Exhaust Fumes - Answer poll please

[swamp donkey]

I have read many posts here about how to reduce exhaust fumes into the cab while going topless. At the end of each thread I still have no answer. It seems everyone disagrees (shocking, no?). I thought maybe if I posted a poll, at the end I would have a clear cut answer (yeah right).

 

[Greg72]

The answer is that when the vehicle is topless (and we are talking about your '69 K5 correct?) there is NO cab! /forums/images/icons/grin.gif

Seriously though, there is nothing to "contain" the exhaust fumes in a full convertible vehicle. The only time I've ever heard of fumes being an issue are on a K5 with the hardtop attached and the rear glass rolled down. In that case, the "low pressure" area created just behind the vehicle allows the exhaust fumes from an "out the back" exhaust system to curl up and into the open rear glass.....

I didn't see the original thread you posted, so my apologies if these points were already argued to death!

/forums/images/icons/shocked.gif

 

[swamp donkey]

We are indeed talking about my '69. I have had TONS of work done to (including new Hugger Orange paint) I will post all the details in about two weeks. My wife ohh soo very concerned with exhaust fumes. I have not driven it with the top off yet, so I do not know what to expect. The current exhaust exits at a 45 deg angle to the body at the rear corner. We'll see how that works.

 

[1Blazin71]

I agree with Greg. With the top off I dont smell any fumes from either the front or back seats. With the soft top on and the rear window rolled up, the low pressure sucks the fumes in. This is only really noticable when decelerating...which seems to create a more intense flavor of fumes.

I've noticed that burbs and such that have roll down rear windows have a kind of a spoiler above the rear door window, presumably to draft air from the top down over the open window to counter the low pressure.

Someday...if I ever get my full cage redone and add a roof rack setup through the soft top I'm considering trying to add a similar wing/spoiler setup.

 

[Steve_Chin]

I also agree with Greg, but if we're talking about with the top on, the best place I can figure to put the taikpipe exits would be behind the rear tires, pointed out the side of the truck (like the factory designed - the engineers spend a lot of time on things like this).

Straight out the back is the absolute *worst* place for the tailpipe exits.

In front of the rear tires is bad because fumes will migrate toward the front seats more easily when stopped in traffic.

 

[kiley]

Mine exits on both sides at a 45 behind the tires. My top is off all summer and I never smell the exhaust.

 

[Michael]

I just put new tailpipes on my '74 (full convert) the exit at 90 degrees behind the wheels and they work sooo much better than straight out the back.
No fumes with the top off, mild with the back window down and front window open on deceleration.