Annoying drone at idle after cam install!

[charlie15]

Hey guys,

Havent been on here since i sold my monaro years ago but I now have a VE SS manual as a daily which has had a cam package done to it.

Its fitted with Sureflo headers and 100 cell cats mated to a 2.5" Di filippo catback.

My issue is that since the cam, at idle, it drones like crazy and its really annoying (freeway and around the streets it sounds fine).

Any ideas on what may be contributing to this bass drone or what i can do to resolve it? The drone is muffled and i know DF exhausts are somewhat muffled on idle usually.

Will a 3" system help?

Thanks heaps

[Micks]

Do you have any zorst leaks? What does your tuner have to say about it?

[charlie15]

nah no leaks at all, had that checked. tuner didn't say much, he tried to increase the idle and it was worse so he dropped it back down to about 750. not sure what else he could do

[Micks]

What about Steve from Sureflow, any comments?

[charlie15]

ill give him a buzz and see what he reckons thanks mate

[macca_779]

What are the exhaust components. Usually not running a rear res does this.

[Red CV8 R]

I have CSV stainless short extractors (from sureflow), 100 cpi sureflow cats and twin 2.5" stainless DF exhaust and don't have this but I run the rear resonator.

[rodders188]

Id if you can afford or in the future putting dpe headersa and cats on which will eliminate all drone. Sometimes mixed systems don't work right I have full DPE Bigboy system and cam also done to my ve ss sedan, and its completely drone free.

[charlie15]

Nothing has been modified which is why I'm finding it so strange. All resonators in place, nothing has been deleted

[whitels1ss]

Id if you can afford or in the future putting dpe headersa and cats on which will eliminate all drone.

Can't say that I would entirely agree with you there buddy!

There is absolutely nothing wrong with Sureflo headers & cats which would cause any drone
at idle, it's far more likely to be a problem somewhere else with the system.

[Xjas]

What are the cam specs?
Are you sure noise your hearing is actually drone? drone is usually described as the noise created by the engine running at the resonate frequency of the exhaust system which is mostly a factor of its length, thats why VEs drone at 1500-2000 rpm.
Is the noise noticeable in a open car park or only in your garage/shed? my cammed VE used to make the most horrible noise in our carport which I could tune out somewhat by changing the RPM but could not get to go away 100% as it was due to the resonate frequency of the carport, was really annoying.

[charlie15]

What are the cam specs?
Are you sure noise your hearing is actually drone? drone is usually described as the noise created by the engine running at the resonate frequency of the exhaust system which is mostly a factor of its length, thats why VEs drone at 1500-2000 rpm.
Is the noise noticeable in a open car park or only in your garage/shed? my cammed VE used to make the most horrible noise in our carport which I could tune out somewhat by changing the RPM but could not get to go away 100% as it was due to the resonate frequency of the carport, was really annoying.

I can hear the drone when im outside of the car also when its idling (when im at the back of the car). Pretty sure its the di filippo. I've had di filippo systems on all my cars but this is the first one thats been cammed. The drone is noticeable no matter where the car is. Its a small cam vcm 532 215/223. when i first start the car it sounds fine, its only after about 20 seconds or so that this drone noise kicks in. maybe its the fact that im running a 2.5" and the di filippos are somewhat over muffled on idle adding to the drone...

[Micks]

nah no leaks at all, had that checked. tuner didn't say much, he tried to increase the idle and it was worse so he dropped it back down to about 750. not sure what else he could do

Depending on where you are in Vic try either APS http://www.apsservicecentre.com.au/
Or Chevs http://www.chevsautorepairs.com.au/

Both know their LS stuff backwards!

[Red CV8 R]

I wouldn't describe it as drone but I know that when I went from standard opened cats to the Sureflow 100cpi cats I heard a lot more exhaust noise. I was quite surprised how much. My car has a similar cam to your car.

[rodders188]

Can't say that I would entirely agree with you there buddy!

There is absolutely nothing wrong with Sureflo headers & cats which would cause any drone
at idle, it's far more likely to be a problem somewhere else with the system.

I don't agree with you entirely there Buddy! Theres nothing wrong with difillipo catbacks, its far more likely to be somewhere else in the system like the headers and cats

[whitels1ss]

I don't agree with you entirely there Buddy! Theres nothing wrong with difillipo catbacks,
its far more likely to be somewhere else in the system like the headers and cats

Headers don't cause drone buddy!

Could perhaps be a damaged cat rattling perhaps but rattles aren't drones.

I never said defillipo made bad catbacks, I never knocked anything about their products,
it could be damaged somehow or a fault in it,
could be some sort of vibration or rattle from a bad exhaust mounting or something else entirely. :lol:

[whitels1ss]

I wouldn't describe it as drone but I know that when I went from standard opened cats to the Sureflow 100cpi cats I heard a lot more exhaust noise.
I was quite surprised how much.
My car has a similar cam to your car.

Yeah 100 cell cats do make the exhaust louder that standard 400 cell opened cats. :yup: