Actuator, how's it work?

[Jezz_S13]

Hello again,

I may well be way off the mark here, but playing around I reckon the actuator does this...

It's purpose it to restrict the amount of boost, correct?

It does this by taking a positive pressure from the induction air feed, this pushes a diaphram, and at a set pressure this opens the waste gate.

Is this right?

Therefore by shortening the actuator rod (or effectively shortening it by moving the actuator further away) you can increase the boost.

If by some miracle this isn't total b0110cks, how much pressure gain am i likely to get? Any buy how much can I 'shorten' the actuator rod before I break everything?

Is there another way of modifying the actuator, stronger spring (or whatever is inside it) or are they totally sealed units?

By the way I have T25 turbo.

Sound like a hack to me! http://300zx.co.uk/200sx/ubb/smile.gif

Cheers for your patience.



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Standard, yet smokey noisy tub of sh-eye-te '92 S13.

[Chimp]

sounds about right. the standard actuators are sealed so you cant mess with internals. Id be wary about going mad with the standard T25, when they pop its a reet bummer. Theres a thread somewhere about sticking washers on to shorten the rod, and increase the boost.

16psi is alot for a t25, hard to tell what its doing without a boost gauge.

*always remember to set boost in 3rd or 4th gear unless you are a muppet like me*



[This message has been edited by Chimp (edited 29-06-2001).]

[Jezz_S13]

Surely it shortens the rod? I.E.moves the actuator further away from the waste gate?

I'd hate to go the wrong way and get less boost. http://300zx.co.uk/200sx/ubb/smile.gif



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Standard, yet smokey noisy tub of sh-eye-te '92 S13.

[olly200sx]

to get more boost you have to actually lengthen the rod, this pushes the spring and diaphram inside the actuator further towards the pressure coming in making it harder to push, thus enabling more boost before opening, a small amount is all you need to make a large difference, go very carefully, if you have a boost guage the best way to test it is find some straight long road, put it in third or fourth and accelerate hard whilst using your left foot to brake and you will see peak boost come up.

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S13 - Lots of Mods

[Jezz_S13]

Cheers,

Okay so where do I put the washers?



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Standard, yet smokey noisy tub of sh-eye-te '92 S13.

[Stuymac]

Jezz, Have you got a chip???

I had the chip and boost upgrade at the same time, so Im not sure about this, but I think the std chip will only allow about 13psi before cutting spark / fuel to protect the engine.

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Stu

DIY T3, FMIC, but need more power!!

[Chimp]

i think the fuel cut is at 15 or 16 psi on the standard chip. I thought by shortening the rod, you are making it harder for the wategate to be opened by the boost.

the shorter the rod, the harder the boost before the wastegate opens. I remember it being an arse to yank the actuator rod over the wategate hinge on the turbo as i had shortened it alot.

[Jezz_S13]

No I don't have a chip.

I suppose I should just set it so that it just stops cutting out (I don't have a guage either).

What kind of power increase am I likely to get bearing in mind that there are no other mods on the car it I increase it to 12-13 psi?

What is the standard boost 5 or 7 psi?

[Jezz_S13]

How did you shorten the rod Chimp?

I have considered cutting it in half, cutting about 4-5 mm off one end then using a die to put a thread on each end.
Then using a piece of tubing with the same thread tapped up it to join the two halves and to make it adjustable.

How does a boost controller work then?

Does it have a solenoid on the waste gate lever and a pressure sensor instead of the actuator? if so time to get the 'electronics is fun' kit out.

[Stuymac]

I would imagine that the washer method is probably the most reliable of all the solutions, a bleed valve is also very cheap, but you do get boost spike http://300zx.co.uk/200sx/ubb/frown.gif

Be careful how much you alter the amount the wastwgate opens though, on the actuator I have, 1/2 turn can make about 3 psi difference.

OH, and make sure the turbo has well and truely cooled down when playing with the actuator. You can tell turbo car owners, they all have burns on the back of their hands http://300zx.co.uk/200sx/ubb/biggrin.gif

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Stu

DIY T3, FMIC, but need more power!!

[Chimp]

soz jez, i didnt cut mine, i went for the wimpy option of buying an uprated actuator. I didnt want to blow anything up... didnt work very well. Standard boost is 10/11 psi. Im not sure its *really* worth the hassle in all honesty.

Stu is right about the heat down there, battle wounds are par for the course with this job unless you are really patient :)

[A8-RICK]

the washer method is dead easy. it only takes around ten mins, although i have a boost gauge to check on things after tampering with them!

i put two washers between the turbo and actuator mouting bracket, this gave me around 14psi no probs.

think i would get a boost gauge first tough, to make sure its running the 10psi it sould be now.

[Mannie]

I fitted a boost gauge and bleed valve over the weekend. What a difference such a simple thing makes. I fitted the boost gauge first and was hitting about 10.5psi which seems right seeing as the only mod I have is a K&N panel filter. I then fitted the bleed valve (yes I too have blisters on my knuckles!!) and now run about 13.5-14psi. Its like another part of the engine has started working. Rev's so much better and pulls so much stronger. I had thought about using the washer method but its dead easy to adjust the bleed valve, although the bleed valve is not the best design as a 20 degree turn equates to about 1psi. Might take it off and stick it in a lathe to make it more adjustable. I also undid the 2 air box clips closest to the nearside wing and used the clips to hold the panel filter tight up against the lid of the air box but leaves it open slightly to suck in more air. The induction noise is great!
btw I bought all the stuff from PTS in luton as I was in the area. They are so helpful in there plus they have a 2wd/4wd rolling road. I have posted something on the decent link section as I have talked them into doing a decent discount for anyone that mentions this web-site.