I'm trying to make my car a lot quieter than what it is. Car makes well over 500rwhp. cam is 257/263-65x/65x. Car has 3" true duals with bullits and dumped. No cats. I'm installing dual 3" e-cutouts off the longtubes then basically into a stock style exhaust. Dual 3' into a wye then single 3' over axel into a magnaflow single in dual 2.5 out into dual/dual tips. My car sounds like a full blown Nascar right now. I've had people come running out of Arby's when I was in the drive thru because they didn't know what was rattling Arby's windows. I can't run cats because off all the overlap on my cam plugs cats. I've got the parts for the stock style exhaust but I was wondering what the sound difference would be in running dual 3" under the axel into a dual inlet dual outlet muffler if the sound would be much cleaner with no rasp. How much rasp will I have on the wye exhaust? Also on the stock wye set up how much noise reduction would i get if I could stuff a spiral flow or sweet thunder in the I pipe. Is one stock style muffler enough to quiet this car down? I like my car to be loud hence the dual cut outs but my car can be heard a 1/2 mile away. This attracts way to much attention. I like to get my race in then be able slip away into the night without every cop in a 1 mile radius being able to track me down.

 

Get rid of the bullits and to get rid of the rattling have the exhaust go all the way out the back.

 

The exhaust is going to go out the back into a stock style magnaflow muffler then into dual/dual tips. I don't know if this is going to be enough with just one muffler and exhaust out the back.

 

It will definitely help. You might want to even put a borla Xr1 style muffer after the y pipe.

 

If I ran 2.5 or 3' duals with a spiral flow on each side under the axel then into the stock muffler would this have a better sound then the wye? It should be quieter. I have to sneak back into my neighborhood at 3 or 4 Am on the weekends.

 

Don't know, yeah should be quieter.

 

Get some speed, turn off car and roll thru neighborhood, open garage and good to go.. LOL

 

Funny but true! Thats exactly what I do. Until I came cruising up my driveway dead stick to find my kids bike laying down in my parking spot. Neighbors will usually state that I had a 'late night" the next day when we meet at the mailbox.

 

I dont have a 408.. But, with a 4K stall and slowly creeping into the garage spot at ~1 in the morning (I work a 2nd shift) it does get loud when I take the car to work.

I think I took it to work ~5 times last year as its just too loud for being 1am in the morning.

I have my truck that I drive all the time soe its not that big of a deal though.

 

I am kinda in the same boat, I have a 396 with 12.2:1 comp. with 1 7/8 Kooks and strait 3" duals into 40 series flowmasters and it sounds great but dam its loud. I am thinking about a Borla catback

 

You could try running it out the back and putting some sprial flows or twisters before the exhaust tips.

 

I had LM ORY LTs, went to LTs with stright bullets and dumped.. I got compaliants all the time.... This was with the LS1

Then I got head/cam installed and got a magnaflow catback with a bullet in the I pipe... it was pretty quiet.

too bad now Im going with a 402, Im probably gonna be restricting flow whereas before with the dumps I was probably too free flowing for he hp I was making(bolton car at the time)

 

i have the hooker catback on a 500+ rw car and it is alot quieter than duals and only lost 6 rwhp compared to a single 3" cutout, maybe pick up alittle more with dual cutouts so lets say 10 rw loss with a decent 3" single catback. i think the magnaflow will quieten you down quite a bit also.