Major Overboosting Issues : 1.6Bar!!

Nistune topics related specifically to the 6303 cpu

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klys
 

Posts: 21
Joined: Tue Jun 09, 2009 1:28 pm
Location: Montreal, Qc, Canada

Major Overboosting Issues : 1.6Bar!!

Post by klys »

So since last year I've been running into some problems with my car.

for the most part, I though it the over boosting was caused by:
- blown turbo
-dirty Intercooler
-oil coming from the broken turbo seal going into manifold, burning in the exhaust manifold

My car is as follows:
R32 GTS-T
Tomei 2.2L stroker
Z32 MAF
rebuilt HKS GT-2535 with ported WG hole
GTR FMIC
Trust recirculating BOV
440 GTR Injectors

No know boost leaks

The problem mainly happens when the engine is race ie: at the track.

most High RPM runs here and there never caused Overboosting.

the symptoms are: while going WOT, boost controls becomes inefficient (with rubber hose from compressor too WG or with AVC-R)
I was reaching 1.6 bar at 3500~4000 RPM !!!
car wasn't accelerating at all - slugish as hell
happens anywhere where boost occurs

I had to lift the throttle when I heard my DEFI beep above 1.3Bar ....

also massive flames coming from the exhaust

so here is my Hypothesis.

I rebuilt my tune last year with rom editor(before I had nistune) and before the turbo blew as my consult wasn't communicating the ECU.


I changed everything I had acces to to reflect my particular setup and everyting went fine.

what I may not have changed is the knock map.

Once the engine bay temperature is hot enough.
could it be that because the engine is modded, the knock sensor thinks it detects knock, goes to the knock table and if the maps is very different like: Way retarded timing / Mega rich

by being extra rich and the timing being retarded, the fuel basically burns up in the exhaust manifold and creates a form of unwanted antilag?

here's the .bin that cause the massive 1.6Bar spikes
Note that my stock WG acuator spring is at 1 Bar

ALSO
the boost was confirmed by both my Defi boost gauge AND AVC-R Boost sensor so..

If you could verify the knock delta compare and tell me if my hypothesis is at all possible it would be greatly appreciated Thanks!

my wideband is almost installed ...

I didn't have my consult cable when this happenned last at the track and can't really recreate it on the roads.

What I did is do a fuel and timing knock copy, and decrease the whole timing map by -2 and enrich the whole map by 2 values
Attachments
Burn R32_RB22_Z32_440_0016.bin
(32 KiB) Downloaded 127 times
TM_S13
 

Posts: 246
Joined: Mon Dec 29, 2008 11:29 pm

Re: Major Overboosting Issues : 1.6Bar!!

Post by TM_S13 »

I don't think it has something to do with the *.bin file...
perhaps too much heat in the engine bay is causing the AVC-R solenoid to malfunction, giving you that massive boost...
do you have a wideband to check AFR's ?
PL
 

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Joined: Fri Feb 03, 2006 3:29 pm
Location: Adelaide, South Oz
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Re: Major Overboosting Issues : 1.6Bar!!

Post by PL »

Yeah, there's really nothing in the tune that could cause this. Gotta be more a mechanical thing - hoses, joints, WG actuator etc.

PL
bachig24u
 

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Joined: Mon Jun 01, 2009 11:46 pm
Location: Campbelltown, NSW
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Re: Major Overboosting Issues : 1.6Bar!!

Post by bachig24u »

correct, If the timing has been wound back to far you can get flames in the exhaust. (look great)
The enrichment from knock map access can also make matters worse.

But really sounds like you don't have enough seat pressure on the valve springs.
klys
 

Posts: 21
Joined: Tue Jun 09, 2009 1:28 pm
Location: Montreal, Qc, Canada

Re: Major Overboosting Issues : 1.6Bar!!

Post by klys »

Well it really looks as if it was the tune...

I'll explain in my dyno thread a bit later

After I copied the regular fuel and timing map to knock map with a slight safety margin,
It never reocured.
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