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Sands

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About Sands

  • Birthday 10/31/1972

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    Iowa
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    Systems Egnieering Manager

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  1. Paul - yup right on. Forgot to talk about the whole cast vs. drilled. thanks IMHO, cross-holed (I'll be generic) just isn't worth the hassle or expense. It's a total PITA to do cirlces in the parking lot waiting to cool the brakes down.
  2. SS lines will also have much better modulation and pedal feal then rubber lines, but only at or near threshold. The caution with SS lines is that dirt can work their way between the braid and the hose under it, causing abrasion and potential failure. This will be a slow process and requires periodic inspection of the lines for weeping. Not a big deal if you pay attention to them. If you are tracking your car, you should be doing a brake job before and after to change pads. This is a good time to do this. The other caveate is that SS lines are often not DOT approved, which can cause issues if you get into an accident due to brake failure. As long as the lines have not failed, there shouldn't be an issue, but forwarned is forwarned. Personally, I am willing to take the microscopic risk for the benefits SS lines bring. Oh, my suggestion on the fluid is not in dispute with the orginal post. I'm making the suggestion to make it easier to bleed brakes.
  3. I disagree on several points. Cross drilled rotors WILL crack if driven on the track. Bad idea. I've never seen a set of cross drilled rotors not crack, but then most track cars don't used cross drilled rotor because they crack. Stainless lines are probably one of the best bang for buck upgrades for a track day. Above 8/10th brakeing effort, your pedal will be linear. With rubber lines, your pedal will require esponentially more force to stop at the same rate as with stainless lines. They do not require uprating your master cylinder or calipers to have an effect. For fluid, I alternate between ATE Super blue and ATE gold. The color change makes it easy to tell when you've changed out fluid.
  4. It's actually good for the AC compressor to run periodically, even in the winter. It keeps the bearings happy in the compressor and it moves the refrigerant around the system so that any condensation can be taken out by the dryer. (Most cars will turn on the AC when you turn on the front windshield defrost anyway, not sure about the Legacy though)
  5. I posted this over on ImprezaWRXSTI: Some information on sound and vibration that some of you might be able to use. I've noticed that a lot of folks who apply, or paid to have applied, a Dynamat type product are getting a bad deal. They either just don't know how noise attenuation works or they are maximizing profits. Here's a semi-technical explanation, from a Master's level Mechanical Engineer, on the proper way to install the stuff. There are two ways to attenuate noise in a car. 1. Sound wave Absorbsion 2. Resonance reduction Absorbsion This is when you have a fiber batt that actually traps and prevents sound waves from propogating. The thicker the batt the lower the frequency that will be absorbed. Thin batts absorb high frequencies. (The thickness of the batt absorbes up to the freqency that is 1/2 the wavelength of the batt thickness) The denser the batt, (normaly ~5 times as dense as fiberglass insulation) the more of the frequencies that are to be affected are absorbed. So dense, thick batts will absorb the most sound. Body cavities or deap space will collect and potentially amplify the noise, much like a wind instrument or guitar. This is where this stuff works best. Resonance Reduction This is what Dynamat and its clones are trying to do. Every panel in the car will have a natural frequency that it will vibrate at then excited; Doors, firewalls, pillars, roofs, etc. simply: Frequency = SQRT [ Stiffness / Mass ] Dynamat essentially adds mass to the panels to alter the vibration charateristics of the panel. They also break up the standing vibration waves in the panels. (denser the better) It doesn't really add stiffness, unless you make a structure and glue or bond it to the panel to increase the cross sectional area. This is the main acoustic differnce between the tinny sounding doors of a stock subaru and the bank vault doors of a lexus. What does this mean? You don't need to plaster the entire inside of the car with dynamat. Simply put 1-2" strips of the stuff over about 20-30% of the surface of the panels, in a chevron, or checkerboard pattern. This will get you 95% of the sound improvement of a full application without all that wasted mass or expense. (Dynamatt is EXPENSIVE!) In the body cavities (firewall, behind the cosmetic peices in the trunk and package shelf, etc.) is where you want to put the batt. This will prevent a megaphone effect. You can also get a drum effect, where a closed cavity (trunk) will make a panel (seat back) vibrate. Applying either one will work there, although Dynamatt is normally easier. The batt will also stuff between a hard structure and a cosmetic panel to keep the panel from humming (like the rear parcel shelf) All strips should be about 1-2" wide, AT MOST So, for the most cost effective solution I would: 1. Chevron the interior wall of the door skin with about a 20-30% surface area application.2. Put a few strip on the interior door structure around the speakers. 3. A few 1-1.5" strips of the stuff on the rear shock mounts from floor to top in sort of a spiral pattern. 4. A few strips on the underside (or topside if you remove the cosmetic shelf) of the package shelf. 5. A few diagonal strips on the rear seat back and the structure around the shock towers. 6. A few strips in the trunk bottom and side walls, but not too much. Probably 20-30 square feet AT MOST for all of this. (it goes fast) Which will add like 6 pounds to the car. This should get you 90% of the benefit of a full application with minimal cost and added weight. If you are brave you can take out the headliner and the dash to get to the firewall. An X or >> pattern in the roof would be enough. Adding two, 1", strips in an X or // pattern under the carpet in each footwell won't hurt either. If you think you can quiet it down more, you can always add more later. But there is no sense in plastering the whole car with $200 of dynamatt if $50 will get you 95% of the benefit. These guys have the products I'm talking about, but I have no affiliation with them, nor have I purchased from them. http://www.b-quiet.com/index.html Sorry, I don't have pics, but I've done this on 3 cars so far with outstanding results.
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