Hello, I have a 2003 alh with gt1752mfs, pp764, pd150 intake/race pipe, darkside smic with 3 bar map and appropriate remap. Ever since I got this turbo in a few weeks ago the performance sucks. It’s very laggy until about 2300 rpm and during wot pulls the boost gauge will spike to 30 psi. The actuator starts moving at 3hg and is fully open at 18hg. Brand new fuel and air filters and vacuum lines. Swapped my n75 for a known good one. Tuner says it’s not the tune. Not sure what else it could be except I read that shortening the actuator arm may help with my lag issue. If that was part of it could that also cause the overboosting as well? Thanks
Xman gt1752mfs lag and overboost
- Thread starter 03Wagn
- Start date
majesty78
Veteran Member
VNT calibration probably not correct.
Yourbuddysatin
Veteran Member
What is your IQ set at? Is the turbo new or used?
Yourbuddysatin
Veteran Member
Is the tune done for that turbo? I use to run my IQ at around 2-2.5. Ever time I’d did any mod on my ALH I always adjusted the IQ. Maybe try that?
BustedBolts
Veteran Member
Either it's a mis adjustment on the actuator, or it's a tune issue. I've tuned alh's with that turbo and similar fueling and it was pretty easy to make a quick spooling spike free tune.
cuban11182
Veteran Member
Who's tune?
Jeff Stevenson
Yourbuddysatin
Veteran Member
Maybe you should post some logs and someone will give better input.
Just a quick follow up. After adjusting the actuator arm to move around 4hg, the car is no longer overboosting. The gauge is wayyyy more stable and seems to quickly boost to around 20psi before more slowly climbing to around 26. The lag is also much less noticable. I think there’s more visible smoke too, but egt’s are much much better than before. I was able to easily hit 1500+ during a hard 3rd gear pull before. Now i’m just barely able to get it there in 5th at wot through every gear. I may try another half turn adjustment to see if I can get it even better but it’s a major improvement for sure.
Nevada_TDI
Top Post Dawg
I am glad to see you have found a remedy, if you had not, I agree with the above poster regarding taking logs. Even now if you can get a N75% and requested boost versus boost log, it may help you to really fine tune your turbo.
Another update. The overboosting is still present and so is the terrible lag. I was able to take a group 011 log and sent it to Jeff. He told me it was overboosting hard and to put the stock file and map back on the car to determine if it’s a tune or turbo issue. Will update with more info as I get it.
Time for a long overdue update. After spending an entire Saturday on the phone with Xman (great customer service btw) resetting all turbo adjustments and still overboosting, the turbo was finally declared bad out of the box. I sent a ton of logs to him trying to get the overboost under control while making small adjustments to the set screw at his guidance. He sent a new one and I was pretty shocked when I had the exact same results. He then spoke with Jeff and I was sent a new tune, and the overboost was gone. Which leads me to believe the tune was the issue the whole time.
I still was not happy with the drivability. It made no power under 2300 rpm. It had no off idle power which made city driving suck with the sb endurance clutch, and would be a smokey pig if I gave it much throttle until boost. So I ended up parking it in June as the support from the tuner was simply not there. Last month while reading through some Facebook groups, I found a guy named Nelson Martin who tunes tdi’s through his company Tekmektronics. I explained what was going on and ended up purchasing a tune from him.
The difference is absolutely night and day. The turbo spools much faster. No overboost or spiking. Off idle power feels similar to my Cummins. My car is now a pleasure to drive again. This is the third tune I’ve had on this car and I can tell you Nelson is the real deal. He’s the one to go to if you’re actually interested in making power, not just smoke. Also, he actually responds when you message him. I’m looking forward to seeing my mileage increase with his tune vs the old one as well. Tekmektronics got my car running awesome and if anyone else is having issue getting this turbo tuned (I know others are) Nelson is the man to talk to.
I still was not happy with the drivability. It made no power under 2300 rpm. It had no off idle power which made city driving suck with the sb endurance clutch, and would be a smokey pig if I gave it much throttle until boost. So I ended up parking it in June as the support from the tuner was simply not there. Last month while reading through some Facebook groups, I found a guy named Nelson Martin who tunes tdi’s through his company Tekmektronics. I explained what was going on and ended up purchasing a tune from him.
The difference is absolutely night and day. The turbo spools much faster. No overboost or spiking. Off idle power feels similar to my Cummins. My car is now a pleasure to drive again. This is the third tune I’ve had on this car and I can tell you Nelson is the real deal. He’s the one to go to if you’re actually interested in making power, not just smoke. Also, he actually responds when you message him. I’m looking forward to seeing my mileage increase with his tune vs the old one as well. Tekmektronics got my car running awesome and if anyone else is having issue getting this turbo tuned (I know others are) Nelson is the man to talk to.