My Bodgy Wastegate actuator mod.

[Sydneykid]

Hi jay95r33, I have done the RB20DET actuator on RB25DET turbo a couple of times, works a charm. Saves the boost controller (bypass, restrictor, solenoid etc) working its butt off.

I am not fan of adjusting the spring tension on the wastegate actuator, all you are going is changing the preload. So if it had a 6 psi spring in it, it still has a 6 psi spring in it. By lengthening the actuator rod or moving the bolts you are not changing this. Adjusting the preload to, say, 10 psi is simply changing the wastegate opening point to 10 psi. But once it is open, it still moves in proportion to its spring rate, ie; 6 psi.

By way of comparison, if you changed to, say, a 10 psi spring rate, then it would still open at 10 psi but once open it would move in proportion to its spring rate ie 10 psi.

So if you have, say, a 2 psi change in boost then the 6 psi spring will allow the wastegate to move 66% further than 10 psi spring. This can mean it can easily open too far or close too much. This leads to far more opening and closing of the wastegate than is necessary to keep the boost stable. Result = unstable boost and a very hard working boost controller (whatever type).

My suggestion, as always, has been to use the closest spring rate you can find to the minimum boost you want to run. Then use the boost controller for achieving the small amount above that you require.

Hi Dayna, I don't think your mods cost you nothing. Do you get paid by the hour? If you do, what would you have made in the time it took you to do the work? At overtime rates? There is always a cost in lost opportunity. This may be outweighed by the satisfaction of doing it yourself of course. However time is irreplaceable, I never value it as being for free.

Hope that makes sense.

[Jay95R33]

Thanks SydneyKid - It'd be nice to find a 12 or 13spi actuator, but I think to get what psi I want I'd be looking at an adjustable one...

How much pressure does the stock R32 actuator hold? 9psi, 10psi ?

J

[Sydneykid]

10 psi

[Guest Robo's]

So this is my assumption. Im running 12/13psi, and the stock R33 Actuator is set to a minimum of 7psi, then this is the problem of boost drop at high rpm. I constantly see 2.5 psi drop.

So, will the R32 Actuator help, as it must have more than the factory R33 boost?

Is it a straight swap??

[Cubes]

I had a VG30BB turbo on my car at one stage.

The car made 8psi of boost with the VG30 actuator.

Ripped it off an slapped on the RB20DET actuator, it held 10.9psi.

With a bleeder or the Blitz SBC-iD in manual mode i could never hold anything more than 1.5-2psi more than the wastegate's stock boost in the higher rev range.

I've fiddled with the adjustment more, now it doesn't creep the slightest as the rev's get higher sits smack on 15.5psi.

Its bodgy but has done the trick to keep my happy until the new turbo etc.

[JAS-25T]

you will definately find that you turbo exhaust housing gets much hotter than normal if the flap is not open enough

[Cubes]

I wouldn't loose any sleep over the slight temp increase, if any.

Really depends on what you mean by normal.

Its obvious, the more you give it sh*t the hotter it gets.

I've had my EBC holding the wastegate virtually shut in order to make 15psi of boost. The SBC-iD's screen has an icon that shows the operation of the solanoids.

No difference.

[JAS-25T]

fair enough

but im just saying

watch you dont restrict its opening travel to much (how ever much that is on yours) to a point where its doesnt open enough

can you get actuators made up or set at different rates?

[omp]

Yea about wastegate mods..........The guy who built my turbo put the actuater can in the wrong spot. It is right in front of the compressor outlet, so if the rod goes to "come out" it hits the outlet pipe. Good thing my car ain't going and I spotted it when I was fitting the intercooler pipes. Not happy to run 10000000000000000000000000000psi boost into my stock RB20DET! I just hope the turbo works out good, T04/T3

[Dayna]

re sydneykid "Hi Dayna, I don't think your mods cost you nothing. Do you get paid by the hour? If you do, what would you have made in the time it took you to do the work? At overtime rates? There is always a cost in lost opportunity. This may be outweighed by the satisfaction of doing it yourself of course. However time is irreplaceable, I never value it as being for free."

yer my hourly rate is $40-50, I understand what you are saying and i do value my time. I will put it in another perspective then....

it cost me approx 1.5 hours (including driving and setup) $60....

compare that with adjustable peak and rise pheumatic system, parts $200, plus time spent to pick up parts, source parts, adjust and setup system, lets say 3 hours +, $320

cheaper bleeding system, get and find parts $30, plus labour, and setup, 2hr, $110..

The base mod ($60) gave a better result than the bleeding setup, and was very comparable with the advanced pheumatic setup(spelling!@!) although i'm sure with more onroad testing i could get a better result from the pheumatic setup.

All the mods take time to install, if anything i would say that the initial mod takes less time and gives a good result.

Less time, plus no cost = bargin.

Dayna

[Cubes]

Here's a pic of the actuator attached to the car.

Not the clean part on the actuator arm next to the actuator.

[Sydneykid]

Hi guys, I think some people have missed the point of my last post. To change the spring rate in the actuator YOU HAVE TO CHANGE THE SPRING. Changing the preload by lengthening the rod or moving the actuator itself DOESN'T CHANGE THE SPRING RATE one little bit.

Take a look at the posts from the guys who have actually increased the spring rate, you will find that they have much better control over their boost. The spring rate is as important (I would argue more important) than the opening pressure.

Hope that clarifies

[Cubes]

I get it Gary, I'm just a bodgy bastard.

[Dayna]

hey sydneykid,

how easy is it to change the spring? is it possible?

looks like a sealed unit, but is it possible to cut it open change spring and reweld,seal....

or basically are ya looking at an aftermarket unit.

and also on topic of springs, if you attached an external spring would it not add to the spring tension of the wastegate actuator? is the actuator just a spring tension against a diaphram which when boost comes in it pushes against that spring. so doing the previous it would be pushing against the external spring pressure as well? just a thought, please clarify if i'm wrong...

cheers

D

[Sydneykid]

Hi Dayna, we change springs in external wastegates all the time but I have never tried it for a internal wastegate actuator. The trick would be resealing the vacuum/pressure chamber, it's a bit thin to weld, that's why they generally have a rolled edge. I might have a go one day, could be an interesting project.

We simply buy or swap actuators, RB20 to RB25 for example.

An external spring is a perfectly acceptable way of increasing the spring rate. You just have to be carefull as they are unprotected and in a hot and nasty environment. You would have to choose the right spring quality for the job. Getting the spring rate right would be easy, if you have 7 psi and want 10 psi, just buy a 3 psi spring.

Both of these alternative methods would take longer than your 1.5 hours though.

Hope that helps some more

[ylwgtr2]

Heres what i would be doing.....make a replacement top and bottom but put screws around it like my dodgy 5 minute paint picture shows ...that way you can change the spring...but use the original diaphram and push rod attachment....

very easy job...it regards to the time it takes you id say your being a bit anal if your talking about billing yourself for the time you spend on stuff.....i mean life is not a business...some of us like to play with our toys as a hobby...if your doing it for someone else...thats a diffrent story....i might try make a set later on tonight,if i have the material in the shed ...let you guys know how it goes

[ylwgtr2]

Heres what i would be doing.....make a replacement top and bottom but put screws around it like my dodgy 5 minute paint picture shows ...that way you can change the spring...but use the original diaphram and push rod attachment....

very easy job...it regards to the time it takes you id say your being a bit anal if your talking about billing yourself for the time you spend on stuff.....i mean life is not a business...some of us like to play with our toys as a hobby...if your doing it for someone else...thats a diffrent story....i might try make a set later on tonight,if i have the material in the shed ...let you guys know how it goes

DAMN!!!The paint picture is too large to attach!!Anyone got any ideas how to attach it?

[ylwgtr2]

DAMN!!!The paint picture is too large to attach!!Anyone got any ideas how to attach it?

[Cubes]

Save it as a JPG.

[ylwgtr2]

Save it as a JPG.