blue2000Z28

hey just saw in a post where somebody said it has been proven that two cut-outs make less power than one? Can somebody explain why! I am going to be changing my set up and was looking at the qtp y-pipe with dual cutouts. So just let me know. Thanks

Strahley

iTrader: (4)

I don't really see why two would make less power than one. But even if it did lose some power, I'd rather have the sound of dual cutouts over a single cutout in the Y pipe. I used to run a single cutout in the Y pipe, and I hated it. A semi-local guy has dual cutouts after his headers, and it sounds great

milleniumZ28

That doesn;t make much sense to me either. I agree with Stahley the sound of true duals would greatly outweigh losing 2-3 rwhp

Order 66

Its not that 2 will make less power. It more of the price for the extra cutout and the couple of hp you get from it.

Lithium

iTrader: (47)

I have seen some dyno numbers between the two. Dual will make less power then a single in the Y. I ll try to dig up that thread...

blue2000Z28

Thanks.Im not saying your wrong, I just never figured that two would make less. I can agree with what some other guys said above, that I would rather have the sound!

Z28/2002

iTrader: (27)

I lost a couple HP on the dyno with the cutouts open on my true duals. But the only reason they are on there is for the sound

SiL3NtXWS6

iTrader: (17)

you guys are nuts. i made 6whp through dual cutouts vs a single dumped 3.5 in pipe.

GXPPOWER

they way im taking it. cutouts HAVE the most potential for power. but if your not pushing enough power it cant hurt more than help. i dont see loosing HP from dual cutouts mabe some tq but not HP. doesnt make sense. and you should see an increase in power on the topend no matter what.

i am completely stock besides the free ram air mod and a cutout. i tested the cutout open and closed multiple times. and i match my 60fts each time all were 2.07's to 2.04. yea on regular ZRI fuzion street tires at that anyhow. all the runs with the cutout closed i lost a mph and almost a full tenth just in the 1/8. when i opened it back up i would go right back to running the usually times. so cutouts do help. an a cutout will out flow any catback.

a true dual exhaust with dumps/ cutouts should net you the Biggest "potential" for power.

now sound wise. mufflers often times are actually louder than a cutout. because they resonate and reverb the exhaust which magnify the sound.

johnpate01

iTrader: (3)

That is assuming that they can be tuned for constructive interference and not destructive. The purpose of a muffler is to dampen/reduce sound

Ferocity02

iTrader: (60)

I have dual cutouts after the headers. You will lose a little low end torque, but the top end power gained is amazing, so is the sound

Sunset'01Z

iTrader: (10)

i'm no expert by any stretch, but too much flow can lead to lower torque which hurts you. a good flowing catback with headers and ypipe will give much better low end torque than cutouts will.

orangeapeel

iTrader: (18)

Scavenging is thrown out the door. It is almost like running open headers. I would put one in the I pipe and call it a day.

GXPPOWER

but in the end you gain more top end HP than you will loose low end TQ.

orangeapeel

iTrader: (18)

If you have gears then it wont really affect you too bad down low.

300bhp/ton

Some of you guys really REALLY ought to read the sticky about exhaust & induction mods (post 6, and 13 onwards ).

The reason some people see less rwhp with duals cutouts is as Orange stated you loose the scavenging ability of the mid pipe. You also affect the exhaust pressure wave, but a single cutout can also do this which is why many people see better gains with twins, but this happens less often as the odds are stacked against you with twin cutouts.

HOWEVER - if you have a good exhaust system with a muffler that flows as well as the tubing then a cutout will offer ZERO gain in HP and will end up just being an expensive volume control.

If your HP level means you are way in excess of the flow rate of 3" tubing in the I pipe then dual cutouts would help, but not because they are by-passing the muffler but because it is by-passing the tubing. This of course assumes the tubing from the collectors to the Y pipe is 3" also, as running dual cutouts would then be like running 3" dual exhausts (miniums the cross over so it will still lack scavenging).