15BF, 15BFT, 15BFTE Toyota OEM Power Specs

[GTSSportCoupe]

Saw these in a youtube video, so copied them out to post here. I'd never seen these before.... Would be neat to find the source documents and translate to english.


15B-F

15B-FT

15B-FTE

 

[Earwigg]

They really fall over at 3k don't they

 

[GTSSportCoupe]

They really fall over at 3k don't they

I remember @Dougal commenting on that in another thread. I think it is a combination of things, but partly the diesel can only burn so fast in a large cylinder with a long stroke. Also, direct injection engines generally don't rev as high as indirect injection. Add to that these motors have the small CT12b turbo which likely runs out of puff pretty quickly on such big displacement. Finally, these motors are designed for commercial and military truck application. Most diesel engines in those types of vehicles are similar high torque low revving motors.

I'm toying with the idea of putting one of these in an LJ78... Megacruiser motor/trans + Prado chassis/body = MegaPrado!

 

[SNLC]

I think they would be great engines in a Prado.

Cheers

 

[GTSSportCoupe]

I think they would be great engines in a Prado.

Cheers

@gotoy put one in a KZJ71. The engine really looks at home in there. Being four cylinder, it fits well in the shorter engine bays of the light duty 70 series. Builds - New kzj71 project - https://forum.ih8mud.com/threads/new-kzj71-project.610109/page-9

 

[Nz Nath]

The torque dropping off at 3k rpm would probably be the governor starting to reduce fueling. There's been at least one thread on the 15b Facebook group where it's been said they suffer valve float issues at 3400rpm and above. Which is why peak power is at lower revs than the 13bt. (On the 13bt peak power is 3400rpm, and that's when fueling starts to be pulled back)

 

[GTSSportCoupe]

I've been reading about these motors, and they seem to be a very popular swap into any Landcruiser series in southeast Asia.

Video showing a couple light duty 70 series and a 100 series with 15BFT's running in them. Look how well the motor fits in there. Almost had to do a double take as it looks similar to a 2LT, haha:

 

[GTSSportCoupe]

Another video showing more of the first LJ7x:

 

[cruiserpilot]

The torque dropping off at 3k rpm would probably be the governor starting to reduce fueling. There's been at least one thread on the 15b Facebook group where it's been said they suffer valve float issues at 3400rpm and above. Which is why peak power is at lower revs than the 13bt. (On the 13bt peak power is 3400rpm, and that's when fueling starts to be pulled back)

I’ve never had my 13BT close to 3000 rpm let alone 3400.

 

[brownbear]

I’ve never had my 13BT close to 3000 rpm let alone 3400.

I was going to say my 3B is the same.
And 4.1 L displacement on the 15Bt is not really that big for bore and stroke. The cummins 6 cylinder is similar.
I would have thought putting B series engine into a Prado would be too heavy?

 

[GTSSportCoupe]

I would have thought putting B series engine into a Prado would be too heavy?

The 1990+ light duty 70 frame is basically identical to the heavy duty 70 series frame. Just some different body mounts up front. Front axle actually shares nearly everything with the heavy duty 70 series also. Just coil springs instead of leafs. So, just needs heavier front coils and it's good to go. There have been lots of heavier engines swapped into 70 series 'light duty' with no issues that I've heard of. In fact, I'd say the 70 series frames are superior to the 40 and 60 series, and those came with heavy B and H engines.

 

[Nz Nath]

You don’t use the revs in your 13bts and 3bs because you don’t feel the need, or because it feels like power is dropping off after the mid 2000s?

My 13bt used to feel a bit asthmatic above 2500rpm or so, but would then pull a bit better above 3000rpm. I’ve always revved up to at least 3000 when hard accelerating in 2nd and 3rd as my truck was running 3.54 diffs, so you’d drop into the next gear out of the torque if you changed up too soon. I could hit 100kph in 3rd gear with that gearing.

I’m now running 4.11 diffs, but with 34” tyres so still fairly high geared. Now with the upgraded injection pump the dyno showed peak power is reached about the same time as peak torque at 2300rpm, but the power holds at that level till 3400rpm when you hit the defueling profile on the torque cam. My twinscroll setup has been on hold for ages due to moving to a different part of the country for work, but now I’ve settled in I should be able to finish that off pretty quickly. I think I should be able to see close to 200hp at the flywheel.

 

[brownbear]

You don’t use the revs in your 13bts and 3bs because you don’t feel the need, or because it feels like power is dropping off after the mid 2000s?

My 3B - T once at 3K sounds and feels like I am screaming. it. I occasionally run it above 3K on spirited acceleration, or when downshifting. Redline is 4K, which I think you could only hit in neutral..
Best TQ is found just above 2K to 2500.

 

[Hulsty]

I’ve never had my 13BT close to 3000 rpm let alone 3400.

Why not? I shift every gear at 3000, have held it at 3000+ for hours at a time, occasionally gets held on the governor. They like to be worked, lugging doesnt help anything.

 

[cruiserpilot]

Why not? I shift every gear at 3000, have held it at 3000+ for hours at a time, occasionally gets held on the governor. They like to be worked, lugging doesnt help anything.

Just don’t drive that fast I guess. I checked yesterday, got up to 3000 on one shift but generally
trying to save fuel, probably just driving like an old man now.

 

[crave reFleXion]

I’ve never had my 13BT close to 3000 rpm let alone 3400.

I get to 3500 no worries at all in my 14BT... I usually shift between 2500 and 3000, but it will make 3500 no worries at all.

 

[Dougal]

I remember @Dougal commenting on that in another thread. I think it is a combination of things, but partly the diesel can only burn so fast in a large cylinder with a long stroke. Also, direct injection engines generally don't rev as high as indirect injection. Add to that these motors have the small CT12b turbo which likely runs out of puff pretty quickly on such big displacement. Finally, these motors are designed for commercial and military truck application. Most diesel engines in those types of vehicles are similar high torque low revving motors.

I'm toying with the idea of putting one of these in an LJ78... Megacruiser motor/trans + Prado chassis/body = MegaPrado!

Yes it's the burn speed of diesel vs piston speed. Interestingly my Isuzu 4BD1T and VW 2.0 tdi hit peak power at roughly the same piston speed.

They would be a great engine in a Prado. Do it! I worked for a company that had two Dyna's, the bigger one was a 15B (not sure on the little). It was incredibly smooth and sweet for an engine that big. Much smoother and quieter than my Isuzu but it was almost 15 years newer and had a lot more sound deadening on the engine itself.

 

[GTSSportCoupe]

Yes it's the burn speed of diesel vs piston speed. Interestingly my Isuzu 4BD1T and VW 2.0 tdi hit peak power at roughly the same piston speed.

They would be a great engine in a Prado. Do it! I worked for a company that had two Dyna's, the bigger one was a 15B (not sure on the little). It was incredibly smooth and sweet for an engine that big. Much smoother and quieter than my Isuzu but it was almost 15 years newer and had a lot more sound deadening on the engine itself.

Thanks Dougal! Really appreciate your opinion on that motor!

Getting away from hot old IDI technology would be so nice; not to mention the significant increase in displacement.