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Discussion Starter #1
Anyone know how to do this on a BPU SupraTT? Thanks for any inputs.
 

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Matt, I was just thinking of doing it a little. :) But seriously, I'm not looking to get 25 psi of boost. My car has typically only ever held 16 to redline. Even before the fmic it was the same. I was trying to get it to maintain maybe 18-20 psi. I was thinking of just adding a couple of washers underneath the bracket held by the 2 bolts behind #2's VSV. Is that how you did it? How much boost did you get when you tried it?
 

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Rviscosi said:
Matt, I was just thinking of doing it a little. :) But seriously, I'm not looking to get 25 psi of boost. My car has typically only ever held 16 to redline. Even before the fmic it was the same. I was trying to get it to maintain maybe 18-20 psi. I was thinking of just adding a couple of washers underneath the bracket held by the 2 bolts behind #2's VSV. Is that how you did it? How much boost did you get when you tried it?
Every car is different but my car actually felt terrible with the shimes. I never really got the chance to prove this b/c my clutch started slipping at the track. Also, I actually hit less boost with the shims...this was even with an open wastegate. Tony feels that his held boost longer but didn't hit higher boost. I definitely did not hit higher boost. Have you pressurized your intake? I would bet you have a boost leak somewhere. Have you pulled the hose to see if it isn't related to the boost controller?

I was thinking of adding a couple of washers underneath the bracket held by the 2 bolts behind the #2' VSV.

Rob I would have to show you...I not sure what bracket but, it is attached to the actuator.


Matt
 

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Discussion Starter #6
I doubt I have a boost leak unless its the pressure tank or something like that. Tony and I did the fmic and its always been 16psi(maintained) since I had a boost gauge. ... I always pull the hose, I still don't have a boost controller yet. I was pulling 119mph consistantly the other night at 16 psi boost so I just wanted to get to 18 psi just to see what it would be like. 12.0 is still my best time. 60' is still in the 1.90's. I still have the stock clutch and have noticed no slipping. I need more boost! I guess if I lose the turbo's it will force me to go single. ;)
 

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I shimmed my wastgate because I believed that it was leaking at high boost (18psi). I used the shims to increase the spring tension to prevent the wastegate door from opening too soon due to the increased exhaust pressure on the door. My car now holds the boost pressure better.



Rviscosi said:
Matt, I was just thinking of doing it a little. :) But seriously, I'm not looking to get 25 psi of boost. My car has typically only ever held 16 to redline. Even before the fmic it was the same. I was trying to get it to maintain maybe 18-20 psi. I was thinking of just adding a couple of washers underneath the bracket held by the 2 bolts behind #2's VSV. Is that how you did it? How much boost did you get when you tried it?
 

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blackbird said:
I shimmed my wastgate because I believed that it was leaking at high boost (18psi). I used the shims to increase the spring tension to prevent the wastegate door from opening too soon due to the increased exhaust pressure on the door. My car now holds the boost pressure better.



Blackbird,

Would you please post some details on how to do this? As long as I've had my car my boost has dropped from whatever it peaks at, to about 16psi by redline. Even if I run 100% on the DSBC and hit 23psi, it will still drop to 16 by redline. And I have no boost leaks.... so I'm thinking the same thing may be happening to me.

Also, did the shim mod cause any boost creep problems for you?

Thanks,
Andi
 

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Discussion Starter #10
^^^
 

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Andi said:


Blackbird,

Would you please post some details on how to do this? As long as I've had my car my boost has dropped from whatever it peaks at, to about 16psi by redline. Even if I run 100% on the DSBC and hit 23psi, it will still drop to 16 by redline. And I have no boost leaks.... so I'm thinking the same thing may be happening to me.

Also, did the shim mod cause any boost creep problems for you?

Thanks,
Andi
Me too!!!
 

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I think you just put washers in with the wastagate spring to increase its stiffness, right? I thought about doing this for a while, and now that I don't really care how long my turbos last I guess I might as well, assuming its not too difficult.

It should be noted though, that the extreme backpressure which opens the wastegate early, can cause detonation... So it might not be such a bad thing on pump gas.

Wait, nevermind (google rules)

http://www.supras.com/sogi/techtips/1_engine/1023_MKIII_wastegate_shimming/

Problem with this is that you would probably get more boost creep, but its so easy to do its worth a try.
 

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Discussion Starter #14
Grant said:
I think you just put washers in with the wastagate spring to increase its stiffness, right? I thought about doing this for a while, and now that I don't really care how long my turbos last I guess I might as well, assuming its not too difficult.

It should be noted though, that the extreme backpressure which opens the wastegate early, can cause detonation... So it might not be such a bad thing on pump gas.

Wait, nevermind (google rules)

http://www.supras.com/sogi/techtips/1_engine/1023_MKIII_wastegate_shimming/

Problem with this is that you would probably get more boost creep, but its so easy to do its worth a try.
I guess pulling the hoses is no longer required when you do it this way. That might be why adding 3 washers behind each bolt won't do anything more than pulling the hoses?
 

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The waste gate in the front of the motor is responsible for boost control. The other waste gate is responsible for the sequential twin function. I have added 3 washers behind the front waste gate mounting bracket, thus moving the waste gate forward and increasing the spring pressure. This will increase boost pressure a little, but it’s mainly done to help prevent the waste gate door from opening prematurely due to the added boost that is generated from using a boost controller. The premise here is that I don’t believe that Toyota designed the stock waste gate to function at anything above 11psi. Above 11 psi the spring in the waste gate cant hold the door closed and it will leak.
 

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The 3 washers don’t move the waste gate far enough to affect the hoses.



Rviscosi said:


I guess pulling the hoses is no longer required when you do it this way. That might be why adding 3 washers behind each bolt won't do anything more than pulling the hoses?
 

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You could try 4 washers but getting 3 on the waste gate was hard enough. Put the washers between the turbo and the waste gate mounting bracket on the 2 bolts.

Euphoric said:
So, what is the general rule for shims used? 3? And the shims are going behind the bolts of the brass actuator right?
 

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Discussion Starter #19
Euphoric said:
So, what is the general rule for shims used? 3? And the shims are going behind the bolts of the brass actuator right?
Heres what the link had.

Shimming the wastegate is a very simple, very safe, very easy and very cheap way to increase
you boost pressure.

Materials: 8-14 washers (8mm)

Procedure:

1. Remove the pipe leading to the 3000 pipe (from the intercooler)

2. Remove the intake pipe disconnecting all the hoses from it (BOV, PCV, Cold start, and the
wee one on the bottom)

3. You should see a silver cylinder, the actuator (looks like the bottom of a pop can) undo the
bolts holding it on to the turbo (12mm socket)Pull this toward the from of the car, it is pretty hard
to move, and place 4-5 washers between the turbo and the actuator and replace the bolts.

4. Use a little super glue to attach the washers together so you have "1 big washer" so you are
dropping them through the car and finding all sorts of new curse word combinations.

5. 4 washers gave me about 9 psi, 5 gives about 10psi. Any more and you will need longer bolts
and if you want more than 10 psi and aftermarket exhaust is most definitely required.

6. Go for a ride and feel the benefits of 3 extra psi (remember 11hp for each psi!!)


I know a guy that did 3 washers first and didn't see any difference than pulling the hoses, then did 6 washers on each bolt and held 25 psi. He went to 100 mph or so about 3 times hitting high boost and then got the death whine and hardly any boost, so I would say 6 is to many. If I do it I will try 3 or 4 washers behind the bracket so 6 or 8 washers total since there are 2 bolts holding the bracket.
 

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this tech article is for the MK3 supra.

Rviscosi said:


Heres what the link had.

Shimming the wastegate is a very simple, very safe, very easy and very cheap way to increase
you boost pressure.

Materials: 8-14 washers (8mm)

Procedure:

1. Remove the pipe leading to the 3000 pipe (from the intercooler)

2. Remove the intake pipe disconnecting all the hoses from it (BOV, PCV, Cold start, and the
wee one on the bottom)

3. You should see a silver cylinder, the actuator (looks like the bottom of a pop can) undo the
bolts holding it on to the turbo (12mm socket)Pull this toward the from of the car, it is pretty hard
to move, and place 4-5 washers between the turbo and the actuator and replace the bolts.

4. Use a little super glue to attach the washers together so you have "1 big washer" so you are
dropping them through the car and finding all sorts of new curse word combinations.

5. 4 washers gave me about 9 psi, 5 gives about 10psi. Any more and you will need longer bolts
and if you want more than 10 psi and aftermarket exhaust is most definitely required.

6. Go for a ride and feel the benefits of 3 extra psi (remember 11hp for each psi!!)


I know a guy that did 3 washers first and didn't see any difference than pulling the hoses, then did 6 washers on each bolt and held 25 psi. He went to 100 mph or so about 3 times hitting high boost and then got the death whine and hardly any boost, so I would say 6 is to many. If I do it I will try 3 or 4 washers behind the bracket so 6 or 8 washers total since there are 2 bolts holding the bracket.
 
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