datsunboy wrote:The wastegate line should be hooked into the I/C piping nice and close to the throttle body, as it will then see the pressure that is closest to the engine, after loosing some through your I/C e.t.c.
gingofthesouth wrote:
What COULD be happening is if somehow he has a VACUUM line on the top side of his wastegate reducing the amount of pressure needed from the turbo to compress the spring instead of a pressure regulator allowing opposing pressure on the top side.
If there was vacuum on the line to the wastegate, then it wouldn't operate, therfore increasing boost....thats how they work.
once 10psi is reached on the line going to the wastegate, it will be enough to overcome the spring pressure and begin to open the wastegate, bypassing some exhaust gas, reducing boost pressure. the more pressure on the wastegate line, the further the wastgate opens
Actually wastegates have two input ports for operation, although only one is absolutely necessary.
The Regulator port at the top pushes from the top of the diaphragm allowing you to control boost pressure and not be stuck with the spring rate only. The compressor port pushes on opposite side of the diaphragm to open the gate. Thus if you had vaccuum on the regulator or boost control port then you would possibly be reducing the pressure needed to open the gate.
For simplicity sake I run my 40mm HKS copy Waste gate with the pressure fitting onto the turbo direct into the Lower wastgate port ( pretty much as Adams Diagram shows )
Corky Bells Maximum Boost also recommends going directly from the turbo to the WG - so that is what i did and it works perfectly for me
I get a reliable 12psi boost every time. I'm not saying its the issue but it could be worth a try setting it up direct from the turbo to the WG - even just to eliminate one thing that it could be.
Ah, woops, my bad......I was explaining a normal wastgate operation.....not an external one lol didnt read that bit.
So how do you suggest that he's getting a vacuum pressure while he's got his foot up it boosting?
but if there was a vacuum on the top port, then it would lower the boost pressure.
Yea I set it up just like that. Minus boost controller. And yes Iv run it into the start of the 1st peice of Cooler piping right up the turbo end. So Shud work mint... Got 5-6 psi today on my way to work so i dunno what that's about lol
datsunboy wrote:Ah, woops, my bad......I was explaining a normal wastgate operation.....not an external one lol didnt read that bit.
So how do you suggest that he's getting a vacuum pressure while he's got his foot up it boosting?
but if there was a vacuum on the top port, then it would lower the boost pressure.
Maybe if he had put the pipe into the intake side of the turbo (before the compressor wheel) which would be creating vacuum.
But it sounds like he hasn't.
Also.
what turbo are you using?
What volume is your plenum?
Where is your boost guage hooked up to? has this been checked? is this a electronic one?
What size throttle body are you using?
"It's ok, we know what to do...we talked about this a lot on the internet."
it's getting to around 5psi after i installed a brand new tial gate. Yeah I can here it spool, reaching 5psi around 3.5k, the turbos a genuine greddy t518z (greddys performance version of a td05-18g) with a 8cm housing. Im unsure of the volume of the plenum as I got it off a mates ca that made 367bhp on 18psi. It's main caps bolts came loose after 20thousand kms so that ruined the motor enough for him to give up on it. It's a fairly well made plenum with tuned length velocity stacks inside. I had it pressure tested for piece of mind.
