dropping boost at 6000rpm

**axnjaksn** · 05-20-2016 06:42 PM

ok fellow enthusiasts, I have not thought of everything which is why Im looking for a random shot into left field one here. I have a 2001.5 manual stage 3 SRM k24's, 3 bar map sensor, awe intercoolers, samco hose set, jhm im spacers, 88mm maf housing, awe s flo intake, awe downpipes with hi flow cats and exhaust, walbro 450 lph pump, bosch ev14 60# injectors, modified im to set injectors into manifold completely, apr bipipe with r1 dv's and i just slapped a new spider hose in. I have pressure and smoke tested the bageezus out of everything. I have found no external leaks to this point.
now for the good stuff, I hit 25 psi like im tuned for, then carry it until I hit appx 6k rpm.....then drops off to 15 psi......is there something im missing.... all my numbers look great until then, then like a lipo battery in an rc car hitting low voltage cut, she just drops to 15 psi and its almost dead on at 6k. somebody give me a path... my brain is mush right now and Im looking for input.
thanks in advance.

**MikeyB3** · 05-20-2016 07:12 PM

... is the tune supposed to taper?

**axnjaksn** · 05-20-2016 08:29 PM

Supposed to hold 25 till redline.

**Corradovolksb** · 05-22-2016 08:34 PM

It seems like you are hitting soft limp. Most of the srm k24 waste gates are set for 15psi. Have you checked for fault codes? Sometimes they are not stored when soft limp mode is activated. If you can, log it and see if you WG duty cycle drops to 5% when your boost drops. Also check the requested and actual boost to see if they are working a few hundred mbar of each other.

**S4gasm aka LOTR** · 05-23-2016 08:53 AM

Did you ever replace your N75 valve? I had a similar issue on same setup as you, tried 2 different USED N75's with same result. Brand new one and zero issues after that.
Are there any codes stored?

**axnjaksn** · 05-23-2016 09:15 AM

negative no codes and yes the N75 is maybe a month old, brand new from the dealer purchased by me. Although I still wouldn't rule it out, ive seen brand new parts fail before, however id chase all other avenues before I went and told my parts guy to warranty it(if they even do that) hahaha. Its very odd, literally holds fine for a good portion of the rpm range, then right around 6k ish....just fades down to 15. even my tuner said it looks odd cuz everything else in the log looks good. LOGS-Another thing im still learning to interpret.

**axnjaksn** · 05-23-2016 09:19 AM

unless there is a relay that is opening up that works the N75....I need to get a factory service manual with wiring diagrams and everything. it really would make my life much easier when do things to the car

**S4gasm aka LOTR** · 05-23-2016 12:56 PM

Codes, do you have any STORED codes? I don't mean a check engine light, but codes. Many codes will not trigger a CEL. I blew a map sensor and never once threw a CEL, let me tell you how fun that was to diagnose.

#forcedinductionproblems lol

**axnjaksn** · 05-23-2016 01:26 PM

Originally Posted by S4gasm aka LOTR

Codes, do you have any STORED codes? I don't mean a check engine light, but codes. Many codes will not trigger a CEL. I blew a map sensor and never once threw a CEL, let me tell you how fun that was to diagnose.

#forcedinductionproblems lol

hahaha BEEEEEFIVE problems ... ill check when I get home, last I looked not a single code..

**vavJETTAw36** · 05-23-2016 06:41 PM

If you having beeefive problems I feel bad for you, son

Sent from my iPhone using Tapatalk

**axnjaksn** · 05-24-2016 08:20 AM

ok, so options im looking at here that could be my issue, diverter valves leaking(APR R1)? spring tension on my diverter valves too weak? green check valves that I did recently replace with new oem ones could possibly be leaking? I have full awe downpipes and exhaust with hi flow cats - possibly a restriction somewhere in there? ive pressure and smoke tested with ZERO leaks showing. is there something else im missing?? is there something with stock manifolds that could be causing this???
It just seems really odd, makes 25-26 psi as it should and holds until right around 6k, my N75(new) looks good (as far as I can tell looking at my last log)

**NOTORIOUS VR** · 05-24-2016 08:24 AM

Originally Posted by axnjaksn

I hit 25 psi like im tuned for, then carry it until I hit appx 6k rpm.....then drops off to 15 psi......is there something im missing....

Since 15 psi is approx what the gates are set for on the K24's, sounds like you hit limp mode.

Logs would help here as usual.

**axnjaksn** · 05-24-2016 11:12 AM

https://goo.gl/gSbHOz

Lemme know if this works

**NOTORIOUS VR** · 05-24-2016 11:43 AM

Originally Posted by axnjaksn

https://goo.gl/gSbHOz

Lemme know if this works

It did.

Unfortunately I still have no idea what is wrong... You're not in limp mode (even though the actual load is well above req. load and usually will trigger limp), and I don't see anything there that would cause you to drop boost like that (WGDC is still normalish, no throttle cut).

It seems like 5800 comes along and you just lose all your boost for no reason. Very, very odd.

Maybe your DV valves are pushing open, or the N249 is fubar. You can try to by pass it to see if that helps?

**axnjaksn** · 05-24-2016 01:33 PM

Originally Posted by NOTORIOUS VR

It did.

Unfortunately I still have no idea what is wrong... You're not in limp mode (even though the actual load is well above req. load and usually will trigger limp), and I don't see anything there that would cause you to drop boost like that (WGDC is still normalish, no throttle cut).

It seems like 5800 comes along and you just lose all your boost for no reason. Very, very odd.

Maybe your DV valves are pushing open, or the N249 is fubar. You can try to by pass it to see if that helps?

thanks my dood, I did bypass the n249 the other day and it didn't change, although she backfired and spit all kinds of nasty while it was bypassed, kinda liked it haha. Ill check my dv's, and recheck my green check valves.....your not the first person to say the same.... maybe my dv's are pushing open.

it doesn't seem to be building boost any slower either...

**NOTORIOUS VR** · 05-24-2016 01:38 PM

Originally Posted by axnjaksn

thanks my dood, I did bypass the n249 the other day and it didn't change, although she backfired and spit all kinds of nasty while it was bypassed, kinda liked it haha. Ill check my dv's, and recheck my green check valves.....your not the first person to say the same.... maybe my dv's are pushing open.

it doesn't seem to be building boost any slower either...

It just seems so..... odd.

The boost just drops without any other sort of change in WG or Throttle control.... I mean, it could be something mechanical like the WG giving out, or a check valve maybe... but I'm at a loss here sorry man.

I'm just not sure it is anything with the tune at this point, so I suppose continue to check for external issues.

Does the car remain smooth (it looks like it does in the logs) when it drops boost? How many PSI have you pressure tested to?

**axnjaksn** · 05-24-2016 04:15 PM

Originally Posted by NOTORIOUS VR

It just seems so..... odd.

The boost just drops without any other sort of change in WG or Throttle control.... I mean, it could be something mechanical like the WG giving out, or a check valve maybe... but I'm at a loss here sorry man.

I'm just not sure it is anything with the tune at this point, so I suppose continue to check for external issues.

Does the car remain smooth (it looks like it does in the logs) when it drops boost? How many PSI have you pressure tested to?

yea it remains smooth, no bucking or weird throttle issues, just no more smiling hahaha. ive pressure tested it pretty high before....usually 15-20 psi maybe a little more like 25-30 before my SWEET homemade pressure tester blew off the y pipe. believe me it helped me find quite a few other small leaks and 1 large one on a suction pipe. when I smoke test is however its much less psi, either way nothing comes out anywhere and im in my the shop with no wind or breezes or fans running so I can spot the smallest little hair of smoke

**axnjaksn** · 05-25-2016 04:54 PM

lemme ask this, if my dv's check out ok and my green check valves pass(haven't had a chance to check because everyone elses car comes before mine)

... wth else could it be??

**axnjaksn** · 05-25-2016 08:24 PM

or maybe i just need to tighten down my wastegates a little more.......thinking out loud here....

**axnjaksn** · 05-26-2016 06:09 PM

ok ok, with the advice of NotoriousVR and Corradvolksb....pulled the pos awe so flow intake off my car and put my stock air filter back....problem solved....the itg filter from the awe kit just collapses ... thanks for the help!!!