My VZ CALAIS!!!

[Surfwagon]

All the HSV VT2-VZ system have a very slight drone even on the V8's, mine was no different.
It is not the sort of drone that gives you a headache or the shits but is there never the less.
But when I fitted 100cpi Ballistic cats to my senator the ever so slight drone dissappeared completely.

 

[showxpony]

All in the cats you rekon? Interesting observation. The stock cats hang a bit too low on my car, i may see about getting them moved higher, and changed at the same time. would 100cpi be suitable for a 6 tho?

 

[Surfwagon]

All in the cats you rekon? Interesting observation. The stock cats hang a bit too low on my car, i may see about getting them moved higher, and changed at the same time. would 100cpi be suitable for a 6 tho?

Thats what happened with mine, my exh from the cats back is stock HSV and until I changed the cats (had already fitted shorty extractors) nothing really changed noise wise.
But as soon as I drove it with the new cats fitted I noticed no drone, even a tiny bit at all.
I can't see why 100cpi cats wouldn't be ok on a V6 (std cats are 400cpi, same for both V6 and V8) so in theory they will flow 4 times as much air as the stockers which means less restriction/more flow.

 

[showxpony]

Only thing is back pressure. Apparently a fair amount is needed for a V6. I'm not too sure about whats what with back pressure tho, not many people can really give a straight answer. But it sounds like it should improve things.

 

[Fishman88]

Good job on getting the exhaust done mate! Sounds like its very similar to my exhaust, being a redback muffler - 2.5inch, as it sounds massive sh!thouse at 2500, pure drone.. But above that, its pistony and very nice sounding. And the rest of the time it's V8ish(its probably a big 'ish', because when im next to a v8 with a zorst, they always sound better, slightly haha). Good to know that yours drones at the same revs, shows that that's just how the engines are. And yours will probably be the same, that drone at 2500rpm is the loudest sounding point too yeah? and after that it doesn't sound as "loud" but the note just improves with more piston sound?

And i felt the same thing, a little more lag until you get over that 2500grand mark and then it feels like it pulls a fair amount harder... Maybe a tune/cai modification would fix that?

What's the diff between the stock air box and an HSV one? just the size? From playing with K&N filters, the airboxs on the 190 alloytecs actually have the same air boxes as the 5.7Ltrs in the VY/VZ SS's... Have you considered OTR?

Cheers bud!

Cheers mate!! Well its a 2 1/4 inch all da way. doesnt sound the best a 2000rpm - 3000rpm but afta that sounds pretty sweet. Under 2000rpm sounds v8ish like. Mine actually drones at bouts 1500pm - 1800rpm but afta that sounds nice has a nice note when you are crusing just enough to know u got an exhaust hahaha yours seem to drone at higher rpms. Not sure if a tune can fix that but definitely afta 3000rpm it pulls man unlike b4 it felt like when it was getting in the higher revs seem to be restricted feeels much freeer in the highend revs. I might just save some $$ and do the 2 Hole mod probaly does the same thing. Heard OTR is useless on VZ's as thers no mafless. Cheers!

 

[Fishman88]

All the HSV VT2-VZ system have a very slight drone even on the V8's, mine was no different.
It is not the sort of drone that gives you a headache or the shits but is there never the less.
But when I fitted 100cpi Ballistic cats to my senator the ever so slight drone dissappeared completely.

I Have those Ballistic cats too!! with pacemaker headers too but mines a V6 so yeee...

 

[Fishman88]

All in the cats you rekon? Interesting observation. The stock cats hang a bit too low on my car, i may see about getting them moved higher, and changed at the same time. would 100cpi be suitable for a 6 tho?

They are suitable for any car!! haha bcos i have them on MINE!!

 

[Fishman88]

Only thing is back pressure. Apparently a fair amount is needed for a V6. I'm not too sure about whats what with back pressure tho, not many people can really give a straight answer. But it sounds like it should improve things.

Probaly to produce the bottom end torque as the stock system is twin then afta the middle mufflers goes into single. Maybe better off just getting the standard muffler replaced with hi hiflow mufflers? But im loving this mid - high end thrust from this HSV system i have!! not the best for street but but good for those weekend drives!!

 

[torana355]

Probaly to produce the bottom end torque as the stock system is twin then afta the middle mufflers goes into single. Maybe better off just getting the standard muffler replaced with hi hiflow mufflers? But im loving this mid - high end thrust from this HSV system i have!! not the best for street but but good for those weekend drives!!

People use the term back pressure incorrectly all the time. An ideal exhaust system will have as little back pressure as possible!!! The reason you need different size exhausts for different motors ect is to do with getting the exhaust pulsing correct. This is the process of getting the exhaust out of the motor most efficiently to increase power.

 

[showxpony]

Hmm i see. I only have one muffler on my car, and its a hi flow redback muffler. But, for a 6, for it to sound loud and deep, your going to cop some drone. As long as its not tin/rattly sounding, then it's all good. Low end torque is all to do with the extractors I believe.

Have you decided on the 2 hole mod for sure?

Cheers torana355 for clearing that up.