Interior noise level

[harshman]

Gentlemen,

I am new to this forum and I had a question about Ultimas. I'm looking to sell my '68 Camaro and buy an Ultima but I wanted to know what is the interior noise level on average? Judging by the layout, I'm guessing it is a bit loud.

andrew

[lvjost]

Hey Harshman,

An Ultima GTR usually is built by yourself, that means it´s up to you, how you work out the interiour, which exhaust system you use etc... Hence the noise level is very depending on your work and choice...
I made a sandwich inclosing the back rollbars between 2 alloy plates fitting a 5cm of sound proofing in it and I had to use (damn!) the orig. GM 400cells Kats, which also kills a lot of noise (Germany restriction...)....If you like a GTR to run in "silent mode", you could add another noise reducing layer between engine bay and pass. cabin....

So it´s up to you to get it at a noise level you like. But at the end of the day it is a fascinating super fast exotic sports car....and so it´ll never reach the interiour silence of a mercedes 600 :-)

Regards

Lutz

[harshman]

Agreed. I know it will be built by me I just didn't know what came from the factory and what I needed to supply. I didn't see any carpet or any sound related products in the kit and I figured I needed to quiet the car a little. Thanks for the reply.

[steve_d]

The factory ethos for the car is very 'stripped out racer' so little attempt has been made to sound deaden. Many builders have done their own thing. In my case I have skinned the roll cage and included sound insulation. The skin is only bonded on as rivets may reduce the roll bar strength.
There are gains to be had by changing the exhaust system as mine is loud at 104db.

Steve

[GTWayne]

There is no carpet or sound deadening supplied in the kit so you will need to sort it all yourself. Personally, I am not to fussed as I will wear ear plugs if necessary but I must say, it would not have been a bad idea to have fitted insulation to areas during the build when they were easier to get to and gauge the situation from there and retro fit sound proofing material later if required. Remember, if you want effective material it will likely be heavy, and that is something you don't need.

[gt_bambi]

I wanted to make sure that the car was nice to drive, on long distance's (Le Mann’s)
So I fitted the same as the STIG it comes from www.woolies-trim.co.uk and sticks in place, great stuff, but it is quite heavy.

[harshman]

I'm wanting to quiet it for longer drives.....with the wife....the one who will help me purchase the car. The weight added in a small cockpit will not be noticeable as I am very confident in the superior performance of this car.

[GTWayne]

If that is the only modification you intend to make then yes, you are quite probably correct, but in my experience it does not end there and although you are correct in what you say it may just be worth keeping an eye on it as it can quickly escalate. My car is almost done now and I already have further plans to make it lighter in certain areas and I have not even driven it yet!.

[luckyp]

I did a lot of research into sound and thermal insulation. I fitted a three layer sandwich of fireproof,insulation and damping materials direct to the bulkhead (cab side) and every available panel cavity.

I did a 900 mile run a couple of weeks ago with only 6, 10 min stops. Hand on heart I can say that the NVH was perfectly acceptable and conversation at cruising RPM is perfectly possible.

Pete

[lvjost]

I´ve made the same experience as luckyd...When cruising with 2k-2.5k Rpm a quite "normal" conversation is possible..above that, :-)

To harshman: I don´t think one has really to worry about the weight. I´ve an A/C, 18 square meetres of leather, lots of carpet, the mentioned "insulating" bulkhead construction....and the car with all tanks filled and engine oil and gearx box oil incl...is 1053 kg.... I think that´s quite o.k.

[GTWayne]

If you are happy with the weight of your car then that is fine but the fact that less weight will accelerate, corner, stop and need less power to do it all surely has to be more appealing and economical, it's just down to the individual to decide what compromise if any is to be made, after all, is that not part of the fun?.

[harshman]

Trust me, I am well aware of what weight can do for handling. My car weighs 3,500 lbs. My point is that the Ultima's performance records are so superior to most other cars that another 50 lbs of sound dampening material in the cab will not affect handling enough to worry about it. It is a preference thing.

[stig]

harshman said:

Trust me, I am well aware of what weight can do for handling. My car weighs 3,500 lbs. My point is that the Ultima's performance records are so superior to most other cars that another 50 lbs of sound dampening material in the cab will not affect handling enough to worry about it. It is a preference thing.

It's a simple equation really.

1) If you want a stripped out, noisy, hot, harsh environment where everything promotes performance to the detriment of the occupants, then don't insulate.

2) If you want to actually be able to drive the car regularly, for long periods, without going insane, fit it - to what extent is up to you.

As you say, the impact on the car's weight is negligable overall. I'd be incredibly suprised if you could feel a difference short of timing on a track and even then, it would be a matter of 10ths. But you'll make a far more noticable difference to the driving experience if you make it more driver-friendly.

[stig]

Also worth remembering that a lot of the noise comes into the cabin from the roof/screens. Not alot you can do to insulate against this.

You can still achieve very comfortable levels though. You can comfortably hold a conversation without raising your voice in my Can-Am at 80mph

[luckyp]

I reckon the noisiest things in the GTR are the mirrors and the helecopter vents. I might try taping over the vents to see what difference it makes.

[GTWayne]

That's interesting P as I have chosen not to have the helicopter vents as I think they are hideous although if I feel them an absolute essential once the car is operational, I will retro fit them. I must say, Ultimas I have travelled in to date do not seem to have suffered from wind noise caused by the vents but I didn't specifically look for the problem. What type of sound proofing/noise insulation did you use on the inside skin of the bulkhead as since contributing to this thread I have been persuaded that for the small increase in weight, it may not be a bad idea to install some, but we will see.

[stig]

GTWayne said:

That's interesting P as I have chosen not to have the helicopter vents as I think they are hideous although if I feel them an absolute essential once the car is operational, I will retro fit them. I must say, Ultimas I have travelled in to date do not seem to have suffered from wind noise caused by the vents but I didn't specifically look for the problem. What type of sound proofing/noise insulation did you use on the inside skin of the bulkhead as since contributing to this thread I have been persuaded that for the small increase in weight, it may not be a bad idea to install some, but we will see.

Most of the heat will come in from the sides (from the send/return pipes going to the rad) and backwash from the radiator from the front. No bad thing to insulate the rear/front bulkheads, but sounds like you've missed the boat on the sides.

I believe you've got aircon Wayne, so it shouldn't be too bad.

[luckyp]

Wayne,

Well - yes, that'll be very interesting to hear your car without heli vents. I take it you are air conin' if no vents yeah?

When you come over I'll show you the insulation I used, although I promised the remainder of it to another PH dude so if you wanna see it you better be quick!

Anyone else think that the GTR mirrors are noisy?

LuckyP

[gtrclive]

Jeeps if you can hear the mirror motors you must have good hearing.....

[k wright]

I'm wearing earplugs when driving.