55.2-59 Body Exit Exhaust

[57FleetsideC4]

Hi All, I am thinking of doing a body exit exhaust on my 57 Fleetside C4 project. Would like to exit in front of the rear wheel well. Does anyone have any experience on this? Are there any cons on this may exhaust residue? Thanks Steve

[Dan in Pasadena]

Of course there will be exhaust soot on your paint and depending on how you do it, the hot exhaust will damage the paint.

I'd not do body exit. It's just unnecessary body work, fabrication, the potential for rattling of the piping if it isn't mounted just right AND because of the residue even if behind the rear fenders.

[57FleetsideC4]

Originally Posted by Dan in Pasadena

Of course there will be exhaust soot on your paint and depending on how you do it, the hot exhaust will damage the paint.

I'd not do body exit. It's just unnecessary body work, fabrication, the potential for rattling of the piping if it isn't mounted just right AND because of the residue even if behind the rear fenders.

Thanks for the input. This is a long ways off but always collecting opinions and information. I figured it make a mess and the body outlet kits aren't cheap. Steve

[joedoh]

have you been behind a school bus lately? they dont have 6" sewer pipe exhausts, actually the same 2.5" piping they always had, but it exits through the bumper in a large 6" diameter pipe called an "ejector".

the way it works is, the big pipe is open on the back side and the 2.5" pipe only sticks about halfway in. the small pipe exhaust pulls cool air in the backside and ejects the exhaust and extra air out the back at a lower temp than just exhaust. I didnt see any soot on the school bus either but I guess it could be there.

if i wanted an exhaust passing through a body panel I would use the same approach. no vibration, cooler temp on the paint, easy to keep clean too.

[57FleetsideC4]

Originally Posted by joedoh

have you been behind a school bus lately? they dont have 6" sewer pipe exhausts, actually the same 2.5" piping they always had, but it exits through the bumper in a large 6" diameter pipe called an "ejector".

the way it works is, the big pipe is open on the back side and the 2.5" pipe only sticks about halfway in. the small pipe exhaust pulls cool air in the backside and ejects the exhaust and extra air out the back at a lower temp than just exhaust. I didnt see any soot on the school bus either but I guess it could be there.

if i wanted an exhaust passing through a body panel I would use the same approach. no vibration, cooler temp on the paint, easy to keep clean too.

Interesting.

[mr48chev]

I'm thinking you would get tired of it just after the "oh cool" part wore off. I ran the pipes out from in front of the rear wheels on my 71 GMC for a long time and the exhaust gets the rear wheels pretty cruddy along with getting real tiring on road trips if you have loud pipes. The sound bouncing off the Johnson barriers on short distance runs is fun for a while but the constant drone hour after hour on long trips is real tiring.

Truth be known I have probably driven way more miles with the exhaust exiting in front of the rear tires on my trucks than out the back.

[Driver_WT]

I don't think you will have much problem with the exhaust heat on the paint. The header pipes on my Cobra are less than 1/2" from the paint and fiberglass body where they exist behind the front wheels and no issues with the heat affecting the paint. And my header pipe is a lot hotter than your tail pipe.

[57FleetsideC4]

I don't think it would be hot enough to burn paint as there is a stainless ring around the opening. I was more concerned with exhaust gas on the body. I was going to exit in front of the rear tire. Again this is a long ways off and worried I won't be able to get a pipe over the C4 rear suspension and not hit the bed. Thanks everyone for the opinions it is much appreciated. Steve

[1project2many]

have you been behind a school bus lately? they dont have 6" sewer pipe exhausts, actually the same 2.5" piping they always had, but it exits through the bumper in a large 6" diameter pipe called an "ejector".

the way it works is, the big pipe is open on the back side and the 2.5" pipe only sticks about halfway in. the small pipe exhaust pulls cool air in the backside and ejects the exhaust and extra air out the back at a lower temp than just exhaust. I didnt see any soot on the school bus either but I guess it could be there.

if i wanted an exhaust passing through a body panel I would use the same approach. no vibration, cooler temp on the paint, easy to keep clean too.

Most likely these are diesel engine vehicles with exhaust particulate filters. Possibly International buses? Current technology is to reduce particulate emissions by trapping them in a particulate filter then burning them off under specific conditions. Burning is accomplished by introducing additional fuel into the exhaust stream prior to the catalytic converter. After the fuel is combusted in the converter exhaust temperature can exceed 1000 degrees F. Exhaust at this temperature can easily start roadside fires in dry areas so cooling tips are attached to the exhaust.

Department of Agriculture study: https://www.fs.fed.us/eng/pubs/pdf/08511816.pdf

As far as dirty exhaust goes, keep the engine tuned properly and use a catalytic converter and you'll greatly reduce the chance that carbon will accumulate.

[Dan in Pasadena]

Originally Posted by 57FleetsideC4

....Again this is a long ways off and worried I won't be able to get a pipe over the C4 rear suspension and not hit the bed. ...Steve

Plenty have the C4 IRS already and have routed exhaust around it. It won't be an issue if done thoughtfully.

[57FleetsideC4]

Originally Posted by Dan in Pasadena

Plenty have the C4 IRS already and have routed exhaust around it. It won't be an issue if done thoughtfully.

I laid the cross rails on the frame today and checked the distance I have to work with and you are right there is plenty of room for exhaust. Thank You Steve

[MiraclePieCo]

Nowadays it's fashionable to have exhaust soot on your paint.

[MiraclePieCo]

How cool is this?

[1project2many]

Originally Posted by MiraclePieCo

Nowadays it's fashionable to have exhaust soot on your paint.

Wait... isn't paint optional?

[MiraclePieCo]

Originally Posted by 1project2many

Wait... isn't paint optional?

Haha, spend $15,000 on a paint job only to have your truck be worth $5000 less! It's crazy to see guys wrecking what once were very expensive paint jobs to cover them with fake patina.

[mick53]

In my day the patina look was the "I haven't got to that yet" look.

[57FleetsideC4]

Thanks for the opinions and pics. I am leaning toward running over the axle and out the sides like a typical dual exhaust. Steve