Tweeting wastegate on LJ70 turbo (1 Viewer)

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Hi all
Continuing on the path of resolving power issues on my 1986 round headlight Lj70, I’ve got a reconditioned turbo arriving shortly, hopefully this will help, the last one wasn’t in amazing condition and was spitting a lot of oil. A few people have told me it’s possible to add washers to the actuator to tweak more power out of the turbo. I’m wondering if anybody has experience of this? I don’t have way of testing boost, is it safe to do this? How much extra can one get out of it? Any advice appreciated
 

GTSSportCoupe

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Hi all
Continuing on the path of resolving power issues on my 1986 round headlight Lj70, I’ve got a reconditioned turbo arriving shortly, hopefully this will help, the last one wasn’t in amazing condition and was spitting a lot of oil. A few people have told me it’s possible to add washers to the actuator to tweak more power out of the turbo. I’m wondering if anybody has experience of this? I don’t have way of testing boost, is it safe to do this? How much extra can one get out of it? Any advice appreciated

I recommend just buying a manual boost controller instead. It's a more controllable way to go, and easy to install. Something like this: NXS MOTORSPORTS MANUAL BOOST CONTROLLER MBC TURBO 4G63 | eBay

I'm not sure about your generation of CT20 turbo, but I can say the 1990+ ones can run reliably at 20psi. Maybe only run the early one up to around 16-17psi if you have an intercooler. If no intercooler 14psi maximum. The early CT20 has a larger turbine and small compressor than the later one. It's also not water cooled if I remember correct....
 
Joined
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I recommend just buying a manual boost controller instead. It's a more controllable way to go, and easy to install. Something like this: NXS MOTORSPORTS MANUAL BOOST CONTROLLER MBC TURBO 4G63 | eBay

I'm not sure about your generation of CT20 turbo, but I can say the 1990+ ones can run reliably at 20psi. Maybe only run the early one up to around 16-17psi if you have an intercooler. If no intercooler 14psi maximum. The early CT20 has a larger turbine and small compressor than the later one. It's also not water cooled if I remember correct....
Thanks for replying, If I remember correctly the original normally stays under 10psi, so u think it can safely go up to 14psi? What would happen if it went over 14psi? We talking about knackered turbo or new engine head, I understand since Toyota introduced the turbo on that model it developed head problems.Thanks again
 

GTSSportCoupe

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Thanks for replying, If I remember correctly the original normally stays under 10psi, so u think it can safely go up to 14psi? What would happen if it went over 14psi? We talking about knackered turbo or new engine head, I understand since Toyota introduced the turbo on that model it developed head problems.Thanks again

Compressing air produces heat. Compressing more air and doing it inefficiently creates even more heat. An intercooler will reduce this heat before it goes into the engine. Without an intercooler, you have to be careful.

The other side of the equation is, more air without an increase in fuel makes for a leaner mixture. This reduces EGT's and will prolong the life of the engine components.

So you need to find the happy medium. A little more air, but not too much (unless you have an intercooler). Around 12-14psi is the commonly accepted value for these old inefficient Toyota turbochargers. After that they produce substantially higher intake air temperatures.

Around 12-14psi will actually be beneficial for the motor as long as you don't increase the fuel. Use a pyrometer (to measure EGT), to know for sure how things change. A manual boost controller will allow you to tune for the sweet spot. Also, if you learn how to adjust the boost compensator (top of the injection pump), you can really fine tune things. Usually increasing fuel pin spring resistance (dial) will allow a boost increase without fuel increase.

This sort of tune will net lower EGTs, and better efficiency. It will actually be better for the engine.
 
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Compressing air produces heat. Compressing more air and doing it inefficiently creates even more heat. An intercooler will reduce this heat before it goes into the engine. Without an intercooler, you have to be careful.

The other side of the equation is, more air without an increase in fuel makes for a leaner mixture. This reduces EGT's and will prolong the life of the engine components.

So you need to find the happy medium. A little more air, but not too much (unless you have an intercooler). Around 12-14psi is the commonly accepted value for these old inefficient Toyota turbochargers. After that they produce substantially higher intake air temperatures.

Around 12-14psi will actually be beneficial for the motor as long as you don't increase the fuel. Use a pyrometer (to measure EGT), to know for sure how things change. A manual boost controller will allow you to tune for the sweet spot. Also, if you learn how to adjust the boost compensator (top of the injection pump), you can really fine tune things. Usually increasing fuel pin spring resistance (dial) will allow a boost increase without fuel increase.

This sort of tune will net lower EGTs, and better efficiency. It will actually be better for the engine.
That’s just the answer I wanted thanks, I know it’s possible to tune the pump and turbo but unfortunately at the moment it’s out of my skill range, I think a good start would be to get a boost gauge and pyrometer, I don’t suppose you’ve got a link to a suitable one for my vehicle? I wish I knew someone here who could tune her up for me, I’m in the south of France and I’ve had 2 mechanics both give it a go on the fuel flow level and injection pump timing but to be honest they don’t know enough to have made any difference. I’ve been told to take the pump off and take it to a shop to get it checked out (not a quick simple thing to do). I understood from various people that there is some tweaking to be done without taking the pump out, hence really liking your answer.
 
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I've had good experiences with Auber pyrometers, they are one of the least expensive options out there and work great. I haven't used one for boost yet, as normal boost gauges are pretty inexpensive in comparison.

 

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