Compound Turbos on a 2nd Edition B Engine

[Eurasiaoverland]

3b noob here. Been reading and learning for the past year, also forced into an informal engine overhaul. I do have a turbo, and I think the broken crank problem might be mitigated by retarding injection timing. These engines have a lot of compression and therefore cylinder pressure, so if you run a turbo, backing the injection timing off a bit can reduce the strain on the crank. I would never try to run more than 15psi either.

That'a a good point - as well as being inhernetly stronger, the DI engines have a reduced compression ratio; I think the 3B is 21.0:1, the 14B is 18.0:1 and the 14B-T is 17.8:1.

 

[dirtyham]

Iv been having a great run out of my little 3B turbo for many many years, burns some oil but that's half the experience, Not sure about the VE pumps but inline pump cant even keep fuel up to 12psi, iv thrashed the little 3B relentlessly and she hasn't died yet....

 

[bsweaty]

3b noob here. Been reading and learning for the past year, also forced into an informal engine overhaul. I do have a turbo, and I think the broken crank problem might be mitigated by retarding injection timing. These engines have a lot of compression and therefore cylinder pressure, so if you run a turbo, backing the injection timing off a bit can reduce the strain on the crank. I would never try to run more than 15psi either.

Thanks for sharing! Out of curiosity, is your engine pre 1988?

I may be naive here. With adding boost, don’t you need to advance the timing a little bit to ensure that the combustion doesn’t equate to too much heat? EGTs being what destroys cylinder heads?

How much boost were you running when the crank snapped?

 

[KiwiDingo]

I may be naive here. With adding boost, don’t you need to advance the timing a little bit to ensure that the combustion doesn’t equate to too much heat? EGTs being what destroys cylinder heads?

No, that's not how it works. Adding nothing but boost will reduce heat in cylinder and reduce EGT.

 

[Smithtec]

Thanks for sharing! Out of curiosity, is your engine pre 1988?

I may be naive here. With adding boost, don’t you need to advance the timing a little bit to ensure that the combustion doesn’t equate to too much heat? EGTs being what destroys cylinder heads?

How much boost were you running when the crank snapped?

Retarding timing reduces peak cylinder pressure. My crank didn't break, but I was only getting 10-12 psi because of the way the intercooler was set up. I have a pretty small turbo, but with the waste gate disconnected I should get 15psi. I have the older B. Yours has 5 cam journals instead of 3, and roller lifters.

 

[bsweaty]

Retarding timing reduces peak cylinder pressure. My crank didn't break, but I was only getting 10-12 psi because of the way the intercooler was set up. I have a pretty small turbo, but with the waste gate disconnected I should get 15psi. I have the older B. Yours has 5 cam journals instead of 3, and roller lifters.

That it does. Any idea of how much power you gained by adding a turbo?

 

[bsweaty]

Iv been having a great run out of my little 3B turbo for many many years, burns some oil but that's half the experience, Not sure about the VE pumps but inline pump cant even keep fuel up to 12psi, iv thrashed the little 3B relentlessly and she hasn't died yet....

Love it. Any idea how much power you’ve gained with 12psi?

 

[Smithtec]

They're about 90hp without the turbo, and 125-130 with. I'm not sure I agree that they can't fuel enough for 15psi, seems a lot of folks have run that much. I plan to put mine on a dyno when I get it back together. With 4.56 gears and 33" tires I can do 70 mph on the freeway with the H55.

 

[FJBen]

They're about 90hp without the turbo, and 125-130 with. I'm not sure I agree that they can't fuel enough for 15psi, seems a lot of folks have run that much. I plan to put mine on a dyno when I get it back together. With 4.56 gears and 33" tires I can do 70 mph on the freeway with the H55.

That’s at crank brand new. Most reports of
The 3B have been anywhere from 35wheel hp to 50 wheel HP being the highest reported.

Dyno of a 3B showed 28whp gain at 11psi and 30tq gained.

Again that’s the highest 3B I’ve seen on here at 50 wheel hp stock. Most are in the 32-42 range.

Should make the the 3B more bearable by far being tubod, but it’s not without risk as others have stated.

 

[bsweaty]

They're about 90hp without the turbo, and 125-130 with. I'm not sure I agree that they can't fuel enough for 15psi, seems a lot of folks have run that much. I plan to put mine on a dyno when I get it back together. With 4.56 gears and 33" tires I can do 70 mph on the freeway with the H55.

I like this. that's likely to crank not wheels. this van isn't small. with stock tires(30" x 6.5")I'd top out around 60mph on flat. I have the M150 trans which is similar to the H55. Hoping to be able to do 70mph on 35s. I am also bumping gears from 5.30 to 4.10s.

 

[bsweaty]

That’s at crank brand new. Most reports of
The 3B have been anywhere from 35wheel hp to 50 wheel HP being the highest reported.

Dyno of a 3B showed 28whp gain at 11psi and 30tq gained.

Again that’s the highest 3B I’ve seen on here at 50 wheel hp stock. Most are in the 32-42 range.

Should make the the 3B more bearable by far being tubod, but it’s not without risk as others have stated.

that's nuts. where's all the power going? I am used to a 15-25% crank to wheel reduction. that's like 50-70% reduction.

 

[FJBen]

that's nuts. where's all the power going? I am used to a 15-25% crank to wheel reduction. that's like 50-70% reduction.

3B new is 90hp at crank according to Toyota.
Transmission/tcase on the cruisers eat a lot of power. Also if you are running mud tires and bigger, that doesn’t help.

According to multiple people on here, dynos of multiple engines, 12ht, 3B, 1HZ, 2LT seem to show 40-45hp loss from crank numbers to
Wheel hp.
That puts the 3B in the 40ish hp range and considering most are high mileage, not surprising at all they are Lower.

 

[bj70bc]

Thanks for sharing! Out of curiosity, is your engine pre 1988?

I may be naive here. With adding boost, don’t you need to advance the timing a little bit to ensure that the combustion doesn’t equate to too much heat? EGTs being what destroys cylinder heads?

How much boost were you running when the crank snapped?

advance timing increases crank pressure, not great for a idi diesel,
retarding it slightly puts it in a safer place.
any egt difference seen is only due to the timing of when the combustion event happens, its the same heat load tho.
retarding it reads slightly higher on egt but just because the heat is going through the head 'later', it helps spin the turbo a bit tho too

 

[Dougal]

Thanks for sharing! Out of curiosity, is your engine pre 1988?

I may be naive here. With adding boost, don’t you need to advance the timing a little bit to ensure that the combustion doesn’t equate to too much heat? EGTs being what destroys cylinder heads?

How much boost were you running when the crank snapped?

Adding boost increases compression temperatures and burn speed already, so advancing timing more is a very bad thing. Especially on engines that weren't intended to be turbocharged.

EGT is only an indication of cylinder temperature. Advancing timing gives you cooler measured EGT but higher in cylinder temperatures (for the same fuel and boost). Likewise retarding timing gives you hotter measured EGT but cooler in cylinder temperatures.

My advice is to keep timing at factory NA marks when turbocharging engines like these. Retarding timing can be used to drop cylinder pressures/temperatures but hurts efficiency and cold-starting.
It's the combination of boost/fuel/timing that dictates cylinder pressures/temperatures. First things you need to keep safe are boost and fuel.

 

[Busted Crank]

Alright so heres the key to breaking 3b cranks, as I have done it twice now, once a tired motor, once a rebuilt motor. Both times, 14-18 psi of boost, intercooled, two different turbos Gt2560r, hx30. First had some timing added, second had timing retarded. So factory timing set at 11 degrees or so.

Now everything I knew about the timing was loosely based around the cummins 4bt (uses 14 - 18 degrees of timing depending on power)


NOW Heres where I went wrong TWICE, I didn't realise that the 3B has an automatic timer, and the cummins platform 4BT 6BT etc, does not

Ok Who cares?

Well the cummins runs stock timing at 11 Degrees - similar to the 3b from 0 - 4000 Rpm
The 3b runs 14 degrees of timing at idle, the automatic timer adds 14 more at 3000 Rpm
So 28 degrees of timing at around 3000 rpm, progressing from 0 Rpm,
So with no turbo, no big deal because it doesn't have the air in the cylinder to combust the fuel fast enough to be a problem.
but with a turbo increasing cylinder pressure as rpm climbs, the ignition delay gets shorter and shorter as you go up in boost, even worse if you feed it hot air with no intercooler.

now I should have figured this out when I couldn't break 109Hp at the wheels on a dyno, with two completly different boosted 3b's, as the power went up i would get to a point that the timing was so far advanced that it is having a hard time building more boost, and the crank is getting hammered before top dead center. Basically pinging, but its a diesel so you cant hear this.

Now 3rd times the charm, shimmed the timer to almost lock it out now, I have great power from 1200-3000 rpm, where I had no torque below 2000 rpm below, and not much boost before.

So if your considering turbocharging any Toyota diesel with an automatic timer, buy shims and lock it out first, then slowly pull shims till you get your top end back, or just snap the crank and save the headache, your choice

sorry with the somewhat off topic reply, just trying to save some one the headache that most haven't figured out.

 

[bsweaty]

Alright so heres the key to breaking 3b cranks, as I have done it twice now, once a tired motor, once a rebuilt motor. Both times, 14-18 psi of boost, intercooled, two different turbos Gt2560r, hx30. First had some timing added, second had timing retarded. So factory timing set at 11 degrees or so.

Now everything I knew about the timing was loosely based around the cummins 4bt (uses 14 - 18 degrees of timing depending on power)


NOW Heres where I went wrong TWICE, I didn't realise that the 3B has an automatic timer, and the cummins platform 4BT 6BT etc, does not

Ok Who cares?

Well the cummins runs stock timing at 11 Degrees - similar to the 3b from 0 - 4000 Rpm
The 3b runs 14 degrees of timing at idle, the automatic timer adds 14 more at 3000 Rpm
So 28 degrees of timing at around 3000 rpm, progressing from 0 Rpm,
So with no turbo, no big deal because it doesn't have the air in the cylinder to combust the fuel fast enough to be a problem.
but with a turbo increasing cylinder pressure as rpm climbs, the ignition delay gets shorter and shorter as you go up in boost, even worse if you feed it hot air with no intercooler.

now I should have figured this out when I couldn't break 109Hp at the wheels on a dyno, with two completly different boosted 3b's, as the power went up i would get to a point that the timing was so far advanced that it is having a hard time building more boost, and the crank is getting hammered before top dead center. Basically pinging, but its a diesel so you cant hear this.

Now 3rd times the charm, shimmed the timer to almost lock it out now, I have great power from 1200-3000 rpm, where I had no torque below 2000 rpm below, and not much boost before.

So if your considering turbocharging any Toyota diesel with an automatic timer, buy shims and lock it out first, then slowly pull shims till you get your top end back, or just snap the crank and save the headache, your choice

sorry with the somewhat off topic reply, just trying to save some one the headache that most haven't figured out.

This might be the most useful piece of advice here so far. When you say automatic timer, are you referring to the injection pump? What year(s) are your 3b?

I’m a Cummins guy. VE and P Pump here and I’m not used to the term of a timer.

Thanks so much!

 

[bj70bc]

no theres a automatic mechanical timer on the gear that drives the inj pump

 

[bj70bc]

ive been wondering this for a while now....
How did you shim the timer... guys gotta know

 

[Busted Crank]

This might be the most useful piece of advice here so far. When you say automatic timer, are you referring to the injection pump? What year(s) are your 3b?

I’m a Cummins guy. VE and P Pump here and I’m not used to the term of a timer.

Thanks so much!

So im talking about the early 3B inline pump, looks similar to a p-pump 4bt. now picture someone fitted a timing advance like a distributor to the timing gear that drives the injection pump.

 

[bsweaty]

So im talking about the early 3B inline pump, looks similar to a p-pump 4bt. now picture someone fitted a timing advance like a distributor to the timing gear that drives the injection pump.

Makes sense. I have the later rotary VE style. I’ll check and adjust when I get to it. Still swapping my solid axle under the front.


Thanks!