61 replies to this topic

[Dave E]

Is there any way to check the operation of the actuator, not so much the on/off bit but more the transition between the two, if that makes any sense. The boost on a 280ish bhp turbo has always come in in a pretty unhelpful way when trying to balance the throttle but at Croft it was bloody awful. It's never been this bad before so I'm trying to track down what changed.

[Duncan VXR]

Check for leaks. Especially vac system bits. Could be getting lazy solenoid You can make something easy to add slight pressure to actuator to see operation. The wastegate penny swing arms can also sometimes start to play up so check for ease of movement DG

[P11 COV]

Mine was a bit like this. I upgraded to the forge recirc valve but that didn't do anything so I bought a new actuator from Courtenays in the end. It certainly made it a bit better but I still find it a bit of a pain on a balance throttle.

[Dave E]

@ Duncan, I've got spare solenoids so will swap them out and I'll try to get a smoke test done to see there are any leaks @Paul in that case it does sound like the actuator can deteriorate, I'm now wondering if there is another more robust type we could use but unsure what would be compatible

[slindborg]

I have a large syringe you could use to pull a vacuum if you want to try that.

[Dave E]

I have a large syringe you could use to pull a vacuum if you want to try that.

Good call, I've got one somewhere too but not sure how much of a vacuum it'll make. I'll give it a go but if it isn't up to it I'll give you a shout cheers. Ideally I'd like something that'll measure how much vac is needed to operate the actuator

[Dave E]

Just bought one of these, http://www.amazon.co...tl&tag=tea01-21 looks like it should do the job

[Duncan VXR]

Mine was a bit like this. I upgraded to the forge recirc valve but that didn't do anything so I bought a new actuator from Courtenays in the end. It certainly made it a bit better but I still find it a bit of a pain on a balance throttle.

Oem management loves stage 4 power part throttle.........not lol. The more boost ran the more it shows itself on oem / vxr turbo etc One of the main reasons I bothered developing the standalone conversion DG

[Dave E]

Yep I understand and accept (for now) the inherent character, it's just that there has been a definite loss of any pretence of subtlety in the on/off transition and would like find the reason.

[Nev]

Dave, I wonder if on some cars the plane that the wastegate rod pushes on is not in line with the hinged operation of the wastegate itself. If this happens, I think the wastegate would sort of lurch open/shut in "chunks" (rather than progressively) due to friction. The only way to realy test this is to take the turbo off the car and observe the angles and operation. Also, the wastegate can be known to stick wide open on the side of the turbine housing. I thought that you'd sold your turbo'd car ?

Edited by Nev, 19 June 2014 - 06:14 AM.

[Dave E]

Sold it? Getting closer by the second I'll have a good look at the angle of the rod and how freely the wastegate moves, ideally I'd like to see it operate under normal conditions but it's impossible unless you load the engine eg on a dyno. With the vacuum pump I've just ordered I hope to be able to operate it and feel if there are any issues, I'll also be able to compare it to my spare actuator. Incidentally when fitting this unit I noticed a slightly redesigned wastegate that didn't appear to foul the casing like the old type could, I had one stick open at Le Mans a couple of years ago and was going to remove a bit of the casting but it didn't look necessary.

[Pidgeon]

Just bought one of these, http://www.amazon.co...tl&tag=tea01-21 looks like it should do the job

 

Liam at MMG has something like that so I hope it will

[siztenboots]

the wastegate actuator is boost pressure , not vacuum , but those kits are good really pleased with mine.

boost pressure is taken after the comp wheel , and feeds the solenoid. This is switched to failsafe actuator , or the ECU controls wastegate duty to pulse switch it back to the turbo intake.

 

The threaded rod moves downward , and pushes the lever which opens the wastegate. Check the nuts are both tight , as any play won't help matters.

I don't know the supplier or donor vehicle for the CS uprated actuator , but from replacing 2/3 of mine they seem fragile. On the look out for something better made a DIY serviceable and spring rates.

one option

[Dave E]

Steve, I remember you saying about other options but couldn't remember what make it was, is the forge unit a straight swap?

[Nev]

I have a feeling the CS uprated actuator is normally used on a Cosworth engine setup for some reason, but I may be wrong. Yes, testing the actuator is done by introducing boost to the nipple (not vacuum). TEST #1: See how much it takes to pull the shaft. This is your base spring pressure in the unit. TEST #2: Introduce say 15 PSI boost into the actuator nipple. Now see how much it takes to pull the shaft. It should be more. The way the actuator works is it allows the ECU to send boost to the actuator (by pulsing the solenoid) in order to increase the point at which the wastgate opens. Thus if you have an actuator with a base spring of say 12 PSI and the solenoid sends another 10 PSI to it, then your actuator will open at 22 PSI. HTH your understanding. All this sort of info is in my ever expanding VXT document that explains how the whole engine works, if you want a copy let me know your regular email address.

Edited by Nev, 19 June 2014 - 10:41 AM.

[siztenboots]

Not quite as I understand it , the spring holds the w/g shut and the boost has to overcome the spring to open the w/g

 

So using the same example , spring 12psi , we adjust the preload on the shaft to 12psi , until the solenoid give us more than 12psi the shaft does not move, w/g stays shut. ( back pressure will also try to push past the w/g )

 

http://www.turbosmar...-wastegate-faq/

 

[Ebo100]

Most of what you are saying is going over my head so can you guys elborate on the symptoms you are trying to correct.

 

My turbo seems to be either one or off, with really strong boost and then nearly nothing when the throttle is relaxed which feels like the brakes have been pressed. Is this what you are describing Dave?

[Dave E]

Precisely, to differing degrees it's the inherent character of a higher powered turbo running the standard/VXR K04 turbo unit. Why I'm looking into it more now is that it's got a lot worse all of a sudden. A lot of the suff from Nev and Steve is going to take a little understanding to get my head round and really understand it.

[P11 COV]

Dave, I wonder if on some cars the plane that the wastegate rod pushes on is not in line with the hinged operation of the wastegate itself. If this happens, I think the wastegate would sort of lurch open/shut in "chunks" (rather than progressively) due to friction. The only way to realy test this is to take the turbo off the car and observe the angles and operation. Also, the wastegate can be known to stick wide open on the side of the turbine housing.

I thought that you'd sold your turbo'd car ?

 

 

This does seem to make sense. My old actuator always looked like the threaded bar looked bent. It had a bit of tubular shaped metal part way down the rod which I discovered later was linking 2 threaded rods. At Dijon last August at the end of the suddenly lost boost completely and it looked like the rod had snapped. Turned out the join in the middle had come unscrewed. It was easily put back together but I decided it looked a little worse for wear generally so got a new CS one.

 

I get the feeling the new one is starting to look a bit bent.  

 

Also the penny valve on the wastegate does stick on mine if it is allowed to go to far back (when the actuator is disconnected) so it could be that the valve is sticky generally which would make it hard work for the actuator to open/shut smoothly. If this is the case the only cure would be removing the turbo.

Edited by P11 COV, 19 June 2014 - 06:43 PM.

[P11 COV]

BTW...I just used a foot pump to test if the actuator was working or not.