pboglio
15+ Year Contributor
- 1,799
- 85
- May 8, 2004
-
Palos Heights,
Illinois
Figured I'd post up my impressions of the differences between these 2 turbos. I'll start off by saying don't buy a T28, go straight to the EVOIII 16g. On with the impressions:
Install:
I thought I covered everything but I had a brain fart and ordered a 2g oil feed line that obviously didn't fit for a 16g. Luckily I bought a stock 1g hard oil feed line for a TD05H a good 12 years ago that I never used, well I used it finally I'm embarrassed to say it took me 2 days to completely finish the job, which included all porting etc. The turbo removal took 2.5 hours but then I got sucked into porting the turbine housing, then figured I'd port the 02 housing which needed it since the turbine outlet was bigger on the 16g. Then I lost interest and started watching alot of TV between breaks, and so on This is what happens when you get older. The coolant lines needed some good bending and I needed to cut new 3/8 rubber hoses to extend the lines to reach. For the boost pressure fitting I stole a trick from "tuners" and tapped the screw hole used for anchoring the oil feed line onto the compressor housing using a 1/8-27 NPT tap. I then drilled a thru hole using the barbed fitting opening as a drill bushing pilot.
This worked out great and it actually looks stock (see pics). I then decided to do a "thorough" intake pressure leak test. I found a huge amount of pressure leaks at 30 psi but nothing a dozen mini zip ties didn't fix. Luckily the car cranked over without so much as a drip of coolant or oil. However, the coolant passages had trapped alot of air when I refilled the engine coolant and coolant temps went a little warm. A shutdown and coolant burping/refill fixed this problem easily.
Driveability:
My plans are roadracing and I need power coming out of slow corners as well as topend grunt. Back in 1995 I ran a small 16g with a clipped turbine wheel and this time around I decided I'd balance out the topend with as much low end grunt as possible. On paper it would appear the T28 would trump the EVOIII 16g in this category but I've always felt the T28 was actually a laggy turbo for its size so I was crossing my fingers.
This time around I would leave the turbine wheel unclipped. My plan seems to have worked. The EVOIII 16g seems to make power fairly early on, I can start to get on it at around 2800 rpm coming out of a slow corner and it pulls cleanly from there. I'm even getting a mini torque hit starting as low as 3200 rpms which is fantastic as my T28 never did that. I was extremely surprised by this, but during the install as previously mentioned I fixed a ton of vacuum leaks, replaced a 70,000 mile 02 sensor that was on its way out, and fixed a leaky downpipe gasket. I believe the larger turbine housing/turbine wheel of the 16g has some benefits on the low end off boost believe it or not.
Sound:
The exhaust note is raspier under full throttle. It sounds nasty on boost with a definite "cammy" bark and I dig it. I'm not surprised by this because the 7cm turbine housing is much bigger than the T28 right where the turbine wheel is exposed to the exhaust gasses, probably 40% bigger. Compressor suction noise is the same, quiet basically without any kind of turbo whining.
Boost Creep:
I did a fairly mild port job on the turbine inlet, just removing the step and no more than that. Wastegate port was completely untouched. Some might say why? Well I actually want boost creep, as much as the turbo can give me. Results: I can still hold a dead solid 15 psi to redline. I believe my very well ported 2g 02 housing and 2.5" downpipe are keeping boost levels in check and very nicely controlled.
Power:
Initially what I was a little surprised with was the power at 15 psi. Very underwhelming. I'm used to a 25 psi spike on my T28 and this felt tame by comparison. O.K., so I say the hell with it, dump in 2 bottles Lucas octane booster & 3 gallons 118 octane xylene and just crank the boost. I believe the boost hit somewhere north of 26 psi but the torque hit is MUCH nastier than my T28. So the 16g wastegate actuator is solid right out of the box without any shimming or the like.
So what kind of power differences are we talking about? Well, now keep in mind I use DSMLink to estimate power. The best my T28 could produce in 2nd gear was about 380 h.p. at the crank given similar mods. It was maxxed out and completely done and I had no desire to squeeze more out of it as I was starting to get nickle and dimed to death trying to get another 10 h.p. out of it.
For the EVOIII 16g, I had calculated a rough estimate of what power I'd be seeing before the install given my current mods, that number was 435 h.p. My initial impressions at 15 psi didn't bode well for big power though. On with the run. I had my Palm Pilot logging during the run which I obviously ignore until I download the log back home. I proceed to pull out of my complex and give the clutch a little time to warm up. First WOT pull is great, nearly full power at 60% throttle. Then I get greedy and crank the boost some more, what that boost level was I have no idea as the xylene usually takes care of any knock. I go WOT again and without exaggeration the torque steer pulls the car close to the curb and nearly onto the grass. The 3rd WOT pull I have a chance to wind it out. This one scares even me. The cam bark is nasty, the car squats so hard my Blizzak winter tires completely squirm sideways on its squishy tread blocks. The pull above 6000 rpms is hard to describe, feels like an electric drill. This was by far the funnest WOT pull I've ever done. I have to remind people this is 2nd gear so I'm still right around 60 mph, yes its a big ticket still but its a compromise.
I get home and review the log. Its hard to tell from the driver's seat, I was hoping for 400h.p. at least. That run felt downright nasty. Well the EVOIII 16g completely blew away the T28 with about 429 h.p. at the crank. That is nearly a 50 h.p. increase from the turbo swap alone. The 16g had more boost in it but I'm waiting for even bigger cams and the re-installation of my speed density setup before I go all out. I'm expecting 470 h.p. all said and done with the colder winter temps. Overall its a
Install:
I thought I covered everything but I had a brain fart and ordered a 2g oil feed line that obviously didn't fit for a 16g. Luckily I bought a stock 1g hard oil feed line for a TD05H a good 12 years ago that I never used, well I used it finally I'm embarrassed to say it took me 2 days to completely finish the job, which included all porting etc. The turbo removal took 2.5 hours but then I got sucked into porting the turbine housing, then figured I'd port the 02 housing which needed it since the turbine outlet was bigger on the 16g. Then I lost interest and started watching alot of TV between breaks, and so on This is what happens when you get older. The coolant lines needed some good bending and I needed to cut new 3/8 rubber hoses to extend the lines to reach. For the boost pressure fitting I stole a trick from "tuners" and tapped the screw hole used for anchoring the oil feed line onto the compressor housing using a 1/8-27 NPT tap. I then drilled a thru hole using the barbed fitting opening as a drill bushing pilot.
This worked out great and it actually looks stock (see pics). I then decided to do a "thorough" intake pressure leak test. I found a huge amount of pressure leaks at 30 psi but nothing a dozen mini zip ties didn't fix. Luckily the car cranked over without so much as a drip of coolant or oil. However, the coolant passages had trapped alot of air when I refilled the engine coolant and coolant temps went a little warm. A shutdown and coolant burping/refill fixed this problem easily.
Driveability:
My plans are roadracing and I need power coming out of slow corners as well as topend grunt. Back in 1995 I ran a small 16g with a clipped turbine wheel and this time around I decided I'd balance out the topend with as much low end grunt as possible. On paper it would appear the T28 would trump the EVOIII 16g in this category but I've always felt the T28 was actually a laggy turbo for its size so I was crossing my fingers.
This time around I would leave the turbine wheel unclipped. My plan seems to have worked. The EVOIII 16g seems to make power fairly early on, I can start to get on it at around 2800 rpm coming out of a slow corner and it pulls cleanly from there. I'm even getting a mini torque hit starting as low as 3200 rpms which is fantastic as my T28 never did that. I was extremely surprised by this, but during the install as previously mentioned I fixed a ton of vacuum leaks, replaced a 70,000 mile 02 sensor that was on its way out, and fixed a leaky downpipe gasket. I believe the larger turbine housing/turbine wheel of the 16g has some benefits on the low end off boost believe it or not.
Sound:
The exhaust note is raspier under full throttle. It sounds nasty on boost with a definite "cammy" bark and I dig it. I'm not surprised by this because the 7cm turbine housing is much bigger than the T28 right where the turbine wheel is exposed to the exhaust gasses, probably 40% bigger. Compressor suction noise is the same, quiet basically without any kind of turbo whining.
Boost Creep:
I did a fairly mild port job on the turbine inlet, just removing the step and no more than that. Wastegate port was completely untouched. Some might say why? Well I actually want boost creep, as much as the turbo can give me. Results: I can still hold a dead solid 15 psi to redline. I believe my very well ported 2g 02 housing and 2.5" downpipe are keeping boost levels in check and very nicely controlled.
Power:
Initially what I was a little surprised with was the power at 15 psi. Very underwhelming. I'm used to a 25 psi spike on my T28 and this felt tame by comparison. O.K., so I say the hell with it, dump in 2 bottles Lucas octane booster & 3 gallons 118 octane xylene and just crank the boost. I believe the boost hit somewhere north of 26 psi but the torque hit is MUCH nastier than my T28. So the 16g wastegate actuator is solid right out of the box without any shimming or the like.
So what kind of power differences are we talking about? Well, now keep in mind I use DSMLink to estimate power. The best my T28 could produce in 2nd gear was about 380 h.p. at the crank given similar mods. It was maxxed out and completely done and I had no desire to squeeze more out of it as I was starting to get nickle and dimed to death trying to get another 10 h.p. out of it.
For the EVOIII 16g, I had calculated a rough estimate of what power I'd be seeing before the install given my current mods, that number was 435 h.p. My initial impressions at 15 psi didn't bode well for big power though. On with the run. I had my Palm Pilot logging during the run which I obviously ignore until I download the log back home. I proceed to pull out of my complex and give the clutch a little time to warm up. First WOT pull is great, nearly full power at 60% throttle. Then I get greedy and crank the boost some more, what that boost level was I have no idea as the xylene usually takes care of any knock. I go WOT again and without exaggeration the torque steer pulls the car close to the curb and nearly onto the grass. The 3rd WOT pull I have a chance to wind it out. This one scares even me. The cam bark is nasty, the car squats so hard my Blizzak winter tires completely squirm sideways on its squishy tread blocks. The pull above 6000 rpms is hard to describe, feels like an electric drill. This was by far the funnest WOT pull I've ever done. I have to remind people this is 2nd gear so I'm still right around 60 mph, yes its a big ticket still but its a compromise.
I get home and review the log. Its hard to tell from the driver's seat, I was hoping for 400h.p. at least. That run felt downright nasty. Well the EVOIII 16g completely blew away the T28 with about 429 h.p. at the crank. That is nearly a 50 h.p. increase from the turbo swap alone. The 16g had more boost in it but I'm waiting for even bigger cams and the re-installation of my speed density setup before I go all out. I'm expecting 470 h.p. all said and done with the colder winter temps. Overall its a