Hi guys.
I apologize if there is already a thread on this but anything will help.
I recently changed out my 9.8 hotside with a 10.5 which was a pain in the ***. After getting everything back together and settled in. Went out for a tune,
I wasnt hitting full boost till 4500k. My peak was at 25psi and then drops to 20 at redline. I attempted to turn the boost up but for some reason it didn't budge. Note before I was at 28psi and held all the way.
Any idea what to check or do??

 

what waste gate actuator you have right now?

 

The 10.5 will spool slower than a 9.8 but definitely not what you're seeing. Are you running a 3-port or an MBC? Did you do a boost leak check?

 

I have a stock wastegate but I never adjusted it before. I'm running a hallaman mbc, I did a boost/exhaust leak test but it came out good.

 

I can't recall but is the evo 8 wastegate for the 9.8 hotside the same length as the evo 9 wastegate for the 10.5 hotside?

 

^ Yes the wastegate actuators are identical between the 8 & 9 turbo

What is your method of boost control? Is you're wideband reading leaner than before?

If you're boost leak test came back good check for the following:
- Is the wastegate flapper seated properly when closed
- Check for an exhaust leak from mani to turbo

 

Already checked the hotside/mani/downpipe etc.
no leaks. Gonna attempt to pre load my wastegate and see if that's any help. According to my tuner my AFR's are on spot. I do not have a wideband

 

When you start modding a turbo car you need a wideband in the car. Otherwise, you're going to be rebuilding the engine.