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Can a rear spoiler reduce exhaust fumes?


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Since Pete invited a response, I shall oblige. It is rather awkward to attempt to “instruct†anyone, but I will try to share some thoughts I had about the Z’s aerodynamics. A proper explanatio

There is a clear path for fumes to enter the car. Up the "hatch latch hole" and into the cabin through the vinyl panel under the hatch. The vinyl panel is no where near airtight. Remove the vinyl panel, put a bead of sealant around the opening, seal off the opening with a sheet of plastic, reinstall the vinyl panel. This eliminates one more path.

 

 

-Does someone have a picture of this?

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This has been addressed a couple of times..about a yer ago. Was it Mark(?) who said the rear spoiler did in fact reduce the fumes from entering the rear? Must be a common problem. I get sick from the stuff too. My hatch could use some tightening.

JS

 

True. A rear spoiler will reduce the fumes from entering the vehicle.

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if the rear spoiler is mounted to the hatch and the hatch only i would assume that the bulk of the downforce added would be on the hatch thus sealing it better. that might be why it helps with some and not others it may have very little to do with the spoiler delaying the wake behind the car. people have reported that it helps greatly and also that it doesnt help at all but have not shown how the spoiler was mounted.

 

just a thought.

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Odd question, but it comes to mind. I'm thinking adding something to the gas that will make color fumes, like green, red, or something else(I saw this on a drift video before, but for fancy reason) This way, I can at least visible trace where the fumes is coming to the cabin. Does anyone have any experience what I can add to gas produce color exhaust fume without damaging the car? Thanks.

 

Ed

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Exhaust velocity at the tailpipe might also be at play here.  I find that you get MUCH more stink when driving at part and low throttle.  I think that at high engine loads, the exhaust stream is fast enough to get mostly out past the tail-wake.  When the exhaust is moving slowly, it gets mixed into the tail-wake and swirls around the rear quarter of the car..

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So, for anyone who wants to take a shot at the actual vacuum caused at the back of your car, I learned this by simple experience. I was driving my 78 a few years ago, and apparently didn't catch the latch on my back hatch. It was shut, it just didn't 'click'. When I was going 90-110 (it was a few years ago, so I'm not sure exactly what speed it was at) the hatch popped WIDE OPEN. ALL THE WAY. I even have good working OEM gas struts on it still, and it POPPPED right open. So, if you take a force gauge (or put yourself on a scale, and see how much more you 'weigh' when you're opening the hatch lid, then see at what speed your hatch opens, that will tell you how much 'upforce' you have at a certain speed. Comparatively, with the addition of a spoiler, the force to open the hatch may increase with the weight of the spoiler, but the speed at which it opens should hopefully be MUCH greater than it was before. Any takers for a some high speed test runs?

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One thing I didn't see mentioned was a rear window louvre in terms of the aerodynamics. Would a louvre provide enough edges in the contour to break up the airflow over the hatch? Maybe enough to relieve some of the lift or even eliminate the exhaust fume circulation?

 

My Louvre is currently off because it broke when the car was getting transported. Before that, I never remember having fume issues, but now that it's gone suffer from all the noted symptoms. Once I can source a new louvre that's not a totally ridiculous price, I can post my results.

Edited by Twistedlizard720
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This is a really old thread.  But I can tell you that with the window louvers on, my hatch (if not locked down) will open at exactly 80 mph.   That was before adding the spoiler.  I have tested this with the hatch unlocked since adding the spoiler.  No more opening and losing loose papers all over the interstate.

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This is a really old thread.  But I can tell you that with the window louvers on, my hatch (if not locked down) will open at exactly 80 mph.   That was before adding the spoiler.  I have tested this with the hatch unlocked since adding the spoiler.  No more opening and losing loose papers all over the interstate.

Added weight of the spoiler at the rear edge of the hatch, or downforce generated by the spoiler, or both?

Dennis

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This is a really old thread.  But I can tell you that with the window louvers on, my hatch (if not locked down) will open at exactly 80 mph.   That was before adding the spoiler.  I have tested this with the hatch unlocked since adding the spoiler.  No more opening and losing loose papers all over the interstate.

 

Ha ha, YES!  I'm glad I'm not the only one this happened to. I don't think I had my louvers on yet, but I have a set on now.  (No noticeable difference.)

 

An interesting thing I found out last year is that if you keep your hatch open about 6" you will get air from the back of the car to flow forwards and out the front windows.  I thought it it was a low pressure zone above/behind the hatch that it would draw air from the front windows, and flow out the back, but apparently there's still MORE low pressure by the front windows (coming off the windshield/front of the car).  I don't have fume issues but it was weird to drive on the highway, have the windows and rear hatch open and have no perceptible air movement inside the car.  The flow is low, but enough to create a high pressure pocket inside the car.  You can put your hand 2-3" past the windows before you feel any turbulence again.

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