Installed a bigger housing on my T76
10-04-2006, 03:17 PM
#1
Installed a bigger housing on my T76 I have been running a .70 divided housing on my R trim 76. I've been having several signs of high back pressure over 10psi though. I had the .70 because when I had headers it was not able to spool the turbo.
At 16psi the car has gone 10.87 @ 126 on the .70 If I turn the boost up any higher trap speed and ET both get slower. At 18 psi it only goes low 11's in the low 120's.
Power falls off fast after 6000 rpms, detonation occurs right after the big power drop even on 111 octane with meth. So I've swapped out my .70 divided for my .81 undivided housing to see how the car would respond. So I did some preliminary testing last night after putting the turbo back on. First thing I noticed is that it barely affected spool up at all. I can still build the same amount of boost on the foot brake and trans brake as before and it comes up at the same speed. The other thing that suprised me was the boost is now lower at the same boost controller setting. The previous setting for 16psi now only gets me 14psi but I am now able to rev past 6000 rpms on my high timing map and 91 octane. Previously I had to run 100 octane to run this timing map.
I tried turning it up and managed to get 15-16psi out of it but the car didn't really feel any faster than perviously and it took a very high boost controller setting. The only way for me to really know whats going on is to get to the track again in a few weeks. I turned the controller up and it didn't want to go any higher than 15-16psi now but it pulls very clean all the way through the rpm range, much nicer than before.
Overall I'd say that spoolup was un-affected by the swap.
I'm curious to see if my MPH will increase with this housing. No matter what combination I've had on the car I've never been able to trap faster than 126 MPH. I have trapped 126 mph at 13psi and 16psi.
Before I have someone jump on here and say my times suck, please keep in mind that all my passes have been at 5000+ DA and 90-100+ degrees.
A t88 is becoming more tempting.
The inability to go higher on boost really puzzles me. A 306 based mustang that was here from minisota that same night said the he normally makes 24psi with a t76 but here in vegas he can't get it to make more than 20psi.
At 16psi the car has gone 10.87 @ 126 on the .70 If I turn the boost up any higher trap speed and ET both get slower. At 18 psi it only goes low 11's in the low 120's.
Power falls off fast after 6000 rpms, detonation occurs right after the big power drop even on 111 octane with meth. So I've swapped out my .70 divided for my .81 undivided housing to see how the car would respond. So I did some preliminary testing last night after putting the turbo back on. First thing I noticed is that it barely affected spool up at all. I can still build the same amount of boost on the foot brake and trans brake as before and it comes up at the same speed. The other thing that suprised me was the boost is now lower at the same boost controller setting. The previous setting for 16psi now only gets me 14psi but I am now able to rev past 6000 rpms on my high timing map and 91 octane. Previously I had to run 100 octane to run this timing map.
I tried turning it up and managed to get 15-16psi out of it but the car didn't really feel any faster than perviously and it took a very high boost controller setting. The only way for me to really know whats going on is to get to the track again in a few weeks. I turned the controller up and it didn't want to go any higher than 15-16psi now but it pulls very clean all the way through the rpm range, much nicer than before.
Overall I'd say that spoolup was un-affected by the swap.
I'm curious to see if my MPH will increase with this housing. No matter what combination I've had on the car I've never been able to trap faster than 126 MPH. I have trapped 126 mph at 13psi and 16psi.
Before I have someone jump on here and say my times suck, please keep in mind that all my passes have been at 5000+ DA and 90-100+ degrees.
A t88 is becoming more tempting.
The inability to go higher on boost really puzzles me. A 306 based mustang that was here from minisota that same night said the he normally makes 24psi with a t76 but here in vegas he can't get it to make more than 20psi.
10-04-2006, 04:04 PM
#4
Sounds like you need a PT88.....
Jose had mentioned you guys talked about it. Also he, Jason and Joseph talked about your car for a good while. They were seeing if their was a combination of wheels they could use to get quick spool and make big power, but not sure if they found anything.
Jose had mentioned you guys talked about it. Also he, Jason and Joseph talked about your car for a good while. They were seeing if their was a combination of wheels they could use to get quick spool and make big power, but not sure if they found anything.
10-04-2006, 04:21 PM
#5
Originally Posted by DrTurbo
Sounds like you need a PT88.....
Jose had mentioned you guys talked about it. Also he, Jason and Joseph talked about your car for a good while. They were seeing if their was a combination of wheels they could use to get quick spool and make big power, but not sure if they found anything.
Jose had mentioned you guys talked about it. Also he, Jason and Joseph talked about your car for a good while. They were seeing if their was a combination of wheels they could use to get quick spool and make big power, but not sure if they found anything.
DO you guys really think that I'm out of turbo, it isn't trapping very high. I'm only going 100-103 in the 1/8th and 6.9-7.0 ET. Car should weigh 3700-3800 with me in it. My 126 trap means i'm only making a little over 600 at the wheels. That would be 700+ at the motor. My HP peak has been around 5600 or so, I shift it at 5800-6100 for my best runs. IATs are 160-170 at 16psi with 95-100 ambient and no meth. With straight meth they are 125ish by the end of the run. 13psi runs with meth have been 100ish with meth and 130-140 without.
What about doing a tv7512 88 with a 1.32 divided housing? I say the divided housing because it gives me some options on spooling it by partially blocking off one of the volutes.
My friend 1320 and I have even thought about taking a a large divided housing turbo like i'm talking about and then running all the exhaust to one side with a large waste gate or even two going to the other valute and then using boost or exhaust back pressure to open the gate and control the back pressure in the exhaust. Then the the "a/r" is variable.
FWIW I can build 10psi of boost on the trans brake without a 2 step or retarding timing in about 4 seconds with the .81 housing. Once I get past 5psi it just takes off. Takes about 5 seconds to get 13-14psi.
I will also be spraying this car in the future, but would like something that spools ok without juice since I drive it 100-200 miles a week.
Last edited by Zombie; 10-04-2006 at 04:40 PM.
