2 quick questions....

[shox75]

im on my way to buy a manual ball and spring boost controller.
- Why can't you install a controller with a T off the metal line between turbo and wastegate, is it T'd off the boost line between manifold and pump because that is where the boost guage is installed? All I want to know is where what is the advantage of getting boost pressure off the intake side rather then right off the turbo.
- if the blow off valve is eliminated, is there no aftermarket replacements? Also with a boost controller why is it not necessary to have it?

[jtanguay]

boost controller is going to control the wastegate.  BOV prevents engine damage due to overboosting.  With a boost gauge + manual boost controller on your dash you don't need the BOV.  Boost controller needs to be put on the line going from compressor housing to the wastegate in order to trick the wastegate as to what the real pressure is.

[shox75]

sorry for souding like a dumbass, just realized the BOV only really applies to a gas vehicle with a throttle.
Anyway, so a ball & spring boost controller goes inline the wastegate and turbo metall line.
And so a solenoid is a different setup using boost off the intake right.
Which setup is better then. I've been studying the diagram that was posted in this forum on how to hook up the hobbs switch and dodge solenoid. I am lost?

[shox75]

can know one help me?
I am going to buy a manual ball & spring boost controller.

As far as i know it can go inline between the turbo and wastegate. Is this wrong? Please help me.

[VWRacer]

Yes, you can install the MBC in the hard line between the compressor and the wastegate on your '90 TD. AFAIK, that is the only place where it will work on these non-computerized engines.

The BOV on your engine functions just like the ones in the Eclipse and other gasser engines, and also acts somewhat as another wastegate. When I was first trying to get more power out of my engine, I capped off the BOV to see if it was the source of the low boost (about 9 psi max) I was seeing.



Capping off the BOV did not help in my case, as the compressor section was knackered. To protect your engine, I do NOT recommend capping the BOV, but rather a graduated shimming of the spring's backside to raise the point at which it opens. To cap the BOV, I simple jammed a spray can cap into the unit. You will have to take the BOV apart to preload the pop-off spring.



Hope that helps...  

[shox75]

thanks vwracer.

so if i have my controller set at lets say 20 psi, and i shim my BOV, its just a matter of trial and error to find the right opening point. this would be something like 21 psi for the BOV
Is there a general rule to where the BOV should be set in order to back up the wastegate?

[VWRacer]

DISCLAIMER: I share this info with you for educational purposes only. Change anything on your engine at YOUR OWN RISK. I accept no responsibility for what you do.

Okay, the nastiness aside...

You can generally tell the difference between the wastegate and the BOV opening, but to tell the difference you HAVE to have a boost gauge. If you don't yet have one, run down to your local auto parts store and buy and install boost and EGT gauges before doing ANY power mods to your engine.

Wastegate opening: the boost rises to a max then levels off or dips a few psi.

BOV opening: the boost rises to a max, then drops suddenly, often by half or more before creeping back up again over 5-10 seconds.

If you install a MBC and crank it wide open, this can cause a big spike in your max boost level if you have played with the max fueling screw (see Smog's Making Your 1.9lTD Faster thread), resulting in engine damage or death.  :cry:

The BOV SHOULD open to relieve the excess boost, preventing the above mentioned scenario. However, if you also shim the BOV spring, you take away this protection to the degree that you increase the stiffness of the spring. BE VERY CAREFUL!  :shock:

On my Quantum, the BOV and wastegate operated at pretty much the same pressure (~10psi boost). I now have a new turbo for the engine, but will be reinstalling my BOV before increasing boost. The Q is not my daily driver, but I see no good reason to blow up the engine through carelessness or ignorance. I've done that to enough engines as it is...  :roll:

Gone for the rest of the day. Have fun!