Car Jerking At Wot After Exhaust Upgrade?

[tripsteady]

Hi Guys

So I installed a 3inch hks front pipe with a gtr cat and then 3inch straight through.

Took the car for a spin , certainly seems much livelier but Ive noticed that at wide open throttle the car seems to jerk and shudder.

This is only after I installed the exhaust. Only happens when at wide open throttle , is this fuel cut? Kept an eye on the boost gauge and its only going 3/4 way at max - which i believe is 9psi?

Could an exhaust upgrade from stock to 3inch straight through cause this to happen?

thanks in advance for any help

Edited September 8, 2012 by tripsteady

[MrStabby]

You may need a smaller spark plug gap now that you're making more power. Pull the plugs, measure the gap and check the condition. If they're still in good nick, try closing the gap a bit and go for a run. If they're old get a new set and install with a smaller gap. Try closing them 0.2mm over what they are now. So if they're currently at the 1.1 standard, try 0.9.

[tripsteady]

its the coilpacks

going for splitfires plus gapping to 0.8 , will let you guys know how it goes.

[tripsteady]

apparently its coilpacks and the plugs. gapping plugs arent hard , but dropping 650 on splitfires are as I dont have that kind of money right now.

would it hurt to gap the plugs and see how it goes?(mechanic advised against this as gapping plugs will raise the power hence strain the coilpacks even more)

should I avoid going to WOT while my car is like this , will this damage my engine in anyway?

[RBC33]

In short, your cars misfiring. If its only doin it at WOT I'd avoid giving it a bootfull till you've fixed the problem. Basically your not combusting what's in the chamber and it gets dumped into your exhaust.

You could try gapping your plugs, have you done as suggested above and pulled your plug and checked if its in decent condition?

[tripsteady]

In short, your cars misfiring. If its only doin it at WOT I'd avoid giving it a bootfull till you've fixed the problem. Basically your not combusting what's in the chamber and it gets dumped into your exhaust.

You could try gapping your plugs, have you done as suggested above and pulled your plug and checked if its in decent condition?

doesnt that mean im in fact running rich so theres no chance of detonation? in any case il avoid going WOT until I get the yellow jackets

plugs are iridium and only 2000km old...however i mistakenly purchased the non turbo one. could this be contributing to it?

[blind_elk]

RB25DE / RB25DET are the same plug, as far as I can determine (BKR5EIX-11).

If the engine is misfiring, then you are putting uneven stresses on the internals - some cylinders get full explosion for power, some get no explosion for power, some get a reduced exploision. Can't be good for the big ends and gudgeons.

[tripsteady]

RB25DE / RB25DET are the same plug, as far as I can determine (BKR5EIX-11).

If the engine is misfiring, then you are putting uneven stresses on the internals - some cylinders get full explosion for power, some get no explosion for power, some get a reduced exploision. Can't be good for the big ends and gudgeons.

will certainly not be going WOT at all then. Guess I just have to bite the bullet and get yellow jackets now.

[RBC33]

If the engine is misfiring, then you are putting uneven stresses on the internals - some cylinders get full explosion for power, some get no explosion for power, some get a reduced exploision. Can't be good for the big ends and gudgeons.

as well as all the unburnt fue hes just dumping into the exhaust, and if hes still got a cat its got to deal with trying to burn it all.

End of the day i wouldnt be doing anything to cause the engine to missfire till the problems rectified, just to be safe

[tripsteady]

bought splitfire coilpacks which will be going it soon

im using NGK Iridium Spark Plug IRIDIUM IX BKR5EIX-11, are these okay for my purpose

[tripsteady]

just and update for those experiencing the same problem

installed splitfires and plugs NGK BCPRES6(0.8 gap)

problem solved , no misfiring at idle and not jerking at WOT. Pulls all the way to 8k

lovin it