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R33 Gtst- Flat Spots

cannabiscorpse

By cannabiscorpse,
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cannabiscorpse Mentor

cannabiscorpse

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Hey guys- I have recently bought a standard 95 gtst and have been having problems with it having flat spots. I have replaced the plugs and gapped them at 0.8, replaced the coils with splitfires, and changed the fuel filter.

The car is stock with only minor mods exhaust, pod, r34 smic and a turbotech boost controller set at 9 (As low as i could..) The problem was definately worse on the old coils and plugs, and its not popping and spluttering anymore but it still has flat spots under hard acceleration. I have noticed that if i back off slightly as it starts to miss, and continue to feed power in it drives really well.. (Eg driving at 3/4 throttle the car accelerates fine)

I realise these are newbie questions but any help is appreciated.

Cheers

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scotty_1989 Enthusiast

scotty_1989

Posted
Posted

hey mate,

i had a few flat spots for a while too. Basically i rekon your timing is abit out. Take to a tuner and get them to run it on the dyno. If the curve dips down then back up then down, or something to that extent i would most definately say its your timing. The tuner should be able to fix it for you.

cheers

cannabiscorpse Mentor

cannabiscorpse

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Just taking it for a drive and feeding it on in third, i noticed that the flat spots are spot on 3500-4000 then again at 4500-5000. The rest of the rev range is pulling really hard. I dont know if i mentioned i am using plugs that are pfr511g. I have gapped them to 0.8 but i have noticed that the other guys on here seem to go with the bcpr6es plugs, so i figure thats my next point of call, hopefully not the ecu!!

cannabiscorpse Mentor

cannabiscorpse

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I have spoken to a tuner (toshi in sydney) and he said that it would be the computer detecting somesort of overboost and that when he remaps the ecu it will be solved. Its a bit of a bummer cause i cant afford the tune for a while. I also tried taking off the boost controller and running the stock t piece, but it still makes around 10-11 pound of boost anyway, and the problem is still there. I think toshi is definately my next priority.

89CAL Grand Master

89CAL

Posted
Posted

It would be more so airflow in excess of expected and the ecu will be most likely chucking fuel and taking timid out of it. And as said when it hits the point where VCT switches off it's dying

R33's dont have boost sensing to the ecu so it will be your AFM saying WTF :)

If he's doing a remap it should fix your problem but you should probably go to the spark plugs you mentioned above as well

BOOZTJUNKEY Proficient

BOOZTJUNKEY

Posted
Posted

In my r32 I was running copper plugs bkr6e then went bcpr6es and had flat spots all thru the rev range I doing think changing your ecu will do anything get it to tuner check timing and afr thats the easyiest and less cost effective way to sort the issue out don't take this negatively but I'm speaking from experience

LANDSCRIBBLE Mentor

LANDSCRIBBLE

Posted
Posted

from what your describing ive had a similiar problem, same thing happened when the boost was set to 10psi, going up through 2nd or 3rd, then in the higher rev range would noticeably *stall* in power. apparently was to do with the stock ecu freaking out and dumping fuel at that moment, or rich and retard they call it

anyway i upgraded the ecu in the end and got it dyno tuned. smooth as silk now.

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