Hi Guy's,
I am building up a 12H-T for more performance over standard.
Thought some might be interested because 12H-T power threads are few and far between. Most owners don't dyno after mods like intercooler or extra boost or exhaust so it is hard to gauge how they compare to other excellent motors such as 1HD-T or FT/FTE.
So far, I have bought or done the following:
* Ported significantly the head, currently fitting larger valves (that I have, they are only slightly larger). Head looks real bad standard. TD42 by comparison looks like an old style racing head
* Bought the full build kit 1mm oversize, pistons have steel top ring land inserts, unlike original - (this makes a big difference)
* Block has been bored and decked, crank has been cleaned up and crack tested.
* Inlet manifold will be ported. I have started it and it wont take long - pretty **** standard. Having said that, I havent done flow tests so it is only what the eye tells me.
* Turbo - secrets here, but aiming for 21psi upwards with view to minimize pressure ratio difference between inlet and exhaust. I will be using a newer GT spec and may use a second turbo for compounding. In this way boost should top at 43psi, rising from 21psi at 1400rpm through to 43psi at 3800rpm. THis is to offset the worsening VE of the engine with revs. Will see how I go
* Intercooling Laminova type; I have the cores (only 4), now got to do the hard stuff. Currently in design stage.
* Lubrication/Cooling - fitting bigger piston collers - which I have
* Pump tune up to delivery whatever it is capable of. I am loathed to go over 150rwkw and even that might be optimistic because the conrods are not at the same level at the 1HD-T rods (nice motor by the way, this time I wanted inline pump though. My 1HD-T got 114rwkw at all 4 33" tyres 21psi boost. made heaps of torque early but suffered from excessive exhaust back pressure - I measured it. It was = to inlet up to ~ 2000rpm then it just got worse. At 3000rpm 25psi boost, backpressure was 37psi, so hardly worth the trouble of boost. This is due to turbine design and housing spec, but since it was auto and I was silly enough to lower the stall speed on the torque converter, I needed the small housing!
Anyway, there you have it. Will definately take 3 months to finish. Please nobody tell me that the motor will die with boost etc etc. It could die if delivering too much power, but that depends on whether the inline pump can flow enough as it is with just rack mods. Diesels die on fuel or power/torque related issues, not boost.
The only other thing I would like to do is bigger rods and head stud kit. I have had them priced up - ~ $1800 for a set rods. But if the pump cant flow the fuel, there is no point.
I will post the odd pic as things go along.
Cheers!
I am building up a 12H-T for more performance over standard.
Thought some might be interested because 12H-T power threads are few and far between. Most owners don't dyno after mods like intercooler or extra boost or exhaust so it is hard to gauge how they compare to other excellent motors such as 1HD-T or FT/FTE.
So far, I have bought or done the following:
* Ported significantly the head, currently fitting larger valves (that I have, they are only slightly larger). Head looks real bad standard. TD42 by comparison looks like an old style racing head
* Bought the full build kit 1mm oversize, pistons have steel top ring land inserts, unlike original - (this makes a big difference)
* Block has been bored and decked, crank has been cleaned up and crack tested.
* Inlet manifold will be ported. I have started it and it wont take long - pretty **** standard. Having said that, I havent done flow tests so it is only what the eye tells me.
* Turbo - secrets here, but aiming for 21psi upwards with view to minimize pressure ratio difference between inlet and exhaust. I will be using a newer GT spec and may use a second turbo for compounding. In this way boost should top at 43psi, rising from 21psi at 1400rpm through to 43psi at 3800rpm. THis is to offset the worsening VE of the engine with revs. Will see how I go
* Intercooling Laminova type; I have the cores (only 4), now got to do the hard stuff. Currently in design stage.
* Lubrication/Cooling - fitting bigger piston collers - which I have
* Pump tune up to delivery whatever it is capable of. I am loathed to go over 150rwkw and even that might be optimistic because the conrods are not at the same level at the 1HD-T rods (nice motor by the way, this time I wanted inline pump though. My 1HD-T got 114rwkw at all 4 33" tyres 21psi boost. made heaps of torque early but suffered from excessive exhaust back pressure - I measured it. It was = to inlet up to ~ 2000rpm then it just got worse. At 3000rpm 25psi boost, backpressure was 37psi, so hardly worth the trouble of boost. This is due to turbine design and housing spec, but since it was auto and I was silly enough to lower the stall speed on the torque converter, I needed the small housing!
Anyway, there you have it. Will definately take 3 months to finish. Please nobody tell me that the motor will die with boost etc etc. It could die if delivering too much power, but that depends on whether the inline pump can flow enough as it is with just rack mods. Diesels die on fuel or power/torque related issues, not boost.
The only other thing I would like to do is bigger rods and head stud kit. I have had them priced up - ~ $1800 for a set rods. But if the pump cant flow the fuel, there is no point.
I will post the odd pic as things go along.
Cheers!