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R34 Gtt Dump/front Pipe And Hi Flow Cat Annoying Rattling Noise

Elegant Skyline
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Elegant Skyline Enthusiast

Elegant Skyline

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Hey guys

Wondering if you can help me out with this annoying problem that has happened since changing to a 3' front/dump pipe and hi flow cat from its stock parts, the noise occurred straight after they bolted on those parts and on my way home the sound is like tiny rattling metallic or cicadas and it only happens on a certain RPM such as near the 2000 rpm range, i also noticed that the rattling sound only appears once the engine/exhaust is hot, the rattling is more pronounce from inside the cabin when driving against a wall.

The cat and front/dump pipe has no heat shield so it cannot be them.

I took my car back to them to see the problem and they said they don't hear anything when driving my car other than the turbo spool up louder then before but everyone that has sat in my car before now notices it too, they also took apart the cat to see if perhaps anything is inside (nothing) and re tighten the bolts but still to me the annoying sound is still there and they said they don't hear anything.

On a another issue (Sorry if i am asking too much ) but I've read on many forums that after changing the dump pipe i need to get a tune to prevent boost rising or detonation etc, but i have personally been to my local mechanics and they say it is not necessary unless i am chasing big power or getting more KW out of my pipes and cats.

My GTT is an auto and is pretty much stock with these aftermarket pipes and cat, i am not chasing big power and not after attention that is why i just changed to these 3' pipes and cat but left the catback stock to avoid attention however from what i have read is dangers of boost rising, detonation, o2 sensor and ecu problems has made me thinking i need to get a tune to stop my car from blowing up.

What do you guys/girls think as on forums they say a tune is a must but my mechanics say it is not needed. This is confusing the crap out of me......

Elegant Skyline Enthusiast

Elegant Skyline

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Dunno about the noise but you won't need a tune.

Get some fibreglass tape heat wrap onto the dump and see if that kills the noise. It's worth it anyway to stop it cooking the engine bay.

Okay thanks for the tip, i did see that my engine bay was more hotter than usual when i got home, i see if supercheap auto has them.

vetter2769 Proficient

vetter2769

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Posted

Truth is it does change your tune, the exhaust is now more "flowable" therefore making it easier for the turbo to spool up, and it should now be making more boost than before (not much maybe 1-2psi more)

I learnt this when I upgraded my standard 34 gtt exhaust, and went and had it tuned with a piggy back + pod + ebc - made 210kw

Im kinda unsure of your question... so no you don't "have" to get it tuned, it will be fine without it, the standard ecu will cope with it, possibly by changing the timing or removing fuel from the map.

Turbo cars are much more sensitive to changes than N/A cars, so just remember everything you do has greater effects, definitely get looking through SAU archives for solid info.

And the rattle - I would never have taken my car to a shop to do a simple exhaust change over, but continuously return to the shop you got it done at till they fix it!!!!!!

Or take them for a drive, and show them.

If you've had a shop put your exhaust on, then it doesn't sound like your the kinda person who will undo all there work to find the problem, otherwise you would have done it yourself in the first place....

Deza3000 Proficient

Deza3000

Posted
Posted

If the rattle occurs when the dump pipe gets hot, that means its coming into contact with something when the metal expands. When i had my 3inch dump pipe installed on my car, it also rattled, the exhaust shop kept adjusting the position until clearance was 100%. Id probably look into that first.

Also, its known for some RBs do have a certain level of piston slap (my old r33 had this above 2000rpm), maybe the bigger pipe is just amplifying the sound.

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