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4jg2 most HP

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4jg2 most HP

Postby rustyvr4 » Fri Jan 04, 2019 5:53 am

just a curious question for those who have or had the 4jg2t engine. what is the most horse power you can get out of them?, and maintain good reliability. what are the steps taken to get the horse power you got or are getting?
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Re: 4jg2 most HP

Postby tonkamu » Fri Jan 04, 2019 8:14 pm

You can get a lot out of any engine if you spend big money. Do you mean decent gain in hp while keeping it reliable? Is it an efi or mechanical pump. Just the usual mods is about all you can do, unless you go bigger turbo and more fuel. But I don't think 4jg2 heads last long with a lot of boost? Even what you're running 20psi is more than what's considered "safe" on 4jg2 from what I've read, safe max is 15?.
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Re: 4jg2 most HP

Postby geeves » Sat Jan 05, 2019 6:12 am

Best way to go with 4jg2 is 4jg1 pistons 4jj1 or 4jg1 head and diesel pump 12mm plunger in pump and tune away. You are looking at a full recon to do this and it would only give a little more power than you can get out of a 4jj1 which would be cheaper to get by buying a low mileage holden ute and stripping
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4jg2 most HP

Postby rustyvr4 » Sat Jan 05, 2019 7:28 am

model i have is mechanical pump. so far on the pump i.v adjusted the boost comp, rotated the cone shaped thing and backed off tension on spring. adjusted fuel rate screw. and backed of, cold start device adjust screw. been running peak 20psi nearly a year. 100kmh on open road she pulls 8psi. yet to do intercooler and proper exhaust. can i go to big on intercooler? thinking about using this as a top mount https://www.trademe.co.nz/motors/car-pa ... 476944.htm
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Re: 4jg2 most HP

Postby geeves » Sat Jan 05, 2019 2:16 pm

That intercooler is designed as a front mount for a smaller engine. Front mount is always going to work better but there are plumbing challenges. Factory intercooler with an added fan will do as well
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4jg2 most HP

Postby handymanny01 » Sat Aug 24, 2019 10:09 pm

Thought I'd share my experience in this area... my 4jg2 had been running 20 psi, VF10 hybrid , and a maxed out std injection pump,, for years,,, with water to air intercooler,, and 3" dump and full 3" system, 3" inlet and pod filter... (and all normal mods like egr delete) dynoed recently at 95kw / 127hp at the wheels,,,, Then fitted a REAL hot rod injection pump,,, Holy shizz!!! Estimated 125kw at wheels (145kw ish at crank) Sadly only lasted 2 weeks,,, serious piston damage,,, (as it flew past 160kph on 33's) So I'd say safe limit on 4jg2 is prob 100 kw at the wheels... and 600 c on the EGT ,,, 650 c for brief periods,,, Next build is 4JG1-T (will post all details , and dyno result) stay tuned!
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Re: 4jg2 most HP

Postby AusZuMu » Sun Aug 25, 2019 8:07 pm

Looking forward to the updates Handymanny01, I have a long list of maintenance and servicing tasks I should do before I get into the performance mods for my 4jg2.
Picking lines and stripping splines.
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Re: 4jg2 most HP

Postby handymanny01 » Sun Sep 08, 2019 6:17 pm

Gotta say,,, these are TOUGH little engines!! (4jg2) Pulled her to bits over the week,,,, over 300'000 kms,,, and the crank is still within service limits! And the recent blow up, damaged 1 piston and liner,, and that's it! 4jb1 head purchased, and slowly sorting which 4jg1t pistons are the most suitable,,,, then the 4jg1t rebuild will begin!! Liner removal pics to come...
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Re: 4jg2 most HP

Postby handymanny01 » Wed Sep 11, 2019 5:23 pm

The damaged piston.... prob the result of squeezing an estimated 140kw (crank) out of it... lol
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Re: 4jg2 most HP

Postby handymanny01 » Wed Sep 11, 2019 7:54 pm

Pressing the liners out of the block,, needed to make a special tool.., bout 5 ton to press them out... block seems totally fine.... will prob get it decked very lightly though.... just so it's perfectly flat,,,
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Last edited by handymanny01 on Thu Sep 12, 2019 4:00 pm, edited 1 time in total.
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Re: 4jg2 most HP

Postby handymanny01 » Wed Sep 11, 2019 7:58 pm

The new 4jb1t head mocked up on on the 4jg2t block,,,, ohh yes! It will be so!!
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Re: 4jg2 most HP

Postby AusZuMu » Wed Jan 08, 2020 4:18 pm

Any more updates Handymanny01?

following with interest, not sure what path I want to go down.
Part of me is now considering power and efficiency of a more modern engine swap like a 4JJ1-TCX or 1KD-FTV as complicated as the wiring/electronics side may be.
Picking lines and stripping splines.
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Re: 4jg2 most HP

Postby handymanny01 » Wed Jan 08, 2020 9:17 pm

Yup! New thread under "4jg1t franken-engine" just working on getting pics resized so I can upload !
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Re: 4jg2 most HP

Postby handymanny01 » Wed Jan 08, 2020 9:23 pm

And common rail swaps are essentialy a no go as they take signals from many things that our older vehicles simply don't have... electronic speedos, gear position sensors and the like, I know of a crusty old Toyota that had a common rail swap,,, the bill for this exceeded the value of the car AND engine... ouchies!
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Re: 4jg2 most HP

Postby mh1989 » Fri Jan 24, 2020 5:46 pm

handymanny01 wrote:And common rail swaps are essentialy a no go as they take signals from many things that our older vehicles simply don't have... electronic speedos, gear position sensors and the like, I know of a crusty old Toyota that had a common rail swap,,, the bill for this exceeded the value of the car AND engine... ouchies!


Its pretty easy to get a 4jj1 running by itself
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Re: 4jg2 most HP

Postby handymanny01 » Fri Jan 24, 2020 9:22 pm

mh1989,, do tell!!! We are all ears! I've got friends in the diesel fuel injection trade, and their opinions are "way too hard" but if you have a short cut idea,, then I'm IN !! I'd love a common rail in the MU!!
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Re: 4jg2 most HP

Postby geeves » Sat Jan 25, 2020 4:37 am

4jj1 is diect injection not common rail
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4jg2 most HP

Postby handymanny01 » Sat Jan 25, 2020 7:28 am

Maybe you're thinking 4jh1 (3.0 rodeo) Geevs ? 4jj1 is current direct injection common rail engine in rodeo and Colorado . The 4jj1 has completely different injection system, common rail ,central injectors, 16v head,,, Thus why we are stuck playing around with the 8v engines, I'm assured by my fuel injection tech that it would just be too hard to make the common rail engine run in an MU cause of all the missing sensors,, As always, I'm super open to hear if anyone has actually got one going in something else though!
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Re: 4jg2 most HP

Postby geeves » Sat Jan 25, 2020 2:22 pm

The base engine is direct injection. Dont know if you could fit a antique pump and make it convential direct injection
Sanding your knuckles before starting work can help. That way you cant skin them
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Re: 4jg2 most HP

Postby isuzurob » Sun Jan 26, 2020 6:05 pm

4jj1 is a straight bolt into any 4jb1 4jg2 4jh1, custom clutch setup, run full factory loom sensors on ecu or be a man and run the motec ecu system for only 10grand then you have a real engine with bigger turbo and 30+injectors, have done a few now, but hey what would I know running 1200 degree Celsius ae
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