In Car Boost Control

[gomulletgo]

Hi pig75,

I did just that, I made a thin blanking plate out of alloy. When I removed the overboost protection valve from the intake manifold I saw that there is alot of junky oily residue in there, here are a couple of pictures to show what I mean.

PICT0076@30.jpg

PICT0078@30.jpg

Here is a picture of the blanking plate installed

PICT0081@30.jpg

Once the blanking plate was installed I took it for another drive, again the most i can squeeze out of it is 13psi even with the screwdriver still blocking the hose that would normally go to the wastegate actuator.

Does anyone have any ideas why my truck won't boost over 13psi?

[pig75]

Maby a restricted exhaust

[geeves]

Try it on a moderate hill in a gear that at full throttle gives around 2500rpm

[gomulletgo]

Try it on a moderate hill in a gear that at full throttle gives around 2500rpm

Already done, there is just such a hill near my house and this is where I have done all of my testing.

pig75 do you think that the junky oil has got to the exhaust gone hard and started to block things up? How do I work out if I have a blocked exhaust? Would I expect to see high EGT if the exhaust was blocked? Could the wastegate spring be weak or something and be blowing open by itself? Thanks all for your help, I'd be totally stumped without you guys who have alot more experience with isuzu's than me

[pig75]

You could try tying a piece of wire from the wast gate arm on the turbo to the diaphragm so it can't move. Check that it moves first. It will take a fair bit of force to move it. About 5kg.
If that doesn't work there should be some flanges on the exhaust flex joint just unbolt one and try it. It will be loud

[electrifying]

I have the same problem, won't go above 10-12 psi (with boost controller at max).
I was going to try un-bolting the exhaust to see if a 'straight-through' muffler would do the trick.

Haven't had time to try yet, but will do so in next few weeks.

[pig75]

I just tested my stock 2.8 MU with the gate disconceted i got 16psi

[gomulletgo]

You could try tying a piece of wire from the wast gate arm on the turbo to the diaphragm so it can't move. Check that it moves first. It will take a fair bit of force to move it. About 5kg.
If that doesn't work there should be some flanges on the exhaust flex joint just unbolt one and try it. It will be loud

I have used a screwdriver to push the wastegate open, it seems to open and close just fine and requires about the same amount of pressure to do so as another 4JB1ITD turbo that I have here.

I haven't wired the wastegate shut yet, I still intend to, just need to work out how to.

I also checked to fins of the compressor turbine, they look just fine to me, rotates nicely, next to no play in the shaft.

I don't follow what you mean about the exhaust flanges, I don't think my exhaust has a flex joint.

Interesting that you got 16psi, do you think the shorter exhaust of the mu could account for the 3psi difference?

I have the same problem, won't go above 10-12 psi (with boost controller at max).
I was going to try un-bolting the exhaust to see if a 'straight-through' muffler would do the trick.

Haven't had time to try yet, but will do so in next few weeks.

I'll be interested to see what results you get

[electrifying]

I tried un-bolting the flange, but the bolts were too tight, so I will cut the pipe off, unless someone else has a better idea.
Vehicle is only just making it to 100km/hr (with big tyres on though)

[electrifying]

ok, i used a grinder & cut the exhaust off.
Huge difference in sound, very little difference in power. In fact the vehicle sounds like a logging truck now, but with less power (i love the spool sound on the turbo ). The neighbours will probably get sick of the sound soon.

Since i have taken the exhaust off, i am going to "up the fuel", as it would have less of a chance overheating with no exhaust. (i haven't installed my pyrometer yet)

Will tell you how it goes (if i can get out without waking the neighbourhood tonight)

[electrifying]

I finally got the "non tamper cover" off the fuel injector, what a heck of a job just trying to get it off!
I had to pull the "green sensor" out of the fuel pump (where the fuel output is) to get at the fuel adjustment screw, as there is not much space to work around.

Anyway, i firstly adjusted the fuel adjustment screw the wrong way (anticlockwise). I noticed greater difficulty in starting, and it wouldn't idol when cold (kept stalling). Taking it for a test drive (after warming it up for 5 mins), i noticed the huge spool time for the turbo; about 5 seconds to get any kind of power . Also, going up a slight hill, it would not accelerate much. Turbo pressure at 3,400RPM was max 10psi.

Second attempt, from the factory position, i then adjusted the fuel screw just over 1/2 a turn clockwise (in). WHAT A DIFFERENCE!!!
The turbo spools up a lot quicker (almost instantly), get's up to speed as it should, and testing it on country roads where it previously struggled to get to (and stay at) 100km/hr with the big tyres on, it was able to easily hit 110km/hr.
I did notice a slight water temperature increase from 80Celcius (previous opperating temp @ 100km/hr) to around 85Celcious (running 100-110km/hr tested at night, cool air), however coming days will show how hot it will get. Will wait for a hot day and a big hill
Max turbo pressure now hitting 14psi @ 3,400RPM.
I will be a lot more confident overtaking people now.

All testing was done on diesel to prevent over adjustment of fuel pump. (compared to vege oil)
- With the new fuel setting, the engine does idol slightly higher than previously. I may adjust this.


I may turn the fuel screw up another 1/4 turn (total = 3/4 past factory setting) to see what difference it will make.
I don't want to overdo it, but would like to see if it is possible to get the turbo pressure a bit higher.
Also, the exhaust is still cut off, so i don't know what kind of power there would be with a standard exhaust on.

[jellis]

if you want more boost why not just buy a boost controller off ebay
http://cgi.ebay.com.au/Turbotech-manual ... 335e98a59b

thats the one i brought worked fine. just make sure you dont have much blow by as it vents to atmosphere and sprays the oil everywhere.

[iananita]

Have a look at this, 2.8 Pajeros apparently use the same Bosch VE injector pump

http://www.pocuk.com/forums/viewtopic.php?t=94105

and also Peugeots, this is a great thread

http://autospeed.com.au/cms/title_Our-P ... ticle.html

[jellis]

Have a look at this, 2.8 Pajeros apparently use the same Bosch VE injector pump

http://www.pocuk.com/forums/viewtopic.php?t=94105

and also Peugeots, this is a great thread

http://autospeed.com.au/cms/title_Our-P ... ticle.html

I think this deserves a thread to it's self.
I wish had the confidence to do something like this to my truck

Has any one played with this stuff? If so what were your results?

[scotts90]

very interested in this thread, im in the process of doing my own testing at the moment

[electrifying]

Thanks "Jellis", but i had already got one second hand, there was just not enough fuel to get the boost pressure up any higher.
I was feeling inquisitive, and thus turned the fuel screw up another 1/2 turn (now 1 turn past factory setting) . I have noticed even better boost pressure, especially when doing 100km/hr (as the engine is revving at about 2,200rpm).
So, some basic data so far:

Speed: 100km/hr
Fuel screw(past factory, turns): --turbo pressure: --engine rpm:
0-----------------------------------------8--------------------2,200
1/2--------------------------------------10-------------------2,200
1-----------------------------------------12-------------------2,200

0-----------------------------------------12--------------------3,500
1/2--------------------------------------14--------------------3,500
1-----------------------------------------14--------------------3,000 (not taken any higher yet due to sump oil strainer blockage...again )

I am very happy with this, basically saying that 1 full turn past factory settings increases the lower-rev torque of the engine (the thing i was trying to measure)
I did notice a slight haze of smoke in the rear vision mirror, but not fussed at the moment.
I have also adjusted the idol control, so it is back to normal idol rpm.

One other thing, engine is not too happy; sump oil has turned thick (due to WVO fuel), the sump oil is like exterior weather paint, and didn't sound too good last two times cold starting (sounded 'tight', sticking, and slow to turn over [like a flat battery, but my battery is not flat], also sounded like how some old American v8's start up) - so i have taken the oil strainer out & am soaking it overnight, and done an engine flush with diesel & oil combo, but that is all for another thread



Also, that thread on Peugeots is very good, not going to try the boost compensator yet, i will leave that to when i want better engine performance.

[iananita]

I would think this is what dyno shops do.
When I had my Rodeo done(4JB1) made a huge difference.
Will be the Jackaroo(4JG2) turn sometime once I get the pump done, slow leak so will be able to get it done on the bench.