PT88 rear mount... so far... it sucks LOL
11-07-2006, 01:07 PM
#1
PT88 rear mount... so far... it sucks LOL Decided to try putting a pt88 .96 a/r in place of my T76 .81 R trim in the search for more power. I haven't driven the car yet but my friend who did the fab work did and he said it was horrible, like when he put headers on his rear mounted turbo car. Just will not make boost quickly. I even insulated the y-pipe to keep the heat in. It evidently will not make 10psi until 3rd gear, this is exactly what my t76 with the .81 housing did when I had headers.
I'm going to have to play with a it a little bit to see if there are any problems (leaks) or if the tune is just way different now. Could just be too much to ask out of a setup like this. The .96 a/r housing is HUGE compared to my little .81 R trim. Maybe I could get a divided housing and try blocking off half of it LOL.
If I can't figure out how to make this thing spool I guess I'll try a .96 housing on my 76 to see how that spools. The switch from a .70 divided to .81 undivided wasn't even noticable but gained me about 50 rwhp.
I'm going to have to play with a it a little bit to see if there are any problems (leaks) or if the tune is just way different now. Could just be too much to ask out of a setup like this. The .96 a/r housing is HUGE compared to my little .81 R trim. Maybe I could get a divided housing and try blocking off half of it LOL.
If I can't figure out how to make this thing spool I guess I'll try a .96 housing on my 76 to see how that spools. The switch from a .70 divided to .81 undivided wasn't even noticable but gained me about 50 rwhp.
11-07-2006, 01:09 PM
#2
Are you running the TV81 style PT88 or the GT series PT88??? Jose said their is a good bit of difference in spool time. The TV he said is laggy compared to the GT sreies version.
11-07-2006, 01:12 PM
#3
Originally Posted by DrTurbo
Are you running the TV81 style PT88 or the GT series PT88??? Jose said their is a good bit of difference in spool time. The TV he said is laggy compared to the GT sreies version.
On the 76 at 15psi I was seeing peak tq on the dyno @ 4500 which is where the converter would flash to. At 10psi I was seeing peak tq @ 4300. This was also on a mustang dyno. The 76 spooled pretty good.
Last edited by Zombie; 11-07-2006 at 01:18 PM.
11-07-2006, 02:04 PM
#5
I know how to fix the problem, get some truck manafolds and move it up front with a 4" downpipe.
seriously my PTE88 doesnt take long to spool or make power
i hit about 12psi around 4000-4200, and when i bump it up to 15psi its around 4200-4300, the needle moves so fast i cant even tell, no laggy feeling at all, i just have to get faster on the shifting otherwise i keep hitting the rev limiter.
i have a built 347 ls1 with 8.9:1 CR
seriously my PTE88 doesnt take long to spool or make power
i hit about 12psi around 4000-4200, and when i bump it up to 15psi its around 4200-4300, the needle moves so fast i cant even tell, no laggy feeling at all, i just have to get faster on the shifting otherwise i keep hitting the rev limiter.
i have a built 347 ls1 with 8.9:1 CR
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11-07-2006, 03:06 PM
#10
drove it at lunch, did a quick retune on the fuel so that it was leaner in spoolup (if you can call it spool up). 1 PSI at 4700 rpms in 2nd gear, take until 100 mph until i see 7-8psi. So there are the results for everyone to see.
Rear mounted PT88 = BAD IDEA, longrange4u isn't going to be happy to hear this.
My 76 works ok for the most part, guess that will go back on eventually or i'll just sell everything off and wait 2yrs until I pay off the car to try something again.
Only other idea i have is if a divided housing is available, i can block off half, monitor the back pressure and see how it works. Is there even a divided housing available for this turbo?
Rear mounted PT88 = BAD IDEA, longrange4u isn't going to be happy to hear this.
My 76 works ok for the most part, guess that will go back on eventually or i'll just sell everything off and wait 2yrs until I pay off the car to try something again.
Only other idea i have is if a divided housing is available, i can block off half, monitor the back pressure and see how it works. Is there even a divided housing available for this turbo?
11-07-2006, 03:47 PM
#12
Originally Posted by Zombie
drove it at lunch, did a quick retune on the fuel so that it was leaner in spoolup (if you can call it spool up). 1 PSI at 4700 rpms in 2nd gear, take until 100 mph until i see 7-8psi. So there are the results for everyone to see.
Rear mounted PT88 = BAD IDEA, longrange4u isn't going to be happy to hear this.
My 76 works ok for the most part, guess that will go back on eventually or i'll just sell everything off and wait 2yrs until I pay off the car to try something again.
Only other idea i have is if a divided housing is available, i can block off half, monitor the back pressure and see how it works. Is there even a divided housing available for this turbo?
Rear mounted PT88 = BAD IDEA, longrange4u isn't going to be happy to hear this.
My 76 works ok for the most part, guess that will go back on eventually or i'll just sell everything off and wait 2yrs until I pay off the car to try something again.
Only other idea i have is if a divided housing is available, i can block off half, monitor the back pressure and see how it works. Is there even a divided housing available for this turbo?
i wouldnt give up yet, with all major spray's car has been doing, it seems like you just have a bug in your set up somewhere. Best of luck to ya
11-07-2006, 05:28 PM
#16
Originally Posted by NA$TY-TA
Time for a Transbrake and a 2 step...... i bet no problem building boost then...........
Your the same cubes as me man......i start seeing boost a lil over 2k rpm's and im at full bt 4K or a lil over that......
Your the same cubes as me man......i start seeing boost a lil over 2k rpm's and im at full bt 4K or a lil over that......
From a roll you floor it, then wait about 4-5 seconds and you have 1 psi. I'll bet it's not even this bad on a 3.0 supra motor. I had a 76 on my 3.0L motor before and it drove and spooled much better than this.
Last edited by Zombie; 11-07-2006 at 05:33 PM.
11-08-2006, 01:25 AM
#20
Got some ideas tonight. One of the pieces left on my car from the STS kit is the t4 flange. It's just a piece of pipe stuck through a t4 flange. It's circular going into a retangular housing. This probably slows down the velocity of the gas since it has to expand to fill the surrounding area of the turbine housing. How much of an effect this has i'm not sure. One of the ideas that we talked about is building a piece that fits inside the turbine housing and necks down slightly acting as a venturi. It should in effect reduce the a/r of the housing. The gas has has to make a sharp turn right before the exhaust housing. I'm not sure how much these affect the velocity and the spoolup though, maybe someone with some more experience will chime in.
The turbo does spool on the highway but it doesn't make full boost until 5500ish rpms in 2nd gear. With the controller off I was seeing 15-17psi on the gage and the car was hauling ***. On the t76 the car would only make 11psi max with the controller turned off. The spring is supposed to be a 14.7psi spring though.
The most boost I saw on the transbrake was 1.5-2psi at 3300 rpms but it would not make any more.
Any other ideas? Nitrous is not an option for street driving, i'm looking for ways to spool it faster on just motor.
The turbo does spool on the highway but it doesn't make full boost until 5500ish rpms in 2nd gear. With the controller off I was seeing 15-17psi on the gage and the car was hauling ***. On the t76 the car would only make 11psi max with the controller turned off. The spring is supposed to be a 14.7psi spring though.
The most boost I saw on the transbrake was 1.5-2psi at 3300 rpms but it would not make any more.
Any other ideas? Nitrous is not an option for street driving, i'm looking for ways to spool it faster on just motor.