I have been having a boost hesitation issue when running high boost - 27psi+. I have all the supporting mods + alky, MR diverter valve, and Greddy EBC.

Here is what happens. I have boost set to 27-28psi, and when I run through the gears to redline under boost, I get a hesitation at about 20psi, until it finally
surges again and climbs to 27+.

Here is something to note - my EBC is turned almost all the way up at this point. It is at 97 out of 100. If I turn the EBC down to 91/92, this issue goes away, but I am only running 25-26 psi.

Also, this will not occur as much if I am driving in 3rd gear, and then hit boost. It will usually climb as normal. It's more evident when going through the gears hard.


Here are my two thoughts on what it could be.
1) The MR diverter valve isn't holding the boost until the turbo catches up and pushes more air.
2) The EBC is close to maxing out, and is just not functioning optimally.
3) It could be partially both of these things. The MR diverter valve isn't quite holding enough enough boost, causing the EBC to work harder. Because I thought this EBC was good enough to hold 35-40psi.


Please let me know your thoughts if any of you expereinced this before. The car runs fine, and boost will go all the way up to set level, however there is a slight hesitation around 20psi before it reaches peak. Thanks in adavnce.

 

Hesitations at full load and during aceleration are often attributed to faulty spark plugs, coil packs and its wires and also sometimes dirty fuel filters.


Carlos

 

i hope u have upgraded fuel pump

 

Your explanation on the MR diverter got me thinking. The issue is that if the BOV were to be too weak to let the pressure go to early then you would really have issues getting you max boost. This is not the case, you are getting max boost , is just hesitating at 20psi during the process of increasing the boost levels.

I have my reservations on thinking that is a faulty MR diverter.



Carlos

 

high flow fuel pump?what plugs are you using? what wires? any misfires?

 

Hows the knock count too? If the car pulls timing it may feel like its hesitating.

 

There are many things that can cause this.


Take your car to a local shop have them data log you car and they will be able to tell you off the logs what your problem is. Dont ask us all where going to do is shoot ideas of what it might or might not be and it not be your problem. Like i said take it to a shop then do a write up about your problem so we dont run into the same issuse down the line.


Good luck.

 

Mind you my hesitation is in the boost building, not the engine. I really wish I had a video. It's almost like two surges, but quick. It's not very noticable, unless you are the driver.

Yes, I don't quite think it is a faulty diverter valvle either since it can hold boost fine. But then again, my EBC should be able to set boost higher than 27.5psi.

That's why I can't get off the diverter valve being the issue....and then my EBC is up too high trying to compensate. Like I said if I turn it down a couple points, all is well. It's just when the boost controller is nearing it's limit....

I guess the only sure fire way to know is to datalog and see what is happening. If I did this with my Utec, do you think I would see anything? The Utec isn't controlling boost...