BigBadWolf

I have a 99 Formula with a Loudmouth on it. At about 2300-2700 RPM the exhaust note carries so loud in the car it is almost deafening. I could deal with that except at normal cruising speed, 65-70mph, the engine sits right in that zone. Of course if the car had a real trunk it wouldn't be so bad due to some isolation.

Would sound deadening material in the back help at all or is there something else I can do? The exhaust tips do extend out past the rear of the car.

RPM WS6

iTrader: (3)

Many people replace the resonator with a dynomax bullet muffler (race magnum). This is a very popular way to take the edge off the LM system. Not sure if any sponsers sell just that muffler alone but I know you can get it from www.jegs.com

And if you don't mind the added weight, you could always add some dynamat material to the hatch area for a tad of extra sound deflection.

shep28

iTrader: (4)

I have duals and will also be deaf very soon

Cstick

From the factory there is not sound deadning or cushion after the rear seats. Nothing but the carpet. Do a search for "Frost King". Its insulation I got at Home Depot and it deffinately helped my car quite down inside. Got 3 rolls of it and did the entire rear half of the car.

Cstick

I put insulation under my carpet starting in front of the rear seats and all the way back. From the factory there is nothing but the interior carpet for the rear half. It helped my car out a lot. Now I can drive for a while without getting a head ache. I bought stuff called Frost King insulation at Home Depot. 3 rolls did the entire rear of the car for like $35?

01TAFlyer

iTrader: (4)

So how would this frost king stuff compare to like dynamat. Would doing this help my interior from vibrating so bad?

SScam68

iTrader: (20)

Nope.

I know because I did it. Bought 5 rolls of the stuff to cover from front to back. I reduced the noise slightly. Nothing like the drastic improvement some people are reporting <shrug>. I layed 1 layer up to the rear seats and then doubled up after that.

The vibration is transmitted throughout the chassis. I've nailed all the loose stuff vibrating except for the ashtry lid. Just going to put a dab of RTV sealant to take care of that one.

It cost me $16 a roll at Lowes.

FWIW

BLASTER

iTrader: (4)

Buddy of mine used the stuff from Home Depot on his cobra and he said it helped alot and his **** is LOUD!!! Not to mention the blower whine. I think he did his whole car with a few rolls. All together cost him about 100 compared to 300-400 for the other stuff. I''m not sure if it was hte Frost king stuff mentioned above. All I know it was flexible metal on one side with adhesive tar on the other. You put in on with a roller. I think it used for a roof. Is that the same stuff?

NOBR8KSS

iTrader: (12)

The Frost King insulation has a thin aluminum backing and 1/8" "slightly" adhesive foam. It isn't like Dynomat or Brown Bread.
I used it in my car and there was a noticable difference in the interior sound level. However, it did nothing towards helping with vibration transmission. You would need a vibration dampener like Dynomat to resolve that issue.

GuitsBoy

iTrader: (4)

Really, the thing to do is add a bullet like stated above.

SScam68

iTrader: (20)

Yup.

Thing is I also removed the rear seat as well and the duals are right there. <shrug>

Spooln

Replace the catback with the ATR Pitbull crossflow. Its very free flowing and quiet.

BigBadWolf

I've heard of people using the Frost King stuff instead of Dynamat for stereo setups but didn't even think of it. Of course I would prefer the Dynamat since it works better but the cost is ridiculous.

If that doesn't work, although the car sounds really mean right now, I'll look into the mufflers and Pitbull cuz sometimes I get a headache from the sound. It's like one of those sounds that encompasses your whole body. :/

rich Z

Whatever you do don't use b-quiet material. I lined the whole trunk area and behind the rear seats and the stuff has melted from the heat. No my trunk had tar melting thru the carpet. I thought this stuff was fine to use anywhere in the car. I have seen pics of others who have lined the whole inside and no problems. My bad luck with cars.

TX Tahoe Z71

iTrader: (28)

You can pick up a bulk pack of Dynamat Extreme on ebay for about $90 plus shipping; that will cover a pretty large area. From what I've heard from stereo people, it's the best stuff out there when it comes to sound deadening.

way2slow

I just went to pep boys and they have a roll of "Thermo-cool". It has aluminum on one side and the normal stuff thats usually under the carpet in a car....the recycled looking furry carpet scrap stuff. It was 11.99 for a 4x6 roll. Much better for this application than the frost king IMHO. I havent put my roll in the car yet so I dont know if it works but I am also looking to kill some of the sound of my true duals.

01TAFlyer

iTrader: (4)

Post how it turns out. Also are your duals out the back, or dumped at the axle?

way2slow

Mine are dumped at the axle. I doubt it will help a tremendous amount but it was cheap, it says it deadens sound on the package, it isnt very heavy at all, and there is a picture of a 93-97 camaro right on the package. Probably won't get to it until next weekend but I'll post up when I do.

DCZ_98TA

i have bullets as my mufflers..........but it comes all the way out the back, so alot of the sound doesnt come inside........lol.

TheBowtieboy

iTrader: (6)

Hehehe.....that "noise" that you're hearing is a drone that is caused by the LM's so called resonator (enlarged hollow pipe). I had the same issues with both of my '99 Z28's and on my '00 WS6. To me the weight and performance were more of a factor as I autocross (or I too would have replaced the resonator).

Good luck !