, etc.

I have posted this info before but don't remember where. These pics are from manual IDE2040 and are given there for calibrating the fuel injection pump number 101401-0660 with boost compensator, as fitted to some 4BD1T engines. This manual also has similar information for a 4BD1.

The 1st pic shows the idling calibration at adjustment point 'H' and shows control rack position vs pump speed, when the control lever is against the idle stop screw.

Note: at point 'H' the control rack position is approximately 9.5 mm. And from 3rd pic at adjusting point 'H' the injection volume is calibrated to 6.7 to 9.3 cc/1000 strokes at a pump speed of 290 rpm.

Another question asked was:

Does anyone know how far the rack has to move to start injection, there is a certain amount off the start to cover the stop position so where does injection start in relation to rack position, or is rack position measured in relation to the point that injection is started.

I think there might be some misunderstanding of what is happening. The control rack does not move each to a start of injection position. The plungers reciprocate in their barrels (driven by a camshaft) and have a pre-stroke to the position where injection starts.

From the same manual above the pre-stroke for the 4BD1 is 3.6 +/- 0.05 mm (3.4 +/- 0.05 mm for 4BD1T).

Another interesting observation when you look at the calibration information is the fuel rate at full load of the 4BD1 vs the 4BD1T.

The 2nd pic shows control rack position vs pump speed for full load calibration. The 3rd pic shows the tabulated data. As stated above these pics are for a 4BD1T ( haven't posted the equivalent for a 4BD1 - it is in the manual if anyone wants to check.

Some full load calibration data is:
rack position, pump speed, injection volume

4BD1, IP id 101401-0290, 'A50' torque cam:
11.05 mm, 650 rpm, 48.7 - 51.9 cc/1000 strokes
11.3 mm, 950 rpm, 67.8 - 69.8 cc/1000 strokes
11.15 mm, 1300 rpm, 70.9 - 74.1 cc/1000 strokes
10.95 mm, 1600 rpm, 67.0 - 70.2 cc/1000 strokes

4BD1T, IP id 101401-0660, 'A75' torque cam:
10.2 mm, 550 rpm, 29.7 cc/1000 strokes (no boost pressure)
10.95 mm, 550 rpm, 49.7 cc/1000 strokes (boost pressure above 2.13 psi)
11.2 mm, 900 rpm, 70.2 - 72.2 cc/1000 strokes (boost above 2.13 psi)
11.0 mm, 1500 rpm, 78.0 cc/1000 strokes (boost pressure above 2.13 psi)

BSFC (Brake Specific Fuel Consumption) is a measure of how much fuel is required for a unit of power (shows how efficient the engine is).

The Isuzu 4BD1 is pretty good, but a turbo improves the BSFC, and an intercooler gives further improvement.

The above figures for full load in the vicinity of 1800 to 2000 engine rpm show that fuel rate is very similar for the 4BD1T is only a little higher than the 4BD1, but we know the torque is much higher.

I have a 4BD1T, but if I had a 4BD1, I would fit a turbo for more torque and power. I considered LPG fumigation many years ago, when a light weight stainless steel LPG tank came my way. But the space that would be occupied by the LPG tank and availability of LPG in remote places, quickly turned me off the idea.

Clearly I could increase fuel flow and turbo boost pressure for all the power I need and carry extra diesel for more range without the problems of LPG tank/supply. For my requirements/situation it was a no-brainer.

Originally Posted by Sparkie

What is the A/F ratio of an idling diesel?

If we use the injection quantities just posted up by Bush65 (6.7-9.3 cc/1000 shots at 290 pump rpm) then a 4BD1 or 4BD1T idling at 580rpm has a minimum A/F ratio of 162.
This is using 80% VE, 280 g/kwh and the 6.7cc figure.
Using the 9.3 figure it would be 116:1

It's reasonable to assume the AF ratio goes down slightly as more fuel is injected to raise the the idle speed. Like most here I run a slightly higher idle speed of 750ish rpm.
Based on this my idle A/F ratio would be somewhere between 100-150:1.