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Discussion Starter · #1 ·
Hello,
On Saturday I helped a fellow TDer install a vacuum block on his 91 Daytona Shelby T-1 Automatic.
He had a crate engine installed (Mopar from Mancini Racing, complete with new turbo, injectors and harness, manifolds, etc.
When it was installed the shop did a good job except they did not take pics or document the vacuum system so when lines broke they got lost.
His problem was he was only getting 4lbs of boost.
After going over all of his basics all I found was ignition timing @ 22 BTDC and base idle was extremly high.
After correcting those items we went to work on the vacuum system.
What I thought was going to be a 2-3 hour job turned into a major Cluster F***!!!
What I expected to see on the turbo was 1 vacuum line to the wastegate with 2 at the solenoid.
What I got was 3 on the turbo and 1 on the wastegate solenoid.
Also Chrysler is using what they call a "vacuum ejector" which is suppling vacuum to numerous components and we tryed without success to eliminate this section.
All we were able to eliminate from that point was the evap system.
My question on the turbo is...
1)How are the internals setup that they need to have a pressure signal into the turbo, out of the turbo to the wastegate and solenoid.
The wastegate solenoids are usually duty cycled to control pressure to the wastegate but in this setup the pressure would be constant as it builds and they would duty cycle to relieve pressure to keep the wastegate closed.
2)What is the purpose of the so called"vacuum ejector" setup?
Was it only to eliminate extra vacuum lines in the harness and off of the main harness?
3)The Red restrictor in the pressure line at the turbo is missing, is it needed?

When we were done we had 5 lbs of boost so my feeling is that the wastegate is opening too soon.
He PMed me today and said the car is running good but thinks he has an exhaust restriction that would also contribute to the lack of boost.

We were looking at vacuum diagrams for the 89 T-2 which uses the setup I anticipated seeing and we looked at a 90 and 92 T-1 and all 3 years are setup differently, WTF?!!!
All of the 91 vehicles with a T-1 use the same vacuum setup.

 

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R.I.P Dennis Jarvis
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NAJ my 88 LeBaron has a simular setup for the wastegate etc. Mine just has an extra orifice.
 

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Discussion Starter · #3 ·
What I am trying to find out is the theroy behind routing it that way as opossed to the T-2 Garret, I am guessing the internals besides the compressor wheel/housing being smaller are different.
I would like to see a cutaway of the Mitsu turbo but could not find one.
Does the 2.2L T-1 use the Mitsu turbo also?
I understand the extra lines on the Garret VNT but I was totally surprised to see that on the T-1.
 

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Discussion Starter · #4 ·
Also...
Has anybody ever tried running the vacuum source to the top port of the wastegate solenoid and the pressure line from the middle port on the solenoid to the wastegate eliminating the 2 other lines on the turbo?

I actuated the wastegate solenoid with a scanner with vacuum applied to the top port(which is closed/blocked off from the factory) and a vacuum gauge on the middle port(runs from wategate to solenoid on factory setup).
The solenoid is normally opened and when actuated closes blocking vacuum/pressure.
The controller duty cycles the solenoid so would that not perform the same function?
That would have helped to eliminate the "vacuum ejector" portion of the vacuum system.
 

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R.I.P Dennis Jarvis
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My 88 LeBaron uses the Mitsu turbo
 

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Discussion Starter · #7 ·
Not getting the answers I am looking for here so I am coping the thread to the "turbo" section.
 

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It was to my understanding that the vacuum ejector was to provide vacuum to the cruise control system while under boost. This is achieved through the venturi effect or something like that.

As for the three vacuum lines on the turbo, all but two can be eliminated. Assuming that the car still has the PAR harness (Positive Actuation Restrictor,) there should be a vacuum line on the wastegate, on the turbo housing, and then those two vacuum lines go to the wastegate solenoid. Here is a picture of the PAR harness that should be found on the turbo and wastegate.



Here are the part numbers if you really want to know.
1 4458188 1 CONNECTOR, F - Orificed 1/4 x 1/4 x 1/4
2 4405119 1 TUBE, Formed
3 4201264 1 TUBE, Expanded End
4 4405112 1 CONNECTOR w/ORIFICE 3/16 x 3/16
5 4287145 1 TUBE, Formed

If you need me to take pictures of my 91 C/S with a vacuum manifold let me know.
 

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1)The wastegate solenoids are usually duty cycled to control pressure to the wastegate but in this setup the pressure would be constant as it builds and they would duty cycle to relieve pressure to keep the wastegate closed.
You are correct, a TII vacuum configuration is a "series" (for lack of a better term) connection where the boost pressure is sent to the solenoid and the solenoid cycles to either vent the pressure or send it to the actuator. The solenoid in this configuration effectively direct the flow of boost pressure, either to the actuator or to vent.

The Mitsubishi T1 vacuum configuration puts the solenoid in branch off between the boost source and the actuator. The actuator and the boost source are in-line to each other with the solenoid in between to vent the pressure. The solenoid in this configuration doesn't send pressure to the actuator, it only controls the venting.

3)The Red restrictor in the pressure line at the turbo is missing, is it needed?
Kinda sorta. From what I understand it dampens the pulsing pressure signal in the vacuum line to the actuator to give a more smooth, modulated motion of the actuator. The solenoid only does OPEN or CLOSED, if the actuator only did that it would make for a jerky ride, so the restrictor slows the flow of air in and out of the actuator to give it a more smooth opening and closing.

You could try without it and see just how the ride is, and if it's too jerky or erratic you know to put one in there.
 

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A lot of headaches can be avoid by going manual boost controller and vacuum block.

T1 Mit has a different way to control boos than TII Garrett car. I'm sure you know by not.
 

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Discussion Starter · #11 ·
Thanks for the info.
The car is not with me anymore so I sent a link to this thread to the TD owner.
He did tell me that the car ran fine on his way home other than only 5 lbs of boost.
He only had 4 lbs before the vacuum block installation.

As far as the orifice I will have to check the old lines that were left after installing the vacuum block to see if it was there.
Cannot remember right now but the turbo lines may have been part of the lines that previously replaced.
He did purchase the universal 3/16" orifice that Dorman/Help sells but it was not installed so will this work in place of the "Red" factory orifice?
Also, are the orifices "directional"?
 

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Discussion Starter · #13 ·
So basically when they went SMEC the T-1's started using the Mitsu.
 

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Hmmm, this is interesting but kind of confusing. I started with a 2.5 with the mitsu. Added a grainger, vacuum block, and switched to Garrett. It boosts just fine but the cruise never builds any boost going up hills and attempts to return to computer controlled boost never seem to work.

It sounds to me like I've underestimated the vacuum system. Anyone have a diagram to make this work properly? I can't be the only one whose done this.
 

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Discussion Starter · #16 ·
Does anybody have a cutaway/exploded veiw of the Mitsu vs Garrett turbo as far as the vacuum/pressure lines/wastegate system?
 

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I don't know if this helps but here is a 1987 Garrett Turbo 1 vacuum system:



And here is a 1988 Mitsubishi Turbo 1 vacuum system:

 

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when I did a t2 swap in my charger I ran big hose from manifold to solenoid, then from there ran small5/32? hard line to wastegate.Had MP computer but it made 16lbs boost from2.5 ENGINE was 90 2.5 w/mitshu turbo MP GLHS STAGE 2,PT cruiser intercooler, 3" exhaust,NO CONTROLLERS,NO TRICKS,made 16lbs, STREET SLICKS,ran 13.7's all day long, AND COMPLETLY DRIVABLE for a DD
 

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R.I.P Dennis Jarvis
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bamman Where did you locate these types of drawings? I can't find them in my factory service manuals for my 88 LeBaron
 

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The reason the Mitsu turbo has a pressure line running from the compressor to the WG and tee'd off to the solenoid is to slow it's spool up. The ECU then vents pressure to close the WG and raise boost. If it were run T2 style the boost would spike too much. If he's only getting 4-5psi then I'd say you have a problem with the solenoid not venting pressure.

Now the funny thing is that "The Pope"s 91 Shadow Vert's diagram shows a T2 boost control routing even with the Mitsu. So maybe late 91-92 they switched back because the ECU could now control it.
 
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