So recently I have been having some boost issues that I can only describe as a surging slip. If I give it full throttle in 4th, 5th or 6th gear from ~0psi it will build up boost then "slip" for a half of second (similar to a clutch slipping) as it reaches ~18psi. It then "catches" boost and continues to function normally.

I have the Greddy Profec B-Spec II and it was tuned by AMS. I have had no problems for the past 2 years. I have tried adjusted almost everything (eg... SET, GAIN, START BOOST, LIMITER) and nothing seems to work. I know it's not the clutch slipping because it grabs fine taking off and full throttling through gears.

Also, I don't seem to have this problem in first, second or third gear; nor when I build a decent amount of boost before going WOT. It's as if the boost builds up too quickly, the EBC or ECU limits it for a second, then continues as normal.

Any thought? Advice? I've tried searching and haven't found anything directly related. Thanks!

 

Sounds like your clutch is slipping.

 

so why would it not slip when I launch or two-step? Or full boost in the lower gears? or with boost pre-built up?

 

Stock clutch??? How many miles?

If your clutch is starting to slip it will be more apparent in the higher gears first. Probably happens around peak torque when the most load is put in the drivetrain. Lower gears help pull the car so it may not show up during WOT runs....but it will as the clutch gets worse.

 

Do the RPM jump up and back down?

 

The RPM's do not slip or jump. They do stall when the boost stalls for that brief half second.

Maybe it is the clutch... It's the stock one with 34,000 miles on it (which is a lifetime considering most people). But I have been very good about not abusing it and it still grabs good with the occasional launch. I've been looking to upgrade in the future though, so maybe it will come sooner than later.

I just want to make sure I'm not have engine/turbo issues instead.

 

Have you logged this?

You can take off your intake to check your turbo. also maybe wanna do a compression test and leak down test to check engine.

 

What are your profec settings?

 

AMS Tune Settings

Set 72%
Gain 7%
Set Gain 18.8psi
Warning 23.5psi
Warning L. 7%
Boosting ~22.5psi PEAK

 

I HAVE A SIMILAR PROBLEM MY RPM JUMPS UP AND DOWN ON ALMOST ALL GEARS. EVEN IN FIRST I STEP ON IT AND IT GOES TO ABOUT 4000 RPM AND ONCE BOOST STARTS TO GO HIGHER RPM COMES DOWN AND THEN UP AGAIN. U SEEM TO KNOW SOMETHING EVO KID. PLEASE HELP. COULD IT B THE CLUTCH? REMEMBER NEWBEE HERE.

 

yes if your RPM jumps up then goes back down, you most likely need a new clutch.

 

Get the car on an open stretch of road with no traffic get the car into 5th gear at about 4K RPM and open it up, watch the Tach as you do it and tell us what happens.

 

that was my first guess but i thought to look around a bit for some help. thanks evo kid.any suggestions on a clutch?thanks.

 

PM me and we'll chat.

 

Sorry to disturb this sleeping beauty, but I am having almost the same issue and am looking for some help here. OP, did you ever find out the real cause and fixed it?? Was it really your clutch or something else??

In my case, my tuner said that it's boost surge. And i'd like to know if it's indeed boost surging problem, what's the solution that doesn't require turbo upgrade nor turning my boost down??