I have an american thunder system on my 88 transam with a newly built 305 tpi motor.It sounds nice and deep at idle and roars at WOT.If i gut the cat will it be too loud or will I not even notice.50 series muffler by the way.Thanx for any help.

 

If you gut the cat, and leave the muffler on, it will still be louder in my opinion. I had the cat off a stock 85 Grand Prix, and i thought I would go deaf. The neighbors came out to see what the commotion was. By putting a muffler on it, it wont get much quieter than "extremely obnoxious loud." I love loud, but when i lived in jersey, the emmissions were too tough...so i had to spend $280 on a Random Tech cat. I have a 2 chamber flowmaster with that cat on there...and it still sounds obnoxious...like it has headers. So either way, it will be next to deafening.

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1986 5.0 TPI Trans Am
Random Tech Cat
Two Chamber Flowmaster Muffler
Megs Custom 4.5" Stainless Steel Tips
1999 Grand Am GT In-Dash CD Player w/Equalizer(fits like '86 original)
5% Tint On Rear, 35% On Sides

[This message has been edited by PhantomTPI (edited March 28, 2001).]

 

Yes w/o the cat it sounds like you have this massive powerplant, its very decieving

 

i have an 84 Z28 with gutted cat and no muffler. WAY TO LOUD. my other car is an 85 Z28 with 80 series flowmaster and gutted cat still WAY TO LOUD!!!!!

 

I have no cat and the stock muffler and its not that loud at all and sounds great

 

car only has 25000 miles on it thats how its the stock muffler

 

Anyone else??

 

There are couple of things to note with gutting the cat. The actual exhaust note should only increase a small amount, it is not designed to be a muffler or to effect note. However, since it does have material the exhaust flows through it does effect the volume. If you gut the cat and leave it alone chances are it will be much louder. The reason is that you have left a big chamber for the air to bang around in and then have to choke back down to a small pipe. This will not only offer and very annoying sound, but actually add backpressure. The best way to do this is to gut the cat and place a pipe inside that matches you exhaust so that it will be a continuous flow back to the muffler. Doing it this way will only make the exhaust a touch louder, good luck and have fun.