Modding my 4jb1t for 250hp

[dieselguy86]

Ill use the 4jb1 sticks then.

On another note, i finally have my other turbo figured out, and its quite the hybrid haha. To start out, im using a vf34 ball bearing center section, a vf38 lightweight turbine, a vi95 (4jg2 turbo) exhaust housing, and a vifb compressor wheel and housing. This gives me a 40mm turbine with the standard ihi bolt pattern to the manifold, and a 41mm compressor. Best part is, i got it all for $850, and its all bolt together, should have really fast spool with the lightweight rotor and ball bearings, and enough air for 200hp. Ill post lots of pics as i build it.

I also ordered some ceramic dry film lube. Ill be coating the main, rod, and cam bearings, valve stems, and the cam and lifters.

[isuzurob]

The 4jh1 injectors will fit and work just spray pattern is different and if your going for high power you want the pattern to match the pistons other wise the risk of cracking them is far greater

[isuzurob]

Oh and if you run 4jh1 injectors you will have to make new injector pipes as the 4jb1 pipes dont work as I found out

[tezbang4jb1trodeo]

Sounds like a fun project. Will be following progress. Just in case you haven't already dont it but will need to run a lot stronger valve springs running 38psi of boost.
Looking forward to progress.
I have a spare 4jb1t that I'll be stripping down and doing something similar and then swapping with my stock one.

[paulthepilot5]

Hey guys, just letting you know that upgrading the crank is probably going to need to be on the table for these hi power builds on the 4JB1T. Snapped the crank a few days ago on my setup, this was with 11mm fuel injection pump on my compound setup whilst running 35psi. Currently looking at options to use a stronger crank. I have a spare engine but reluctant to just use it as the same thing will probably happen. Not too many options when it come to cranks with these things.

[paulthepilot5]

tezbang4jb1trodeo wrote:Sounds like a fun project. Will be following progress. Just in case you haven't already dont it but will need to run a lot stronger valve springs running 38psi of boost.
Looking forward to progress.
I have a spare 4jb1t that I'll be stripping down and doing something similar and then swapping with my stock one.

Doesn’t seem to be an issue, ran up to 46psi on my compound setup without valve issues.

[geeves]

valves are held closed by cylinder pressure. The issue that requires stronger springs is higher revs. This doesnt really apply to diesels

[tezbang4jb1trodeo]

Ah yeah okay, have always done springs on petrols when doing high horse power, high revs makes sense.

Upgrading crank sounds expensive.

[paulthepilot5]

Ytezbang4jb1trodeo wrote:Ah yeah okay, have always done springs on petrols when doing high horse power, high revs makes sense.

Upgrading crank sounds expensive.

Yes upgrading the crank is expensive, billet crank would have to be made probably $4k. The only other option is to get the factory crank Cryo treated to strengthen, which is the path I am going to go down. Anything around the 200hp + is going to be playing with fire on a stock crank. The crank in mine had a hard life, around 60-70 runs down the quarter mile and daily driven. Hopefully cryo treatment gets it over the line strength wise, pretty much out of options otherwise.

[dieselguy86]

Hard to believe it snapped, these isuzu cranks are built really heavy duty. 200hp isn't far from the stock hp, i wouldn't think they'd spec such a critical part so close to failure.

On another note, how'd that 2871r do? My math said it was a little small for smoke free power higher in the revs, but i bet it spools up really nice!