Exhaust making weird noises. [sound vid]

[robbyj]

Ok guys after my extractors and high flow cat went on, all was good, drove it hard a few times naturally to test it out.

Now this weird sorta flapping noise has started when plant the foot.
Kinda sounds sometimes like backfiring.. flapping.. possibly a hole?

or is it just normal now its 'worn in'
The sound doesnt really sound normal to me.

The problem is you have to hear it to understand.. i dont really know how to explain it.

There doesnt seem to be any power loss.. still goes hard.

Listen here anyway (the end of the Vid gives the best sound description.)

[Falconxr68]

I honesty would not have a clue but I can certainly hear that "flapping" sound

[robbyj]

Yea its got me beat.
Might have to take it to an exhaust shop.. but then again to show him he'll have to jump in with me.

[frd906]

sounds like its blocked or just needs to carbon up

[robbyj]

They've been on for over a month. And its done a fair bit of driving in between then.. i don't think it needs to carbon up anymore..

Blocked? possibly..

[frd906]

Have u check the gaskets between the flanges,

[Windsor220]

Sounds like it could be a misfire but you reckon you dont feel a power loss. Very difficult to tell what it is without driving the thing.

[POELWYK]

hmm that dosent sound right

[robbyj]

Although i did notice a week ago.. going thru a round-a-bout.. i planted it a bit.. and it did it with maybe a second delay before any power came through.

Could possibly be the gaskets.. i dont know what ill be looking for tho.
A mate when i showed him them said to watch the gaskets cos they looked a bit cheap or something..

[Jack91]

Possibly but I used old super crappy ruined gaskets and a bit of gasket maker on mine and never got that noise. That sure is a weird sound

[robbyj]

hmm ok, well it could be the obvious such as a dodgy weld or the join from the extractors to the pipe?

[frd906]

I had a few blow out on mine, gaskets that is, should try and get under and retighten the bolts etc

[robbyj]

I think tomorrow ill get a mate and see if we can spot a leak anywhere,

[Day-mow]

check the welds/gaskets with your hands and mayb some water on them and see if you can feel any air coming out. somethings not right

[adrian k]

could just be a resonance pulse wave in the system. only thing that will fix that is adding a restriction eg a resonator or changing the length.

[FTE72]

Have the manifold bolts been retensioned a few days after the extractors being fitted?
It is pretty std practise to retorque extractors once they have been to temp a few times.
I would say you have a flange gasket leak.

[robbyj]

Ok, got the mate, put water on extractors, gaskets etc. Checked under car for leaks. No luck. Went to the exhaust shop i got it done. One of the blokes came for a ride

He reckons it is miss-firing. So i'm going to check spark plugs. If not them its possible time for ignition leads and coil pack change.

He also said it could be the fuel mixture is not right.. leaving unburnt fuel in the system.. which when it is burnt out the exhaust makes the noise. o2 sensor could be stuffed but it is still economic so i doubt it.

Plus i doubt this would make a delay in power. So miss firing seems to be the best bet.

He also recommended a tune. Which after i change the leads/plugs/coils will be on the cards i think. Dyno and tune.

[frd906]

I took my car to ultra tune and they did a power test for me before i changed the leads and plugs and it showed number 3 and 4 cylinder wasnt firing,

Cost me about 100 bucks to put it on a machine, they go through and check eveything

[robbyj]

Yea i was wondering how much it would cost.

[frd906]

Was worth the money, shows that everything else was aok, i replaced the leads and spark plugs a week later and bingo worked a treat,

Ive kept me old leads, just got to buy new plugs for me low k engine i put in

[robbyj]

So was the $100 for a tune aswell?

If i get a dyno + tune.. roughly what am i looking at?

[au11futura]

i had the same but it was the cat converter.

[robbyj]

hmmm hopefully its not the cat. Its brand new.
Might nip out to my mechanic before i purchase all the leads/plugs etc and see what he reckons

[frd906]

nah a tune and dyno run is about 1300 bucks

[robbyj]

Originally Posted by frd906

nah a tune and dyno run is about 1300 bucks

For REAL??

[frd906]

the hand held tuner is about 600 to 800 unless u find a second hand on on ebay, and the runs are about 100 hundred bucks and hour, usualy take 3 hours to tune or something unless u can find some one cheaper but yeh for real

[robbyj]

Alright, might have to have a chat to them.
Thanks mate.

[frd906]

id wait till u do a full cold air intake and a cam etc before a tune, cause u dont wanna keep going back everytime u do a preformance mod

[robbyj]

Yea, well i got the XRT snorkel and high flow filter in there.
If the changing of plugs leads etc all doesnt work, i might go talk to some people, and if they reckon they could fix it in an hour or something, id get em to do it. While iv got 2 1/2 years of uni left i dont ill have the spare money for something like a cam/tune anything major anyway.

[Jack91]

Dont really need a tune anyway, AU's adapt pretty well to exhausts and intake after a couple of hours driving