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Hey guys,

Yesterday, I had installed an Apexi FMIC kit (return to stock piping type) and one of BATMBL's split dump pipes. Current performance mods are:

Apexi FMIC Kit. 3" exhaust. K&N pod filter. Boost solenoid grounded (so it's in high mode 100%)

Normal driving is perfectly fine, and also a bit of boost (ie not flooring it) is perfect. However, when I give the car some shit it will feel like it's being held back by something... it doesn't want to pull all the way to redline.

Now I've searched and read up on ECU R&R and the taping coils and stuff but the car doesn't sound like it's misfiring. In fact, it sounds pretty normal except it doesn't feel like it's going anywhere. I doubt it's clutch slip either. (does anyone know what a stock clutch will hold?)

Anyone had similar experiences or know what could be the problem?

Cheers.

Edited by lordsnipe

does it happen around the 4500 - 6000 rpm range?

does it feel better from 6000 - redline?

If so most likely it is b/c it runs so rich in that rev range to compensate for the increased airflow.

Cheapest options are SAFC or the jaycar kit.

I had this issue when i had similar mods at 10psi of boost. SAFC fixed it very nicely for me, also gained me 35rwkw (better A/F ratios made better use of my other mods).

This is very common on the RB25DET.

hey alan,

i'll have a look into that .. it's definitely cheaper than a new computer! powerfc wouldn't fix the problem if it was the bov anyway!

i have a greddy type-s which vents to air, so it may well be that opening under full load. it explains why normal driving is still fine.

Yeah, my Stagea was like that after I installed the same kit (apexi with custom return feed to standard area). Felt great, until the rpms started climbing higher, plus it ran around 15% richer (ie used 15% more fuel).

I already had a SAFC tuned, but went back and had it retuned along with a SITC piggyback & a Z32 AFM, now have 160AWkw and a very nice power curve all thru the rev range (being held back slightly in a couple of areas due to the adjustable fuel regulator).

Id suggest its now 'reading' too much air and therefore putting in more fuel to compensate? Grab some piggybacks!!!

  • 10 months later...

My problem was due to the BOV. It was opening on boost so the spring had to be adjusted.

I have now since changed to a GFB StealthFX (with very little venting to atmo ... like a psst) and my symptoms are like 95% gone. The other 5% i think is due to the ECU... it'll flatspot every now and again but not to the extent it did earlier, where it did every run.

I had similar experiences.

but in first gear on say 10-12psi, if i take off very normally, then ease on the throttle to full say from 10-20kph - the car just dies in the arse.

give it a good launch - car goes hard.

could it be injectors?

its got the hks fuel cut defender also...

My problem sounds just like many of the above. ever since i got the cooler and dump / exhaust etc installed the car seems to spool up a whole lot after about 5000 rpm to about 12psi and yet not seem to pull any harder. Sometimes it does but when it's colder it doesn't and it just backfires on high boost. Which leads me to believe that its got to do with a /f ratio's from the std ecu and the car is therfore running way to rich especially on the higher boost. I am gonna get an safc and hopefully that will fix the problem when i lean it out a little. Also shortly after i got the exhaust done the a /f ratio display on the apexi pen timer ceased to work. :D Do you think my oxy censor has carked it?

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