OK, first let me say I don't care about the thermal insulation factor (unless there are down sides)

I am thinking about this for sound damping reasons ? Thought ?

Opinions ? Experiences ? Knowledge ?

Also would like to hear about material used in thing like glasspac exhausts, can I get it, etc.... I am think of making some silencer inserts for my tail pipes

 

Hey good buddie. I've read on FA that many guys have used the dynamat to insulate their hood to reduce engine noise from the Kinetix Plenums. This has been reported to be a good fix so maybe you should check into that.

Do you still have the stock resinators in place on the intake just before the z-tube?

 

I have the Dynamat and another Brand also (m ost will arrive Tuesday) I have done the trunk and under the back seat. I am waiting for the other supplies since I will pull the seats, carpet, and sidewalls/doors - I want it to be a one shot deal.
I will also do the Hoodliner and areas of the engine compartment.

But the Stillen Exhuast resonates a good bit, and killing it where it happens would be a good thing also.

I have the stillen CAI (sealed off to prevent hot engine air, but the lower resonator is still there, I blocked it off - that offered no difference.

My goal is "the most power - with the least sound" we'll see how the whole sound damping and sound absorbing project goes.

 

ive heard that the header wrap stuff will cause your headers to crack within a year. so BIG no no.

 

I don't think thermal wrapping your headers will greatly reduce the noise. To tell you the truth, I don't even think it'll really improve your performance. I konw for turbo engines, this is definitely beneficial, mainly due to the turbo attached to the headers. But for a NA engine and on top of the fact that you don't wnat to do it for performance reasons, I would probably recomend the sound dampenign that you're planning.

That's very interesting that you're going for the most power and the lesat sound. Any reason why?

 

reason for most power with least noise is simple....

I want power, not noise... it is my daily driver.

 

If you are trying to reduce exhaust noise, a headerwrap won't do anything. The exhaust noises you hear do not come from the resonating of the metal(otherwise you'ld hear the exhaust noise at the front of your car). To reduce exhaust noise, you need to provide areas where the noise in the exhaust stream can cancel out. Chambered mufflers are the best at doing this but tend to be the poorest flowing. Exhaust restrictions tend to have a natural tendency of reducing noise. If you have the room, putting a couple glass packs of different sizes may help. This would help reduce noise at different frequencies. This will leave the muffler to have to do less dampening and it will be more effective. Especially with a straight thruogh muffler. But I doubt you'll get stock-like noise levels with any straight through design.

As far as manifolds/headers cracking, yes, they can cause this effect. It has to do more with varying rates of expansion at different points. The materials in the headers will run hotter with a wrap. This means they will expand more. However, the flange that attaches to the head will runs significantly cooler. Portions of the flage are further away from the heat source and are in contact with the heads, which run cooler than the header as well. As such, the heads will pull the heat from the flange area. This means the flange will expand less than the pipes. This tends to pult a lot of stress on the pipes and the collector. This problem is common on turbo motors that can run glowing hot quite easily. And even moreso on stainless steel manifolds since the rate of expansion is higher. Thankfully, in many cars the solution is fairly simple. If the bolt pattern does not require that ports share common studs to properly seal the flange to the ports, then you can cut the flange so that each port essentially has it's own flange. This will allow the pipes and collector to expand without restriction from the flange. Also, you can drill out the holes on the flange, progressively larger as from middle to outer holes, so the studs aren't getting in the way of expansion. This also saves the studs as they can get sheared off from expansion as well.

As far as performance, they have two effects. #1, and the most important, it helps retain the heat. This keeps exhaust gas velocity higher and more consistent. This helps to increase the scavenging effect insiude the cylinders, especially in a tuned header. #2, it lowers underhood temps. Lower underhood temps is always good as it allows a slight increase in the aircooling of the motor(which helps to make th cooling system more effective and reduce the work it has to do), keeps heat sensitive components(most of the plastics and rubber parts) happier longer, and in cases where air is drawn from under the hood into the motor, you get a denser, cooler intake charge.

 

Yeah, I could care less about any possible performance a wrap would bring, I was considering it for sound damping only.

Some of the noise is absolutely the vibration and resonance in the firewall and floorboard area. At the same time addition canceling as suggested by CKwik has also been on the list. The Stillden exhuast has a couple of pipe sections that are about 12 - 14" long, maybe I can find something could be attached there.

 

I tried to keep then temps down in the hatch in my boat by using header wraps. I just spent $2400 for new headers (twin engine) because they were cracked at the flange on the block and on the flange to the rest of the exhaust. I took the wrap off of the old ones to see whats goin on in there and they were very very corroded. The shop that builds my headers told me that the adhesive is somewhat corrosive once it gets to a certian temp.

 

Get a header wrap that doesn't use adhesive if you do this. The ones I
I've seen, you wet down to make it pliable then wrap it and then use safety wire to hold it in place. I had some on a downpipe on my last car, but it fell apart after too much handling of the downpipe. I ended up pulling it off. I'm sure it would have stayed on had I not been messing witht he car so much.

As far as the noise on the firewall and floorboard, try to determine if the noise is coming from the firewall or floorboard itself. If so, some body sound damping matrials attached to those areas might help.