Stacks - how hot, how loud??

["Mad Max"]

For those with double stacks, curious question - The heat shields around stacks... how hot do they really get? I know the end of a regular exhaust gets very, very hot, especially after more than just a trip to the corner store - definitely hot enough to burn ya, but with double the exhaust pipes does anyone notice that the heat is somewhat divided between the two stacks... or... is it all just hothothot?



Reason I'm asking - I'm planning to kinda-sorta run stacks along the outside rear corners of the cab - it's hard to describe but it should look sweet, and I will be using the nice chromed heat shields, and, we're planning to have the dogs ride in the bed. So, I'm trying to figure a way to keep the pups from accidentally getting burned, and if the shields will do the job, great. I'll make sure the shields go all the way from the floor to up near the roof line.



Has anyone used dynamat or some other type of heat/sound deadening material around the cab corners to cool and quiet down stacks?



Second, how loud? Is it a matter of mufflers, or more the location of the exhaust tip? Mine won't be straight-piped - probably one dynomax 4" straight-thru muffler per stack. We're building the rig for long-distance cross-country travelling and we do not want to have to shout over the exhaust drone over the course of a multi-day trip.



Any thoughts are welcome. Thanks in advance.



- M2

 

[Greenleaf]

Pack Stacks. Insulated internally w/packing material and flow straight through. Think of them as a performance muffler, mounted verticle.



You'd like the Nelson/Fleetguard Catalog Book No. 3 LT32002. Get one from your local OTR trucking dealership. It's a Nelson Exhaust Product Guide.



Yeah. My stacks are loud. Really loud. I installed a performance muffler and sounds purty now.







Forgot the heat thing...



I have a bed cover and the two pipes pass directly thorough it. The holes are cut in a fashion that the material just touches the OD of the chrome. The pipes cannot be touched by the bare hand during a run but the material never melts or burns.

 

[MXTMOPR]

Here is a fun link for design and build projects

Its a large file.

http://www.peterbilt.com/parts/pb/includes/catalogs/Acrafit_Exhaust.pdf

 

[Forrest Nearing]

they don't get that hot really...



but please dont' run them outside the bed... especially on a single wheel truck

 

[Ncostello]

Shields could easily be put around them and hidden well inside the bed to protect the pups. I've seen stacks outside the bed. Is this a first gen? Either way its my opinion that stacks outside the bed look... well... goofy. But to each his own. Unless you are planning a camper shell for this cross country rig or a hard tonneau. Then you have no choice really.

 

[dpuckett]

I've seen stacks outside the bed, and have to agree with Forrest and Ncostello- all I've seen look goofy and ridiculous. I still hold firm to the belief that stacks belong on semis, or maybe the occasional flatbed, IF the front of the bed is bevelled, it's on a club cab, they pass close to the cab, etc, etc. Though I am seeing more and more stacks around here for some reason. At least most of them are in the 5-6" range.



Daniel

 

[MMiller]

Larger diameter stacks will be more mellow. My brother found out that stack mounting, and height/direction of the turnouts had a large effect on noise in the cab. Had very tall turn outs, 6" I think, that sounded nice, not too loud, and was just fine in his standard cab. He cut the stacks down to just above the cab line and it would almost make your ears bleed in the cab, at 1800-2100 rpms. The resonance was horrible. He turned the stacks straight back, then mounted them a little different to the bed, and it was nicer.



Is it manual or auto? Autos are louder, because the engine is usually turning more rpms, for longer on take off. My 727 equipped truck, with 5" flattops, that are not as tall as the cab are quite loud in the cab. Its offroad only truck so then its ok. Not riding in it at 2000 rpms all day.



I agree with the above on stacks outside the bed. Unless you have a camper or something for them to go up beside, the seem to be along ways away from the cab, just to clear the box side. But I have seen your work, and it always looks good when done, I'll trust you on this project.



You also have to remember the rule with stacks on a pickup truck. They must emit black smoke from them on demand. Stacks are goofy if no smoke comes from them, and especially goofy on gassers... .....



Michael

 

["Mad Max"]

Y'all can breath easy - yer fears and well founded and I can complete reassure you that I'll be doing the oil burners justice. See, there's the way the truck is now... and the way it's gonna be after it's all built, which will include the stacks. Currently it's a srw 2wd... but when I'm done it's gonna be a lifted and stretched 4xdually megacab... and the stacks are gonna be... well... ummm... European... . as in 'Frenched', in to the back corners of the cab and the actual stacks will be completely recessed within the outer skin of the body. The chrome heat shields will be the outer 'skin' where the corners of the cab used to be. That's why I was interested in the heat issue, but it looks like it'll be good to go. It's also going to be a 6-speed and it'll have a Snow kit, so it'll be over 300 hp. And as far as the cloud, well let's just say that with the current fuel mods and the big honkin' sidepipe, it has 'smoke potential' written all over the r-rear wheel .

It'll be painted similar to the Ramcharger... only in 'blue'.

It aught to be a fun project .



- M2

 

[Moab4x4]

Sounds like a fun project! If you do a build thread like on Nacho, let us know. I learned a bit on the Nacho build thread and it has to be the beefiest RC out there. That attitude for the 1st gen Mega would be impressive to see on the road. When you get it done, use it to tow Nacho over for EJS.

Ken

 

[bmoeller]

If you tow, and have stacks positioned to where you might have a chance to bump them with bare skin, heat shields would be a good idea. I burnt my arm last week on the KW stack. Just came off of the road and was fueling up. Was messing with my pants to slip them back over my boot, and slipped off the step.

Blistered pretty quick, and still red as of this morning. The burnt skin is pretty much flaked off, and a little itchy. lol Kink of like a good sun burn.

 

[Ncostello]

Sounds like Stacks by Boyd's then. Frenched into the body. Cool.

 

[sdstriper]

With a little imagination I don't mind them. Otherwise there not for me...



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