devil_z33

Hi, just want to ask those who has your Greddy TT installed about the Boost PSI. I found out that the reading of the boost gauge went to 10psi when I step about half of gas panel. Is that abnormal? Does the emanage limited the boost at 5.6 psi? If so, how come I could see the gauge went to 10psi. Please help

Thanks for all opinion in advance.

7 eleven

It sounds like you don't have the waste gate vacum line connected at all. If the wategate vacum line is connected it will limit boost to 5-5.6 psi. I would not drive it until you fix it or at least do not go into boost. You will damage the motor if you don't fix it.
Gary

devil_z33

Really?But I do hear the sound come out from the wastegate when I release the gas panel or shifting. Beside, I have not installed the BOV yet, but will install it tomorrow. Is that a reason too?
Thanks for opinion.

devil_z33

Where is the wastegate vacuum line connected to. I do see the installer connect a line to the wastegate, but not sure where it connect to.

7 eleven

You can not hear the wastegate on a closed system like the Greddy kit has. The wastegate does not open when you lift off he gas, it closes. You are probably hearing the pressure surge due to the closing of the throttle with boost in the charge piping and no BOV.

Did you install it? If not you need to take it back and let them know that the wastegate is not opening under boost. If you did you need to connect the wastegate vacum line to a good vacum port.
Good luck,
Gary

7 eleven

There are 2 wastegates on the kit you need to tee them together and connect them to a good vacum port. the instructions say to use the vacum port that is on the front left side when you lookng at it, of the intake manifold under the cover. From the factory it's capped with a rubber cap.

The insrtuctions are on the Greddy site. I'd be concerned with the quality of the install if they let the car leave in this condition. This is a big issue that will cause total engine failure with one wide open throttle run. Left uncontrolled our turbos will produce well over 20psi of boost. At that level the stock motor will be destroyed. I'd go over the install with a fine tooth comb or have another person that has the knowledge to do so.

Things like this is why so many Greddy kits blow, it's scary to think how many people's cars have been damaged by things like this and the installer just blames the kit and wants more money to fix it.

devil_z33

If the vacuum line did ont connect it, the turbo won't work right?

7 eleven

No, will work but you will not have any control over boost.

350zDCalb

iTrader: (21)

the wastegate is what limits the amount of boost the turbos are creating...think about it this way, if a turbo system didn't have a wastegate, the turbos would spool and compress air and route this boost back into the motor without anything limiting HOW MUCH BOOST was being created...the turbos would only be limited by their rated efficiency...the greddy kit with the two td05 18gs, can produce in excess of 23-26 psi...that means, unless you get this issue resolved and get the wastegate(s) functioning properly, you can definately overboost past 10psi..the car is not tuned for that, you will go lean, detonate and destroy the motor, or the rods will fail mechanically from the high stresses of such high amounts of boost
good luck, check the vacuum lines...

devil_z33

I check the vacuum line, and both connected to the wastegate and the T adaptor to the intake manifold. However, I saw the wastegate has a long silver thing. what is that for? Do I need to connect that as well.?

7 eleven

There are two nipples on the wastegate, which one is your vacuum line connected to? The upper or lower nipple?

devil_z33

Lower one (the one on the side of the wastegate)

Sharif@Forged

iTrader: (92)

Seems like the lines are connected properly. The side port is for the wastegate, and the top port is for a boost controller...or left alone if you dont have a boost controller.

Double check the lines havent melted or something. Only other thing I can think of is that the wrong wastegate springs were installed. But under no circumstances should you be seeing 10psi of continuous boost pressure. You might see a small spike to 7psi or something...when transitioning from off-throttle to full throttle, but even that is extreme.

If you are seeing 10psi at part throttle, something is wrong with your wastegates/vaccum lines.

Also, what type/brand of boost gauge are you using?

devil_z33

I am using Autometer mechanical boost gauge. I brought my car to the place i have the TT installed. They fix that for me. One of the vacuum line has a small hole on it. They replace a new line for me. How I am having a constant of 5 psi max.
Thanks for you guys help.
Very appreciate it.

Sharif@Forged

iTrader: (92)

Good...glad you solved the issue.