Jan 12 Report post Posted February 5, 2016 Hi, When driving my 69 Sportsoof the air pressure in the cockpit builds up. This is quite annoying and the only thing to do is to open the window a bit. This is acceptable at low speeds but quite noisy at highway speeds. I believe the 70 model has a “vent†at the bottom of the b-post on each side to let air escape. I was wondering if anyone has done this mod on a 69 and what the result was. Thanks Quote Share this post Link to post Share on other sites
MikeStang 247 Report post Posted February 5, 2016 Ha.. I never have pressure build up because the damn window to upper weather stripping seal is a constant leak haha. Are you referring to the kick panel vents? Quote Share this post Link to post Share on other sites
Mach1 Driver 560 Report post Posted February 5, 2016 huh, I've never seen it and a search didn't turn anything up- somebody got a picture? Quote Share this post Link to post Share on other sites
Grenadier116 24 Report post Posted February 5, 2016 The '69 b-post looks to be the same as a '70, just without the opening. If originality is not a concern, you could probably make a template from a '70 and cut the opening in yours. Installing the grills might help relieve some of the pressure build-up. There must have been some factory provision for airflow in the '69's but I'm not sure how it works. Quote Share this post Link to post Share on other sites
Brian Conway 264 Report post Posted February 5, 2016 Just open the kick panel vent ? Brian Quote Share this post Link to post Share on other sites
Jan 12 Report post Posted February 5, 2016 The problem is not getting the air in, it is getting it out. There is actually no way air can escape. I presume that's why the vent was introduced in 70. Quote Share this post Link to post Share on other sites
Jan 12 Report post Posted February 5, 2016 I found this pic on the web, not too good but shows the opening. Here's a link showing to the vent grill. http://www.eddiemotorsports.com/product/interior-parts/1970-1973-mustang-door-vents-prmachined-finish/ so you know what I am refering to. Thinking about making this opening to release pressure. Quote Share this post Link to post Share on other sites
MikeStang 247 Report post Posted February 5, 2016 Aaahhh in the door sill area. My car doesn't build pressure inside, despite everything being lizard skinned and Dynamatted LOL... Not sure why it don't tho Quote Share this post Link to post Share on other sites
RogerC 136 Report post Posted February 6, 2016 I always noticed how well he kick panel vents flow with the windows open and not so good with the windows closed. I'm with Jan, ford probably added the B-pillar vents in 70 to help the airflow from the kick panel vents. Quote Share this post Link to post Share on other sites
barnett468 418 Report post Posted February 6, 2016 The problem is not getting the air in, it is getting it out. There is actually no way air can escape. . Sure there is, just open the rear vent windows. Quote Share this post Link to post Share on other sites
barnett468 418 Report post Posted February 6, 2016 Just open the kick panel vent ? Brian That will increase pressure. Quote Share this post Link to post Share on other sites
Brian Conway 264 Report post Posted February 6, 2016 Well I guess I need to admit that I haven't a clue what this ' pressure build up ' is you guys seem to be so familiar with. Quote Share this post Link to post Share on other sites
Jan 12 Report post Posted February 6, 2016 For me it feels like the pressure rise works like a parachute putting increased drag on the car. I found a pic of Allan Moffats 69 Trans Am Mustang which has two openings just in front of the deck lid which I presume is to release pressure. Also note the two bars holding the rear window in place.Anyway I think I will make the opening in the b-post as next winters project. Quote Share this post Link to post Share on other sites
Mach1 Driver 560 Report post Posted February 6, 2016 Jan, I wonder if the "outside recirc door" in the heating system is stuck open? Look at this link: http://www.mustangandfords.com/how-to/interior-electrical/mump-0409-ac-repair/ Under Vacuum Actuated there is a diagram that shows the door Quote Share this post Link to post Share on other sites
fvike 173 Report post Posted February 6, 2016 I always thought the '70 B-pillar vent was there to prevent rust in that area. The vent would be on the other side of the door gasket, so I don't see how it will relive pressure in the cabin? Quote Share this post Link to post Share on other sites
RogerC 136 Report post Posted February 8, 2016 FYI, I'm providing air exhaust at trunk drops via ducting to tube behind wheel well in pic below. A little elaborate maybe, but unique & functional. Quote Share this post Link to post Share on other sites
Jan 12 Report post Posted February 8, 2016 This will definitely work, and at the same time prevent water entering the trunk. I always thought the '70 B-pillar vent was there to prevent rust in that area. The vent would be on the other side of the door gasket, so I don't see how it will relive pressure in the cabin? Fvike, the trunk also gets pressurised which presses air forward over the rear wheel well towards the b-post and escaping outside of the rubber door gasket. This location is fairly well protected from the elements and together with the “grill†prevents water entering. Barnett468, opening the rear vent windows is the same thing as opening the door window = noise. When you think about it the only provision Ford make for air escape in 69 was the rubber “check valve†on the trunk drops just under Roger’s pipe. Quote Share this post Link to post Share on other sites
Vicfreg 773 Report post Posted February 9, 2016 The 1970 Mustang Sales Flyer for dealerships notes the changes for 1970 with the flow through ventilation. Quote Share this post Link to post Share on other sites
fvike 173 Report post Posted February 9, 2016 Cool stuff. Never knew that. But where's the pressure-relief valve located? Quote Share this post Link to post Share on other sites
Rsmach1 71 Report post Posted February 10, 2016 Nice find Vicfreg. Quote Share this post Link to post Share on other sites
Ridge Runner 1,113 Report post Posted February 10, 2016 It is a plastic louverd vent in the b pillar with a rubber flapper in it if i remember corectly ,been a while since i worked on a 70 .It should be easy to fit to a 69 if you had the placement from a 70 to go by . Quote Share this post Link to post Share on other sites
fvike 173 Report post Posted February 10, 2016 So the vent is the valve. Come to think about it, you don't need a '70 to find the placement of the vent. Quote Share this post Link to post Share on other sites
Jan 12 Report post Posted February 11, 2016 At last I found a good picture of the vent. I have tried to find someone that sells these vents/grills without success. NPD usually has everything but not this piece. Quote Share this post Link to post Share on other sites
Mach1 Driver 560 Report post Posted February 11, 2016 D'oh, I finally looked at the door seal and figured this out. The door seal is inboard of the vent. Air comes out of this thing and exits from the crack around the door. Jeez I had it bassackwards. Quote Share this post Link to post Share on other sites
SWPruett 83 Report post Posted February 11, 2016 I think Eddie Motorsports makes the only "replacement" to these vents and they are machined billet pieces. I have always wondered why someone hasn't made decent repros of these after all these years. Quote Share this post Link to post Share on other sites