S2002S

We spend extra $$ for smooth, mandrell bent exhaust system components. Has anyone seen any data on the affect of the turbulence/affect on flow caused by the presence of cutouts (when they are capped)?

LS1derfull

This is a good question, i havent done testing but most electric cutouts appear to restrictive to flow when butterfly is open because its too small and not conducive to flow. As for flow when closed i say it would act like a accumulator or resovoir pocket and probably doesnt affect or hurt flow at all.

Blk98Bird

I'm not 100% sure but I think there was a post on this quite a while back. From what I remember it was concluded that the cutout basically acts as an accumulator when closed (ie what LS1derfull stated) and only has a minimal affect on flow when open. Something like a ~1-2 horsepower difference at best because of the high velocity of the air as it's exiting.

I could be wrong though, this is just from memory...

Blk98Bird

Forgot to add...I think the issue of a flow restriction elsewhere in the exhaust is more of an issue because there's more of an overall impact. Aka, if there's a bad bend real early it negatively impacts flow for the entire rest of the exhaust gas' path of travel, whereas with a cutout the gas is basically at the end of it's path. Just a theory

WILWAXU

iTrader: (6)

That "flow disturbance" is well worth whatever it causes when you open it up

S2002S

Thanks for the info, but I don't understand the affect of an "accumulator" in the exhaust line.

I'm wondering if I'll be paying a flow penalty for the 90% of the time when the cutouts are capped.

Colonel

"I'm wondering if I'll be paying a flow penalty for the 90% of the time when the cutouts are capped."

No. If there is a penalty, it would be so small that you couldn't prove it on a dyno. That extra path is filled and therefore plugged with air. Think about it. The air in that part will actually act as a wall to guide the moving air on by. That's what was meant by an accumulator.

And yes, the farther away from the engine a restriction is, the less effect it has. Why? Because the exhaust cools and shrinks as it moves away from the engine.

Blk98Bird

Colonel pretty much took the words out of my mouth . Basically, the hanging piece of the cutout would "fill up" with air and exhaust gas, thus putting the remaining gases back on a linear path.

edit: bottom line you'll gain a lot more than you'll lose with the cutout so I wouldn't too much over it .