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Can a rear spoiler reduce exhaust fumes?


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Fumes?? I got em too unfortunatly...

BRE Rear deck and unknown lower spoiler. My hatch does not fit perfect. I don think it matters the spoilers under 60 mph, the fumes would be there anyways. Getting everything sealed the best you can is about the only option really. Venting the cabin too. The Z has sexy lines of Art but not built in wind tunnels. A fair mount of vertical frontal area with low pressure over the rear hatch glass I read once. Who knows??

The serious race cars had spoilers. Bet Paul Newmann didn't breath fumes.

 

The BRE spoiler was not easy to fit right!! At all! A complete joke. It took Considerable mods to get it to fit. Mine was the 2 mounting bolts at each side of the hatch as decribed above. The mounts sucked and were unuseable. Deck shape and gaps to the body not even close. If you go with this one be ready to do some body work. Out of the box I was dissapointed with the so called fit. All it does is gives you something to work with. Far from bolt on. Maybe others had better luck but just my 2 cents worth.

 

One a side note:

3M VHB tape (yes tape!) available these days would have no problems at all holding this part down. With proper surface area say 60% of the BRE outside footprint you would never be able to get it off the hatch even if you wanted too. 3M also provides a solvent to remove the tape and it is clear coat safe. The stuff is awesome.

No, I didn't tape down the spolier. Made 5 inside blind mounts and drilled the hatch. If I were to do it over again... I would have no problem or lack of confidence taping that sucker right on.

 

rear1.jpg

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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

Would a "Pantera" style hatch help or hurt the fumes situation?

 

 

Not really, but I don't have any weatherstripping around the doors right now. The fumes are so thick you can almost see it. My Z used to have a triple carbed L28 and i thought that changing the engine would help. Now my '73 is sr20det powered, and the fumes are as bad as ever. I'm going to sell my hatch and install all the proper weatherstripping soon. At speed on the freeway it's like tear gas up in the cabin. I hope changing the hatch will help. I hope to get one of those beta motorsports carbon fiber hatches.

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there are also other 'spots' on our z cars where those nasty gasses can enter the cabin. i'd check the following; grommet for fuel filler neck, grommet for fuel pump/sender wiring, grommet for license plate wiring, grommets for vapor tank lines, rubber plug in spare tire well, hatch plugs [side and/or underside of hatch] and finally, the hatch seals themselves. additionally, check hatch fitment [ie-closing tightly enough]. once that's complete, i'd also check the length of the pipe that extends from your muffler. it should be at least to the trailing edge of the bumper, if not a couple of inches beyond. i've done all of the above and get almost no fumes in my z at all.

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Venture... If I read Michael's post correctly, yes, a Pantera treatmenjt should help:

"Here’s a paradoxical (but verified!) trick: remove the hatch lid of the Z completely, turning your Z into a mini-El Camino. The exhaust smell will go away (for various reasons)."

The Pantera has the flying butresses of an El Camino, but covers the bed. Should still work (in my none too humble opinion) as the shape is more brick like, and no longer has the absolutely horrible hatch angle.

 

 

.

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I just wanted to add something to this thread, I haven't read the whole thread so if this has been mentioned already, I apologize. I was replying to anouther thread about the bottom of the fenders rusting out because of the water draining from the plenum getting caught in the fender. Here is a link to the thread http://forums.hybridz.org/showthread.php?t=107620

 

As I mentioned in that thread, leaves and pine needle often get trapped in the fender bottom where the plenum drains and cause rust. Well from experience as a paint and body man for over twenty five years, I know junk can also get trapped in the plenum itself, causing the firewall to rust. Sometimes this causes exhaust fumes to be vented into the interior from the engine compartment. Also, because the pressure inside the car is lower then on the outside, any holes in the floor boards can also allow exhaust to leak into the car. Often people don't even realize there are holes in the floor boards because carpet or undercoat is hiding them.

If you have replaced your rear hatch seal and the tail light seals or confirmed they are in good shape and exhaust is still entering the car, this may be your problem. Checking the floor panels for holes isn't that difficult, but really checking the firewall is tougher. The dash really must be removed to get a good look. Sometimes you can crawl under the dash with some caulk. Also any holes in the trunk / spare tire area or even the inner quarter panels could allow fumes in.

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Sadly' date=' the 240-60-80Z has one of the worse shapes in terms of aerodynamics of cars in recent memory. It has small cross sectional area, which greatly helps. But apples-to-apples, it had more drag and un-downforce (lift) than cars like the Chevy Chevelle. Basically, the reason is that for good aero performance, the car’s body should be smooth and swoopy in some places, but sharp and abrupt in others. Generally, the smooth part should be up front – the grill area, the headlights, the hood/windshield juncture. The sharp and abrupt part should be in back – the trunk, rear of the cabin, etc. The Z is swoopy and smooth in precisely the wrong places, and sharp and abrupt – again! – in precisely the wrong places. It’s almost as if the Z’s designers worked long and hard to deliberately do a bad job on the car’s aerodynamics. And to add to the injustice – cars like the VW Rabbit and Ford Pinto had far superior aerodynamics![/quote']

 

dose that mean i need to swap my Z so i drive looking out the hatch? >_> or swap the shell around..... err sorry ill stop beign cute..... But let me ask this is a 240z more aerodynamic in Reverse then it is when in 1st gear?

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I question whether the fumes come through the hatch. My 280Z smelled horrible. I put all new weatherstripping in. My 280Z smelled horrible. I put a new exhaust on the car. My 280Z smelled horrible. I put in an SR20DET. Smell was gone. Does anyone wonder whether the smell is coming through the firewall or up the transmission tunnel? Now, when I blow a turbo gasket, I get the smell again. The rest of the time, I have no odor issues.

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In all the efforts to reduce or eliminate exhaust fumes drawn into the car has anyone tried to minimize the low pressure area in the rear? I was thinking that narrow plastic scoops mounted in the rear wheelwell opening (out of view) could be vented up and out the rear valance, just below the bumper, via hose. The outlets could be installed to look factory and visually pleasing. The idea is the low pressure would draw air out of the wheelwell (and from under the car). This might have a positive effect on downforce and lower that notorious low pressure area too. It might help to reduce fumes getting pulled into the car with open windows. I wish I had access to a windtunnel to test the theory. This would supplement the replacement of all rubber and filling of all holes, of course. It's just a thought... What are your opinons?

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I think it makes a lot of sense. (That holes in the floor board would let fumes in)

 

As long as I keep my windows up imy car stays fume free. But the second I even crack a window I get a proverbial smack in the face from obnoxious fumes. I'm gessing that its coming up through a couple small dime sized holes right beneath the seat. I'm going to make it a point to seal those up. Somehow. Suggestions?

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You might try body seam sealer to plug the holes and gaps in the floor and firewall. it`s also possible that your fan is drawng exhaust fumes from the engine compartment through the cowl panel. BUT...

If your exhaust system if working properly, you should NEVER get exhaust fumes from the engine compartment.

 

DENNY

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Guest Heuristicism

I AGREE with Denny411 !!

 

Take care of the problem that exists, you don't need a 'band-aid' ahemm I mean spoiler.

 

Lets see, smelly fumes could equal, rich running engine, oil leaks, coolant leaks (headgasket), bad cat, bad exhaust system, bad sealer for tailights, rust holes, and the list goes on.

 

I think that if you FIRST address these possible problems it would reduce the smells that you are experiencing.

 

Once solved, go ahead and get that spoiler....

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rear quarter panel damage can end up leaving a gap between the inner fender and the out rear quarter panel... it can also cause gaps in the little panel that has the filler neck gromet... Nissan used a thick bead of tar-like substance to seal the inner and outer fenders... check that this is still in place and actually touching the outer quarters.

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I suspect some of the problem might be because of the Carbs too. I've long suspected that my un-filtered su's are not sucking in all the fuel that is getting to them, because as soon as you open the hood, you get hit by the fume fist-stinging eyes and all. I read an article in Grass Roots Motorsports detailing their conversion of a Volvo 122 from dual Su's to megasquirt fuel injection, and they described how their fume problem magically went away after that too. This is in keeping with the Sr20det story mentioned above, as well. It can't be the only thing, but it's something to think about. Anybody have any "I used no filters/open element filters, and when I switched to a plenum my fumes went away" stories?

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Great thread to revisit.

 

I may have missed it and if I did, I apologize for being redundant, but in regards to “sealing” the back of the car, I saw no mention of sealing the latch under the hatch and behind the license plate. These are areas that exhaust fumes from behind the car come into the rear hatch area via the vinyl interior cover of the underside of the hatch itself.

Back in the early to mid ‘90’s when I had the dual exhaust on my L-28 powered 280-Z exiting out of the OE rear bumper holes, only about 2” out past the rear valance, I did get fair amount of exhaust fumes in the car. I had no fin, wing etc, see pic below… When I swapped in the V-8, I retained this exhaust arrangement, except it was dual 2.5” instead of dual 2”.

 

 

280Z1.jpg

 

 

 

 

So I set out to seal the back of car 100% from any air flow in or out. What I mean by the “back of the car” is the entire rear valence/taillight area.

At first I recognized that even if the taillights are sealed good, and the rear hatch sea itself is in good condition, that the exhaust fumes can easily get behind the license plate and between the hatch and body itself, then up through the hatch lock, and into the space between the outer and inner hatch skin and ultimately into the interior through vinyl covering that allows access the hatch lock mechanism. In the first picture using a parts car as the example, the upper circle is the area between the hatch and the body of the car that needs to be sealed, (the bottom picture shows one method of using weathering strip to do just that). The lower green circle in the upper picture shows the latch hook as it is behind the license plate which allows exhaust fumes up into the hatch itself. (These pics are of a 280, the 240 would be similar). On my personal Z car back in the day, I just used duct tape to seal off the latch hook under the license plate. This is the BUBBA way out, but it did help. I’m sure that someone could easily make a Fiber Glass cup that could easily be attached under the license plate to seal that off, of course make it removable to be able to make hatch hook adjustments.

 

 

 

 

 

LAtchLarge.jpg

 

 

Latch1Medium.jpg

 

 

Just thought I’d throw out my $.02

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