Hey fellas hopefully someone has an answer for me. 01 turbo k24/18g custom EPL tuned to 1.3 bar. Recently car would only boost to .7 no codes found when I scanned ecu. Replaced newer MAF with my old one which was fine (originally replaced because of age not issues) took the car out again and it would boost to 1.5 now? That kind of through my boost leak issue out the window I took it easy on it and filled her up withh 112 race gas to cover my *** from hopefully detonating at that boost level. Next day I take it out and now the car was boosting at 1.2-1.3 as it normally does. Hallelujah! Maybe the ecu had to relearn the parameters of the old MAF? I go get the car washed and fill up 5 gallons of 93 for my usual mix as the car IMO doesn't need to run near straight 112 at the power/mod level I'm at and the car was tuned for 93 although the extra octane does help with timing a little. So I leave the gas station thinking all is well and to my disbelief it's back to .6-.7 again! In the past when I had an ic pipe pop off the car would obviously run like crap and not boost. Could I still possibly have a boost leak? I inspected my ic hoses and connections and they all seem fine. Plus if I had a boost leak I wouldn't think the car would boost to 1.5 which was the most I've ever seen outta the car. My tuner says it sounds like a mechanical issue and I asked him plus another pcar mechanic about the n75 valve possibly being a culprit and they both didnt think it was the case. Again no cel on car. Anyone have this same issue? I was thinking dv's maybe leaking but again when I changed back to my old MAF it over boosted? Was hoping someone has an answer for me before I bring it to my shop to smoke check it. I also checked vac lines off of wastegates and they are on good too although I haven't checked the vac lines under the tb yet. Any help or suggestions would be greatly appreciated!
Thanks,
Ron

 

Check for boost leaks and then I would possibly swap the n75. Sounds to me like the n75 is on the fritz.

 

Double check the lines going to waste actuators. I had one line off and it acted almost exactly the same. Maby add a little pressure to them to make sure they do not have a leek. I have k16 buillet from epl. The actuators arrived a few weeks after the turbos so I set them ... They were set at 12.5 psi to crack I believe... Just add a little pressure to test.

 

your running 112 oct LEADED race fuel on a regular basis? i dont believe thats good for the engine as you valves and cats are built for unleaded gas. even mixing still results in excessively high metal levels in the oil. you may want to cut back and have a oil sample sent to blackstone for examination

 

Agreed on the N75. I had the same issue and it was the Valve. Crazy little part that would drive you nuts never knowing what the boost would be at.
The other issue i found which i dont think is your problem was i had a cracked intake that was a hard thing to find.

 

Thanks Val I'll try the n75 first and see what happens. If I still have issues, boost leak check then. Btw you'll love the gt2 and stg 3 cm. hopefully see you on the road or at Pete's.

 

Thanks I will swap the n75 first and double check for leaks. When you say you had a crack in the intake are you referring to intake pipes? As I have the Gemballa cf intake pipes and Im wondering if they have any damage to them? Wouldn't that cause a cel if it's after the MAF though? Thanks!

 

No i had swapped to the 997 upper and with the boost i was running i cracked it open at the seams. Not the same issue im sure but it's 1-10000 im sure.

 

I just run it here and there I do 5 gallons of 112 and fill the rest of the tank with 93. I don't have cats and I've never heard it affecting valves before but I'll do some research.

 

Lead will only hurt cats and O2 sensors...It might cause a build up on valves and injectors after a long time and straight leaded gas only..
Sounds like you aren't going to have a major problems with your car and how you mix it.

 

Any update on this after changing the n75?

 

.6-.7 bar is limp mode. u r probably overboosting and the car goes in limp mode, then it resets which is when you see the higher boost levels. check vacuum lines all around the N75 and off the TB. maybe even replace the N75 itself

 

Can't wait to get her back on the road, she's been down for about a month...trying to coordinate w/Tim on dropping her off for some goodies.

 

Ordered it today. P of Rockville said 2 days to get in. Will keep you guys posted and thanks for all the help!

 

Will do bro. Thanks you always help and give great advice!