Rerouting exhaust to a low pressure point

[chipX]

Sorry to bump up an older thread.
But ( cant remmember which team ) there was a motorcycle racing team that decided to install the exhaust under the seat - and it gave trememdous advantages.

[Frank Lee]

Sure, things are a bit different when you're going 180 mph and seeking tenth-of-a-second advantages.

[BamZipPow]

I bet that kinda heated up their rear end a little bit...kinda like putting the fire to their butt.

[aerohead]

Originally Posted by ConnClark

Right now my exhaust exits right below the bumper on the drivers side. I could get it to route just above the bumper with a slight bend just in front of the muffler and a 6 inch extension. The exit would be right in the slipstream then and hence in a slight vacuum.

I would have to cut the body work which makes me uneasy with this mod.

Edit: CO poisoning isn't a problem on diesels unless they are way out of tune. Fumes wouldn't getting into the passenger compartment wouldn't be a problem anyway

The base pressure behind the 300 will essentially be at the same pressure as where the air separates.If the side tailpipe is within 6-inches of the tail,there may be little Delta-P between the two locations.Also,the side flow is dilluting the exhaust stream through mixing,which wouldn't necessarily occur behind the car,making it nastier for following motorists.

[mwebb]

just placing the exhaust tip willy nilly somewhere may put it in an area of pressure or ...
so
it would not be too hard
to measure , just get a MAP or FuelTankPressuresensor sensor from somewhere (junk yard) get the connector too ...
three pins on the MAP or FuelTankPressure sensor.
power 5v , ground , signal .
,tap into the 5volt reference in the car OR make up a 5v power supply , use a dvom or labscope on the MAP or FuelTankPressure sensor sensor signal pin
and position a vacuum line from the MAP or FuelTankPressure sensor in the car
to the area you suspect has lower "pressure " , drive the car .

not moving signal voltage will be about 4.5 volts on a MAP sensor from GM or 3 volts on a Honda MAP sensor , what ever the value
assign it to be "local Ambient Barometric pressure "

for this test ;
lower voltage is better because it will show (lower pressure),
you will be searching for the vacuum hose position that yields the lowest value

there are charts that will give up voltage vs "pressure" values.
depending on which MAP or FuelTankPressuresensor you can scavenge from ...
a FuelTankPressure sensor will have better resolution .(differences will be easier to measure and see)

or use a real pressure transducer .
or a water filled vertical "U" shaped tube with the vacuum line on one end of the "U" permanent marker graduation s ...
either way , differences will not be large

[winkosmosis]

Originally Posted by aerohead

The base pressure behind the 300 will essentially be at the same pressure as where the air separates.If the side tailpipe is within 6-inches of the tail,there may be little Delta-P between the two locations.Also,the side flow is dilluting the exhaust stream through mixing,which wouldn't necessarily occur behind the car,making it nastier for following motorists.

I think sending more concentrated exhaust to following cars is reason enough not to do it. It could be a pretty significant difference considering that cars intake air for the HVAC at the cowl... So someone drafting you would get your exhaust in the cabin.

[Frank Lee]

I usually smell smokers in the cars ahead of me (with all my windows up) before I see them!

[matt36415]

You could buy a length of flexible tube that is aluminium, like aic con ducting in a small diameter, clamp it on to your exhaust and locate it in different spots to test.

Cost would be small, easy to remove and no damage to car if you scrap it. Do an easy experiment and tell us what happens.

All research is good research.

[arcosine]

behind the back wheel would be a good spot.

[aerohead]

Originally Posted by winkosmosis

I think sending more concentrated exhaust to following cars is reason enough not to do it. It could be a pretty significant difference considering that cars intake air for the HVAC at the cowl... So someone drafting you would get your exhaust in the cabin.

One argument for forbidding NASCAR racers from routing the exhaust to the rear was essentially the same rationale.
In long lines of traffic on the track the exhaust would be sequestered within the ganged-wakes,concentrating as you moved further down the train of cars.
Without the dilution of the side slipstream,the gases could reach dangerous levels for the drivers.
I believe that all cars have exhaust to the driver's 'right',and open window ventilation on their 'left'.