- Joined
- May 12, 2009
- Threads
- 27
- Messages
- 138
- Location
- Camp Verde, AZ and Parks, AZ
- Website
- www.vicsmba.com
My wife and I have a 1981 BJ42 from Canada. I won't go through the non-drivetrain upgrades (like stainless screws and bolts, bedlliner paint, powder coating, on-the-fly adjustable power steering, tach, etc, unless anyone is interested -- ask.
Many people ignore the gearing related to what transmission and tire size and lift. I'll start there. Toyota had 3.70 and 4.11 gears with 4 or 5 speeds and 30 inch tires. Some math will tell you that the final drive of a 4 speed with 3.70 gears and 30 inch tires is approximately the same as the final drive with a 5 speed, 4.11 gears, and 33 inch tires. This is how ours is set up -- so we have a Toyota stock final drive more or less, with the advantage of lower gears when needed and larger tires which are always needed
We have a 3" OME lift with one leaf removed from the rear (to make it sit flat instead of tipped forward).
The 3B has many iterations. Toyota made the same engine for commercial trucks -- with turbos. My intention was to build the engine enough to travel on the highway at a cruising speed of 75 (AZ speed limit) while still having the low-end torque of the 3B. See gearing -- most important to start there!
I purchased an AXT turbo and intercooler from AU. Many people don't know this but a turbo does NOTHING for power. It is not the compression that gives power. The turbo performs one function -- compresses the intake air. This increases the oxygen. This allows the burning of more fuel. If you don't add more fuel, it is of no use at all. Intercooler also allows more oxygen with lower temps.
Increasing the compression with a turbo requires that more air be allowed into the engine and to exit the engine. If not, heat will increase dramatically. We used a K&N intake filter and 2.5" exhaust.
Next comes the fuel. The 3B injection pump is NOT adjustable except for a limit on the max fuel when your foot is to the floor. We rebuilt the pump with 15% across the board more fuel. Great -- gotta get it into the engine though. So we got injectors with 15% more fuel.
Now we get to the fun part. So the intake and exhaust pipe are big enough (down pipe, intercooler too). The intercooler helps not only drop temps. but cooler air is also more compressed and has more oxygen. However ... there are intake and exhaust valves. So we forced the air in, sucked it out, added fuel ... and it ran too hot.
So we got a new (from Toyota) head and purchased 13-BT intake and exhaust valves and had the engine machined for these valves. There is no real difference in the heads except the bolts that hold it to the block so this is easy. Follow 13-BT instructions for valve adjustment. And to make up for the lesser number of bolts on the head, we used stronger studs.
The result: it will do at least 85 on flat ground to rolling hills (I have not gone beyond that due to suspension and brake issues, not power issues). It will cruise all day long at 75 mph. EGT temps remain in the 600-850 range which is excellent. Max boost (with a controller) is set to 12 lbs. Which is all it needs. We live at 3500 feet altitude but 20 miles in any direction is 6,000 feet (and up to 8,000 feet not much further). When climbing out of our valley and maintaining 75 EGT will creep to mid 900s. I did set the "max fuel" setting high and with the right foot all the way on the floor I get a lot more power but EGTs still stay under 1,100. Smoke is only seen when floored like this or lugging too low. Mostly you never see smoke.
BTW I have two probes, one analog, one digital, one before the turbo, one after -- I am confident my numbers are correct. Oddly, there is not a huge difference despite what one read between before and after the turbo numbers.
And in 4 low with 4.11 gears (and ARB lockers front/rear) it goes anywhere with a final drive as Toyota intended ... and with 5 speeds some pretty low gears.
The point of this post I suppose is that EVERYTHING must be addressed as a system -- gear rations, transmission, turbo boost, intercooler, intake and exhaust, fuel levels at the injector and pump levels, and the valves in the head. If you do everything you can easily get a "driver" for the street that will cruise at 75 and at the same time get the famous Land Cruiser off-road low gear capability.
No -- when going at 75 it no longer gets 25 mpg. 18-20 is more like it. BUT -- if one drives at 55 on the freeway it still gets 25-30 mpg. MPG is based really on fuel used which is based on your right foot and how well the turbo feeds air to burn the fuel properly. Black smoke is merely wasted fuel -- it did not burn. On the other hand, never smoking can mean a lean condition and lead to over heating.
When I see builds that advertise big V-8 engines and 4 speeds and 65 mph cruising speed I cringe. The 3B can be built for mileage and performance at modern street levels while keeping the off road capability we expect from a diesel Toyota.
Downside -- it was NOT cheap to do all this. But that is what my wife wanted, so she got it
Many people ignore the gearing related to what transmission and tire size and lift. I'll start there. Toyota had 3.70 and 4.11 gears with 4 or 5 speeds and 30 inch tires. Some math will tell you that the final drive of a 4 speed with 3.70 gears and 30 inch tires is approximately the same as the final drive with a 5 speed, 4.11 gears, and 33 inch tires. This is how ours is set up -- so we have a Toyota stock final drive more or less, with the advantage of lower gears when needed and larger tires which are always needed
We have a 3" OME lift with one leaf removed from the rear (to make it sit flat instead of tipped forward).The 3B has many iterations. Toyota made the same engine for commercial trucks -- with turbos. My intention was to build the engine enough to travel on the highway at a cruising speed of 75 (AZ speed limit) while still having the low-end torque of the 3B. See gearing -- most important to start there!
I purchased an AXT turbo and intercooler from AU. Many people don't know this but a turbo does NOTHING for power. It is not the compression that gives power. The turbo performs one function -- compresses the intake air. This increases the oxygen. This allows the burning of more fuel. If you don't add more fuel, it is of no use at all. Intercooler also allows more oxygen with lower temps.
Increasing the compression with a turbo requires that more air be allowed into the engine and to exit the engine. If not, heat will increase dramatically. We used a K&N intake filter and 2.5" exhaust.
Next comes the fuel. The 3B injection pump is NOT adjustable except for a limit on the max fuel when your foot is to the floor. We rebuilt the pump with 15% across the board more fuel. Great -- gotta get it into the engine though. So we got injectors with 15% more fuel.
Now we get to the fun part. So the intake and exhaust pipe are big enough (down pipe, intercooler too). The intercooler helps not only drop temps. but cooler air is also more compressed and has more oxygen. However ... there are intake and exhaust valves. So we forced the air in, sucked it out, added fuel ... and it ran too hot.
So we got a new (from Toyota) head and purchased 13-BT intake and exhaust valves and had the engine machined for these valves. There is no real difference in the heads except the bolts that hold it to the block so this is easy. Follow 13-BT instructions for valve adjustment. And to make up for the lesser number of bolts on the head, we used stronger studs.
The result: it will do at least 85 on flat ground to rolling hills (I have not gone beyond that due to suspension and brake issues, not power issues). It will cruise all day long at 75 mph. EGT temps remain in the 600-850 range which is excellent. Max boost (with a controller) is set to 12 lbs. Which is all it needs. We live at 3500 feet altitude but 20 miles in any direction is 6,000 feet (and up to 8,000 feet not much further). When climbing out of our valley and maintaining 75 EGT will creep to mid 900s. I did set the "max fuel" setting high and with the right foot all the way on the floor I get a lot more power but EGTs still stay under 1,100. Smoke is only seen when floored like this or lugging too low. Mostly you never see smoke.
BTW I have two probes, one analog, one digital, one before the turbo, one after -- I am confident my numbers are correct. Oddly, there is not a huge difference despite what one read between before and after the turbo numbers.
And in 4 low with 4.11 gears (and ARB lockers front/rear) it goes anywhere with a final drive as Toyota intended ... and with 5 speeds some pretty low gears.
The point of this post I suppose is that EVERYTHING must be addressed as a system -- gear rations, transmission, turbo boost, intercooler, intake and exhaust, fuel levels at the injector and pump levels, and the valves in the head. If you do everything you can easily get a "driver" for the street that will cruise at 75 and at the same time get the famous Land Cruiser off-road low gear capability.
No -- when going at 75 it no longer gets 25 mpg. 18-20 is more like it. BUT -- if one drives at 55 on the freeway it still gets 25-30 mpg. MPG is based really on fuel used which is based on your right foot and how well the turbo feeds air to burn the fuel properly. Black smoke is merely wasted fuel -- it did not burn. On the other hand, never smoking can mean a lean condition and lead to over heating.
When I see builds that advertise big V-8 engines and 4 speeds and 65 mph cruising speed I cringe. The 3B can be built for mileage and performance at modern street levels while keeping the off road capability we expect from a diesel Toyota.
Downside -- it was NOT cheap to do all this. But that is what my wife wanted, so she got it
