On the trip to Carlisle this past weekend it became more obvious than ever that my nearly straight through exhaust ( that uses an Afterburner Mufffler) makes for a ride that it louder than I care for it to be.
I started experimenting with this Cool It Thermotec stuff that seems to help a bit but its only installed in a small area right now:

The label says that this stuff is good for 1100*F so its probably safe to use on the firewall
With a loud exhaust it seems like the noise is coming throught the firewall or perhaps from under the floorboard as well. One thing that is obvious is that there is no interior insulation under the center console so this may be an area to insulate. There is also an exhaust cone made by Dynatech that inserts in the muffler in pipe but it might be a litle restrictive. Claims to cut noise though.

I was just wondering if any of you have had success with quieting the passenger compartment using any particular technique.


------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 06-29-2009).]

I mad e thread about this a while back, got some useful information and very good ideas, here's the link:
https://www.fiero.nl/cgi-bin...orum=2&thread=093957

One thing I want to do, but STILL haven't for some reason, is to use spray the truck bed liner on my firewall and floorboards and double up the carpet with a set from the junkyard. Hard to find carpet that isn't wet and soggy at the yard.

Good luck with that, lol.

Is just to having a louder exhaust worth having to haul around 100pnds of sound deadeners, I roll down my windows so I can hear my loud exhaust better myself. To me it seems that is an impossible problem, you have to have the best acceptable balance. Thats like wanting a foot of snow, but a outside temp of 80*.

Just got my '88 back driving agai, after doing the interior. I used the RAAM mat - came out about the best cost vs perfomance on a couple of tests. It is similar to dynamat. Idrove the bare shell around, listened for noise, and added some wherever the noise seemed to come from. I wound up with three layers on the firewall, two on the floor, doing the inside of the console underneath all of the junk, but, probably the biggest thing that made a lot of differance in road noise - as opposed to engine/exhaust noise was the scuttle area. I pulled the HVAC unit, and pedals, etc to get access to do it right, but that whole area is one layer of really thin sheet metal. Made a LOT of differance. The other area that seemed to help was the underside of the back portion of the roof - took two-three layers to quieten it down.

I finished with some overall closed cell foam, padded up the floor level with multiple laminations of closed cell foam, added a layer of 1 lb/sq ft Mass-dampaned vinyl to the floor, another layer of 1/8" closed cell foam, then mass-backed carpet. Do a good job on the inside of the actual finish console as well, it makes a big differance.

I have not done the doors yet.

Used about 2 1/2 rolls (50' x 15") total -hated to add the weight, but I am happy with the results.

Hope this helps,

Mike

You can never overcome the fact that there is an engine behind that single-pane glass window and your ears are 5" from it.

[This message has been edited by TK (edited 06-29-2009).]

quote Originally posted by TK: You can never overcome the fact that there is an engine behind that single-pane glass window and your ears are 5" from it.

That remark certainly has merit but the exhaust noise is coming from the rear of the engine ( no turn around pipe on mine) and directed out of the dual tips. While I don't believe that the passenger compartment can ever be completely quiet with a strainght through exhaust, I do believe that some improvement can be made like Fast40 and Mordac have achieved.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by TK: You can never overcome the fact that there is an engine behind that single-pane glass window and your ears are 5" from it.

Yes, You can quiet it down.


Dennis, You need to buy 1/4" Dynaliner. Cover the area behind the seats under the carpet then cover the underside of the decklid. This will knock down the noise level by a great deal. (A little more than half volume) You will still get sound from the side grates and the actual exhaust out the back but the dynaliner does a very good job of cutting the levels down.

The Dynaliner is made for under hood applications. It is basically a high temp Dynamat.
You will need two boxes. One will cover behind the seats and one will cover the decklid.
This is the cheapest price I found when I bought mine:
http://www.onlinecarstereo....aspx?ProductID=17215

Here is my decklid:


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Happiness isn't around the corner...
Happiness IS the corner.
ZZ4 Powered !!

[This message has been edited by Oreif (edited 06-29-2009).]

quote Originally posted by Oreif: Yes, You can quiet it down. Dennis, You need to buy 1/4" Dynaliner. Cover the area behind the seats under the carpet then cover the underside of the decklid. This will knock down the noise level by a great deal. (A little more than half volume) You will still get sound from the side grates and the actual exhaust out the back but the dynaliner does a very good job of cutting the levels down. The Dynaliner is made for under hood applications. It is basically a high temp Dynamat. You will need two boxes. One will cover behind the seats and one will cover the decklid. This is the cheapest price I found when I bought mine: http://www.onlinecarstereo....aspx?ProductID=17215 Here is my decklid:

Thank you for suggesting this method and I have no doubts that it will work. However, by covering the bottom of the deck lid with Dynamat you will undoubtedy be quieting things down BUT at the expense of trapping HEAT inside. I don't know if you have done some tests or not but I would venture to guess that the deck lid lining will raise underhood temps by at least 20*F and it will have an adverse efffect there. If you disagree please explain.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

"Quieting it down" is one thing, making it quiet with a loud exhaust is another. That's all I meant.

Maybe you need to define "quiet". I have Damplifer everywhere, extra padding and a stock exhaust, and it's not quiet. It's not bad, but it's not quiet. I certainly impacted the road noise. Most of the exhaust noise is coming from the rear window.

[This message has been edited by TK (edited 06-29-2009).]

Been thinking about that rear window, especially starting on a Fino with a Finale rear deck - seemed like the sound would get worse with the enclosure of the engine area. My Audi has dual pane side windows - glass companies actually work pretty cheaply. I have had glazing laminated up for boats with a custom tint at not to much money. Wondered about having say a triple pane laminate made to replace the back window. There are some pretty impressive CLAIMS made for the sound deadning on double pane laminate windows. At least a window cut from safety laminate might help. The noise transmission numbers of acrylic are quite a bit less than those of glass -I wondered about say a 1" thick back glass of acrylic. Optically, it is pretty clear, you could rout down the perimeter if needed to fit, although that won't be a problem with the Fino. From the temp readings I have on the existing back glass it SHOULD live - although I would check a little more first.

Mike

quote Originally posted by Dennis LaGrua: Thank you for suggesting this method and I have no doubts that it will work. However, by covering the bottom of the deck lid with Dynamat you will undoubtedy be quieting things down BUT at the expense of trapping HEAT inside. I don't know if you have done some tests or not but I would venture to guess that the deck lid lining will raise underhood temps by at least 20*F and it will have an adverse efffect there. If you disagree please explain.

Actually it keeps it cooler. The hoodliner acts as a heat disperser, helping the engine stay cool by drawing the engine’s heat into the hoodliner and dispersing it more effectively. It also helps the hood/decklid so paint doesn't fade as fast nor the hood/decklid warp from hot spots. Many hoods use a hoodliner for this purpose including new Corvette's. Look under nearly all hoods and you'll see that many have hoodliners. The older cars used a fiberglass style but many new vehicles use a foam filled cardboard.

I haven't done any testing yet, But I have some data on the engine compartment temps on my car with a stock V-6 with the stock decklid and the engine compartment temps when I had my 3.4L in it with the present decklid (scoop and spoiler). I can hook up the digital temp probe again and see what I read now. The decklid was lined about two weeks ago and I haven't noticed any temp difference's yet with respect to the engines temp gauge and when the front fan comes on. The front fan switch is a 176* switch from Rodney. I should have some time next week to get actual temp readings.

[This message has been edited by Oreif (edited 06-29-2009).]

I found an inexpensive way to quiet the exhaust. I have straight 3" exhaust to 4" tip. I have a buddy who builds race bikes. He suggested I mount a couple of stock motorcycle mufflers into the tips. I tried several different ones until I came up with a 2 stroke exhaust. I had to drill several holes in each one to ensure there were no backpressure issues. Almost eliminated the lower rpm droning and it improved the sound of the 3800sc. They are simple to remove when I go to the strip.

quote Originally posted by Oreif: Actually it keeps it cooler. The hoodliner acts as a heat disperser, helping the engine stay cool by drawing the engine’s heat into the hoodliner and dispersing it more effectively. It also helps the hood/decklid so paint doesn't fade as fast nor the hood/decklid warp from hot spots. Many hoods use a hoodliner for this purpose including new Corvette's. Look under nearly all hoods and you'll see that many have hoodliners. The older cars used a fiberglass style but many new vehicles use a foam filled cardboard. I haven't done any testing yet, But I have some data on the engine compartment temps on my car with a stock V-6 with the stock decklid and the engine compartment temps when I had my 3.4L in it with the present decklid (scoop and spoiler). I can hook up the digital temp probe again and see what I read now. The decklid was lined about two weeks ago and I haven't noticed any temp difference's yet with respect to the engines temp gauge and when the front fan comes on. The front fan switch is a 176* switch from Rodney. I should have some time next week to get actual temp readings.

In theory the deck should be acting as somewhat of a heatsink albeit a very inefficient one. That is why the paint doesn't last as long on it. Now if you insulate it, that might alter the properties and result in underhood temps changing but if we are talking mainly sound insulation then only measurements will tell the story.
I am aware that many cars have and still do use underhood insulation and it does suppress sound but they are front engine vehicles so heat may not be much of a factor. While I certainly do not have any conclusive evidence to confirm higher or lower underhood temps with the Dynaliner, it would be interesting to confirm the effect it would have. At road speed when you have good air flow the effect of the under deck Dynaliner would probably be negligible. Its stop and go traffic conditions that might tell the story but again not having actual numbers I can't say.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 06-30-2009).]

Two pieces of glass with an air gap between them would help but I don't think it would be cost effective. You still have the chassis bolted to the window at the perimeter. Adding mass the the window might help unless it moves the resonance into the same range as the exhaust. Then you would have to lighten the window as much a possible. A vacuum between the glass sheets would be really nice but impractical.

About the only thing I can suggest is keep the engine and exhaust as isolated from the chassis as possible (rubber and no springs) then work on the acoustics of the exhaust itself. If you can keep the sound waves perpendicular to the rear window (and chassis for that matter front to rear), it will help some. Side dumps would look weird though.

Or turn up the stereo!

[This message has been edited by TK (edited 06-30-2009).]

Just adding my .02 cents. To lower the sound, is it really a simple matter of wrapping the exhaust pipes with 'exhaust tape'? I don't know the brand name, but I am refering to the stuff the NHRA guys uses on their dragsters (among other race applications).

Cordially,
Keviin

quote Originally posted by Dennis LaGrua: In theory the deck should be acting as somewhat of a heatsink albeit a very inefficient one. That is why the paint doesn't last as long on it. Now if you insulate it, that might alter the properties and result in underhood temps changing but if we are talking mainly sound insulation then only measurements will tell the story. I am aware that many cars have and still do use underhood insulation and it does suppress sound but they are front engine vehicles so heat may not be much of a factor. While I certainly do not have any conclusive evidence to confirm higher or lower underhood temps with the Dynaliner, it would be interesting to confirm the effect it would have. At road speed when you have good air flow the effect of the under deck Dynaliner would probably be negligible. Its stop and go traffic conditions that might tell the story but again not having actual numbers I can't say. but they are all front engine cars.

Lamborghini, Ferrari, and Porsche all use hoodliners as well (except on the decklids that have the windows.)

I plan on taking temps next Tuesday so that I can take the data when the outside air temp is about the same.
Here is the data I have from previous tests:
Outside air temp 82* Temp probe in center of engine compartment.
First temp is at 60mph after engine fully warmed up. (Ran for 5 miles on highway)
Second reading is after the highway drive and let it idle in the driveway for 5 minutes.

Stock Decklid 2.8L
60mph = 163*
Idle = 192*

Open Indy Scoop 2.8L
60mph = 136*
Idle = 177*

T/A scoop 3.4L
60mph = 142*
Idle = 182*

Four years after installation my exhaust started to lose some of it's initial appeal to me. True duals w/ mandrel bent 2-1/2 and Flowmasters sound mean as hell behind the SBC but the short pipes and resulting high flow came at the price of being ridiculously loud under acceleration. I hate to think it was my age coming into play at making the decision but I wanted to reduce the noise level to a more reasonable level. Due to my unique set up with the 40 series mufflers mounted in place of the original megaphone tips my choices were limited. I tried the Car Chemistry collector inserts at first but they made virtually no difference. About the only option I had was adding spark arrestors aka Super Trapp tips welded directly to the outlets of the mufflers. I was pretty worried about ineffectiveness and a potential ugly factor but in all honesty they did the job better than I could have ever hoped and don't look too terrible. Now I have the baffle plate stack tuned for a nice mellow note throughout the entire engine load and RPM range and it sounds amazing. It's easy to change at any time too; add more plates to increase noise, reduce plates decrease. One important thing to note is Super Trapps do have the side effect of increasing back pressure a fair amount but my exhaust was a little too free flowing to begin with for the street. In my case I have two separate modes programmed in my Edelbrock injection system - one for every day with the tips on and one for when I take them off at the track so excessive back pressure and lost top end isn't a trade off I'm stuck with.

I run the same 3" in dual 2 1/2" afterburner muffler on my SBC and 4.3 cars. The SBC is on the loud side, but I like it. To cut down some of the noise in the passenger area, I went with a double firewall by adding an aluminum firewall panel on the engine side of the firewall. Between the stock firewall and the new aluminum one I added a layer of tacmat sound deadener and a layer of thermal insulation.

One of the things forgotten is the muffler. Most mufflers are not lined and therefore transmit sound through the casing. The Magnaflow round muffler I have in the CAT position has a layer of sound deadening material around the circumference of the muffler case. This means no sound radiates out through the case.

Another issue is the under hood exhaust pipes. I sprayed mine with DEI header spray and then wrapped them in header wrap. I then re-sprayed with DEI on the outside of the header wrap. The result is a great reduction in both sound and heat.

I believe that wrapping pipes is the best sound deadener followed closely by the muffler having a sound insulation in the case.

BTW, the stock CAT is really hot and really loud.

Arn

quote Originally posted by Arns85GT: One of the things forgotten is the muffler. Most mufflers are not lined and therefore transmit sound through the casing. The Magnaflow round muffler I have in the CAT position has a layer of sound deadening material around the circumference of the muffler case. This means no sound radiates out through the case. Another issue is the under hood exhaust pipes. I sprayed mine with DEI header spray and then wrapped them in header wrap. I then re-sprayed with DEI on the outside of the header wrap. The result is a great reduction in both sound and heat. I believe that wrapping pipes is the best sound deadener followed closely by the muffler having a sound insulation in the case. BTW, the stock CAT is really hot and really loud. Arn

Lots of good ideas here on this thread but I agree that my loud afterburner muffler is because it has no internal insulation or restrictive baffling.. However, the Heddman Hot Tip resonators at the end of the exhaust pipes are like small glasspacks and are insulated. Still my exhaust is pretty loud. Not bad for short trips but a bit much on the longer ones. I believe that Orief is on the right track by insulating the deck lid and applying additional sound deadening material to the firewall interior. The question on the possible effect on engine compartment heat by the deck lid insulation has me concerned but Orief has said that he will take some actual measurements so that we will know for sure. If I can achieve a 40-50% reduction in sound I would be very pleased. We shall see.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

To understand this sound problem is kind of a musical issue like speaker cabinets.

Sound generators, like speakers or horns, or in this case small contained explosions, rely on the source of the sound, a sound conveyor (the metal or the air surrounding it), and a resonator surface.

In our case, the exhaust pipes under the hood are the lions' share of the sound generator in the car cavity. The sound coming out the tips is directional in nature and is the loudest behind the car. By way of example, roll down your windows and accellerate. Now try it with the windows up. The sound you hear with the windows up is mostly the sound generated within the cavity. (unless the tip volume is really obnoxious, in which case you are likely attracting unwanted attention.)

The engine compartment is, in effect, a resonator box. If you line the box with packing material, it is true the sound will be not coming up through your deck lid and therefore through the glass of the rear window, however, it is more the sound coming through the body into the cab that you are trying to kill. Vibrations in the metal.

The best way by far to reduce this is to insulate the sound source, namely the pipes. So, you would end up insulating the manifolds/Y/ downpipe/ and CAT. The problem is that it is almost impossible to insulate the CAT. In my case I use the muffler.

Wrapping stainless pipes is not a problem, but mild steel is. So you have to coat the steel, before you wrap.

The insulation on the firewall will help alot, and the insulation on the deck lid will help some, however, you won't get the best bang for that particular buck unless you wrap your pipes.

I hope this makes some sense and helps out a bit.

Arn

I am most interested in the solutions that insulate the firewall in the passenger cabin. Just how effective is this? Those of you who have done this with good results could you explain your solution and how it was done?

3800SC's with restrictive (aka quiet) exhausts, are no fun.

quote Originally posted by darkhorizon: 3800SC's with restrictive (aka quiet) exhausts, are no fun.

But try a long trip with a straight through exhaust and you'll see what I mean. My rumbling exhaust is great around town. I rev the pipes going though main street Somerville on cruise nights and all the heads turn. Its an enjoyable sound for cruising locally but on the highway you can hardly converse. I'd like to get the sound level down 50%.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Quiet exhausts are not necessarily restrictive. Measure the back pressure on some you think are quiet and you might be surprised at the results.

My chamber exhaust was loud, but not at all restrictive...

If you can find a 3 chamber style with plenty of baffling, you may be able to make a decent system that flows.

My friend has a magna flow full body camaro muffler, and his car is very quiet around town, but very loud at wide open.

quote Originally posted by fast40driver: Idrove the bare shell around, listened for noise, and added some wherever the noise seemed to come from. Mike

Holy crap, that's a really good idea. I never would have thought of that.... but I'm totally going to do that when I re-do my Fiero this winter.

quote Originally posted by rogergarrison: To me it seems that is an impossible problem, you have to have the best acceptable balance. Thats like wanting a foot of snow, but a outside temp of 80*.

Hah.... well put....

quote Originally posted by RyanFromMichigan: Four years after installation my exhaust started to lose some of it's initial appeal to me. True duals w/ mandrel bent 2-1/2 and Flowmasters sound mean as hell behind the SBC but the short pipes and resulting high flow came at the price of being ridiculously loud under acceleration. I hate to think it was my age coming into play at making the decision but I wanted to reduce the noise level to a more reasonable level.

What age did you notice this "change" in preference? I'm 31 now, and I was TOTALLY and completely over the loud exhaust system I had on my Solstice. I had a cold air intake, ceramic coated shorty header, and a high-flow cat. It wasn't horrendously loud, but anything over 1/2 throttle, and it sounded like I was racing... around the time I turned 30, I really started to get tired of it...

------------------
Todd,
2006 Pontiac Solstice
2004 Volkswagen Beetle Convt. (Wife's)
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6
1981 EZ-GO Xi875-A "Miami Dolphins" Medical Cart
1973 Volkswagen Type-2 Transporter
1973 Oldsmobile Cutlass Supreme 350

My system uses the Flotech Afterburner Crossflow Performance Muffler. Its 3" in and dual 2 1/.2" outs ( fairly small) and not a whole lot of baffling in there. I thought that the addition of Heddman Hot tIps resonators would make a difference but everything still roars loudly. Again its great on the street and around town but on a long trip its so loud that it makes conversations with the passenger difficult. We could change the muffler but that may cost horsepower. I will try Oriefs trick in adding a layer of Dynaliner to the interior firewall and to the roof of the trunk providing that the tests do not show an increase in engine compartment temperatures. Heat will probably not be a problem at highway speed but at idle and in stop and go traffic it could be. I believe that Orief has promised to share some test data and I hope that he does.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

I also wanted to add (but forgot to), that I recently did a rather clean and simple sound deadening job on my 73 VW Bus.

Mine is a transporter, so it doesn't have much interior. A headliner, a carpet, and two sets of bench seats, and that's it.

It was LOUD, LOUD, LOUD inside, and that's with a totally stock, BRAND NEW, OEM VW exhaust system, on a non-modified 1800cc motor.

I used "Rubberized Undercoating". I know a lot of people might have an aversion to this first and foremost, but it really, REALLY works well. Primarily, what it does is prevent reverberation on firewalls and sheetmetal. That's the biggest improvement.

On my 73 VW Bus, I sprayed it over every interior piece of sheet metal I could find. Obviously, I didn't do it to the metal parts that are exposed to the interior when the panels are put back on (IE: the A, B, C, D, and E pillar... haha), but I sprayed the inside ceiling of the roof, the floor, the side panels... everything. It took about a month (honestly) for the smell to finally subside.

But now, the interior is so quiet, and I haven't even installed any of the interior panels yet (I actually tossed out all the old panels). I can drive around with all the window open with the engine and cruising speed, and can have a conversation.


I also did this to a Porsche 944 that I restored. It sounded amazing... the exhaust was great... the interior cabin was SOOO quiet. I used dynomat, but every place that I could NOT get dynomat into, I used rubberized undercoating.

I intend to do this on my Fiero as well.

------------------
Todd,
2006 Pontiac Solstice
2004 Volkswagen Beetle Convt. (Wife's)
2002 Ford Crown Victoria LX
1987 Pontiac Fiero SE / V6
1981 EZ-GO Xi875-A "Miami Dolphins" Medical Cart
1973 Volkswagen Type-2 Transporter
1973 Oldsmobile Cutlass Supreme 350

OK, I was able to do some measurements yesterday.
Outside temp was 81* at the time.

V-8 - T/A scoop - Dynaliner on decklid
60mph = 138*
Idle = 179*

I have no idea what the temps are without the dynaliner and the V-8 so I really cannot say if the engine compartment is hotter/cooler because of the liner stuff.
But it appears to be a degree or two cooler than when I had the 3.4L V-6. Since the temps are cooler than stock and the drivetrain noise level inside the car has been reduced I'm happy with the results.

If someone is thinking of doing the dynaliner mod, If you could take temp readings before and after, let us know how it compares.


BTW ~ The reason it should cool the engine compartment temps is because the Dynaliner does not retain/store heat. The analogy of having a linolieum floor or a carpeted floor in a room full of windows. Aside from the normal heat of the sun, it would also heat up the linoleum floor and radiate that heat into the room. This would raise the temp of the room. With carpeting the room would be cooler as the carpet doesn't retain or store heat due to it's insulating/dispersing properties so no extra radiated heat would be present.

[This message has been edited by Oreif (edited 07-07-2009).]

quote Originally posted by Oreif: OK, I was able to do some measurements yesterday. Outside temp was 81* at the time. V-8 - T/A scoop - Dynaliner on decklid 60mph = 138* Idle = 179* I have no idea what the temps are without the dynaliner and the V-8 so I really cannot say if the engine compartment is hotter/cooler because of the liner stuff. But it appears to be a degree or two cooler than when I had the 3.4L V-6. Since the temps are cooler than stock and the drivetrain noise level inside the car has been reduced I'm happy with the results. If someone is thinking of doing the dynaliner mod, If you could take temp readings before and after, let us know how it compares. BTW ~ The reason it should cool the engine compartment temps is because the Dynaliner does not retain/store heat. The analogy of having a linolieum floor or a carpeted floor in a room full of windows. Aside from the normal heat of the sun, it would also heat up the linoleum floor and radiate that heat into the room. This would raise the temp of the room. With carpeting the room would be cooler as the carpet doesn't retain or store heat due to it's insulating/dispersing properties so no extra radiated heat would be present.

Those temps are very reasonable but the T/A scoop is bound to be helping out. I would tend to agree that the Dynaliner probably doesn't make all that much difference in underhood temps. Even if the deck had some small heat sink properties; as you have indicated, the Dynaliner shouldn't change that. I have Dynaliner on order and have some Cool-Tec foil faced mats here in the shop. I decided that we will try extra insulation on the firewall inner, put pieces on the deck lid and see what results.
BTW, a while back I discovered that the Fiero trunk was far hotter than those on most other cars. If I kept a cooler back there with ice in it; the ice melted faster than in my other cars. Aslo my MSD ign box was there and getting hotter than I wanted it to be. On a whim I just cut a foil faced front window sunscreen to size ( that I bought at the 99 cent shop) and placed it between the carpet and the front trunk wall. It made a big difference in trunk temps.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, 3.4" Pulley, N* TB, LS1 MAF, Flotech Exhaust Autolite 104's Custom CAI 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

quote Originally posted by Dennis LaGrua: On a whim I just cut a foil faced front window sunscreen to size ( that I bought at the 99 cent shop) and placed it between the carpet and the front trunk wall. It made a big difference in trunk temps.

Any pics of this? My trunk in the 87GT gets fairly hot also. It feels like I could bake bread in there.

Someone recently posted about using the rubberized undercoating in their VW Van. I did this in my old 89 Mustang also. Sprayed every nook and cranny. Made a huge difference in the highway drone that came from her.

What about a better louder, stereo system?

Or, Earplugs?


I agree. I ran an open exhaust for a while and for short trips and by yourself its not a problem. But, you will soon find yourself traveling alone, as my GF said she did not like the noise and you cant have a conversation in the Fiero with all the background noise. After a while its very annoying.