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well iv had this problem pretty much since day 1 of my turbo conversion. basically, on cold mornings, it runs like a box of shit. attempt to give it the slightest throttle, or put it under any sort of load (more than 2 passengers, driving up a hill, give it a moderate bootful) and pretty much, can hear the boost being spooled, motor amping up the revs, but no go. can feel spulttering etc from the motor ie: misfireing. it comes good once its warmed up, but hey, it shouldnt really do that in the first place, even if it was cold?

mods are:

RB25DE (highcomp NA motor)

standard RB25 series 2 turbo @7psi

standard turbo injectors (again, series 2)

std front/dump pipe

2.5" catback exhaust (noticably restrictive, getting replaced soon)

running castrol edge 10W60 with a bottle of lucas stabiliser

standard airbox with K&N filter

turbosmart supersonic (?) BOV (basically, single port to a trumpet)

new set of spark plugs put in (standard champions, RC10YX4)

standard fuel pump (dunno if turbo/nonturbo pumps are diff?)

standard GTST series 1 ECU

Standard GTST S1 AFM

this issue of spluttering is also apparent in revs higher than 4.5k, when warmed. i dont know exactly what it is. a few theories me and people who look at it are:

blowby caused by incorrect gap in spark plugs

not enough fuel ie leaning out because the injectors arnt reaching the proper duty cycle (solution, bosch 040w/ rising rate fuel regulator)

just needs a decent tune

another issue im having is purging aswell. let it sit at the traffic lights for a minute or so and watch the revs fluctuate! :D this has only happend since i put the GTST ECU in) again possible theories behind that are the need of a tune, or leaning out at idle for some strange reason?

i just need some input from you guys whov had more exp with turbo motors than i have. im still on a steep learning curve but iv learnt alot about it on the way :thanks:

ideas?

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only solution I can give you is get a powerFC, then go to the water temp/fuel settings and add more fuel for 10, 30, 50 degrees Celsius. Seems like it's not getting enough fuel into the motor...

revs fluctuating, are you running a vented catch can, that's connected to the cam cover? and being N/A I don't think it has the same PCV as normal turbo models.

There's probably more air being sucked into the motor and the AFM isn't registering it hence it's running like shet when cold.

yeah about the rev fluctuating, it is running an air filter ontop of the cam cover, that does explain it alot now :P will get a can...is there anywhere else it can plug into? (ie theres a hose running up from the turbo atm thats just plugged up with a bolt cos we didnt know where to put it)

as for the air/fuel issue, would that be casued because the camshaft profiles on the NA and turbo motors are different? if so then that makes complete sense. correct me if im wrong but it isnt possible to remap the air/fuel mixture on the 25DET ECUs is it, which is where id have to go with johnnys sugestion

Air Breathers big no no...!

Make sure your cam cover has a PCV on it, it should connect like this.

Plenum -> PCV -> Driver Side Cam Cover -> Passenger Side Cam Cover -> Intake Pipe.

You want the catch can to be between Passenger Side Cam Cover & Intake Pipe, i.e. only collects on boost, as PCV shuts off flow to the plenum when there's +ve pressure in the plenum.

Contact a dude name Toshi, he will sort you out. He is able to remap RB25DET ecu's using NISTUNE daughter boards, I think CEFF1E (Nic) will be able to help you out as well, he lives in VIC now so it would be easier!

All the best, if all else fails, powerFC, O2 Wideband, datalogit and tune it yourself for Cruise/Mid throttle, and leave the top end for a tuner.

pretty sure thered be a PCV in there somewhere from stock, yes? if not then thats no biggy, will invest. what part/stage of the intake should i plumb into?

thanks for you help johnny, much appreciated :)

Plenum -> PCV -> Driver Side Cam Cover -> Passenger Side Cam Cover -> Intake Pipe

Blowby has nothing to do with spark plugs. Duty cycle has nothing to do with the type of fuel pump or FPR.

High compression motor running a turbo - standby for detonation.

The car isn't idling properly, it's because the motor is ingesting more air than it's registering because of his breather setup, I didn't say anything about blow-by & spark plugs dude.

I didn't say you did. It's in the OP by GODZLR.

BTW - I'm not a DUDE.

sorry, but in "The Hills" Audrina's on and off boyfriend Justin calls her "dude" :down:

well GODZLR, just fix up your PCV & catch can issues, at least your idle will be sorted.

I had the same problem with my old car, because the old owner vented the cam cover's into an atmospheric catch can without blocking up the PCV, so on idle the car would idle like a wild bull puffing. I soon fixed that as soon as I got the car, plumped everything back together.

Not sure if Toshi will fly down to Melbs, bue CEFF1E is already there, which might make it easier!

toshi does long distance tunes, did for me anyway. sorted out the tune on a dyno

Id seriously suggest ditching the BOV and get a stock one installed, dont use an atmospheric bov.

Grab the Bosch 040 fuel pump and a Nismo FPR, total $400 all together

Also get rid of the little pod filter "air breather" on the cam covers.

then get on a dyno

one day you might want to save for a thick head gasket re: compression / detonation

OK few things i noticed straight off the bat..

- atmo breathing but still with PCV? bad news.

- untuned stock ecu on a de+T, asking for a meltdown.

- shit spark plugs, get some NGK coppers (BCP6ES-11, and gap down to 0.8mm if still misfiring).

- possible fkd coils if it gets worse over 4500rpm.

yep...going on a spending spree tomorow. picking up the following;

-sealed catch can

-ordering a bosch 040

-ordering the plumbback adapter for that BOV (gotta love turbosmart interchangable :)

-putting money down for an ECU off toshi

-some new hosing here and there

-start pricing some decent coilpacks (most likely splitfires)

and as i said earlier, looking into a larger exhaust, front/dump pipes atleast to try and minimise some of the detonation.

update: have placed money down with toshi, hes working on my new ECU now :( cant wait, very exciting stuff. also, 040 is here now, have to pick it up in the next couple of days...

plumbed up my oil overflow/breather into the intake, idles perfectly now. also got some black silicone hose, so once i put that on itl be nice n stealthy :) have booked in for a day in the workshop with a dyno so will spend the day putting the pump in, ECU, and giving it the final touchup tune with the new ECU :P

once this is done, its time for a bigger exhaust and new coilpacks.... :thumbsup: anyone had experience with anything other/cheaper than splitfires?

^ neg,

holding up fine on my 200rwkw skyline, have not had an issue with them at all!

running .8mm gapped plugs also.

but whatever you get, make sure they come with warranty as anything can go wrong with any brand - superspark, jjr, splitfires etc

there has been issues with all 3 brands with them failing str8 out of the box and ppl who buy them without warranty get stung & lose out :)

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