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Thread: Tuning the new turbo

  1. #1
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    Tuning the new turbo

    Since getting my 110 up and running with the TDO4 HL-19T (Kinugawa), I've been playing with fuel and boost settings. Some potentially relevant background info: no intercooler; homemade 3" dump from a mandrel half donut, reducing into a 2.25" short exhaust with no muffler exiting in front of the LH rear wheel. N/A pump on a 1988 (Perentie) block. There is still one 60 degree crush bend under the front outrigger, but a replacement mandrel bend is on order from ebay. I've fitted egt gauges pre and post turbo (the latter out of curiosity to see the differences and because it was cheap). Later, I'll connect the post turbo gauge to a cylinder head thermocouple along the lines of an engine Watchdog. EGT numbers in this post will all be pre-turbo. This thermocouple is mounted in the T2/T3 adaptor.

    My local test hill is hardly a mountain range but prior to the turbo, I was down to 95 km/h by the top, with the foot pinned and a small amount of grey haze. Since the turbo, I can get up at 120 and this is where I've seen the max EGT's so far - that may help to give some indication of the hill.
    I've been fairly happy with the way its been running but the search for more performance at low cost is addictive and its hard to wind back a setting if it results in more go.

    I started with a 1 bar (almost 15 psi) actuator spring, the actuator rod in the shortest position (full preload) and the fuel screw about 2 turns out.
    Results: max EGT about 680 - 14-15 lbs boost. Noticeable operation of the wastegate between each gear change. Cruise (100 km/h & flat road) EGT appx 440 @ 8- 10 lbs boost. It would make about 5 lbs just by reving it at idle. No smoke under load but grey haze under low rpm off boost throttle. Pre and post turbo EGT's varied by about 50 degrees at cruise and 100 degrees at max load.

    Next, I thought I'd disconnect the actuator and wire the wastegate shut. Result: noticeable improvement in performance: Cruise EGT's appeared to drop to about 400 and boost down also ?around 8 lbs. This could have been due to headwind/tailwind factors as this seems counter intuitive? Max EGT dropped to about 630 and boost up to 23 lbs. The difference between pre and post turbo EGT's has now increased to about 150 degrees at max load. Plant the foot at 100 and the boost gauge responds instantly. Governed RPM in top gear is achievable on level ground, but I think the canvas top is going to separate from the vehicle so that wont happen again..

    Another half a turn out on the fuel screw, Max EGT up to 680 and 25 lbs boost, starting to think this seems a bit high for a non-intercooled setup... Cruise conditions - no change. Grey off-boost haze is now more like a big puff of black smoke until the turbo spools up (which is quickly) and can be avoided or reduced a lot under normal driving, ie not wringing its neck. Its hard to resist not to taking it to the governor on each gear change, but this tank of fuel is allocated to 'testing'. We'll see about economy later. I think its going to be OK because nearly 400km of thrashing it there's still a quarter tank left.

    I notice the restrictor indicator on the air filter has now popped (new filters), so out comes the safety element. I'm telling myself I'll replace it when I exchange the last crush bend in the exhaust for a mandrel bend... Fuel screw in about a quarter turn and the off boost smoke is not so antisocial.

    I have no current plans to intercool it and would appreciate thoughts on whether running it up to 23 lbs is a bad idea, even if I keep the max EGT's below 680 - 700 (and for short periods only)? If this is OK, would I be better off with a stronger actuator spring, or just leave the wastegate wired shut?

    While I didnt set out to tune it with a super logical plan, I'd appreciate thoughts on whether I've made any major mistakes, or should do things differently.

    I've also noticed that I can hear the turbo spin down after the engine is shut off. At first I thought the noise was a weak radiator fan clutch spinning down but it is definitely the turbo, maybe 3-4 seconds even if the engine has only been started and not revved past idle. Is this normal?

  2. #2
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    wire that wastegate closed, run 25psi and keep the egt under it'll be good.

    add a`n intercooler and the egt's will improve.

    jut be carefull using it for extended periods, your cooling system, piston and crank are not up to it.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

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  3. #3
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    Quote Originally Posted by mark2 View Post
    Its hard to resist not to taking it to the governor on each gear change

    ...
    I find that interesting, I make the fastest progress changing at 2200-2500rpm. Anything beyond that is just making more noise.

  4. #4
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    Following this post closely, please let us know any other changes you make.

    Sent from my SM-G900I using AULRO mobile app

  5. #5
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    Quote Originally Posted by Dervish View Post
    I find that interesting, I make the fastest progress changing at 2200-2500rpm. Anything beyond that is just making more noise.
    Pretty sure my governor is set to 3200 rpm - some may be higher? With this turbo it does get there willingly and quickly, unlike when it was N/A, where going to the governor took a conscious effort and was a waste of time and fuel. Once I start thinking about economy, no doubt my driving style will change..

    Just looked at my LT95 gear ratio spreadsheet; taking it to 3200 at each gear change leaves it at about 1800 - 2000 in the next gear, which is roughly the peak of the torque curve. The ratio gaps aren't ideal, I'd much prefer a 5 speed. I recall the ratio deficiencies being less noticable with the stroker V8 in a previous vehicle.

  6. #6
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    from my previous previou post max pre turbo egt (sutained) should be 650 degrees.
    Dave

    "In a Landrover the other vehicle is your crumple zone."

    For spelling call Rogets, for mechanicing call me.

    Fozzy, 2.25D SIII Ex DCA Ute
    Tdi autoManual d1 (gave it to the Mupion)
    Archaeoptersix 1990 6x6 dual cab(This things staying)


    If you've benefited from one or more of my posts please remember, your taxes paid for my skill sets, I'm just trying to make sure you get your monies worth.
    If you think you're in front on the deal, pay it forwards.

  7. #7
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    Quote Originally Posted by Blknight.aus View Post
    from my previous previou post max pre turbo egt (sutained) should be 650 degrees.
    My visual alarm is set to go off at 600; with the current settings it will go to the high 600's +, but that will not be sustained. The gauge has two programmable alarms, with the second alarm being set up setup to trigger an annoying buzzer at 650 for extra insurance.

  8. #8
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    I generally hit the governer in the first 3 gears (Isuzu msa5g gearbox), it gets there easily with this turbo, egt's have hit 720, but should be a lot better with the new intercooler I hope, ( running around 25psi with a 22 psi spring) same turbo as you mark, hoping for some improved tuning once its back on the road.

  9. #9
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    Vern - have you noticed the noise of the turbo running down after engine shut down? I've never heard this before with my other turbo diesels.

  10. #10
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    Quote Originally Posted by mark2 View Post
    Vern - have you noticed the noise of the turbo running down after engine shut down? I've never heard this before with my other turbo diesels.
    my EFR6258 does this, always has - but it is a noisy turbo in all respects.
    Hercules: 1986 110 Isuzu 3.9 (4BD1-T)
    Brutus: 1969 109 ExMil 2a FFT (loved and lost)

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