I recently installed a TD05 16g on my 1990 jdm vr4 and I am now experiencing abnormally bad turbo lag. On this current setup I will not see any positive pressure below 3k rpm. In 2nd gear at WOT past 3k rpm i will see about 0.1 to 0.2 bar between 3k rpm and 4k rpm. going up the rev range I will see about 0.5 to 0.6 bar at 5k rpm and I will see 0.9 bar of boost at around 6k rpm. This was done without a manual boost controller although the same problem happened with a MBC on the lowest setting. The car was previously running a TD04 with no issues whatsoever. on that setup I would see boost as early as 2000 - 2500 rpm given enough load and would see wastegate pressure, around 0.6 bar as early as 3500 rpm even when im not WOT. I could not find any boost leaks on the cold side and don't see how boost leaks could appear as the only piping I removed was the the piping from turbo to the metal intercooler piping and pre turbo.
I'm running stock exhaust, stock inter cooler and piping, stock injectors, walbro 255 fuel pump, stock O2 housing(although the housing was machined a little to account for the bigger sized hole of the turbine of the TD05).
I have seen some other people run into similar issues with other dsms and even other cars but could not find any solutions.
The turbo spins freely and seems to flow a good amount of air at idle and no load, and the waste gate seems to be closed shut. Im unsure what could be causing this issue. I know that TD05 would spool later compared to a TD04 but im not seeing any boost at all below 3k rpm and the boost slowly increases as I go up the rev range.
Any advice or suggestions would be greatly appreciated, Thanks.
I'm running stock exhaust, stock inter cooler and piping, stock injectors, walbro 255 fuel pump, stock O2 housing(although the housing was machined a little to account for the bigger sized hole of the turbine of the TD05).
I have seen some other people run into similar issues with other dsms and even other cars but could not find any solutions.
The turbo spins freely and seems to flow a good amount of air at idle and no load, and the waste gate seems to be closed shut. Im unsure what could be causing this issue. I know that TD05 would spool later compared to a TD04 but im not seeing any boost at all below 3k rpm and the boost slowly increases as I go up the rev range.
Any advice or suggestions would be greatly appreciated, Thanks.