I have had my car running great for about 2 mos now, my 1 issue was I needed a boost controller so I bought a Greddy Profec B and had it installed early in Nov. Since it's been great, I could drive it however I wanted while never going above 12 lbs of boost. I was very happy...

well 3 days ago it was very cold and I was driving to work, a new RX8 pulled along side me on the I-10 and wanted to see what I had so we each jumped on it and I noticed my boost going to 15-16 lbs. I got off the gas and turned the Boost controler all the way down. I gave it a test and it held around 10 lbs of boost, I was happy enough with this as I did not want to over boost my new engine.

The RX8 and myself gave it another go and at 10 lbs I left him very quickly, I slowed down and he asked me to pull over to see my car, I did and we talked for a few, nice guy.

The next day I was headed to work and it was just as cold, I went to pass a car on a 2-lane rd and WOT in 3rd gear, I quickly saw the Boost gauge go up to almost 18 lbs. I almost ****. I checked the Boost Controller and it was still turned all the way down. I thought it could just be the cold but hell isn't that what the boost controller is for, after all it's called a "BOOST CONTROLLER".

I was on the way to work today and the temp has gone up at least 15 deg and is in the upper 40's or lower 50's, I thought that this might get me in check again but no, even in lower gears, on primary turbo the car wants to make 16-20 lbs of boost when you just give it anything past half-throttle.

So needless to say I am babying the throttle to save my engine....

Please help, just FYI I have Defi Boost Gauge and don't think it's inaccurate.

P.S. Worst part is I have a famous passenger I need to give a ride in my FD tomorrow and It would break my heart for it not to be running good. (I work for GE Plastics and we are a asscociate sponsor for the NASCAR DeWalt Ford #17 and Matt Kenseth is coming in town tomorrow to do a autograph meet and greet at my site and I was chosen to pick him up from the airport, cool enough a NASCAR Champ riding shotgun in my FD! However I'll be sad if I can't give him a quick show of what our FD's can do...

Please help if you can!

 

Could it be boost creep? That's what it sounds like to me but I'm certainly no expert.

 

Most boost controllers can not keep boost exactly set as they have no feedback mechanism. My Blitz DSBC does a job of controlling boost on my single turbo but has a very important feature that many do not have: over boost protection. You set the amount of overboost that you will accept and set the amount of boost reduction you want.

I have mine set to never go over 15.7PSI and it works well.

Be sure to check your setup as some combinations work better than others.

You did not say what turbo setup you are running. The stock turbo waste gate is too small for accurate boost control. I run a 46mm external WG with my GT35R and temperature has little affect compared to when I ran stock turbos.

 

When you added the Profec B, did you modify any settings on te Power FC. You shouldn't need a boost controller with PFC and bolt-ons.

Do you have a midpipe?

Jack

 

If it was working before and all of a sudden it freaks out then it doesn't matter if he has a down pipe or not.

I tried to manage boost with my PFC for about 3 months and it never did a good job. I ended up going with the profec B and it's awaesome now...

I would most likely be wastgate related...sticking closed or partially closed... Wait till the temperature warms up and see what it does.

 

I would check the boost gauge to see if it has gone south.

 

I recall this same person posting about overboosting problems in recent months so for all you or I know, this may be an ongoing issue. As always, trouble shooting a car over the internet is very difficult so I rarely get in these discussions unless the person is local to me.

A midpipe and cold weather is certainly a pertanent question. Many folks have no problem with boost creep until the cold weather hits. I don't know this car except seeing it at DCP this summer getting bolt-ons.

Weird how some have problems with PFC boost control. I know of many including myself using it on sequential twins. I'm running a ported motor with all the bolt-ons and don't have problems with it. The only time I've had boost problems since using a PFC, it was due to a bad solenoid. I have a feeling that this may tie into the health of the control system/solenoids.

I have found that adjustments are needed to keep boost consistent when the weather changes drastically, which isn't much problem if you save summer and winter setting on datalogit.

Jack