Author Topic: Adjusting the boost and fuel on aaz, Ko3  (Read 731 times)

October 29, 2018, 11:52:46 am


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Adjusting the boost and fuel on aaz, Ko3
« on: October 29, 2018, 11:52:46 am »
 I'm looking for the correct procedure to adjust the boost [ increase ] on a Ko3 turbo, and to adjust the max fuel screw and install a 1.6TD boost pin into the aaz pump. I'm wanting these mods / adjustments to work in harmony together so that the engine gets maximum efficiency with moderate torque gains.......too much power and I'll destroy the Samurai trans in short order. I'm looking for direction on how to begin.

 I have the Ko3 turbo on a newly rebuilt aaz engine......and it's still being broken in, with under 500 kms on it at this time. It was a factory rebuild to oem specs, so no, there are no ARP head studs installed.
 I have not made any adjustments to the Ko3 from factory.  I have removed the vacuum egr stuff from the top of the inj pump. The small vacuum hose that goes to the diaphram cam is not connected to anything, and is open to atmosphere.

 To adjust the boost on a I just unscrew the lock nuts on the threaded rod coming out of the diaphram can, and move them to the far end of the rod?

 Do I set the boost [ this way ] first, and then do the fuel mods to compliment the desired boost?

  Fuel mods......... I have the max fuel screw turned in on the pump, just far enough to set the hot idle speed to 950 rpm. The residual fuel screw has been screwed inward to "just" increase the idle speed from 950, then "just" backed out enough to get the idle back to 950 rpm. Any adjustments to the idle speed screw / cold idle / warm idle screws can only increase rpms at this point, as they were backed way off to facilitate setting idle speed just with the max fuel screw at the beginning.

 I have a 1.6TD boost pin coming that I want to install. Not sure where to install it regarding the aggressive / non-aggressive orientation of taper of the pin............remembering that I'm wanting moderate power gains at this point only.
 I do not have the 1.6TD boost pin spring. Is it needed? Better results with it or does it matter? If so, I will source one from somewhere.

 If stock boost for this Ko3 turbo is 8-10 psi......I guess I'll start at 12 or 13 psi and see how it performs. I'll need to adjust / set  fuel mods to compliment this boost.

 Pic is of the Ko3


Reply #1October 29, 2018, 02:49:35 pm


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Re: Adjusting the boost and fuel on aaz, Ko3
« Reply #1 on: October 29, 2018, 02:49:35 pm »
After running a gasoline turbo engine for a long time before getting an AAZ, I had/have a lot to learn.

For instance, within the specs of the turbo (and head gasket) boost is safe. IE damage comes from running rich, not lean.

From my reading and experience, your turbo can probably handle up to 18 psi, though that's less than optimal for efficiency. Mine will spike to 18 but doesn't hold anything below 15. I have an intercooler.

Anyway, it's a really good idea to run an EGT gauge, if you're messing with fueling. Consider grabbing one.

Also, changing the nuts on the wastegate rod is less than ideal. Get a manual boost controller -- it's a valve that can be had for under $30.

You might start by disconnecting altogether the vacuum line to the wastegate. With stock fueling, you might not reach a very high boost level! Until I installed a performance pump, I never saw more than 12-15 psi. Just, of course, be very careful driving with the wastegate disconnected, that you don't push the turbo too hard.

Once you see the maximum boost your fuel level will permit, you can either use the boost controller to set a reasonable boost, or turn up the fueling, and then set the boost controller.

Unlike on a gasoline engine, and contrary to what you were saying, you may need to increase fuel to raise boost.

So, anyway, there's a bit of back and forth between fueling and boost. Obviously you need a boost gauge and it's a really good idea to have an EGT gauge! (I wouldn't want to touch fueling without one.)

I had a pump with a 1.6td boost pin, which pushed too much fuel for my K03. I saw a significant amount of smoke under boost. Give it a try and see what happens. You will likely need to change your fuel setting and maybe boost.

I have a vanagon and likewise would prefer not to blow up my transmission, but I tuned my motor for as much power as possible with reasonable EGTs. Indeed, it's tuned such that my EGTs can get dangerously high under certain circumstances -- but I control it with the fuel pedal. Nobody else drives my van! Anyway this allows me to have as much power as possible when I might need it. I have a digital EGT gauge with a buzzer set to sound at I think just over 1300. It only goes off at highway speeds, up grades, at full throttle.

This approach might not make as much sense for you. My vanagon is a lot heavier than your Samurai and I need all the power I can get. You probably don't

Reply #2October 30, 2018, 10:44:32 am


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Re: Adjusting the boost and fuel on aaz, Ko3
« Reply #2 on: October 30, 2018, 10:44:32 am »
Thank you for taking the time to reply to my questions.

 Yes, I want to go slow with the boost and fuel mods....never was one for just charging forward and seeing what happens.......

 I do have an egt gauge installed, pre turbo.
  I do have a boost gauge that I'll install in the cab temporarily, by just running the boost hose out the window and under the hood to the turbo. Thinking once I get the boost dialed in, the gauge will not be needed.

 My samurai is getting heavy. As a guess, with HD bumpers, sliders, diesel engine, frame mods, suspension and steering mods installed, etc, it's prolly close to 2800 lbs. OEM is approx 2200 for a tin top. Dunno what a vw van weighs.

  So installing a manual boost controller is a better option than adjusting the waste gate rod nuts. I'll look into one then.
 About setting the balance between fuel and boost....... IF increased boost also requires more fuel to achieve a product of increased power, how can I get this without replacing the aaz boost pin with a 1.6td pin? You mention that on a stock pump, the 1.6td pin was too much fuel for your pump.....useless black smoke and higher egts for nuttin. What about installing the 1.6td pin in the less than max fuel grind orientation? Would that be better?
 My pump is otherwise stock. 
 What effect does the max fuel screw have with higher boost settings? Anything? Or, is it just the boost pin that meters the fuel when boost increases?

 If I'm reading your thots right, I need to set the boost to an increased level, say......14 psi.......then adjust the boost pin [ by rotating it  ] to try to match the fuel to 14 psi boost, so it's not causing excess fuel [ black smoke ], and if the 1.6td pin is already at the less aggressive grind orientation, increase the boost further in order to "use up" the black smoke......all the while watching the egt's.

 Sound right?


Reply #3November 11, 2018, 05:03:30 am


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Re: Adjusting the boost and fuel on aaz, Ko3
« Reply #3 on: November 11, 2018, 05:03:30 am »
Spoke that nipple on the top the injection pump is the lda. It's meant to control smoke when off of boost. It basically acts as a second throttle lever that adds more fuel when boost kicks in then lessens fuel when off boat to reduce smoke. If you have the hose disconnected then you arnt getting extra fuel when on boost. Connect it back up. I'd try and find a pin from a 1.6td to replace with the aaz one as its junk and doesnt add much fuel. Im pretty sure i have one I can give you. Pm me if interested.

As for controlling boost just leave the wastegate alone on the turbo and buy a cheap manual boost controller. Adding boost/fuel before its fully broken in isnt going to hurt it really, especially with the limitations of the k03. I think the k03 is good for like 15 psi. I'd set it to that, install a 1.6td boost pin, do a governor mod on the pump and then turn your fuel screw in as far as you can while keeping egt under control. You wont kill the sammi tranny at that point but itll give you a nice bump in performance and be just as reliable as the level you are running it at now

The max fuel screw increases all fueling in the pump. The lda is what allows you to take advantage of the majority of that excess fuel. My truck has a massive performance hit with that hose disconnected,  but i have a giles pump and a super aggressive pin

The 1.6td pin will work fine for you. Like you said its adjustable and you can play with it..

Read the how to make power sticky in the faq section. Basically you want to find a balance between the max fuel screw, the lda, egt and desired smoke level. The max fuel screw will kind of give you your top end and smoke at full throttle/boost, while the lda pin is what will let you control how soon the fuel kicks in and how aggressively and is how you adjust your power curve. How much boost the turbo can make is determined by fuel. More Fuel = turbo spinning faster.
« Last Edit: November 11, 2018, 05:14:34 am by RunninWild »

Reply #4November 12, 2018, 02:08:56 pm


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Re: Adjusting the boost and fuel on aaz, Ko3
« Reply #4 on: November 12, 2018, 02:08:56 pm »
Thank you Mike, that helps.
 I have a 1.6 boost pin in the mail. Just need to buy a boost controller now.