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Post by jjcymru on Apr 18, 2006 6:00:02 GMT 11
rite then folks ive an intercooled 4jb1 2.8 and am looking for more oomph.. suggestions on how to achieve this very much appreciated. Cheers Jon
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Post by mudgrip4 on Apr 18, 2006 13:18:09 GMT 11
As people have noted elsewhere for you, there are a few things you can do to improve performance markedly from the 4jb1T. It is easy to tune.
Bigbore exhaust ex turbo will improve low down grunt helping turbo kick in well from 1500rpm plus useful hp gain. Increasing diesel flow to this motor can help up to 15hp and takes 20 minutes. Advancing diesel pump injection timing (get a diesel specialist to do this) also big power increase with more usable revs at top end - takes about 30 minutes. And fit K&N performance filter - you may find you can buy one that fits straight into existing airbox.
These steps will give you a very perky isuzu.
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Post by dani4JB1T on Apr 18, 2006 14:42:23 GMT 11
Increasing diesel flow to this motor can help up to 15hp and takes 20 minutes. How`s that mudgrip4 ?? |
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Post by mudgrip4 on Apr 18, 2006 21:28:03 GMT 11
there is a fuel delivery increase screw on the pump - get a mechanic to show it to you if you can't find it - sometimes has a little metal cap on it Remove cap and turn screw inwards (clockwise) maybe a quarter turn to start, then if warm, roadtest. You should notice improvement straight away. Then continue to adjust screw clockwise by say one eighth or even one twelfth of a turn until the motor starts to blow a fair bit of black at 3000 rpm. Then come back one adjustment as max hp/kw on dyno occurs just before big black smoke which is unburnt diesel. No need to road test after each adjustment - just rev to 3000 while standing and hold for a second until you get increase right.
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Post by jjcymru on May 3, 2006 22:47:41 GMT 11
done that and it flies, and i get better economy now  anything else worth doing? im thinking about removing the egr's |
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Post by Graham on May 4, 2006 1:20:00 GMT 11
Better economy too? DAmn, I'm playing with that this weekend then. Does anyone have a pic to show a dummy like me where the fuel pump & adjustment screw are?
Cheers, Graham.
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Post by mustu on May 9, 2006 10:34:14 GMT 11
Has anyone got a photo of this little screw?  I think I know which one it is (mine still has the cap on) but want to make certain.  Cheers, Stu |
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Post by sneeble on May 9, 2006 11:58:33 GMT 11
mine is turning into the black and white ministrel, burns black white and after a few curses blue. The local mechanic fiddled with mine and its steadily got worse from there.
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Post by jjcymru on May 9, 2006 20:01:52 GMT 11
white means your not burning it hot enough.
Glow plugs prob required.
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mattmurdoch
Isuzu Junior
when the going gets rough..
Posts: 68
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Post by mattmurdoch on May 10, 2006 8:04:55 GMT 11
im withthe others about wanting a pic but only if thisl work on my 3.1 mu....
Matt
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Post by mulover on May 10, 2006 19:14:05 GMT 11
It will work on any mu, pic is hard to take as it is right under neath the fuel pump unit, its a slot headed thread with a locking nut on it, if it hasn't been tampered with then it should have a alloy cap on it which is easyily knocked off with a screw driver.
I found the easyist way to get at it is to take the passanger wheel off and go in from there. Remember to lock the nut up tight whist holding the thread so that it doesn't turn.
Sneeble, i would suspect the screw may be loose if its getting worse??
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Post by jjcymru on May 12, 2006 21:07:24 GMT 11
besides the max fuel screw is there anything else i can do?
injection timing, boost compensator? Alternative fuel?
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Post by 280inyati on May 29, 2006 21:24:05 GMT 11
Good day to all of you guys, introductions first, my callsign is 280iNyati; ie 280=280DT Isuzu DC 4x4 iNyati=Zulu word for African Buffello hence, I'm from South Africa and a member of the Isuzu Offroad Club and 4xforum www.isuzuoffroad.co.zawww.4xforum.co.zaFor more oomph, you must look at the following: EGT = exhaust gas temperature - to high and your pistons and turbo will get damaged. turbo boost amount of fuel delivered exhaust gasses intercooling You've got the intercooler, next step would be to fit a 63mm dia freeflow exhuast fom the turbo. Recalibrate your diesel pump as mentioned above, BE CAREFULL OF TOO HIGH EGT'S - recommend in doing it on a dyno for quantity and timing. Your boost levels, amount of fuel and fuel timing determine your power curve and EGT levels. Max reliable setting should be at 750deg C. Too counter this problem and get more out off your engine, do ceramic coatings on all relevant internal parts, combustion chamber etc. On such a conversion we normally get 95kw and 320nm of torque on the wheels. Just for thought, install an electric fan in front off or above intercooler, connected to a thermal switch in the inlet manifold after the intercooler. If you do slow speed 4x4 in thick sand etc, is there not enough air going through your intercooler for the desired powercurves, the electric fan will adress this. |
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Post by Witchdoctor on May 29, 2006 21:36:01 GMT 11
Great post & welcome aboard 280inyati Dave |
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Post by dasnoboarder on Aug 4, 2008 15:21:03 GMT 11
Hey all. Bringing up a thread from May '06...
Been in contact with one diesel shop. Asking about increasing my injection timing. They said they wouldn't do it without exact specs. "Increasing it untill the motor begins to knock, then back off a bit" wasn't accurate enough for them... Anyone have the measurement from standard that it needs to be increased by? Or any approximate value?
Alternatively, anyone had experience with a diesel shop in Auckland that has done this type of stuff for them?
4JB1T by the way...
Cheers, Andy.
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Post by superturbocompound on Aug 6, 2008 2:37:24 GMT 11
Hey all. Bringing up a thread from May '06... Been in contact with one diesel shop. Asking about increasing my injection timing. They said they wouldn't do it without exact specs. "Increasing it untill the motor begins to knock, then back off a bit" wasn't accurate enough for them... Anyone have the measurement from standard that it needs to be increased by? Or any approximate value? Alternatively, anyone had experience with a diesel shop in Auckland that has done this type of stuff for them? 4JB1T by the way... Cheers, Andy. basically the knocking sounds is rapid rise in cyclinder pressure,so retarding the timing until the sounds disappear should work.advancing the timing 'can' yield more power/torque cos it'll give the diesel more time to burn at the proper crank angle.maybe the shop wanted to know the timing map of the fuel pump,this is based on the spring rate that defies the timing curve of a given pump.(little round thing at the bottom of the pump)they can change the spring rate by shimming or changing the spring all together. |
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Post by superturbocompound on Aug 9, 2008 10:56:34 GMT 11
another way of playing with the fuel is to rotate the boost compensator pin,located on top of the fuel pump,this increases or decreases the amount of fuel under boost,
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Post by alfabomb on Aug 11, 2008 8:44:56 GMT 11
first block of the waste gate on the turbo, then instal a good qualtey boost guage, not a crappy $40 guage. next youl want to drill and tapp a hole as close as you can get to the port which is the hottest part of the exhaust gas and screw in a pyro metter senser and guage. these can get expencive but onley needed if you want big gains without destroing the engin. a pyro meter test the engine temp, and when pouring in the diesel things get hot very fast when under load. next take a look at your fuel injection pump, look on the top and you should be looking at the boost compensater. what this part does is leans of the fuel when boosting past a set limit. it governs how much fuel to hold back when at a certin boost. it has a dirfram, a spring and a cam rod in it. some models have a screw in the middel of the top cover, these ones dont need to be modderfied. if there is no screw you need to take the cover of very carefully not to move the direfram as it spins around and can upset everything and yyoul need to pay for it to be reset with the right specialty tools. once you have the cover off drill a 6mm hole in the center then braize a 6mm nut over the hole then screw a 6mm bolt with another bolt so you can lock both bolts together. bolt cover back on without moving the dirafram. probley best to mark its position first. next thing is to look for the main fuel screw on the back of the pump, it will probley have a cap over it. pop the cap of and your reddy for action. start the engine and get it to running temp. next wind down the compensater screw 1 turn and taking a drive, youl notice an incress of power. keep adjusting it down until youl sudinley losse most of that gained power, wind back half a turn and lock it with the other bolt. next wind the main fuel screw in half a turn then take a little drive and look for black sotty smoke out the exhaust. keep adjusting the main fuel screw and taking test drives until you got quite a bit of black smoke and the pyro temp is under 800 degres. next you may need to advance the pump timing. theres a mark on the engine side cover where the pump bolts to the engine. that mark is the timing mark, the pump has one also that should be about 3 to 7mm above the cover mark. lossen of the bolts holding the pump and then twist the pump up about 1/4 a mill and tighten the bolts back up. start the engine then place a screwdriver handel in your ear and the other end pressed as close to the bottom of the cylinder head as you can probley the lip between the head and the block. now listen for any sharp banging popping sounds out of the norm, this noise is you engine squiting the dieses in to soon and it is to much pressure on the compresion cycle. diesel is injected just before top dead centre because it takes time for it to ignight and burn. you have to useley advanced the pump because your putting more fule in and its taking longer to ignight so keep anvanceding the pump but listen for the banging popping noise as this will probley end up smashing holes in your pistons.
and that is everthing you can do to ya pump without special tools.
keep adjusting both fuel and compensater screws to get better power gains but remember to keep it under 800 deg, 900 max but not for long peroids just passing and burning rubber.
hope this helps.
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