exhaust fumes again

[wa5ngp]

I read the previous posts on this and there was someone trying some customized tip lengths and shapes to help solve the exhaust fume problem.

I'd like to know what results he got if he's still around here and can post them.

I've go a 73 240 I've had since '76. Its always had an exhaust fume issue with the window(s) down. Since here in Texas we usually always have the AC on its really not much an issue. However, lately the ac is on the fritz and besides it sure would be nice to have a breeze and not be smoked out.

The exhaust is an old turbo flow 2.5" from Motosport a long time ago. Basically a big muffler on the end. It has held up remarkably well. I should say that I've also had Monza and stock exhausts and they had the same fume problem.

I can't find any obvious gasket voids. My most recent effort to fix it involved caulking around the fuel tank downspout on the rear back corner as it comes into and out of the car on the way to the fuel tank. There was quite a bit of light showing thru there. Everthing else from tailights, hatch, hatch gaskets seem to be in good order. Not new but not rotten either. That helped some but I still smell it with the window open.

I have never tried the tailpipe extension trick so I'm about ready to try that. At the moment the tip goes about 2" beyond the tiny rear bumper. I've noticed some vehicles with exhausts that come straight out then curve down so that the exhaust tip is perpendicular to the air flow of the vehicle. So I was wondering what if any experience have people had with the curved tailpipe extension and direction change. Curved down or curved to the side. You could make it go either way. And suggestions on max length to start with would be appreciated.

I suppose someplace like a generic muffler shop would be the best place to get something bent like this. I know it won't look cool but I'll try to fix that later after I can breathe while I drive.:sleepy:

The AC needs a new idler pulley and that is in the works.

tks

Don

[Z train]

Tail pipe length is not the answer.Your problem is somewhere else.My tip is flush with the vertical plane of the bumper and wether the windows are up or down,i have no exhaust in the cabin issues.

[AndysPlit]

I read the previous posts on this and there was someone trying some customized tip lengths and shapes to help solve the exhaust fume problem.

I'd like to know what results he got if he's still around here and can post them.

I've go a 73 240 I've had since '76. Its always had an exhaust fume issue with the window(s) down. Since here in Texas we usually always have the AC on its really not much an issue. However, lately the ac is on the fritz and besides it sure would be nice to have a breeze and not be smoked out.

The exhaust is an old turbo flow 2.5" from Motosport a long time ago. Basically a big muffler on the end. It has held up remarkably well. I should say that I've also had Monza and stock exhausts and they had the same fume problem.

I can't find any obvious gasket voids. My most recent effort to fix it involved caulking around the fuel tank downspout on the rear back corner as it comes into and out of the car on the way to the fuel tank. There was quite a bit of light showing thru there. Everthing else from tailights, hatch, hatch gaskets seem to be in good order. Not new but not rotten either. That helped some but I still smell it with the window open.

I have never tried the tailpipe extension trick so I'm about ready to try that. At the moment the tip goes about 2" beyond the tiny rear bumper. I've noticed some vehicles with exhausts that come straight out then curve down so that the exhaust tip is perpendicular to the air flow of the vehicle. So I was wondering what if any experience have people had with the curved tailpipe extension and direction change. Curved down or curved to the side. You could make it go either way. And suggestions on max length to start with would be appreciated.

I suppose someplace like a generic muffler shop would be the best place to get something bent like this. I know it won't look cool but I'll try to fix that later after I can breathe while I drive.:sleepy:

The AC needs a new idler pulley and that is in the works.

tks

Don

I've replaced the tail light gaskets, extended the tail pipe (same muffler as yours), redone the weather stripping, and so on. These things have helped, but the fumes are still there. I'm at the point where I really think there is only so much that can be done. It's a flaw in the aerodynamics, and that's that.

However, I am going to try to seal the inside of the tail gate with some silicone and see what happens. I've read that recommendation before.

.....Or has anyone COMPLETELY eliminated fumes?

[AndysPlit]

Tail pipe length is not the answer.Your problem is somewhere else.My tip is flush with the vertical plane of the bumper and wether the windows are up or down,i have no exhaust in the cabin issues.

What did you do?

[Arne]

Two separate issues. Fumes with the windows up seem to be mostly seals and such. But fumes ONLY when a window is down is aerodynamics and where the exhaust dumps. I got fumes with the window down until I extended the tip slightly. Mine is now maybe a 1/2" past the bumper bar, but well shorter than the bumper guards. Seems to have cured my window-down problem.

But angle of the tip may have an affect as well. My tip is angled down a few degrees as well.

My last thought is that this problem -- like other Z problems -- may have more than one cure, depending on the car. No single 'fix' seems to work for all cars.

[Z Speed]

Don, I found this info from the search button above. Here are a few threads with a wealth of info. This is a very common problem among early S30 Z cars. There is a lot of good info and tips in just these three threads alone. I hope they help....

Thread link 1:

Thead link 2:

Thread link 3:

Good luck....

[AndysPlit]

Don, I found this info from the search button above. Here are a few threads with a wealth of info. This is a very common problem among early S30 Z cars. There is a lot of good info and tips in just these three threads alone. I hope they help....

Thread link 1:

Thead link 2:

Thread link 3:

Good luck....

Great. I just copied a bunch of this for for my Z notes. I am curious though; Has anyone had good luck with the BRE spoiler eliminating or reducing the fumes? I noticed Carl B. mentioned this.

[Z train]

What did you do?

Everything is new.seals,gaskets etc.Here is the bizarre part-I have a fuel cell where the spare tire should be.Cells are vented to atmosphere.I used to get a raw fuel odor in the car because the vent line just ran down the side of the tank.But since i extended the vent line just below the rear valance,the fuel odor went away.

[Arne]

Has anyone had good luck with the BRE spoiler eliminating or reducing the fumes?

Carl mentioned the rear BRE spoiler as a potential cure. I can't speak to whether that works or not, since I don't have one. But now that you mention it, I installed my front BRE spook about the same time as I extended the tailpipe. Since the spook keeps air from going under the car, I suspect that it may have an effect on the aerodynamics at the rear as well, and could have been part of what fixed mine.

[a7dz]

So far four cars with the exhaust smell with the window down all were cured with the tail pipe being extended. Past the bumper.

[wa5ngp]

I'll go surf those links, good data I'm sure. My post was long, but from day one windows down was exhausty, windows up never a problem. Maybe I'll just fix the ac and forget about it like I've done for 30+ years.

I've always thought a front air dam would be cool but then I think about those parking lot curbs being there and pieces of rubber flying off 18 wheeler recaps like hit my poor old 73 capri front air dam.

I'm gonna play with the exhaust tips just for the heck of it. Who knows make it exit out the side or down.

I do have a nice non-rattling loover on the rear window. Helps keep the temp down and reduce need to lower windows as cabin temp stays lower with the shade.

tks for posts guys

Don

[Zs-ondabrain]

I have the BRE style spoiler and the problem did NOT change, at all.

Here is one thing you can do. Get a smoke machine, a shop vaccum and some cardboard.

Cut the card board to fit in the window opening with the window 1/4 of the way down. Cut a hole the size of the vaccum hose into the card board and slide the card board into the felt groove in the upper part of the window frame. Then tape the lower part of the cardboard to the upper part of the open window.

Turn on the vaccum. Start the smoke machine and blow the smoke to the suspected areas and there ya go. Or have someone on the inside watching for the exact spot that the smoke comes in, while you're out side with the machine.

I say all this cause I lit the tires up today and smoke came pouring out of the 1/4 window between the glass and the plastic window trim. Turns out the filler neck had a gap between the filler neck and the floor opening.

Also check the Antenna drain hole on the drivers side rear quarter.

JM2CW,

Dave.