Car running strange

[Northy1985]

Under hard acceleration the car sounds strange. I am running a neuspeed induction so its got the loud sucking under hard load but noticed last night on the motorway in 6th i went to overtake and once car hit its boost it was almost like a chattering sound hard to explain almost like a misfire sound. Its had new coils and plugs not too long ago

[slix]

It's normal. I have the Ramair induction and under heavy foot eg. On the motorway I get the chatter.

[Northy1985]

Its never done it before its under hard acceleration in every gear almost like a coil breaking down but they are all new

[ROH ECHT]

Plugs may be the issue. Could be gauged improperly...should be 0.028" to 0.030". Another thing it could be is sometimes an old plug leaves behind its washer when removed and causes a misfire under load. When you remove the plugs to recheck its gauge...run a magnet down to check for extra washers left behind by the old plugs. If no washers are present...the magnet will not attract to the aluminum head. If you feel an attraction from the magnet...there is a washer down there. I have heard of brand new coils not working well. Best thing to do is read the error codes and determine if misfires are present and localized or at every cylinder. Run some injector cleaner in the meantime.

[Northy1985]

I changed couls and plugs about 1000 miles ago if not more and when i changed plugs at same time i always check the plugs that come out and all was the same so no washers in there. I aint used the car for a couple weeks now this happens makes me wonder if its a torn dv as i can hear it through the induction. On the spot revs up lovely its still pulls well just not like it did its running stage2 rtech amd wondered if the extra boost has killed the dv

[doylebros]

It's not valve float caused by weak valve springs resulting in a missing fire at high Rev range - there's a colour code on the valve springs to check if you have the early or up rated springs?

[Northy1985]

It's just so weird as its run fine up until now like I say on the spot revs up crisp and after 4K revs under load does this.

[Northy1985]

Just been out in the old girl and put her in 4th doing 20mph and put my foot down the boost picked up nicely but as the pressure got higher it made the noise again sound like boost leaking. Would I be hearing this through the induction if the DV is split making me think that it may have split as she still pulls like a train yet goes flat when this funny fluttering happens

[AJP]

N75 valve maybe?

Get it scanned, remedy any faults that flag up, and put in a revision G diverter valve while you're at it.

Then come back to us.

[Northy1985]

N75 valve what is that. I believe it had a new DV put in on the day it was mapped so in theory that should be fine? I have seen these gfb DV was thinking do I use this as it has a stage 2 map. I will get it scanned and see if any faults come up

[AJP]

N75 valve what is that. I believe it had a new DV put in on the day it was mapped so in theory that should be fine? I have seen these gfb DV was thinking do I use this as it has a stage 2 map. I will get it scanned and see if any faults come up

Regulates the wastegate.

I wouldn't bother with the gfb valve, rev g oem has proven to be best overall.

Good luck with it pal, hope you get it sorted

[Northy1985]

Cheers buddy I will get her scanned and check the DV just to eliminate if it's that and also check which revision is in there now

[Dan_FR]

Are you K03 or K04?

Sounds very much like a split rev G to me, mine went just before Christmas after 25 months and about 12k of use

Shouldn't sound like a misfire though, just sounds like the DV is open all the time, you hear the loud hiss/tsh noise whenever you hit boost, not a chattering noise.....

A good indication before you take the DV out to inspect is to log the MAF values under load, mine usually peak at around 220-230 g/s, but I was down to 150g/s when it split. Don't drive around flat out too much as the turbo will be working REALLY hard to try and make up for the lost pressure

[Northy1985]

Mine is k03 its not really a misfire at first i thought it was but after driving again its deffo not missfire its a hard one to explain as its not a loud noise just like a fluttering of air at high boost low boost its perfect just hard acceleration just wondered if i could hear it worse as i am tunning the neuspeed inductiong which is loud anyway. It had a new dv fitted on the same day as it was mapped at r-tech as i have the reciepts to show he replaced dv and cam follower after a health check on the rollers.

[Dan_FR]

The intake will allow you to hear it, whereas the standard airbox would mask the sound entirely and the car would just feel slow

Rev G can split at any time, it's only a thin piece of rubber that splits.

Would definitely be the first thing I check.