Anyone here running exhaust straight out the back? Mine stop right under the rear bumper and I get the exhaust fumes(not real bad though). I've heard that if I run them "past" the rear bumper that will solve the problem. I also heard that they need to run a little past the bumper, but with turndowns. And a few others say NEVER run them out the back of a wagon because of the rear window, always out the sides. Can someone set the record straight? Thanks for any help!
Run them out the side in the exact same location as stock. Been there done that, and had to do it again because of exhaust coming into the open back window.
I get nasty exhaust in the car from the rear wing windows on my Roadmaster and my pipe dumps in the stock location. I only get it when I am letting off the gas as I am going down the road or a hill or sitting at a stop sign/light. Its so dang bad it makes my eyes water. Though I also get a faint smell of it when doing normal driving down the highway with the right vent window open. So I now have leave the passenger rear vent window close now at all times, really sucks balls in this heat, coz my AC does not work for squat and I am not paying to have it converted to the new stuff since we are selling it and leaving the country in March.
Unfortunately, no, someone cannot set the record straight because every shape is different aerodynamically. The flow at the back of the car is different for every differently shaped car at every different speed. Subsonic aerodynamics are NOT intuitive - a shape that APPEARS to have one flow characteristic will actually be completely different in a wind tunnel. Bottom line, run them out the sides behind the rear wheels. Rear quarter vent windows will complicate this, as noted above, but most wagons do not have these.
Yeah, I see your point Joe. Black, having no experience with the buble wagons of the 90's I can understand what you meen about those rear side vent windows. My experiences with the exhaust problem are related to 80's style box wagons. I myself put dual exhaust on my 80 Colony to only have to change the pipe location back to where it would have been stock and with the rear window down, no smell. My Crewzer and Buick, although single exhaust still, the pipe is in the stock location and with the window down (Buick) or the rear glass hinged open (Crewzer) I don't get any smell inside the car street or highway.
I ran them straight back beyond the bumper on my 88 Electra wagon...big mistake. I don't care WHICH window was open...it sucked the fumes right in big time. I heard it was the same with my 96 Cappy too. Might not sound quite as cool to run them out the sides behind the tires like the 90's GM, B bodies do but it should help keep the fumes out. I really hated to open a window in my Buick....and that's not a fun thing. Like Joe said...it is a counter intuitive thing so just run them out the sides behind the rear wheels.
Older post but Ditto, I have straights that dump under the car just before the axle, and if you open the rear hatch window it sucks fumes big time. Gotta dump out the sides like stock so it doens't get caught in the back draft. Though no smell comes in the rear side door windows.
Mine is out the left side. Only one is necessary with the itty bitty engine. Which makes me wonder. Most of the later midsize and smaller wagons had "liftgates" in the rear instead of a true tailgate. With that configuration the window did not roll down in to the tailgate thus no fumes. Also most did not have the third seat. I wonder if that configuration was just cheaper or was exhaust fumes actually considered in the equation.
I have a friend who owns a repair garage not far from me and he owes me money. (He's the one who did all the work on my CP 2 months ago.) Anyway, I was talking to him about putting Flowmasters on it, after seeing Tiki's video on his Roadmaster. He told me he'd do it and install duals as well. Claims I would pick up about 25 horsepower. I think the only way I'll ever see any of my money again is take it out in trade, so I very well may go for it. Oh, for those of you who can remember things a whole lot better than me, eventhough I took the wagon to Carlisle to sell last weekend, I didn't get any takers so she's back in my garage. I'm glad because I don't want to sell it, but bummed because I could've really used the bux.
Snooter, watch out that he doesn't go too big on the pipes. Without enough back pressure, you could lose power. I think they're 2" for dual exhaust, and 2.5" for single on a 302. Don't know what you have but its worth a check. Walker used to have an estimating calculator. http://www.walkerexhaust.com/support/support_default.asp
hmm they ought to send that one to Mythbusters. There probably isn't a forum on which that hasn't been debated.
http://www.pontiacstreetperformance.com/psp/exhaust.html The Strong Silent Type "You can build a quiet exhaust system that performs almost like open headers." By Jim Hand & Tom Hand
Wow Norm, thanks alot for the heads up. I'll definitely talk to my guy about it and see what he says. The Tiki Wagon just sounded so awesome that it made me think about doing the same to mine.
Jim Hand’s 1971 Le Mans wagon is freakin' awesome. His tech articles really helped during my build process. This one I had not seen before.
Its a good one, I whip it out any time exhausts come up. Why reinvent the wheel, just copy whats been done Though I didn't follow it all; I don't use a H or X pipe, true duals. Hate having the exhaust cross over in the way if and when other work needs done, plus I can run it tighter.
