I’ve been running my MMP ceramic ball bearing turbo for about three weeks now and I’ve logged about 3000 kms in this time. The following is a bit of a review of the turbo with the current setup/tune. The tune was done by a shop and I haven’t tried to tinker with it since it was set up. Any comments that could be perceived as complaints about the current setup are not intended to be directed at the turbo manufacturer or the shop that did the tune. They are merely comments about the current setup and I have not discussed any of this with either the shop or the turbo manufacturer.
Setup:
It seems like the truck drives nicer than before. It’s better off the line, but the boost level is actually lower than the stock turbo at all speeds. I suspect that the off the line improvement is down to a better tune. It has been mentioned that even though the boost is lower the turbo could be flowing more air than the old stock CT26 turbo. Once the boost starts to build it builds in a more linear fashion compared to the stock CT26 and I only see higher boost when the RPMs climb. I’m not seeing the high boost levels below 2000 RPM that were claimed in the group buy, but I haven’t tried to adjust settings to make this happen.
The Long Version:
As with the short version above, the truck seems to drive nicer with the new turbo. I can’t really say if this is down to the tune or the turbo. After the install was completed I also noticed that the exhaust smoke had been cleaned up, so I don’t know if maybe the seals were leaking a bit on the old turbo. It had 260,000kms on it, so it had a good run. As above boost levels with the new turbo are presently lower than with the stock turbo. The interesting thing is that it doesn’t feel like there is more lag than the stock turbo even though I’m getting lower boost levels. Yes, my gauge is reading properly because the overboost light on the dash comes on when the gauge is reading just over 14psi.
I can’t comment on EGT’s before and after because I had the probe moved pre-turbo during the install since I had it post before. The bung is still there and I have a second gauge, so I’m hoping to to a pre-post EGT reading comparison after I get one part I’m waiting for. It wouldn’t really matter to compare to the stock turbo anyway since the tune has been adjusted.
With the current setup-tune on flat ground I’m seeing 600 F @ 90km/hr with 3 psi boost and 700F @ 100km/hr with 5 psi boost. With the stock CT26 I was seeing about 8 psi just over 90km/hr and 10 psi or so at about 100km/hr. I’m definitely not seeing the higher boost levels at lower RPMs that I was hoping for. As has been commented, I’ll see if I can get in and adjust the preload on the wastegate actuator to bring the boost up at lower RPMs. Presently, I have set the max boost level at 22 psi, but only see that if I get over 3000 RPM.
Compared to the stock turbo the thing that is nice with the current setup is that it seems much more willing to do highway hill runs at higher speeds. With my old set up if I was doing 100km/hr my EGT’s would run hot really fast if I hit any hills. Now, it takes a while before my EGT’s get to warning levels and if I just take the OD off (since I have the ECT transmission) I can just keep going. It’s just a lot louder with the higher RPMs
Passing on two lane highways also seems easier than before. I did have to watch EGT’s though because when I was booting it to pass they climbed quickly and there was noticeable black smoke from the exhaust. I could probably dial back the fueling a bit, but I’d really like to look at getting the turbo to boost earlier before I start messing with fuel and the adjustment on the star wheel in the pump.
Overall, I’m happy with the setup, but it’s not as much of an improvement over the stock that I was hoping for. Hopefully I can get there with a few adjustments. As others have commented I was expecting this turbo to be a bit more ready to go out of the box. I realize there were likely some variations in what people wanted from their turbo in the group buy, but it would have been nice to have the wastegate set or have the ability to adjust the preload on the wastegate without adding shims especially since it was supposed to be hitting higher boost below 2k RPMs. I feel like that was a big selling feature, so it should have been easy to get that result without modifications to the wastegate mounting.
Setup:
- 1994 HDJ81
- 285/75/16 Duratrac Tires
- 3-4” lift
- 3” exhaust (using the factory elbow at the turbo)
- Dawes MBC (22 psi)
- Factory air intake
It seems like the truck drives nicer than before. It’s better off the line, but the boost level is actually lower than the stock turbo at all speeds. I suspect that the off the line improvement is down to a better tune. It has been mentioned that even though the boost is lower the turbo could be flowing more air than the old stock CT26 turbo. Once the boost starts to build it builds in a more linear fashion compared to the stock CT26 and I only see higher boost when the RPMs climb. I’m not seeing the high boost levels below 2000 RPM that were claimed in the group buy, but I haven’t tried to adjust settings to make this happen.
The Long Version:
As with the short version above, the truck seems to drive nicer with the new turbo. I can’t really say if this is down to the tune or the turbo. After the install was completed I also noticed that the exhaust smoke had been cleaned up, so I don’t know if maybe the seals were leaking a bit on the old turbo. It had 260,000kms on it, so it had a good run. As above boost levels with the new turbo are presently lower than with the stock turbo. The interesting thing is that it doesn’t feel like there is more lag than the stock turbo even though I’m getting lower boost levels. Yes, my gauge is reading properly because the overboost light on the dash comes on when the gauge is reading just over 14psi.
I can’t comment on EGT’s before and after because I had the probe moved pre-turbo during the install since I had it post before. The bung is still there and I have a second gauge, so I’m hoping to to a pre-post EGT reading comparison after I get one part I’m waiting for. It wouldn’t really matter to compare to the stock turbo anyway since the tune has been adjusted.
With the current setup-tune on flat ground I’m seeing 600 F @ 90km/hr with 3 psi boost and 700F @ 100km/hr with 5 psi boost. With the stock CT26 I was seeing about 8 psi just over 90km/hr and 10 psi or so at about 100km/hr. I’m definitely not seeing the higher boost levels at lower RPMs that I was hoping for. As has been commented, I’ll see if I can get in and adjust the preload on the wastegate actuator to bring the boost up at lower RPMs. Presently, I have set the max boost level at 22 psi, but only see that if I get over 3000 RPM.
Compared to the stock turbo the thing that is nice with the current setup is that it seems much more willing to do highway hill runs at higher speeds. With my old set up if I was doing 100km/hr my EGT’s would run hot really fast if I hit any hills. Now, it takes a while before my EGT’s get to warning levels and if I just take the OD off (since I have the ECT transmission) I can just keep going. It’s just a lot louder with the higher RPMs
Passing on two lane highways also seems easier than before. I did have to watch EGT’s though because when I was booting it to pass they climbed quickly and there was noticeable black smoke from the exhaust. I could probably dial back the fueling a bit, but I’d really like to look at getting the turbo to boost earlier before I start messing with fuel and the adjustment on the star wheel in the pump.Overall, I’m happy with the setup, but it’s not as much of an improvement over the stock that I was hoping for. Hopefully I can get there with a few adjustments. As others have commented I was expecting this turbo to be a bit more ready to go out of the box. I realize there were likely some variations in what people wanted from their turbo in the group buy, but it would have been nice to have the wastegate set or have the ability to adjust the preload on the wastegate without adding shims especially since it was supposed to be hitting higher boost below 2k RPMs. I feel like that was a big selling feature, so it should have been easy to get that result without modifications to the wastegate mounting.
