Sorry for the long post. I'm looking for guidance...

I swapped in a p-pump 4bt in my Scout a couple of years ago. I did a restoration at the same time so it took a while. (My full build thread is under my same user name on 4btswaps)

I am now in the performance tuning side of things. I have been struggling to get more power. I have found and fixed a bunch of odds and ends that I thought were related, but I'm still coming up empty on the performance side. Here is where I'm at:

-Motor got a lower gasket kit and valves adjusted.
-P-pump got rebuilt this week on the rack side, governor was rebuilt 3 years ago.
-Has a 4k GSK spring set
-Plate has been ground to a #100 and slid all the way forward
-AFC is pushed all the way forward
-Star wheel has been cranked
-Smoke screw turned in a little
-New lift pump
-Stock Injectors pop tested and are at 250BAR (should be 260BAR)
-Fuel filter has been changed
-Performance overflow valve has been installed
-Boost elbow installed and tightened all the way
-Factory HX30w turbo rebuilt
-Wastegate actuator tightened
-Large CAC intercooler

My pump was rebuilt this week and on the bench it is flowing a bunch of fuel. My problem is that I expect that I would be absolutely blowing black smoke out of the tailpipe. I'm not. I have an HX35 ready on my bench because soon I'm going to a twin setup. Before I do that though, I want to know where all my fuel is? Mysteriously I used to be able to get to 29psi in 4th and 5th gear under full load. Now all I am getting is 21psi max. That is with a slight haze at WOT. I was able to get my EGT's to 1050 this week, but that was seriously beating on it WOT up a steep hill. It touched that for a moment then backed off to 850. My injection shop claims that my stock injectors will flow that fuel and because I don't have enough air that I should be smoking like crazy. Is that true? I feel like my injectors must be restricting the flow enough to bottle neck. I have researched for days and I can't seem to find a good thread on any forum to fully explain injectors. Yes, they talk about 5x.012's etc, but not specifically if they truly restrict flow.

Should I just bite the bullet and buy new injectors? Is that my problem?

I am seeking as much clean power as I can get with twin turbos. My research tells me that will probably be about 275hp. I haven't dyno'd it and it drives great and it will set you back in the seat if you ask it to.

Anyone have any suggestions or personal experience to share?

Thanks!

 

I don't have any experience with the 4BT, but if you go to the Hardcore Corner (sub-forum) on ih8mud.com and look for boots4 (screen name). Anyway, he is in Portland, Oregon, and has a Toyota FJ60 with a 4BT in it. He has done a lot of mods to boost performance, and is currently working bugs out of a twin turbo set up. Find him, and do a lot of reading about what he has done. Then, maybe contact him.

Don

 

Hey Guys check out my new blog on Diesel Engines. Got some real cool informa

 

I would be putting a set of injectors in it for sure. If you send me a pm I can set you set up with a builder that i use, honestly the smartest man in the business, what exactly did this pump shop do? What are the flow numbers of the pump? What is your timing set at? What are your goals? There is a lot going on here, with more info I can send you in the right direction

 

So the pump shop put in new barrels, plungers, springs etc. He went through the governor and didn't find anything wrong with it. He did not change my settings and gave it back to me the way I gave it to him which he benched at 280cc/1000. He told me I'd blow up my motor at that flow rate. I signed his invoice saying he wasn't responsible for my motor.

He internally pin timed my pump at 16.5 degrees. My goals 'I think' are 250-300hp running twins with no smoke. I believe that will be in the neighborhood of 45psi of boost.

My theory is that the stock sticks are just bottlenecking my flow. WOT under a load I finally touched 1150 degrees on my pyro for a second before it dropped, but I'm not smoking at all. A slight haze is all I get even if I'm really on it. There is no way they are flowing 280cc, maybe not even half of that.

Thanks for the reply and help.

 

In a perfect world you can make 2hp per 1cc. Not easy to do, but I would say you could make around 400hp with that pump. Those injectors however need to be upgraded to achieve that imo. Timing at 16.5 is pretty decent, if it was my build I would advance it a little bit. But 280cc is not nearly as high of a number as he thinks it is. People throw over 1000cc into the 6bt engines all the time. I would contact him and ask him the specs on the delivery valves as well.
A set of HSI injectors may be in order.