VS V8 Exhaust System???

[vs-ss-kiwi]

Hi all, new to this site. I have a VS SS Commodore, I have just had the exhaust system upgraded. It has 2/5" from headers into a 3" into a super 44 flowmaster. It sounds very average, not too bad down low and idiling but sounds really crackly and almost fluttery when driving. So not the sound I was wanting, any ideas where they went wrong or ideas of what can be done. Pictures or any information would be much appreciated.. Thanks

 

[vs-ss-kiwi]

Also feels like I have lost abit of power??? I thought id gain a little power?? Cost me $750 so not too happy! Cheers

 

[_R_J_K_]

What was the original exhaust?

 

[vs-ss-kiwi]

Hi, just factory system. 2.1/4 pipes splits into two with two mufflers than back into one pipe and another muffler. As far as I Know, sorry not 100%.

 

[vs-ss-kiwi]

Should I add a resonator?

 

[Immortality]

Super 44 is one of the more aggressive sounding mufflers from Flowmaster. Who fitted it?

From what I have seen, flowmasters are happiest if dumped soon after the muffler, my exhaust guy says to fit a resonator if the pipe after the muffler is more than 6 inches long LOL.

Might need a tune to compensate for the exhaust system change.

 

[vs-ss-kiwi]

The muffler is sitting about halfway/middle of the car so there's well over 6" of pipe lol. More than a meter of pipe! Some local mechanic fitted/designed it. Not a muffler guy but he assured me he new what he was doing and apparently had done heaps before.. Its too loud and the loss of power isn't cool. Im not sure where to go from here? hoping its a quick/cheap fix not overly keen on paying for a whole new exhaust.

 

[vs-ss-kiwi]

Oh, he told me I don't need to tune these cars as they tune them selves?? I have no idea, I thought all cars need tuning at some stage.

 

[Immortality]

These cars tune themselves but only under certain conditions and only in the 14.7:1 AFR target VE MAP area. These cars do not tune themselves for full power.

The bigger exhaust system will effect the torque curve somewhat. The factory system is somewhat on the small size which is ideal for low to mid rpm torque but somewhat restrictive at higher rpms. changing to a system like you have will tend to benefit the mid - high rpm but at the cost of the low rpm area.

I think the problem your probably suffering is drone in the exhaust system, if you have a look on the flowmaster website they have sound files for the various muffler designs. From memory the super 44 is one of the more aggressive sounding mufflers which does have a lot of cabin noise. Fitting a resonator may reduce this.

As for the power loss, your best bet would be to check the base timing on the dizzy, it should be 10° BTDC. Ideally a bit of a tune up should find back most of your lost power at low rpm and notice a decent gain at higher rpms. In the mean time, you could try advancing the dizzy to 12°BTDC as a cheap tune alternative.

 

[BottleFedVS]

I found going to the 3" has made the power a little later in the rpm range on a more or less stock engine.
The 3" cat back exhaust is more suited to a supercharged, Turbo or nitrous application.
Just for sound and power with a reasonably stock motor I think the 2.5" is the better way to go with a lukey muffler.
Just in my opinion.
I hope that helps.