gnxtc2
Active member
The background:
My truck is a 1997 OBS, auto, 3.55 with 285 tires. The trans is fully built by Paul aka The Punisher out of CT with a PI converter. I don't drag race nor pull, my truck is my daily driver and tow vehicle, a working truck.
I had injectors known as Baby Hybrids (hybrids with stock nozzles) from Swamps. Truck was live tuned by Jonathan at Jason's place in NJ on Aug 2011. Aside from the injectors, the motor was all stock: stock turbo, stock fuel, stock HPOP; it put down 380 HP to the wheels.
Truck was running great. A year or 2 later I installed a D66 with a 1.15 housing from Beans. Left tuning alone. When I installed the D66, it was laggy, smoked a little. Did some reading about it and most found it laggy down low. I left it alone.
Dec 2013, I had to pull the motor due a severly leaking oil pan. Since the motor was out, I sent the injectors (had 90K on them) to Tim. I installed a Honey Badger Jr, ARPs, 910s, Smith Bros PR, fixed the broken bolts on the manifolds and did some other maintenance items. Got the report from Tim and the injectors were worn and he recommended 175/80s.
Dropped the motor in, got tunes for the new set up and that's when the issue began: turbo (D66) was now really lazy to spool and high EGTs. Yes, checked for boost leaks and exhaust leaks....all checked fine. I tried different tuners (DynoProven, DP, Gearhead) and they all had the same result: smoke and high EGTs and loss of fuel mileage (2-4 MPGs). In the meantime, the oil seal on the exhaust side of D66 sprung a leak and a Brute 66 went in with a billet wheel (6/6).
When driving/cruising, there would hardly be any boost. When I press down on the throttle, I couldn't see the cars behind me. The boost would slowly build, then at 30lbs the EGTs were at 1300*. Felt like the fuel was putting out the fire or "snuffing" the turbo. Couldn't stand the smoke and EGTs so I pulled the chip and drove around on the stock TDE1 ECM. The truck was responsive and peppy like a chipped stock truck but didn't have the raw power.
I began to research turbos (TP38, GTP38R, S366) and reading the forums of 66 style turbos. I called up a few turbo shops and went over my issue. They all told me it was due to 66 wheel installed in the stock turbo. The 38r turbo has a ball bearing which really helps the spool up and hence the reason it has 66 wheel. The journal bearing (TP38) just doesn't respond the same way as the BB. All the turbo builders said to put the stock wheel or better yet a WW2. I ordered a WW2 from Dieselsite.
I then did my research.
TP38 specs
Compressor wheel inducer diameter: 59.87 mm (60 mm)
Compressor wheel exducer diameter: 80 mm
Compressor housing A/R: 1.10
Turbine wheel inducer diameter: 76.2 mm
Turbine wheel exducer diameter: 69.84 mm (70 mm)
GTP38R (ball bearing center section)
Compressor Inducer: 65.91mm (66mm)
Compressor Exducer: 88.14mm
Same turbine
Each turbo has a choice of turbine housings which up to the user.
So I decided to do some testing:
Since I have Irate's one piece up-pipes, I am able to swap exhaust housings without removing the turbo. So I swapped in a 1.0 housing on the D66. Still chipless, the boost build better but nothing great.
While waiting for the WW2 to arrive, I put the chips back and tried each one. Went on 20 mile rides with each tuner's tunes and made mental notes. I am not going to go into a tuner report. The motor was making 0-1lb boost while cruising with the 1.0 housing. But the turbo spool up was better but still laggy and the smoke/EGT issue was still present. The mileage started to come back around.
The WW2 arrived on Tuesday. Today, I removed the turbo to swap in the wheel because I couldn't get to the bottom compressor housing bolt. Swapped wheels and put the 1.15 housing back in.....basically going back to a stock turbo with a WW2.
Now with a stock size turbo, cruising boost is in the 2-3lb range, the smoke is down to haze and the EGT issue is now managable on how much I beat on the truck. The turbo makes 25lbs boost with a slight haze which kinda good for a stock turbo for longevity. The EGTs climb very slowly. I hit 1400* after staying at WOT for 10 secs on the highway climbing an incline, the speedo needle was pinned. As soon it 1400*, I lifted and the EGTs dropped instantly. Tripped the CEL with P1211 but that's a tuning issue.
What I concluded with this:
The 66 style turbos have their place. There is a reason why Garrett built a 66mm turbo with a ball bearing instead of a journal bearing. Why would they make a ball bearing turbo if they already had a journal bearing turbo out there? Wouldn't it been easier to machine a cover that was already made rather than casting a whole new cover?
What I found out with my truck, to spool the 66 turbo, either the rpms have to be high or fuel needs to be cut back. At no time did I alter the tunes.
Is my truck not correctly built for a 66 style turbo with 3.55s and 285 tire? My cruising rpms at 55 is 1450 and at 70 is 1850. Remember this is my daily driver running around empty most of the time. I enjoy not having to turn high rpms. Maybe a BASB/T4 conversion might be better for me due to the rpm range I cruise. I also tow my trailer at 70. The BASB starts to boost at 1500 rpms
I am supposed to tow my trailer Friday for track rental if the weather holds out. I gross out at 21K. I will see if the 1.15 is fine or should try the 1.0 housing.
Here is thread from PSN with another truck with 3.55 and a zf5.
http://powerstrokenation.com/forums/showthread.php?t=256858
Oh yea, getting my truck live tuned will be the best thing to do. All this testing I did was with the butt dyno and looking out the side mirror for smoke conditions.
Fire away
Billy T.
[email protected]
My truck is a 1997 OBS, auto, 3.55 with 285 tires. The trans is fully built by Paul aka The Punisher out of CT with a PI converter. I don't drag race nor pull, my truck is my daily driver and tow vehicle, a working truck.
I had injectors known as Baby Hybrids (hybrids with stock nozzles) from Swamps. Truck was live tuned by Jonathan at Jason's place in NJ on Aug 2011. Aside from the injectors, the motor was all stock: stock turbo, stock fuel, stock HPOP; it put down 380 HP to the wheels.
Truck was running great. A year or 2 later I installed a D66 with a 1.15 housing from Beans. Left tuning alone. When I installed the D66, it was laggy, smoked a little. Did some reading about it and most found it laggy down low. I left it alone.
Dec 2013, I had to pull the motor due a severly leaking oil pan. Since the motor was out, I sent the injectors (had 90K on them) to Tim. I installed a Honey Badger Jr, ARPs, 910s, Smith Bros PR, fixed the broken bolts on the manifolds and did some other maintenance items. Got the report from Tim and the injectors were worn and he recommended 175/80s.
Dropped the motor in, got tunes for the new set up and that's when the issue began: turbo (D66) was now really lazy to spool and high EGTs. Yes, checked for boost leaks and exhaust leaks....all checked fine. I tried different tuners (DynoProven, DP, Gearhead) and they all had the same result: smoke and high EGTs and loss of fuel mileage (2-4 MPGs). In the meantime, the oil seal on the exhaust side of D66 sprung a leak and a Brute 66 went in with a billet wheel (6/6).
When driving/cruising, there would hardly be any boost. When I press down on the throttle, I couldn't see the cars behind me. The boost would slowly build, then at 30lbs the EGTs were at 1300*. Felt like the fuel was putting out the fire or "snuffing" the turbo. Couldn't stand the smoke and EGTs so I pulled the chip and drove around on the stock TDE1 ECM. The truck was responsive and peppy like a chipped stock truck but didn't have the raw power.
I began to research turbos (TP38, GTP38R, S366) and reading the forums of 66 style turbos. I called up a few turbo shops and went over my issue. They all told me it was due to 66 wheel installed in the stock turbo. The 38r turbo has a ball bearing which really helps the spool up and hence the reason it has 66 wheel. The journal bearing (TP38) just doesn't respond the same way as the BB. All the turbo builders said to put the stock wheel or better yet a WW2. I ordered a WW2 from Dieselsite.
I then did my research.
TP38 specs
Compressor wheel inducer diameter: 59.87 mm (60 mm)
Compressor wheel exducer diameter: 80 mm
Compressor housing A/R: 1.10
Turbine wheel inducer diameter: 76.2 mm
Turbine wheel exducer diameter: 69.84 mm (70 mm)
GTP38R (ball bearing center section)
Compressor Inducer: 65.91mm (66mm)
Compressor Exducer: 88.14mm
Same turbine
Each turbo has a choice of turbine housings which up to the user.
So I decided to do some testing:
Since I have Irate's one piece up-pipes, I am able to swap exhaust housings without removing the turbo. So I swapped in a 1.0 housing on the D66. Still chipless, the boost build better but nothing great.
While waiting for the WW2 to arrive, I put the chips back and tried each one. Went on 20 mile rides with each tuner's tunes and made mental notes. I am not going to go into a tuner report. The motor was making 0-1lb boost while cruising with the 1.0 housing. But the turbo spool up was better but still laggy and the smoke/EGT issue was still present. The mileage started to come back around.
The WW2 arrived on Tuesday. Today, I removed the turbo to swap in the wheel because I couldn't get to the bottom compressor housing bolt. Swapped wheels and put the 1.15 housing back in.....basically going back to a stock turbo with a WW2.
Now with a stock size turbo, cruising boost is in the 2-3lb range, the smoke is down to haze and the EGT issue is now managable on how much I beat on the truck. The turbo makes 25lbs boost with a slight haze which kinda good for a stock turbo for longevity. The EGTs climb very slowly. I hit 1400* after staying at WOT for 10 secs on the highway climbing an incline, the speedo needle was pinned. As soon it 1400*, I lifted and the EGTs dropped instantly. Tripped the CEL with P1211 but that's a tuning issue.
What I concluded with this:
The 66 style turbos have their place. There is a reason why Garrett built a 66mm turbo with a ball bearing instead of a journal bearing. Why would they make a ball bearing turbo if they already had a journal bearing turbo out there? Wouldn't it been easier to machine a cover that was already made rather than casting a whole new cover?
What I found out with my truck, to spool the 66 turbo, either the rpms have to be high or fuel needs to be cut back. At no time did I alter the tunes.
Is my truck not correctly built for a 66 style turbo with 3.55s and 285 tire? My cruising rpms at 55 is 1450 and at 70 is 1850. Remember this is my daily driver running around empty most of the time. I enjoy not having to turn high rpms. Maybe a BASB/T4 conversion might be better for me due to the rpm range I cruise. I also tow my trailer at 70. The BASB starts to boost at 1500 rpms
I am supposed to tow my trailer Friday for track rental if the weather holds out. I gross out at 21K. I will see if the 1.15 is fine or should try the 1.0 housing.
Here is thread from PSN with another truck with 3.55 and a zf5.
http://powerstrokenation.com/forums/showthread.php?t=256858
Oh yea, getting my truck live tuned will be the best thing to do. All this testing I did was with the butt dyno and looking out the side mirror for smoke conditions.
Fire away
Billy T.
[email protected]
