Thanks guys.

 

Really???? That switch itself will actually gain 10 hp (RWHP!). Is this on stock car or mod??? I would be interested in that number.

 

To clear a few things up, its the 80 series or crossflow style Flowmasters that sound like *** and don't flow very well. They use these exclusively for our cars in the single in dual out configuration. The 10, 30, and 40 series Flowmasters sound awesome and flow very well. You can buy a single in/out catback from Flowmaster for our cars that uses a 40 series muffler, and it sounds great.

 

It has been demonstrated that the Flowmaster catback for an F-body is good for about 5rwhp less than stock. I believe this was on an LT1 F-body. Not sure about their LS1 kit.

It has also been demonstrated that pretty much every other popular F-body catback, including Magnaflow, is good for at least 5rwhp more than stock. This is true for both LT1 and LS1 cars. The straight-through muffler designs (Corsa, Borla, and Dynomax; maybe others that I'm not aware of) offer the best gains. Magnaflow is decidedly better (in terms of flow) than a Flowmaster, but I'm not sure where it falls among your other options.

On an otherwise stock LS1, Borla and Corsa catbacks typically gain 10-15rwhp over stock. I'm not sure what numbers can be expected on an LT1, but I would be surprised if the gains were significantly different.

As far as I know, the Flowmaster disadvantage only gets worse as you modify other parts of the car.

 

Previous posts on this subject have said on a modified Lt1,that the power loss was 40 H.P.(blown).Leave the slowmasters to the big suv's,.They seem to think it sounds great,even though thier gas mileage is suffering,and are soo common.Beer time.My02.

 

Something doesn't seem right when you are paying money to lose power.

 

Yeah, that's what I was saying. The more power you add, the more the restriction is going to be a problem.

I completely agree; that's why I'm saying he should get rid of his Flowmaster! With a 4th gen F-body, Flowmaster is about sound and attitude, not horsepower.

 

The Flowmaster catback itself is a decent design and that is why i am just changing the 80 series muffler for a Hooker Aero Chamber.My first choice was the Hooker c/b but there was a backorderin(2000)so i got the Flowmaster instead.I want something w/less resonance on highway and quieter at idle,not to mention better flow.

 

True -- it's just the muffler that's the problem. Any 3" mandrel-bent pipe is going to perform pretty much the same. They all route the same way anyway!

 

I've cut apart a 80 series to show one of my buddies why they are such a restriction, and I wouldn't be surprised if it were more than a 5hp loss. I believe your higher end catbacks are the ones that get the best gains like you said JakeRobb, Magnaflow and SLP are the in-between types netting you a 5-7 hp gain while the corsa and borla more like 10-15 hp. It all changes with cats, and no cats...w/ a 3-5 hp gain there.

 

I just put the magna on my 94z and love the sound like everone has said that are using the magna it is quite at idle and putting speeds but sounds good at wot. i will never go back to that crapmaster sound. Plus the noise reduction has brought out noises that i could not hear before. good luck.