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Discussion Starter #1
after fitting my apexi filter, 3" downpipe with 1.5" screamer, de cat and full 3.75" exhaust i have noticed that when i go from 4th to 3rd or 5th to 4th and accelerate my cars making **** loads of noise but holding back like fook then hitting 6k revs and suddenly picking up like mad but then your near redline and have to change, asoon as you change the same thing happens loads of noise holding back then 6k revs gone.....
im still getting full boost on the boost gauge as i was before this happened.

im lost.
 

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I would say your car is now running dangerously lean due to removing the cat & making it breath a bit easier.

Have you still got the exhaust/cat temp sensor in the new pipe or have you tucked it in the chassis?

The reason I ask is if the car is lean the exhaust gas will be hotter & should trigger the dashboard warning lamp warning you of imminent danger.

I would have someone with a wide band O2 sensor check your car over before you melt it or fook the turbo.
 

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stuck in the middle .....with you
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it wont be running lean,in fact the opposite,the ecu will tell it to run richer due to the mods,its a common skyline problem that you will get when modifying,get an safc to lean off but have it done on rr
 

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stuck in the middle .....with you
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SAFC,super air flow converter,about £150 from fleebay or Apex do em,it alters the signal from the MAF to adjust fuel,type safc into e-bay
 

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Running rich, most skylines with mods are running rich, mines spits flames and pops n bangs!!!

Running lean is VERY BAD!!! But i doubt you are, with your mods you will be running rich.

What plugs do you have and what gap?
 

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tdi power
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it will be running rich like otherpeople have said, mine does and pops and bangs all the time but i like the sound :D
 

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Discussion Starter #12
i have not checked what plugs are in it since i bought it, doesnt seem like its a problem with them, its holding back no missfiring, it does pop the odd flame out but doesnt bang or anything like that, something does seem wrong though as my mods have made the car slower than it was before, until it hits 6k!
 

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i have not checked what plugs are in it since i bought it, doesnt seem like its a problem with them, its holding back no missfiring, it does pop the odd flame out but doesnt bang or anything like that, something does seem wrong though as my mods have made the car slower than it was before, until it hits 6k!
have you got a boost gauge? try gaping your plugs to o.8 and take it for a run,if anything you can rule them out of your problem
 

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Discussion Starter #17
yeh but if it was a plug problem it would have a missfire am i not right? it runs very smooth but holds back then takes off at 6k? why would the power alter at 6k? i have washed it for the first time in 2 weeks today and the rear bumper, gtr spoiler and boot were covered in fuel, and i mean covered!!! so looks like it is overfueling?
 

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yeh but if it was a plug problem it would have a missfire am i not right? it runs very smooth but holds back then takes off at 6k? why would the power alter at 6k? i have washed it for the first time in 2 weeks today and the rear bumper, gtr spoiler and boot were covered in fuel, and i mean covered!!! so looks like it is overfueling?
its a nice idea but youve got a lamda sensor so unless your lamda is faulty it wouldnt over fuel if youve got a fmic and exhaust youre turbo will woking harder and generating more heat so your injector duration is higher so you will have alot more fuel being burnt
 

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I have washed it for the first time in 2 weeks today and the rear bumper, gtr spoiler and boot were covered in fuel, and i mean covered!!! so looks like it is overfueling?
Well at least you proved one point it isn't lean & its not going to melt.

Running that rich will wash the boars smooth after a period of time & it will also thin/dilute your engine oil so keep an eye on it.

I don't want you to think I am an asshole for telling you it could be lean but 2 weeks ago I fitted a HKS elbow & a 3 inch decated & middleboxless system to an R33 GTS it has an air/fuel Gauge fitted & it went lean as hell & had to be dramatically richened up. The only difference is this car has an aftermarket ECU Z32 etc etc which must behave completely different to the standard ECU in this instance definitely something to remember though.
 

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Discussion Starter #20
to begin with i thought it felt very lean as it was asif it wasnt getting any fuel but what i want to no is why the hell is the problem solving at 6k revs?? its all happened ever since i fitted my 3" downpipe with 1.5" screamer 3" de cat and 3.75" sytem with only a back box silencer. i wondered weather it was a problem with back presure?
 
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