R700 Exhaust Routing.

[ducky698]

Hello Guys, what route does the exhaust take on R model when there is 4 fuel tanks and a air start tank under nieth? how much clearance should i give the exhaust? I am running them up either side next to back of cab, between cab and sleeper, but how does one get it to this place? I was considering, out of engine, over chassis, then go under chassis and pop back in next to gearbox on right side then go directly above drive shaft and over chassis to the stacks, but room is tite, how much room would you allow as minimum clearance?

regars Grant

[Lmackattack]

the standard R models had the exhaust run from the turbo down below the frame rail, along the bottom of the rail, exiting and bending upwards behind the RH fuel tank. If the RH fuel tank was large and did not permit the exhaust to route up behind it, you can have it come up between the frame rails. If you ever watch Mad Max the road warrior you will see a good example of how you can get twin stacks to work on a R model with big fuel tanks.

hope this helps.

[ozrad7]

i just put twin stacks on my r 688 so here are some pics of how i did it, it may not work in your case but it might give you a better idea of how to go about it, i didnt have a lot of room to work with either but managed to make it work but discarding the original exhaust mounts and making my own. i would be lucky to have 10mm of clearance going over the tanks and have not had any dramas.

[ducky698]

Hi, thanks for the help, yes room is tite, my tanks are longer than that to. I will take some pics tomorrow. I have an air start tank that sits under the truck, its a great tank, and gets it off the side of the truck, now I have room problems for exhaust, and also how to get it to come out to the Y section to go into 2, plus do I mount the exhaust on or off the cab?

regards Grant

[ozrad7]

i mounted mine off the cab because my cab has a air bag under it and made my own y piece from 2 90 bends cut down the middle and welded together, its cheaper and you can make the y suit your application by making it angle up or down instead of being flat.

[ducky698]

Hi, here is where i am up to so far, its 5inch, will pop cab on tomorrow and work out y piece and what room i have between cab and chassis, the air start tank has made things tite.

Grant

[ozrad7]

mine was only 4 inch so it fitted between the rail and fuel tank , when i decided to do my stacks i wanted 5 inch but i mesured everything up i found it wouldnt fit.if it was a prime mover it would becuase the y piece could of gone above the rails behind the cab wich would be a better setup as mine is mounted directly in the muffler there is a split second delay between the stacks when i put the foot down. , what gearbox are you using because my mack box is the perfect shape on the drivers side for the muffler to be mounted beside it.

[ducky698]

mine was only 4 inch so it fitted between the rail and fuel tank , when i decided to do my stacks i wanted 5 inch but i mesured everything up i found it wouldnt fit.if it was a prime mover it would becuase the y piece could of gone above the rails behind the cab wich would be a better setup as mine is mounted directly in the muffler there is a split second delay between the stacks when i put the foot down. , what gearbox are you using because my mack box is the perfect shape on the drivers side for the muffler to be mounted beside it.

Hello, its a 20speed spicer. am not sure if my cab is in correct spot either, will put a post in cab section for that. I hope it is, as its going to be a pain to shift.

regards Grant