Exhaust fumes

[phillpot]

My Taimar has two little grilles on the tailgate and a fake speaker grille inside, I guess the idea is to give a bit of thro-flow ventilation?
I've never noticed it but out with a friend the other day (door window open and glass sun roof tilted) and she commented on the fumes in the car, mainly at lower speeds (so not very often )

So, are they getting drawn in through those vents? I know I could just bung them up and try it but thought I'd ask first if it is a "known issue" ?

[bluezeeland]

Dunno bout these vents, they dont look original, dont they leak (as if you would go out in the rain............)
Noted your taimar is the same colour as my 3000S, nice !

[spikep]

Does the sun roof just give a gap at the back? If so I found that my M when open and water on it that the water would actually go up the rear window showing the direction of the air flow. I originally had the exhaust close together and the fumes came in, but stopped when I put an exhaust on with the pipes further apart.

[oldgeebee]

There was a nice thread on the TVRCC M-series forum here where various methods of finding out the pressure differentials across the bodywork were discussed. If you have the time (and the inclination!) then you could experiment with windows/sunroof open/closed etc to see what's happening.

GB

[BP-TVR]

Hi Mike, this is a known problem apparently, ealy Taimars had these vents but they were quickly dropped because fumes were drawn in to the cockpit when the windows were open. Some early cars had these vents "removed" to remove the problem. This information was passed to me by "the Oracle" when I recently asked him which rear hatch to use; vented or non vented, since I have one of each, on my Taimar project. I'm surpised my apprentice (Thomas) has not beat me to it to tell you this! Best regards, Brian

[phillpot]

BP-TVR said:

Hi Mike, this is a known problem apparently, ealy Taimars had these vents but they were quickly dropped because fumes were drawn in to the cockpit when the windows were open.

So, just as I suspected ! thankyou

bluezeeland said:

dont they leak?

No, they don't. any water that runs in runs back out some holes in the lower edge.


It is a nice colour but may go for a change when I get around to a respray seen a nice Saab colour, think it's called Nocturne Blue Metallic? Like the look of those grilles so will probably keep them and blank off the hole behind that speaker grille thingy

[bluezeeland]

Good idea to blank the vents, not so good idea to change the colour.........imho

[whitewolf]

Mine has the same vents... But mine isn't too bad lol

[DavidY]

Mine had the vents, a couple of solutions, block the vent off on the inside (which I did), this left the outside vents, which I thought looked quite good. Another one is to lengthen the exhaust pipes slightly so that they are about 50mm proud of the body, this causes less exhaust fumes to get caught in the turbulence behind the car and less then gets sucked in.

davidy

[Adrian@]

phillpot said:

My Taimar has two little grilles on the tailgate and a fake speaker grille inside, I guess the idea is to give a bit of thro-flow ventilation?
I've never noticed it but out with a friend the other day (door window open and glass sun roof tilted) and she commented on the fumes in the car, mainly at lower speeds (so not very often )

So, are they getting drawn in through those vents? I know I could just bung them up and try it but thought I'd ask first if it is a "known issue" ?

Start off by taping them up and see if that is where the issue is ...
Adrian@

[GTRene]

what could help is make the system a little different with a rubber "valve"

BMW has such system, when I was working on my car I noticed these>>



when the cabin pressure goes up the rubber valve opens/bows and when not its closed (sort or less) it works automatically so I guess that when you open up the window is will close?

I think a Porsche 911 (older models) breaths through the roof on top of the rear window with sort like system.
the rubber "valve" overlaps the hole so when you powerwash your car I guess it seals also a bit...

works better (against water) then say some racecars TVR have plastic rear windows with a lot of holes drilled in

some use helicopter vents though, or holes with some cover protection only from above, but also helps get the pressure out instead of your window blowing out I guess?

[maicoh]

Rene, are the BMW vents you show upside down, so the rubber flaps hang down flush and open up with pressure from the inside of the car?

[GTRene]

maicoh said:

Rene, are the BMW vents you show upside down, so the rubber flaps hang down flush and open up with pressure from the inside of the car?

yes, your correct, the picture I took from the web is a bit confusing, it is showed up side down, it is as you say, its a very simple and logical concept me thinks.
could also work when its lays horizontal/flat, then the rubber flap lays on the vent-hole protecting it a bit from rain or dust coming in and when pressure rises in the cabin it automatically opens the rubber valve and also closes automatically if pressure is "normal" you can make it also more resistant by say making the flap ticker so it only opens a bit later when really needed.

Edited by GTRene on Monday 10th September 12:39