If I put a cutout before the muffler will I really see 10 rwhp? Also if I keep plugging it and unplugging it is it gonna mess up my car since it is changing the backpressure etc. so much? My car is 100% stock.

 

You will see anywhere from 7-10 RWHP on a stock car with the addition of a cutout. There will be no issues with backpressure or tripping any SES codes because the cutout goes in the I-pipe so your cats and manifold is still creating backpreasure and satisfying the emmissions requirements.

In other words it's money well spent and there is no reason not to get one. I would just consider spending the extra hundred and getting one with an electric plate. It'll be so nice to flip a switch and go from loud to quiet when a cop pulls into traffic near you. You'll still be emmissions legal but local noise ordinances are another story.

Good luck

 

it will be a nice gain....definately do it.

i had no problems going form open to capped with my car.

 

I've never seen proof of how much gain you get from a cutout though.....

I got 5hp and 14ft lbs from a cat back though

 

It's about the same gain you get from a catback maybe a few horses more then some. Most aftermarket catbacks have been dyno proven to gain 5-10 RWHP over a stock setup. It's the stock muffler that is killing airflow so anyone with a catback all ready would gain very little if anything from a cutout. But a 100% stock exhaust setup will gain between 7-10 RWHP most of which is being gained because your not using that highly restrictive stock muffler any more.

Realistically if you or I added a cutout it would gain us maybe 1 or 2 horses. Hardly worth the expense. But if the guy is 100% stock and not interested in catbacks ATM then I think the cutout is a good route to go. They sound good with cats on the car. But take off the cats and a cutout sounds too raspy IMO.

 

My car has the stock WS6 exhaust with FlowMaster muffler. Opening the cutout is an instant 13 RWHP gain.

http://www.wtfba.org/dyno/

Our webmaster doesn't allow direct linking, so look for my dyno results ... "Roger Cotton"

 

I gained 6 rwhp with my cutout open and I have a Mac catback. This is also running at about 15:1 lean on the wideband due to a bad fuel pump only putting out around 20 psi. So I probably would have had better runs had I been running richer.

Also, I have heard that Flowmasters actually don't flow too much better than a stock muffler. That is probably one reason for the 14 rwhp increase, that, other mods and LS1.

 

I'm running a cutout on an otherwise stock exhaust setup. I keep my cutout open all the time. The stock manifolds and cats keep it quiet enough not to be annoying, but gives an awesome rumble