Is this normal to still get boost taper from 21-22 to 18-19 climbing to redline with a MBC installed? I did a boost leak test and i found one small leak and fixed it from a ICP coupling. Cant find any others. I thought when i installed this MBC it would have held a steady boost above 20 psi. Just need some input on others with this MBC

 

I know the taper is worse with IX's than VIII's and I still get taper. People always claim they can hold 22 psi till 7K, but they're BSing.

 

I dont have that particular mbc but when I log cars with MBC's they all still have some taper. Normal.

 

this is normal

 

would the taper still occur if u had a ebc?

 

I have a hallman and a forge, and they both taper.

 

Yes, most likely anyhow. The underlying problem is that the stock turbo runs out of breath above 7K. Very few people hold over 20psi past 7K. Alot of people think they are boosting higher but it's probably just their gauge is off unless they've modifed the wastegate / turbo.

 

i hold 22 psi almost perfect throughout to my powerband. I got the graphs to proove it. I also have a halman...I am not BSing as mentioned above

 

Yeah i believe you b/c before i changed all my IC piping i DID hold 22psi steady then developed this problem. And that was with the ecu controlling the boost. So i thought maybe i was not remembering correctly or my gauge was off but apparently not

 

But how much taper are you getting from what to what?

 

For the non believers...here is my recent dyno yesterday. You will see a quick spike to 23ish and hold pretty steady around 22psi to redline.

https://www.evolutionm.net/forums/sh...d.php?t=340236