GTQ 70 with PTC 17 blade

Mike T

Well-Known Member
Joined
May 3, 2013
Got the motor back together (new cam,crank and ported heads) and all is well so far. Ran the 70 with the PTC on the old combo and the spool was surprisingly good.

Now it actually seems to be better with this combo. The brakes absolutely suck on this car and will be upgraded soon. Motor has about 300 miles on it so I'm still taking it easy but I did pull the e brake while standing on the brakes to get an idea of how far off the converter was. I'm pretty sure it should stall around 3k @ zero boost but it was making about 3 pounds at 2850 and starting to come alive. It's a tiny bit sluggish from a dead stop just flooring it but It seems like with good brakes it may be just right. I've always heard it took around a 3500 to make the GTQ work.
 
Ok cool.. So do you have a question

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Ok cool.. So do you have a question

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Yes, I've read that this converter should stall around 3k with the waste gate open. It seems a little odd to me that a turbo that should be a dog on my car is starting to spool before 3k.
 
Light little hit of the throttle at a standing start (.85 housing no brakes)







boost no brakes 1psi.jpg
 
I recently had a conversation with my transmission builder on testing out a new converter to get a baseline on it, to use it in the future to determine if it's going bad or not. He told me to get on the transbrake, record the RPM where boost pressure is 0, then mash on the pedal and it should be limited to about 5000-5300 rpms. Record that number. It shouldn't go to 6000 or 7000 rpms, or whatever your RPM limit is. if it does the converter is bad. Try doing that and see what you come up with, I'll be doing it once I get my 17 blade from marleyskater420, hopefully by the end of this week.


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No trans brake yet and I really don't think the brakes will hold it past 3200 or so. Really not sure what I'm seeing here. Just got the PL working again so maybe I'll take the waste gate rod loose to see where the converter will stall then see where it stalls with all the boost the brakes will hold.
 
I have s
Light little hit of the throttle at a standing start (.85 housing no brakes)







View attachment 307156
I have seen this before,but how is the boost curve climb after it tickles the boost gauge?the ones I have seen just struggle to get up to a boost range that moves the car like the torque has been reduced in favor of horsepower.
 
Tiny bit sluggish til about 7 or 8 psi and then keeping boost under control is a problem. It will make 12psi with the WG unhooked and wide open.
 
Yes, I've read that this converter should stall around 3k with the waste gate open. It seems a little odd to me that a turbo that should be a dog on my car is starting to spool before 3k.
Tickling the boost gauge is much different then getting fast response time with the boost/rpm curve.it will get to a point where is it possible if you can even get enough speed for the compressor to move some big air
 
Tiny bit sluggish til about 7 or 8 psi and then keeping boost under control is a problem. It will make 12psi with the WG unhooked and wide open.
Start getting the boost up so you can see the response curve.rich flat spots down low are common will need to be tuned if you can't move enough air early.
 
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