Isuzu Dmax Owners [continued]

**d_mac** · May 24th, 2013 11:14 PM

Originally Posted by arsen

The pneumatic actuator of your waste gate turbocharger is connected to the outlet/discharge of the turbocharge itself. See blue hose.

If the pressure at the outlet/discharge of the turbocharger create enough force to overcome the spring, the actuator rod will extend.

The actuator rod is the part that opens up the gate

The above photos just showed that in wastegate turbocharger, the gate is normally closed. Which means all exhaust gases passes through the turbine which causes your wastegate type turbocharger to spool even if the vehicle is at neutral.

You may not hear it when you rev the engine in neutral because the engine is not loaded.

If the engine is not loaded: less fuel >> less combustion pressure >> less violent is the whistling sound coming out from the turbo or wastegate.

When it comes to VGT, VNT, VGS turbo, its a different story... just don't mix it up.

Thanks for this idol ;)

How much chief is the air : fuel mix ratio in a typical CRDi engine at idle mode - 100 : 1?

How about when it's really loaded to keep the temperature at check (assuming with an EGR), about 20 : 1 air : fuel ratio. Can it also be around 30 : 1 or no?

Gasoline-fed EFU typically ilan, around 14 : 1 as against carbureted but say re-jetted about 13.5 : 1? kaya mas tipid consumption ba ng diesel- kaysa sa gas-fed?

i know kabisado mo nga ito chief why am asking ;) ....Cheers!

**arsen** · May 25th, 2013 08:48 PM

Originally Posted by d_mac

Thanks for this idol ;)

How much chief is the air : fuel mix ratio in a typical CRDi engine at idle mode - 100 : 1?

How about when it's really loaded to keep the temperature at check (assuming with an EGR), about 20 : 1 air : fuel ratio. Can it also be around 30 : 1 or no?

Gasoline-fed EFU typically ilan, around 14 : 1 as against carbureted but say re-jetted about 13.5 : 1? kaya mas tipid consumption ba ng diesel- kaysa sa gas-fed?

i know kabisado mo nga ito chief why am asking ;) ....Cheers!

Hindi ko to kabisado ha pero just want to share na rin some info that I have.

These are actually regarding your 4JJ1-TC engine

Mass Air Flow
min = 0.3 (grams/cylinder)
max = 0.6 (grams/cylinder)

Desired fuel injection volume
* Idle (700rpm):
min = 6 cubic millimeter, mm3 (each injector stroke)
max = 12
* 2000rpm:
min = 9 cubic millimeter, mm3 (each injector stroke)
max = 13

Using diesel density of 850g/L, we can get the 0.850g/cc, and reduce the unit further to 0.00085g/mm3

M.F. Mass of Fuel can now be computed as follows:
*Idle(700rpm):
min = 0.0051grams (6mm3 x 0.00085g/mm3)
max = 0.0102 grams (12mm3 x 0.00085g/mm3)
*2000rpm:
min = 0.00765grams (9mm3 x 0.00085g/mm3)
max = 0.01105 grams (13mm3 x 0.00085g/mm3)

4JJ1-TC Air-Fuel Ratio (mass of air/ mass of fuel) can now be computed as follows:
*Idle(700rpm):
bihira = max M.A.F / min M.F. = 0.6 / 0.0051 = 117:1
possible1 = max M.A.F / max M.F. = 0.6 / 0.0102 = 59:1
possible2 = min M.A.F / min M.F. = 0.3 / 0.0051 = 59:1
possible3 = min M.A.F / min M.F. = 0.3 / 0.0102 = 29:1

*2000rpm:
bihira = max M.A.F / min M.F. = 0.6 / 0.00765 = 78:1
possible1 = max M.A.F / max M.F. = 0.6 / 0.01105 = 54:1
possible2 = min M.A.F / min M.F. = 0.3 / 0.00765 = 39:1
possible3 = min M.A.F / min M.F. = 0.3 / 0.01105 = 27:1

Sa gasoline engines, kapag sumara na ang intake valve. Larga na. No additional fuel is added. The Air/Fuel ratio of the mixture has been determined. The thermal potential of the combustible mixture is already set and just waiting for that spark

Sa Diesel engines.... Air/Fuel ratio is variable... very variable that even if desired values and tight tolerance are set. the value of variations is still very significant.
Even if you both have the same 4JJ1-TC engine by nameplate. The performance and characteristic may not be exactly the same.
Simply because even with tight tolerances,
*Idle, A/F ratio can be as lean as 117:1 or as rich as 29:1
For example at operating speed of 2000rpm, A/F ratio can be as lean as 78:1 or as rich as 27:1

What more if the engine is operating outside the tolerance or outside of the desired values of the manufacturer/designer?

**bugoys** · May 28th, 2013 01:24 PM

Originally Posted by arsen

The pneumatic actuator of your waste gate turbocharger is connected to the outlet/discharge of the turbocharge itself. See blue hose.

If the pressure at the outlet/discharge of the turbocharger create enough force to overcome the spring, the actuator rod will extend.

The actuator rod is the part that opens up the gate

The above photos just showed that in wastegate turbocharger, the gate is normally closed. Which means all exhaust gases passes through the turbine which causes your wastegate type turbocharger to spool even if the vehicle is at neutral.

You may not hear it when you rev the engine in neutral because the engine is not loaded.

If the engine is not loaded: less fuel >> less combustion pressure >> less violent is the whistling sound coming out from the turbo or wastegate.

When it comes to VGT, VNT, VGS turbo, its a different story... just don't mix it up.

Thank you sir! Appreciate it.

**Gerbo** · May 30th, 2013 05:43 PM

Originally Posted by d_mac

October 2013 sir, but please do not fret yet ;).... You know what the possible backlash is ---- they at IPC still don't know if the engine mated to the new D-max will be the:

1. Relatively new and tweaked-out 4JJ1-TCX engine (180 hp, 380 Nm torque from 1800-3000 rpm); or
2. The old 2004 model and currently existing on offer 4JJ1-TC (146 hp, 294 Nm torque from 1400-3400 rpm); or
3. The also 2004 model 2.5-litre 4JK1-TC, but with a single VNT (136 hp, 320 Nm from 1400-2400 rpm yata); and
4. Never will be the 2.5-litre 4JK1-TC with twin-turbo (163 hp, 400 Nm from 1400-2400 rpm) will be offered here as it's only for the European market.

Honestly, i feel we "might" be duped again or "short-handed" again (and again) by Isuzu Phils. Tsk tsk tsk.... In case new body yan at 4JJ1-TC pa rin makina, then this is going to be the totally irresponsible offer ever by Isuzu Phils that it will be referred to as "the mother of all cosmetics!" tsk tsk tsk tsk.... i hope we get the new 3.0 iTEQ VGS Turbo engine (4JJ1-TCX).

Kung sanang all-out lang ang Isuzu Phils, the same way as Toyota Phils., Mitsubishi Phils., Ford Phils., Chevrolet Phils., and Nissan Phils. we feel OK with the offers....

Cheers!

This is most sensible option given what is current in the Ranger and the Colorado. The new DMax is expected to bulk up so its imperative to have an upgrade in the powertrain.

**d_mac** · May 30th, 2013 10:33 PM

Originally Posted by arsen

Hindi ko to kabisado ha pero just want to share na rin some info that I have.

These are actually regarding your 4JJ1-TC engine

Mass Air Flow
min = 0.3 (grams/cylinder)
max = 0.6 (grams/cylinder)

Desired fuel injection volume
* Idle (700rpm):
min = 6 cubic millimeter, mm3 (each injector stroke)
max = 12
* 2000rpm:
min = 9 cubic millimeter, mm3 (each injector stroke)
max = 13

Using diesel density of 850g/L, we can get the 0.850g/cc, and reduce the unit further to 0.00085g/mm3

M.F. Mass of Fuel can now be computed as follows:
*Idle(700rpm):
min = 0.0051grams (6mm3 x 0.00085g/mm3)
max = 0.0102 grams (12mm3 x 0.00085g/mm3)
*2000rpm:
min = 0.00765grams (9mm3 x 0.00085g/mm3)
max = 0.01105 grams (13mm3 x 0.00085g/mm3)

4JJ1-TC Air-Fuel Ratio (mass of air/ mass of fuel) can now be computed as follows:
*Idle(700rpm):
bihira = max M.A.F / min M.F. = 0.6 / 0.0051 = 117:1
possible1 = max M.A.F / max M.F. = 0.6 / 0.0102 = 59:1
possible2 = min M.A.F / min M.F. = 0.3 / 0.0051 = 59:1
possible3 = min M.A.F / min M.F. = 0.3 / 0.0102 = 29:1

*2000rpm:
bihira = max M.A.F / min M.F. = 0.6 / 0.00765 = 78:1
possible1 = max M.A.F / max M.F. = 0.6 / 0.01105 = 54:1
possible2 = min M.A.F / min M.F. = 0.3 / 0.00765 = 39:1
possible3 = min M.A.F / min M.F. = 0.3 / 0.01105 = 27:1

Sa gasoline engines, kapag sumara na ang intake valve. Larga na. No additional fuel is added. The Air/Fuel ratio of the mixture has been determined. The thermal potential of the combustible mixture is already set and just waiting for that spark

Sa Diesel engines.... Air/Fuel ratio is variable... very variable that even if desired values and tight tolerance are set. the value of variations is still very significant.
Even if you both have the same 4JJ1-TC engine by nameplate. The performance and characteristic may not be exactly the same.
Simply because even with tight tolerances,
*Idle, A/F ratio can be as lean as 117:1 or as rich as 29:1
For example at operating speed of 2000rpm, A/F ratio can be as lean as 78:1 or as rich as 27:1

What more if the engine is operating outside the tolerance or outside of the desired values of the manufacturer/designer?

Chief, thanks a lot for this summary

.... So it's somehow still within the 100 : 1 air is to fuel in idle and 30 : 1 within those revs mentioned? Matipid-tipid nga ang diesel compared to gasoline EFi if i were to judge only on the basis of air : fuel ratio to achieve combustion whether direct or by pressure, cc-for-cc.

i don't have specific knowledge on these info you shared neither ways to compute, now, can the air : fuel ratio, say at peak hp 3800 rpm, be extrapolated using the info above just to give an indicative figure, or no?

Thanks idol. Cheers!

**d_mac** · May 30th, 2013 10:45 PM

Originally Posted by Gerbo

This is most sensible option given what is current in the Ranger and the Colorado. The new DMax is expected to bulk up so its imperative to have an upgrade in the powertrain.

Harinawa sir that we get the slightly-upgraded year 2006 model 4JJ1-TCX engine. Ang tagal na ng makinang yan nasa ibang bansa/ continents, ni hindi man lamang pinarating ng Isuzu Phils. sa atin. Proven engine pa naman where a lot can be tapped out from it with just the slightest mod, wika ng mga rallye at race teams. Matipid pa sa diesel consumption.

Ang assumption ko lang na baka hindi i-offer ang 3.0-litre engine na ito into the new D-max slated to be offered is that other SE Asian countries outside of Thailand that have this D-max now come only in 2.5-litre 4JK1-TC engine configuration (136 hp, 320 Nm torque from 1400-2400 rpm).

Cheers!

**Gerbo** · June 1st, 2013 04:40 PM

Originally Posted by d_mac

Harinawa sir that we get the slightly-upgraded year 2006 model 4JJ1-TCX engine. Ang tagal na ng makinang yan nasa ibang bansa/ continents, ni hindi man lamang pinarating ng Isuzu Phils. sa atin. Proven engine pa naman where a lot can be tapped out from it with just the slightest mod, wika ng mga rallye at race teams. Matipid pa sa diesel consumption.

Ang assumption ko lang na baka hindi i-offer ang 3.0-litre engine na ito into the new D-max slated to be offered is that other SE Asian countries outside of Thailand that have this D-max now come only in 2.5-litre 4JK1-TC engine configuration (136 hp, 320 Nm torque from 1400-2400 rpm).

Cheers!

Kung ito ilalagay nila, I would pity IPC. They would surely disappoint their core buyers. Parang 2.5 VNT Hilux lang yan. They have to benchmark what is in the Ranger and Colorado.

Even the purported MU-7 look like the Trailblazer.

O baka naman 2.5 2.5-litre 4JK1-TC engine for the 4x2, then the 3.0-liter 4JJ1-TCX engine for the 4x4.

Better if Isuzu would divulge what is incoming so that the loyalists will know. Marami nag iisip bumili ng Ranger at Colorado but are just being held kasi hindi pa matapatan ang reliability and fuel economy ng Isuzu.

**noygelo** · June 5th, 2013 04:56 PM

Fellow Tsikoteers and Fellow Dmax Owners...

My current Dmax LS SE was purchased last Sep 2012 and it's already 9 mos with me...It is my daily ride from home to office to home averaging 100 km/day with an occasional long drive during the weekend. Current ODO reading is 26,000 kms (so far wala namang problema, I'm religiously following it's PMS) and based on my computation, it will reach more or less 35,000 kms pag nag 1 year na sa akin. In view of this, although Isuzu engines are durable and dependable, hindi kaya over used ang unit ko? I mean, as what I've read and heard from car forums (there's aplenty), the average healthy/ideal mileage of a car per year in order for it to last long is 10,000 km. OMG!...9 mos pa lang si Dmax ko 26,000 km na tinakbo! I said to myself, kelangan ko na mag commute from time to time para mabawasan man lang ng konti and engine stress ni Dmax....sa kabilang banda, bugbog sarado naman ako sa commute na 100 kilometro lunes-biernes

...paano na si wifey???

Any advise will be greatly appreciated....

Thanks!

**rna800** · June 5th, 2013 05:10 PM

*noygelo: Hindi yan overused, sir. Gamitin mo lang ng gamitin, wag kang kabahan and wag mong isipin ung mileage. As long as you will religiously follow the PMS and choose your gasoline stations wisely, itatakbo ka niyan kahit ilang hundred thousand kilometers pa yan.

And remember that the warranty of stealerships, I mean, dealerships, is 100k kms or 3 yrs. So if your computation is right on and you are looking at 35k kms in 1 yr, that is just about right.

Ang abangan mo lang diyan sir, based from my experience is the EGR and SCV. Usually those are the parts that will have problems due to our dirty fuel here. Pero once na naayos and/or napalitan yan, it's back to normal.

Mine is almost 90k kms already, bought it way back in 08, so far so good. Though there were parts that were replaced that I was totally caught off guard due to the vehicle's early age, what can I do, it is what it is. Now I am loving it again.

**rna800** · June 5th, 2013 05:13 PM

Originally Posted by d_mac

Galing mong mag-source out sir ah! Way more than 20k kms. odo na ako sir since pinalitan ni Isuzu libre ang EGR ko noong 2011. Dapat pala pa-linis ko na rin hehe

Thanks for sharing chief!

Kailangan mag source out, sir, kaysa magpa goyo tayo sa stealership na hindi daw pwedeng ipalinis kasi ang tanging at kaisa isang solution lang na alam nila ay palitan ang EGR.hehe