boost issue.. hummm
 

so i built my setup using what was called a 10spi actuator for my internally gated turbo. the first thing i did was to test it on the bench, in case they made a mistake and sent either a 5psi or 15psi actuator. on the bench, the rod started moving at 7.5psi, the gate would be halft open at 8 and fully at 10psi, great that what i asked for, but in practice it besing half open at 8 would only make me boost 8 and not reach 10.. perfect, that is exactly what i wanted!

well tonight i got the chance too look at my gauges properly while driving, or the wife did..try anyways... i am sure that i ve seen 8psi 2 days ago, but tonight it did hit 6 but its holding 5... funny thing is it should even be open at that point. i rechecked all of my hoses, connections couplers, piping etc, everything is fine! i checked the actuator for some play and if its opened a bit on idle and its not...

should i try to tighten the actuator rod a bit more, maybe the tension will solve this and bring up the boost a bit or is my only solution to go with a boost controller... 5psi is not enough but not at all...

Several things here.

As you go to a higher RPM, you should see more boost. Boost functions with engine load, so the more load you put on the engine, the more boost you'll see. I see 7.5 in 2nd, ~8.5 in 3rd almost 9 in 4th, so maybe you are looking at different gears and different loads?

You can adjust the preload on the spring and it should help a bit.Try a bit more than half the hole of preload.

Are you using any type of MBC or is the line directly from the compressor to the Wastegate?

Oh one last thing, the vaccum signal should come from the compressor, not from the intake manifold.

Edit: second last thing! When on the bench, you will have to apply more pressure than it will be required when the turbo is installed in the car. This is because the exhaust gases themselves preload the WG with about 3psi of pressure. So that means that if in the bench it started opening at 8, you can safely subtract 3 psi (the 3 psi the exhaust gases will be pushing already) and that is the pressure that will be needed to open the WG.

I hope I made myself clear because I think I didn't :D

in which ever gear i peak 6psi with full load on. i ll try a bit more tension on the actuator rod.. also the vaccum cannot come from the compressor, there is no vaccum in the turbo, vaccum is only created after the throttlebody, but boost is even at the copressor or after the throttlebody, my vacuum/boostgauge is hokked up on my BOV which is hooked up on the brakebooster vacuum line.. before the builtin check valve obviously

also, the actuator is directy hooked up to the turbine housing, nothing in between.

i ll go out right away anf test with a bit more tension, brb in 10 minutes brah! lol

:bonk:

I knew I didn't make myself clear. :D What I meant was exactly your setup. The vaccum input to the WG actuator coming out of the compressor directly. The gauge is correctly installed like you have it. I would recommend a Vaccum manifold to make it a bit cleaner, but its not necessary at all.

Also, my "gear by boost" condition is helped because I have an MBC installed.

its a bit tighter, now im holding 6...hummm im thinking the actuator got softer with using since new...

I see an MBC in your near future!!

If you had 8psi a few days ago, Im willing to bet its a boost leak.

http://www.vfaq.com/mods/ICtester.html

This is a required tool for anyone equipped with a turbo who wants to be certain they are getting the proper performance out of their kit.

If he had 8 psi, and one day lost two, I'd be more inclined to find out what happened before adding a fun knob.

i have one of those.... but its at work :( got to wait till monday

for sure im getting a boost controller in the near future.. thing is i only have access to 94 octane, no e85 available here, so 8psi is my limit due to compression, but next winter im going low compression so im going to need a MBC.. i said i saw 8 but i might of been wrong, i just just got the tune that day its was 10pm on a monday and i did 1-2 pulls, since then i only checked it out tonight

Get injectors and fuel pump, you can go up to 14, I'd say safely 10-12. I will be running at the end of the day most probably 12 psi on 93 oct.

No you had 8, I remember.

o really... i ll shoot John an email about it, if he confirms, im ordering those injectors and fuekl pump next week.... i need more power.. my wife wont understand it but i know you guys do

:lol:

it feels just as fast as it did, also because the tune is learning im guessing, imagine with the extra 2psi.. i need it so bad

maybe the actuator got hot and the spring soft, man im gonna have problems sleeping now! i need to figure it out and get more boost

You are like me when something does,nt work at my taste, i'll keep searching till I find the answer.

This bit from David is the bit that makes sense with your problem.

Edit: second last thing! When on the bench, you will have to apply more pressure than it will be required when the turbo is installed in the car. This is because the exhaust gases themselves preload the WG with about 3psi of pressure. So that means that if in the bench it started opening at 8, you can safely subtract 3 psi (the 3 psi the exhaust gases will be pushing already) and that is the pressure that will be needed to open the WG.

If the residual pressure from the exhaust on the other side of the wastegate is 3psi then you need to add that to the pressure when you test it. 8psi in the bench test is only 5psi on the car which is close to the result you got.

It makes sense and thought about it but didnt know it would be like 3psi! Now i need to find a MBC, hopefully with some 1/8th barbs and not 1/4

Yep, living proof is @King Tut, who is running 14 psi, Visconti tuned @93 oct.

If you need a MBC, you can have my Grimmspeed black MBC for a great price. I am definitely running 13-14 psi every day on 93 octane. The Grimmspeed comes with 1/8" to 1/4" adapters and 1/4" vacuum hose by the way. I wonder how my boost curve would change if I tapped the housing on my GT2871R instead of pulling from my vacuum manifold.

Why do you want to get rid of it?

MY guess is it would change for the good (more consistent).

He got an EBC.

David knows me so well. I switched to a Go Fast Bits EBC.

Profec b? Herd good stuff about them but they are expensive

Go fast bits... Ill research it.

Sorry... :bonk: I thought for a moment before posting if I should have since I knew you were online....

Dude I say get a boost controller I had issues like this before with a actuated wastegate but I say boost controller.

1. Pressure test the system. Hardly anyone does this and most people, especially DIY'ers and crap shops fitting kits have boost leaks. You're a fabricator, right? Turn up a bung on a lathe which you put in the intake hose to the turbo, drill and tap a hole for a air compressor quick release valve and with a regulator feed it some pressure at 5, 10, 15 psi, maybe twice what you intend to run for safety. Any leaks, fix 'em! Very important.

2. It doesn't strictly matter where exactly you take the vac feed for the actuator from. All that happens is the behaviour changes, not the amount of boost you end up with. Some boost control algorithms (on electronic controllers) work better with it in a certain place and only trial and error will prove that. Even moving it from the outlet of the compressor to half way round the snail (sometimes they are blanks ready to be drilled & tapped) will make a big difference.

3. You probably want some pre-load on your actuator. "Half a hole" is a good starting point, or at least quarter. It may change how much boost it produces so be careful, but it does give better control. To do this take the arm of the wastegate arm and wind it in until it doesn't quite go over the wastegate arm. Then you pull on the arm to locate it. Et voila. Should give you a better time.

These are the basics and a good place to start.

I agree with ft_sjo. Better off finding and eliminating problems and getting your WG acting correctly instead of just band-aiding it with a solenoid. Get a turbosmart or similar mbc, so you know you'll have a quality consistent bleed and then yeah... test entire system for leaks, test actuator, get to happy place, do your fuel upgrades and then add an ebc (my 2c).