GTQ71 Turbo

[snipersixx]

Who here has problems controlling there boost with the GTQ71 ?

I've tried porting the hole on turbo housing nothing.

Tried changing to a standard acturator from a heavy duty nothing again.

Also tried boost controller from RJC nothing.

 

[Turbo38V6]

What wastegate do you have??

 

[John Wilde]

If you are running a stock type waste gate I think that is your problem. You should consider an external upgrade.

 

[azgn]

there is no reason you shouldn't be able to control boost with a stock type wastegate.....set it up without the solenoid (compressor to wastegate) with a bleeder valve (like the RJC)

this should work just fine unless there is something wrong with your actuator or the wastegate hole isn't properly sized (this ASSumes an aftermarket downpipe with larger flapper)

I have done this with a GTQ70 no problem

 

[Louie L.]

I totally agree with the above. I never had any problems with a THDP system on any of my 70 GTQs

 

[John Wilde]

Have either of you run the GTQ71 that he is speaking of?
Maybe there is a little difference???

 

[Louie L.]

John,
I honestly dont think there is much difference in between the 2 turbos. One is rated at 30 hp more but the center sec,exh wheel and housing are same as the 70. I have actually owned a 71 GTQ but never did install it.

He should not be having any issues controlling boost either way. Unless as AZGN said, the wastegate hole is not the correct size or a issue with the puck or actuator assembly.

 

[BUICKTR]

controlling boost on PT 71 GTQ

I had the same exact problem. I had a THDP and my stock type actuators would not work properly. I could not control boost at all. I had tried a HD actuator with solenoid and without. I also tried boost valves, bleeder valves and I had my turbo housing opened to 1". The puck seal perfectly on the turbine hole but no help! It was very frustrating that I could not control boost. I talk to Precision turbos and explained problem as well as other vendors and they stated I would have to go to an external wastegate. I'm in the middle of a new combo and trust me I'm putting on an external wastegate this time.

 

[Cheeseburger]

I had no problems controlling boost with a TH downpipe/stock style hd wastegate and a LT76GTQ.

 

[John Wilde]

So according to this thread, the one other person with a 71GTQ that has responded has the some problem. Several people with smaller turbos don't have the problem and one person with a larger does not have the problem. I wonder if this has anything to do with the 71Compressor Wheel being a non Garrett Product .
Maybe the Turbine Side is not matched as well as the full Garrett Products.

850 PT-70 70mm 2.756" 3.502" 62 4" / 3" 360 Race On Center .69 or .85 GT-Q 3.110" 2.675" 70

880 PT-71 71mm 2.795" 3.850" 52 4" / 3" 360 Race Tan .68 .81 or .96 GT-Q 3.110" 2.695" 70


As you can see here the inducer is not much bigger on the compressor side but the exducer is 10% larger.

 

[top gun]

I had a boost problem a few years ago with the 71 using the 3 1/2 thdp. I switched to an external gate and it solved the problem.

 

[snipersixx]

Re: controlling boost on PT 71 GTQ

Originally posted by BUICKTR
I had the same exact problem. I had a THDP and my stock type actuators would not work properly. I could not control boost at all. I had tried a HD actuator with solenoid and without. I also tried boost valves, bleeder valves and I had my turbo housing opened to 1". The puck seal perfectly on the turbine hole but no help! It was very frustrating that I could not control boost. I talk to Precision turbos and explained problem as well as other vendors and they stated I would have to go to an external wastegate. I'm in the middle of a new combo and trust me I'm putting on an external wastegate this time.

Well that's about where I'm left at , tried all the different ways to fix problem. I didn't think I was the only one with this problem. Is there away to converter a thdp to external waste gate ( really don't want to change pipe for the reason that it's 3.5 set up for Q wheel )

 

[ttypewhite]

I run the GTQ71 on my car with no boost issues. But I run a external Racegate( ATR 4 bolt headers). Boost is steady as a rock. I think your problem is wastegate related.

 

[Race Jace]

no problems running a 71GTQ with 3.5" dp heavy duty actuator and RJC boost controller. can adjust the boost from 17-30# and the boost stays within 1 # of where i set it at.

 

[norbs]

I would not worry about it the criag limit lt-70 p-trim makes more power

 

[S2V6RACER]

Originally posted by norbs
I would not worry about it the criag limit lt-70 p-trim makes more power

Now all we need to do is convince Top Gun to use one now!!

 

[86brick]

Originally posted by Ted A.
Now all we need to do is convince Top Gun to use one now!!

LOL good luck...