I need a pair of wastegate actuators for the T28 hybrids I'm fitting.

Where can I get them quick and what pressure should they work at to give something similar to safety boost when my controller is switched off?

 

How do they work? Do they open progressively or just snap fully open at a preset pressure?

They open progressively (it's just a spring pushing back against a diaphram which has boost pressure presented to it, basically).

 

You want a set that are at full extension by ~ 7psi to give you SB boost levels, or get an adjustable set that have a base opening pressure of somewhere around that - you can then use a vacuum pump while they're on the turbo (before fitting to the car) to adjust them so the WG is fully open at 7psi.

 

Adjustable ones have variable length actuator rods, btw - you adjust the pressure they're fully open at by shortening or lengthening the rod (it's called adjusting the pre-load). Shorter = higher pressure, longer = lower.

 

 

The fact that they creep open as pressure builds is the reason why boost controllers let you build boost quicker, as they make sure zero pressure is presented to the actuator until the turbos have spooled to your preset level, and then they present full pressure to the actuator, snapping it full open. As pressure reduces again, the boost controller presents atmospheric pressure to the actuator, and it shuts again, then opens, and so on. (The frequency of all that is what you are adjusting when you alter the 'gain' setting on your boost controller).

 

Any turbo suppliers should be able to get you a set, but you'd need them mounting on custom brackets..

I've got the brackets and in fact have 1 actuator that looks to be adjustable on the arm.

I have no idea what spring will be fitted but I know it's from SE.

I presume I had best replace them as a pair really...

hhhhmmmm sounds like I'm going to have problems if they need setting up as I have no vacuum pump :(

and how open is fully open?!

Ah er yeah, hard to set up without a vacuum pump.. d'oh!

 

And fully open is, generally anyway - attach to turbo, yank on actuator arm, and see how far it opens.. it'll only go so far :) That's fully open..

 

Technical, I know.. :D

 

Best bet would be either to buy them as a preset pair, or get somewhere like SE to set them up off the car..

 

It's all so much easier on a car with only one blower :)

 

Oh yeah - and if your one is adjustable (it'll have a threaded rod part to it), then it's not an original Nissan 300ZX part, as stock actuators are non adjustable (at least, they were on Series 1's, I believe on 2's too)

As a T28 will presumably be putting more air through at 7psi than a stock turbo is this OK?

I've been told that I'll have to run them at lower boost than I was with stock turbos to avoid blowing things until I get some 555's in...?

 

Thanks for the help, learn't a lot about a boring gadget that usually just does it's job in the depths... LOL

IMHO, 7psi on T28's will be fine - 9psi ought to be fine too, although I wouldn't try pushing 14psi on stock injectors and bigger tubs if I were you ;)

 

Depending on what you want to run boost wise, you might be OK just getting it rolling roaded and checked for correct fuelling - you might find you can, for example, run 12psi, and find that acceptable. On the other hand, if you definitely want to run with 555's, you should be able to push quite a bit more boost.. ;)

 

HTH

Aaron

Well I was running 16 to 17psi on stock turbos with hardly any detonation before I had to replace the engine due to the bottom end bearings going!

This is a different engine however so things will be different I suppose and I'll have to check all is well before starting to up the boost again.

Yeah - you never know, you might find yourself able to push 14psi on the T28's, even with stock injectors..

 

But if you do want to try it - as you say - gradually working your way up is the way to do it, rather than going right in at the top.

 

 

Just try not to lunch the bottom end again this time Chris... ;) :o :D

Well all I can say mate is get those oil leaks of yours fixed!

 

I put up with a few on my old engine and just topped it up every couple of weeks.

Then one day I was "racing" a big Range Rover and as I blasted past him I heard the sound of spanners inside my engine!

Quite embarrassing as I slammed the brakes on in front of him and did the slowest 1/4 mile home ever LOL

 

On draining the oil there was almost nothing there so what had happened for all the oil to go I just don't know :(

 

Having said that the engine would have had to come out to fix the leaks so it's cost me a "new" engine but now I can rebuild the old one at my leisure to monster performance ;)

I do need to - trouble with only having one car though is that if I start taking the Z apart to try and fix these oil leaks, I can't get to work anymore..

 

Which is a bit of a pain..

 

Trying to scrape together some cash to get a banger, but sadly it's not happening..

I think it is sadly essential to have a second car with these z's :(

Either that or pay huge amounts for someone to do the work and still be without the car a few days.