R.I.P Dennis Jarvis
Join Date: Oct 2009
Location: Saint Cloud Florida
My Ride: 1988 Labaron Convert
Engine: Turbo 2 2.2 liter
Thanked 0 Times in 0 Posts
Re: Installing Vacuum Blocks 84-93 T-1 thru T-4
"As for the "mbc/grainger or solonoid-----wastegate can" Not too sure about this??"
DCTZ wrote this up. Quite informative.
2.2 / 2.5 Liter Engine Turbo Bleeds
A bleed is when the air system has an alternate route to let air escape so that the device being controlled (wastegate) will see less pressure. This will make the wastegate open fully at say 10 PSI instead of 7 PSI. Most of you do a bleed combined with the stock solenoid bleed.
#2 Stock Solenoid Bleed
The stock wastegate control system uses the solenoid to create a bleed. The solenoid opens and closes real fast at different rates (duty cycles) to create more and less bleed on the wastegate. The more often the solenoid is open, the more it bleeds, and the less often the wastegate is open, allowing more boost. If the solenoid is open less, the wastegate will see more air pressure, and be further opened, allowing less boost. The solenoid is controlled by the computer by the feedback it gets from the MAP sensor. If the solenoid is stuck closed not allowing a bleed, or if you connect the vacuum line directly to the wastegate, the boost level should be about 5 PSI max. So if you only get 5 PSI your solenoid is likely shot.
A G-Valve does not let air escape but holds it back from the wastegate until a certain pressure is obtained. Then the valve opens allowing the air pressure to open the wastegate. There is a bleed which is not the major controlling factor on the wastegate side of the G-Valve that allows for the wastegate to close again after the pressure closes the G-Valve. If this very small bleed was not on the wastegate side, the wastegate would remain open and you could boost no more than 5 PSI. So maybe some of you consider this small bleed on the wastegate side a bleed that controls the boost? The vacuum line never sees this small bleed.
The 1st 2 systems (bleed and stock solenoid bleed) always puts some pressure on the wastegate allowing it to open a little at low boost. This is what causes some of the turbo lag. A G-Valve does not let the wastegate open at all until is sees the set pressure so it has less lag.
I tossed in a quick layout of the bleed method in use by your car.
I hate to disagree with NAJ, but if you look at your vacuum diagram and follow the PCV valve towards the air cleaner box you will see it hooks up to the air cleaner box. This circuit is how the PCV valve sees a vacuum any time the engine is running, and even if the engine is in boost.
When I converted my T1 over to a T2 and installed a cold air intake turismolover22 posted this drawing so I could retain my Cruise control, PCV valve, etc..
Also inside the air box where the PCV enters is a small air filter. Most people forget they have one and never change it.
I also am posting a pic on one of the many ways to install a g-valve. You can delete and plug off where required the hose from the wastegate solenoid valve and the small 5/32" vacuum fitting on the turbo it's self.
Sorry for rambling!
88 LeBaron convertible. Msd ignition, 2-piece w/ 52mm, ported exhaust manifold,inter-cooled, converted T2. Running a stage 3 cal. from FWD performance
Gone too soon, you will be missed
R.I.P Dennis, September 3, 1957 - July 7, 2014