4 Inch Exhaust?

[OD_Coyote]

The “j” pipe on my M35A2 will need to be replaced in the near future and I was thinking about going to 4” diameter pipe instead of 3.5”. Has anyone gone down this road before or have any thoughts/observations to share? I am hoping that the larger exhaust may help lower the EGTs a little and perhaps make the truck sound even better. I was wondering what I could do to improve the air intake system as well?

 

[gimpyrobb]

Use the 525 cfm air intake from a 5ton instead of a stock deuce 410 cfm air filter.

 

[LanceRobson]

The size of the multi-fuel exhaust was purposely kept a little small to accelerate the exhaust fumes up and away from the troop compartment (the bed). The Army knew from the start that the truck would breath easier with the bigger pipe but saw it as a troop safety issue.

I'd say "change it" and post the results, please!

Thanks

Lance

EDIT: Anybody know where to find a couple of 5-ton air cleaners? That mod has been on my mind for a while.

 

[Somemedic]

Does that move the AC outside onto the fender or would it still be under the hood?

 

[doghead]

On the fender.

 

[Hammer]

I put 4" exhaust and muffler on mine starting at the fender. It still has the stock bottom 3.5" section, then it necks up at the hole in the fender.
Sounds good, and runs well, but I didn't have a before/after comparison for EGTs.
Just make sure to keep the bends nice and smooth when making it with 4", and it should work well.
Worst case is you spent some money on a bigger exhaust that sounds a little different from stock.

 

[OD_Coyote]

Thanks for the feedback folks. I will post updates on this project as it progresses. Does anyone know where I can get a 5 ton air intake/filter assy?

Thanks.

 

[joec]

Plus with the 3.5" exhaust you get some back pressure.

 

[bgekky3]

My dad's shop is next to a chrome shop. They are always throwing away 6" stacks. Once I get there (next week) and get settled, I am going to run a duel 6" straight pipe set up. I will post the before and after data. Right now I think I am overfueling, but I am going to get that straightened out this week. I am at 1100 unloaded accelerating so I think the fuel was turned up on the new engine. On hills the pyro climbs faster than the tach.

 

[SasquatchSanta]

I installed a vacuum gauge under the steering column in place of the air breather warning devise on my deuce. Even with the LDS-1A engine the stock deuce aid breather pulls very little vacuum. The exact numbers are posted somewhere on the site but I can't recall what they are at this time. I would say as long as you keep the stock deuce air cleaner clean you're not going to gain anything by installing a 5-ton unit.

As someone that has gone the route of turning down the fuel I would say not to neglect the droop screw. My LDS engine was seriously over fueled from the rebuild depot. I turned down the main fuel setting two flats and the droop screw 1/4 turn. It didn't stop smoking until I turned down the droop screw.

I made several posts on this subject. In one I even did an on-road manifold pressure test. If you scan my previous posts you may find some insight.

I think you're on the right track in increasing the exhaust pipe size.

Good Luck.

 

[ken]

Witch turbo do you have?

 

[Alex400]

Has anyone made the exhaust come out behind the cab of the truck or right behind the passenger door? I was thinking of doing this and putting the muffler under the truck when i own one someday. I was also thinking about the 4" exhaust and changing the air intake a little bit.

Also has anyone used the Hushpower diesel mufflers?

http://www.hushpower.com/products/19/PRO+Series.html

 

[Alex400]

Bump.....

 

[brianp454]

Anybody ever make a recording or video of the sound before and after converting to a 4 inch stack?

 

[USN_Green_Addict]

Anybody ever make a recording or video of the sound before and after converting to a 4 inch stack?

I can send you an after if you have facebook

Sent from my LG-H918 using Tapatalk

 

[Larry Weibert]

I have been reading the deuce exhaust treads for some time. I plan on doing monthly camping 2.5 hrs from my home for local Rocket launches. Its probubly 3.5 hr in a deuce. I am thinking of going out the back of the deuce with the exhaust and using the exhaust stack placement for the intake. Any thoughts on that.

 

[Hammer]

Exhaust out the back makes a BIG difference!
The motor is a high compression motor, so it makes it's own noises. But moving the exhaust down and back makes the biggest difference you could for these trucks.

 

[MattMajcher123]

Why not do a 5 inch stack, put on the 5 ton air filter and then turn up the fuel? The larger pipe should keep the EGT's within reason from the fuel being turned up.

 

[77 AMG]

Exhaust out the back makes a BIG difference!
The motor is a high compression motor, so it makes it's own noises. But moving the exhaust down and back makes the biggest difference you could for these trucks.

@Hammer. Would care to explain how this would work better for the engine, as opposed to the stack style exhaust? Both of my Semis' were "stack" trucks, so, I am not seeing how this would be a benefit? Thanks

 

[rustystud]

@Hammer. Would care to explain how this would work better for the engine, as opposed to the stack style exhaust? Both of my Semis' were "stack" trucks, so, I am not seeing how this would be a benefit? Thanks

I think he was referring to the noise levels inside the cab.