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SS VZ Exhaust

timcn

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a mate has a 2005 vz ss and he cut the rear muffler box out (just before the tip), and he put it on the dyno and make 5kw more, is this possible??, would it improve it or loose power?, would anyone know, or the dyno was reading wrong??;)
 

naf33n

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it wouldnt suprise me. buy cutting out the rear muffler its creating less restriction. so its possible i guess
 

timcn

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has anyone else had experience with this?
 

wablacksv8

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How many runs did he do with it off? When was the original run done? If on different day results can vary depending on weather conditions. The rear muffler is only a resinator so in general they don't restrict the gases as they are straight thru. Gains can be made if the centre mufflers are changed to straight thru type or they can removed and rear resinator left in. Any gains would still only be small ,most restriction is in the cats and headers.
 

timcn

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his brother owns a performance shop with a dyno so he has access to it when ever.....he only had the car 2 weeks and put it on the dyno, it read 252.7kw, he was told to take the rear muffler out and he did,and it read 256.8kw, so i dunno what the go is...if the centre mufflers were takin out and the rear left in, wouldn.t it be too loud?
 

BLACKVZSV8

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Its possible to run a car up on a dyno 3 times in a row and have a difference of 5kw or more without changing anything. Doing seperate runs on seperate days brings even more variables into place such as temp humidity etc. Dropping a resonator could well give a small increase in power but its hard to tell on the dyno with so many other factors to consider.
 

timcn

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what exhaust should i put on my vz to get the most power and make it loud and actually sound like a roaring v8???, tri-y headers?,
 

wablacksv8

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timcn said:
his brother owns a performance shop with a dyno so he has access to it when ever.....he only had the car 2 weeks and put it on the dyno, it read 252.7kw, he was told to take the rear muffler out and he did,and it read 256.8kw, so i dunno what the go is...if the centre mufflers were takin out and the rear left in, wouldn.t it be too loud?
Think you mean rwhp or what mods have been done. 250 rwkw would amount to 320 fwkw. A stock VZ usually runs up between 190-200 rwkw(250 fwkw or around 250 rwhp). As a rough guide rwhp equal fwkw, 1kw=1.34hp and drive train losses around 25%. So multiply rwkw x1.333 to get fwkw.

And dyno results do vary slightly between runs even on the best setup one. 4hp is less than 3kw, very normal variation, most operators would be happy for consistency of this amount between runs.

With centre mufflers out it is pretty loud but because you have rear resinator you don't have as much drone as centres in rear and reso out. The cats act as a muffler a little.
 

06Calais

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20 years ago when I got my P plates, and for the next few years after that, I used to get my mufflers cut out and only run the baffles, or resonators. Mind you, the cars I had back then where no where near as technologically advanced as modern cars. I mainly did it for sound, and in some cars it would sound quite good. I dont know how back pressure dependant alloytecs, or any modern engine for that matter are, how ever Rotary's must have very carefully planned Exhaust or (Apparently) Damage can occur to the Engine. the exhaust mods I did where tolerated more by the law in those days. Now Im not so sure the law would be so kind. If you have the money, perhaps high flow, exhaust components would be a better idea, and Im hoping im right in saying they would be legal?!?!?!

Speaking of Exhaust and the fact I am 20 years into my license, im not about to just cut bits out of my exhaust like its some $500 VB commy. Can some body recommend some brand names (and fitters) of very nice sounding Alloytec exhausts. The reason I ask is because some of the Sounds I hear from V6's are terrible. I don't want that. I like a sound that resonates at a particular RPM. I hate to say it, but the old Ford 6's I used to play around with where very easy to resonate. What I mean by resonate is at a particular RPM sound waves coming through the exhaust would hit a frequency that would be "in tune" with the Exhaust pipes, causing a magnificent sound. I think the science behind it, would be similar to the way a didgeridoo works. For that matter, I imagine many musical Wind instruments would work that way too. So Id really also love to get some links to you tube or something of videos with good sounds of V6's, in particular Alloytecs.

Cheers ;)
 
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