I am really confused here. is it the ECU or the wastegate?

if the ECU was programmed to boost between 1.3 to 1.4 bar but you have the 1 bar wastegates which one will get the control? the ECU or the Wastegate? which one will over ride the other?

 

The wastegate has a spring in it that is fed by a vac\pressure hose from the manifold. Barring "interferance" this will allow the wastegate to open at the pressure the wastegate is set at.....

Now, place a solenoid in that vac\boost line and allow a computer to control the bleed off. The wastegate will only open when IT sees it's preset amount of boost. If you are bleeding that pressure off via this solenoid then the pressure it sees is LOWER and it will allow boost to go higher - it's kept in the dark so to speak. The ECU in these cars controls boost just as an add-on boost controller might on other turbo cars, sometimes this control is superseeded by add-on controllers as well. The reason why springs are soemtimes upgraded anyway is because weak springs can allow the gate to be pushed shut at high boost and because you can only bleed off but so much boost - take say a 10PSI spring and try to run 30PSI (!) and you will find that you cannot easily bleed off enough boost to allow for that level of control - a stronger spring in the gate is needed.

That help?

P.S. If it helps more - the wastegate acts like the spillway on a dam. When boost is too high the wastegate allows exhaust gas to go around the turbo much like the spillway on a dam allows water past the dam\electric turbines - keeps the dam thing from overflowing

 

BLKMGC beat me to it, I deleted my post.

Btw, I would NOT adjust the wastegate unless you know EXACTLY what you are doing.

 

Very well explained BLKMGK thanks.

 

D33PBLU3, isn't it a matter of a couple of turns on each turbo's wastegate supported that you turn them each to the same level?

 

isn't there a more precise or accurate way of doing it? getting more boost by manipulating the wastegate?

 

yes, once they have been "referenced" then euqal turns would keep them equal.

I had a suituation where a tuner told me to adjust the wastegates so I could get 1.2bar. unfortunately, in retrospect the ecu wasnt programmed to deliver 1.2

I eventually blew a turbo I also had the infamous evoms wastegate rod snap, so who knows what caused what. Seriously be careful with what you are doing.

 

Ive heard of some poeple using boost controllers, but Ive also heard accompanying horror stories. I even tried to reference the wastegates with a vaccuum tester, its not very black and white and not as easy as it seems, at least for me.

One of the issues with the adjusting the wastegates is you really dont know how much boost each turbo is producing, might be .2 and 1.0, you really dont know. You could adjust both, now you have .4 and 1.2, see where I am going with this?

I guess the question is are these stock? if so get some good aftermarket ones. UMW makes some very good ones. Whoever sends you some, they should already referenced for whatever your needs. If not, I'd call the vendor if you're having issues.

There is an amazing amount of talent and resources here, but this is my experience after reading up on everything I could, might be cheaper and safer to either get new wastegates and send the current ones to be reset, while youre at it, maybe get stiffer springs etc...

 

Thanks for the advice, either i'll send them in or just force myself to accept 1.2bar for now.

 

Look for the post from ARD on Rennlist...he devised a home made wastegate device that allowed him to set the wastegates to open at precisely 8.5 to 8.75 psi using plastic tubing and a pressure gauge hooked up to a compressor...he did itfor me and they work perfectly....do a search for his post or maybe he'll chime in and explain it. I couldn not have done it myself. Some guys set them by turning the lock nut XX mmillimeters from the end of the rod (IIRC it was 10mm)....but the passenger rod is longer than the driver's side.

 

A hand pump ought to allow you to pressurize the W/G can and to look for movement on the rod. I obviously haven't done it but I'd think this would allow you to set the initial opening pressure anyway. I would agree that having them balanced is a good idea, if one is WAY out of whack then it's going to be working VERY hard while the other keeps pulling back trying not to go too high. As it pulls back the other has to work harder to maintain even boost - ouch! The computer control might change this, I'm not sure. I can see where the bleed off might balance them up until the point you're making more boost than the spring is set for and then things might go out of whack. Spins my head trying to think about the interactions there lol!

 

So the best way to control boost levels is through the ECU? Is that what we are saying? Or is the Ecu not able to be programmed to run 1.4 and infact you have to trick it by adjusting the wastegates or bleeding more off independently?