How to check actuator pressure on the car?

[HTC]

I need to check my actuator. I'm thinking of attempting this with it fitted.

Am I correct in thinking that if I connect the actuator directly to the inlet manifold then as boost builds it will hit a point overcoming the spring pressure and begin to open the wastegate. At this point I read of the value on my boost gauge and this would be it's pressure setting..........correct?

If boost continues to build up and up, then I can assume the actuator is faulty?

 

[ibizacupra]

yep. that will confirm its effective "spring" pressure yes.
expecty std actuator to be in the range of 6 to 9 psi on a VF34.

 

[HTC]

Cheers Bill

 

[ibizacupra]

wotcha get?

 

[HTC]

Unable to play with my car until early next week. Let you know how I get on.

 

[jonathanp]

wouldn't unplugging the n75 connector do the same thing? That is if you still use the N75

 

[pj1985]

Yes if he has got one.

 

[HTC]

Yes I do. So the N75's resting state is a straight connection to vacuum. That will make things easier if it is.

 

[pj1985]

Unplug electronically the n75. Leave the vac lines plumbed in. This will give you actuatr pressure aswell as only the actuator spring pressure is holding wastegate.

 

[ibizacupra]

response thru n75 (electrically disconnected) is subject to the internal orifice.. same end result tho yes.

 

[HTC]

I've just run the car with the N75 unplugged and with the vac lines connected in the OEM configuration.

The result was a uniform 8psi under WOT....everytime. Bost builds and never goes over this level what ever I try to do. No surging or overboost. So I am going to assume that the wastegate is functioning correctly.

I will now swap out the N75 (which is only 3 months old) for another one and see how I get on then.

N

 

[ryan_s3]

why waste money on another n75,just fit a boost controller .

 

[HTC]

I have a spare that I lent to a friend, so it won't cost me anything just to try it. Hadn't considered a boost controller. Would that make a difference to wastegate control reliability then?

 

[ibizacupra]

if it can control on actuator pressure alone, then a more controllable boost controller will give you more adjustment.. be it MBC or EBC

 

[HTC]

Okay, this is where my understanding breaks down a little. My ECU adjusts boost via load measured from the engine, rather than requested and measured boost via a MAP sensor on later engines.

Is it a complex process to set boost levels depending on full or part throttle. With an EBC I would have to set these limits myself?

I should have another N75 soon so I'll see how that goes first.

 

[ryan_s3]

Is the boost control closed loop,or can you just keep the factory solenoid connected and fit a EBC,i used to do this on my evo before i went full standalone although i've kept the EBC as it's brilliant as i can set any boost,overboost limit/warn,gain.

 

[ibizacupra]

Okay, this is where my understanding breaks down a little. My ECU adjusts boost via load measured from the engine, rather than requested and measured boost via a MAP sensor on later engines.

Is it a complex process to set boost levels depending on full or part throttle. With an EBC I would have to set these limits myself?

I should have another N75 soon so I'll see how that goes first.

ebc like an apexi avc i used to use, was set easily for rpm levels and boost you wanted at those rpm levels, as well as having 2 boost ranges to select as well as off which was actuator pressure

the n75 map on your early ecu is crude compared to the later dbw units. your map should be able to control this fine tho. (return to cc for fixing it if its gone wonky for some reason, after swapping n75's to confirm this first. if it worked fine once it should continue to do so)

 

[ryan_s3]

Hi Bill,i use a Blitz spec R,absolutely brilliant i found the apexi far to overcomplicated and didn't have overboost limit also sometimes seem to lose setting and adapt without input.
My Tuner uses it on all his cars ran upto 2.5bar with no problems.So whats up with the skoda ? I thought 450bhp was on the cards?

 

[ibizacupra]

Octavia has a dyno plot with 460bhp from EddyH ownership.

It has never had that power since I've had it. go figure
(I know what that sort of power level feels like)

New turbo, appropriately sized is on its way to me. Something more suited for spread of power delivery not claimed peak power which clearly does'nt happen.

Some odd figure from the rollers on that day running in 4wd mode. Would have liked to have run 2wd to see comparison, as I know 260lb is not what its got. Its got more than that given the way it accelerates when its eventually spooled up.
It will be a far better car once done, thats for sure. Nice to drive, not the lag monstor it is now.

 

[ryan_s3]

like you said lag is a product of wrongly spec'd turbo and inadaquate manifold design.I was passengered in a 600bhp evo on race fuel recently and it didn't seem laggy at all, what i will say is that it was so fast that it was almost undrivable on the road!How you cope with 600 with 2wd is unbelievable!