12H-T power boost

[Tim-HJ61]

Hello,

Warning: modifying the settings for your turbo boost and injection pump can cause an adrenalin rush: so I did it! Touch any of these settings at your own risk.


After enjoying the extra torque of the fat exhaust, I set about increasing the boost and fuel to get more performance. Some had suggested my 12H-T was a bit of a slug.


First. Boost.
Ages ago I had installed a simple bleed boost controller purchased from ebay. Standard boost is 7psi. I have been running at 12.5psi for a year or so. My advisors suggested 16 psi or more. I've settled on 15psi as it is what my gauge measures and also it matches the overboost warning light provided by Toyota.







Second, measurement.
Instal a quality EGT, Exhaust Gas Temperature, Gauge or Pyrometer I could tell what EGT I was running. EGT is affected by load, fuel, boost and is an excellent indicator of the stress on the engine. I back off the throttle when the EGT reach 600°C, my advisors say I could go higher. I'm nervous about pushing it too much.








Third, more fuel.
The little screw that holds the key to more power.
Required 2x 10mm spanners, and 1 x 3mm allen key.
As shown in the photo, undo the cap cover off fitting marked in yellow paint. The outer most is a cap. the inner nut is a lock nut. Under the cap is a long screw into which fits an Allen Key. Mark your start point, undo the lock nut, unscrew the long fuel screw half a turn, tighten the lock nut and test. Keep doing this until you get the solution you are seeking. Caution needs to be exercised and this adjustment should not be done by the faint hearted or those wanting iron clad guarantees of consequences. Things may break.....









Outcome.
I unwound the fuel screw two full turns and have been amazed at the power increase. I now get full boost at 1800 rpm where it used to be around 2000rpm. The engine is very keen and willing in the higher rev range and spins easily to the orange line of 3500 rpm. Acceleration from 80kmh to 110kmh in 4th or 5th gear is brisk.



Downside is the ease of too high EGT.



Solution, add more air ie increase boost. As a test, I ran without the waste gate actuator connected and found the turbo spun to about 22psi and EGT's did not rise as much as before. Even at full power climbing a hill at 110kmh EGT dropped from 600°C to 500°C in the same circumstances. This was far more acceptable with regards EGT, but driving without waste gate connected is just too risky for my liking. The orange warning light was flashing on when I accelerate hard and can become annoying and ignored rather than a valuable tool. Boost is now comfortable at 15psi maximum and EGT only rise to danger levels when I push hard at 15psi, essentially creating an overfuelling leading to high EGT.


Fuel consumption has not changed to any noticeable extent. I recently completed 3000km on vege oil with the high power settings and got 12.5l/100km.



EGT was the most expensive component. Boost controller about $30 from ebay, fuel screw adjustment is free! All these mods are interdependent with the exhaust upgrade.


Hope this helps someone looking to play with their 12H-T.



Tim

[WALKS]

mate thats a good wright up thanks for that ,do you have any pictures of where your boost guage is plumbed in ive been having trouble getting mine to work properly,if i connect the guage up it feels like i have lost power and the little green led doesnt come on.

[Tim-HJ61]

For the light to not come on, I suspect you have knocked off a hose, they come off easily. If you feel you have lost power, you may have an open hose somewhere and be losing a bit of pressure. I have plumbed in my gauge as per this pikkie, see the green rectangle marking the hose feeding the gauge.



My gauges are mounted in the roof console. Gauges are vege oil temp, vege oil pressure, Turbo boost, EGT


Off topic, I put some H1 HID inserts into the high beam, centre, lights. Outer light is still high/low beam. Inner light is HID only and switched separately as if they were spotlights. i.e. only coming on when high beam is on, AND their own switch is on. I power each of the 12v HID ballast separately from each battery via a 24v relay switched as I have described. Wiring diagram for 12v HID's into 24v Landcruiser. Download PDF


On topic; click on this link to see a movie of start up smoke and exhaust note

Tim

[Buttons]

whats the water temp like now? does it warm up a bit quiker and are you going to run an intercooler.

that roof console you have up there in that lst pic is that a factory one or have it made up

nice work on makeing the jump to boost it, makes a big difference and as you know the turbo can take up to about 18. as long as your motors in good condition should be good for a few k's

[Tim-HJ61]

The overhead console is a Safari item. Normally it housed a indoor/outdoor temperature and an altimeter. I took them out and squeezed in the four gauges.

Turbo will run up to about 21psi with waste gate actuator disconnected.

Coolant temp rises according to how hard engine is being pushed; I've never been really all that happy with the cooling capacity of the system and would like to see it stay cooler, but as it never goes above the top mark of normal, I've got nothing to fuss about really.

So, yes, coolant temp does rise - perhaps more quickly than it used to.

Intercooler. I really like mods that give me more power at the turn of a screw, not costing anything. Running a front mount intercooler has been suggested by the gents that lead me astray, but the woman who keeps me in line would not be amused I suspect - time and money issues. She wins....

Tim

[Buttons]

LOL nice.

yeh i was looking at running an ewp but may just stick to the original pump take the fan off and run thermo fans instead, possible look at beter mix of coolant too.

intercooler would be the way to go but 12psi i think you said you were running is fine. and egt gauge as long as you keep an eye on it can be very usefull.

hope it all holds up for you. good luck

[Tim-HJ61]

Originally Posted by Buttons

LOL nice.

yeh i was looking at running an ewp but may just stick to the original pump take the fan off and run thermo fans instead, possible look at beter mix of coolant too.

intercooler would be the way to go but 12psi i think you said you were running is fine. and egt gauge as long as you keep an eye on it can be very usefull.

hope it all holds up for you. good luck

What's an EWP?

I'm running 14.5psi, just enough to trigger the orange overboost light on a cold morning.

Tim

[Buttons]

What's an EWP?

Electric Water Pump.

around town i would say yes there would probably be good, but i have heard a few stories about there reliability, having said that it was on a couple of the older models, i havnt found anything on a curent model or anyone thats been running one over the pst 12 months.

i think i will just stick to the factory cooling system, but change the fan to an elctric thermo setup

[Tim-HJ61]

Update:

I've unwound the fuel screw another turn, making three turns in total.

No visible smoke on vege, maybe a light haze under full power on diesel = probably enough fuel at the moment.

Comparison:
Welshpool Road Hill.

Before adding the 3" exhaust and adding more fuel I used to hit the bottom of Welshpool Road hill at 80kmh in 4th at 2000rpm and holding full boost at that stage of 12.5psi.

By the time I got to the top I'd be looking for third gear.

Add 3" exhaust
Add more boost up to 14.5psi
Add 3 turns of fuel screw.

Hit bottom of hill at 80kmh in 5th gear
Held speed all the way up the hill in 5th gear pushing 12psi boost and climbing EGT up around 550°C. I predict that if I had been in 4th, boost would have maxed out at 14.5psi, EGT would have been lower, and I would have been able to accelerate at any point up the hill.

Overall an impressive power and torque gain. Fuel consumption has not changed to any noticable extent since increasing fuel supply screw.

Tim

[BigNic]

G'day mate,

Whats your EGT like when driving in sand/towing with this setup?

I'm going to up the boost and fuel on mine (not to 14.5psi though, probably 10-12) but if EGT become an issue I might reconsider. I have 3" exhaust fitted.