Boost won't go higher

bad V6

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I am unable to get the boost above 20-21#. The car is running good, just could use some more airflow. I got personal bests at BG this weekend, a 1.48 60', a 6.86 1/8, and 10.81 1/4 @ 124 mph.

With the stroker in my sig, am I beyond the capabilities of the GT6152 or is there something else that I could try? I'm happy, just know that there is more to be had. Anyone have suggestions on how to get more BOOST with the RJC bleeder valve?
 
whats the exhaust housing size? could be too much back pressure

63 Precision exhaust housing. Back pressure shouldn't be an issue with the exhaust that is on the car.

I had a conversation yesterday with RUQWKNF at BG. He gave me some ideas on what to try, however he feels that the turbo is unable to supply the engine with the volume of air that it needs. I may try a few things to get a little more out of it, before stepping up to a new billet 6765 or 67HPQ.
 
63 Precision exhaust housing. Back pressure shouldn't be an issue with the exhaust that is on the car.

I had a conversation yesterday with RUQWKNF at BG. He gave me some ideas on what to try, however he feels that the turbo is unable to supply the engine with the volume of air that it needs. I may try a few things to get a little more out of it, before stepping up to a new billet 6765 or 67HPQ.

He's not talking about the exhaust, he's talking about the pressure in the headers which can be lessened by using a larger exhaust housing, or just moving on to a larger turbo.
 
He's not talking about the exhaust, he's talking about the pressure in the headers which can be lessened by using a larger exhaust housing, or just moving on to a larger turbo.

How much improvement might I see out of a bigger exhaust housing and heavy duty wastegate actuator? Would it be enough to justify keeping this turbo, or would I be better off upgrading to a larger turbo?
 
IMHO.... you are probably done with that turbo...... back pressure is probably high... you are probably overspeeding the compressor wheel..... etc. Time to step up to a new hairdrier.... maybe a 6765?

What exactly are your goals?
 
How much improvement might I see out of a bigger exhaust housing and heavy duty wastegate actuator? Would it be enough to justify keeping this turbo, or would I be better off upgrading to a larger turbo?

Probably not enough to justify that.

Unless it's more of a street car and you love the instant spool that I'm sure it has now.
 
Does the pressure go higher in 1st and then rest lower?

So the boost won't go higher even after you screw in the adjustable wastegate rod?
 
Your bigger higher flowing motor has used up the CFM of that turbo with less boost.
Remember Boost is a measurement of restriction, your higher flowing motor will restrict the turbo less in reaching max power/cfm.
That turbine wheel is small for making much more power than you have.
There could possibly be a little left of the compressor.
However I would sell the turbo to a street car and go with a billet 6765 or 6768 if you can spool it.
 
I figured that the next logical step would be to step up to a bigger turbo, instead of spending the money and time reworking this one for only a marginal gain.

I adjusted the wastegate rod in 2 rounds Saturday before eliminations with no change in the boost level. As shown on the Power Logger, the change resulted in about a 1# increase in boost.
 
Your bigger higher flowing motor has used up the CFM of that turbo with less boost.
Remember Boost is a measurement of restriction, your higher flowing motor will restrict the turbo less in reaching max power/cfm.
That turbine wheel is small for making much more power than you have.
There could possibly be a little left of the compressor.
However I would sell the turbo to a street car and go with a billet 6765 or 6768 if you can spool it.

I know that I will have to change converters, probably go with a PTC. Do you think that the engine is capable of spooling a 6768 and still be streetable? I do drive it on the street, however I try to refrain from playing on it.
 
I know that I will have to change converters, probably go with a PTC. Do you think that the engine is capable of spooling a 6768 and still be streetable? I do drive it on the street, however I try to refrain from playing on it.

The stroker motor in your sig??? Oh yeah it'll spool it, no doubt.
 
I am unable to get the boost above 20-21#. The car is running good, just could use some more airflow. I got personal bests at BG this weekend, a 1.48 60', a 6.86 1/8, and 10.81 1/4 @ 124 mph.

With the stroker in my sig, am I beyond the capabilities of the GT6152 or is there something else that I could try? I'm happy, just know that there is more to be had. Anyone have suggestions on how to get more BOOST with the RJC bleeder valve?

nice times with that stroker. i guess i am $hit out of luck with my 6031. hope to hit 10's. did you try to turn in the wastegate after you have the bleeder valve maxed. worked for me i would turn the valve in all the way and get 23 and then turn the rod 3 turns to get 26
 
I ran a 6.76 @102.77 with a 1.57 60ft boost was 20 psi till like the last 50feet and it creeped up to 22 but the A/F went to 10/1. This was on the 6152e turbo.


your rite there with me.


I went ahead and got a billet 67hpq dbb and installed it a few days before BG. i ran a best of 10.77 @ 124 1.5260ft @ 19 psi boost on it.



Bite the bullet and get a billet 67. This turbo pulls like a mofo on the big end over the 61.

i just wish i could figure out why i can't get the motor to turn over 5700. so i had to shift to OD in the 1/4 :mad:


i think the type II set-up is the issue. i changed the plugs and wires at the track. NGK's set @ 26k
 
Bad V6, two turns on the wastegate rod is pretty much 1psi of boost increase. It's never been 1:1 for me so keep cranking in the rod.

FWIW, there have been TA49's and TE44's run 123mph and those turbos are the older cast 58/57 so you have more left in this turbo for sure. I've seen dyno graphs of the 6152 well over 500awhp at 9k with way better flowing heads than ours so it would surprise me if the 6152 is 100% done.
 
I also think that the turbo capable of a little more, however my converter may be the culprit that is robbing the MPH. What do you think? I know that I'll need to change converters when stepping up to a bigger turbo, just don't want to take that step until it is needed.

Would you suggest setting the wategate rod to say 15-16# then dial it in with the RJC valve?
 
cant get boost any higher

i have the same problem, got the rjc valve all the way in, the rod is turned all the way in, barely get the rod on the puck, and cant get over 26 lbs, this is with a gtq 76 turbo??
 
i have the same problem, got the rjc valve all the way in, the rod is turned all the way in, barely get the rod on the puck, and cant get over 26 lbs, this is with a gtq 76 turbo??

you can try stretching the spring in the bleeder valve
 
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