back woods
Well-known member
- Joined
- May 21, 2020
- Member Number
- 1010
- Messages
- 219
Got more time for a better response. The other FTE member is running the electronic actuator. He seems to have it dialed in and isn't having the problems he originally had. He has 205/80 injectors and a 4r100. Mine is the 3 Stage mechanical, the problem I have is similar but not the exact same. Because it's mechanical when I let off to shift the exhaust back pressure drops. (Actuator runs off ebp) When it drops it slams the veins closed causing a surge situation. Luckily it only does it in low boost/low rpm/low fuel situations. So it's not like it is super hard on the turbo. It is annoying when I'm driving or towing slow. Slow with a heavy load is the worst, shifting at say 1900rpm it will "chhhhtttt---tttt-ttt".
Of course I could open up the veins a little on the low end. It may help but I don't want to give up low end if possible. If I lose much low end I may as well go back to a 363/68/.83 imo. Lesser tuning helps but I like the power of an 80hp file when towing. So next I put together a Blow Off Valve that runs off the idle validation switch and a 10psi Hobbs switch. Made it from a 1-1/2" solenoid valve. Well, it works great but no matter what I can't cure the shift surge. VGT and BOV makes all the magic sounds one could wish for in a diesel. (BTW a bov can be pretty annoying). So far the best way is to drive around it. Don't slow shift, or low rpm shift. If you accelerate slightly spirited it doesn't surge at all. Still kicking around some ideas, a different compressor wheel or a dampener of some sort on the actuator.
Performance is great but some claims don't add up. 1500rpm will easily make 10psi+ boost and around 25psi @ 1900rpm. Overall boost is down from my 363/68/.83 (33psi vs 42psi). The claims of higher than a 1:1 boost/drive ratio are false. This thing makes a lot of back pressure. 33psi boost nets approx 54psi ebp. It will level out on longer pulls to approx 1:1.2. Typical to how VGT turbos run so quite normal IMO. At low RPMs EBP will be almost double of boost pressure. Just don't understand the claims, sales tactic maybe.
The VGT turbo runs the larger 73mm turbine wheel and the non-vgt 363 I run has the smaller 68mm turbine. Put tons of towing miles on the non-vgt it is IMO the best turbo for a mild 7.3. No EGT concerns ever but when towing heavy it will go hours without dipping below 25-30psi @ 2200rpm. It's a boost monster. The VGT tows different, boost levels out instead of climbing. It also takes less throttle input on low rolling grades to maintain speed. The VGT adjusts to keep turbo happy with less input.
Of course I could open up the veins a little on the low end. It may help but I don't want to give up low end if possible. If I lose much low end I may as well go back to a 363/68/.83 imo. Lesser tuning helps but I like the power of an 80hp file when towing. So next I put together a Blow Off Valve that runs off the idle validation switch and a 10psi Hobbs switch. Made it from a 1-1/2" solenoid valve. Well, it works great but no matter what I can't cure the shift surge. VGT and BOV makes all the magic sounds one could wish for in a diesel. (BTW a bov can be pretty annoying). So far the best way is to drive around it. Don't slow shift, or low rpm shift. If you accelerate slightly spirited it doesn't surge at all. Still kicking around some ideas, a different compressor wheel or a dampener of some sort on the actuator.
Performance is great but some claims don't add up. 1500rpm will easily make 10psi+ boost and around 25psi @ 1900rpm. Overall boost is down from my 363/68/.83 (33psi vs 42psi). The claims of higher than a 1:1 boost/drive ratio are false. This thing makes a lot of back pressure. 33psi boost nets approx 54psi ebp. It will level out on longer pulls to approx 1:1.2. Typical to how VGT turbos run so quite normal IMO. At low RPMs EBP will be almost double of boost pressure. Just don't understand the claims, sales tactic maybe.
The VGT turbo runs the larger 73mm turbine wheel and the non-vgt 363 I run has the smaller 68mm turbine. Put tons of towing miles on the non-vgt it is IMO the best turbo for a mild 7.3. No EGT concerns ever but when towing heavy it will go hours without dipping below 25-30psi @ 2200rpm. It's a boost monster. The VGT tows different, boost levels out instead of climbing. It also takes less throttle input on low rolling grades to maintain speed. The VGT adjusts to keep turbo happy with less input.
)
