So I have taken most of the underside apart to replace rear main seal and other stuff.. While taking it apart, I busted off almost all of the Exhaust manifold bolts to where they connect to the pipes. I will now have to take them off and cut drill and all that fun stuff..

However, I did see this seat of headman headers for my truck. Will these actually fit inside that engine bay? Has anyone tried this??

Also, what's the consensus from everyone on putting a louder, maybe 3 chamber Flowmaster, muffler on my truck since I have it lifted and decked out with safari racks and stuff..

Would altering stock stuff cause Engine Codes??

Thanks for any advice or linked threads on custom DIY exhaust ideas!

 

I think I've probably had more exhaust configurations on my Disco than pretty much anyone else. I'm actually about to re-do it to pass inspection.

First things first, the Hedman Headers for the Range Rover Classic fit perfectly in the engine bay. Where you run into a problem is the frame. They fit, but clearance is tight. Doesn't really matter because the ball and cup collector they come installed with is trash. Cut it off, have a few inches of 2.5" pipe welded onto each collector, have the O2 bungs welded into the collector, and then use band clamps to hold your exhaust onto the headers. Tried and true method and it's what I'm moving to. That will also give you more frame clearance.

Second, you'll want to use 2.5" pipe for your y-pipe. The factory 2-1/8" worked fine with the manifolds, but you're going to want more flow now. USE MANDREL BENDS. Find a shop that does mandrel bent exhaust or order a bunch of mandrel bends online to weld together. Crush bent exhaust is the devil. Creates turbulence, bottlenecks the exhaust, and causes drone.

Third, your catalytic converters will not fit in the factory location because of how close the pipe is to the frame. You'll have to put them right behind the second crossmember, past the transfer case. That's about where the factory muffler is. After the cat's y it together into a single 3" pipe. That will make your rear O2 sensors quite a ways back, but they will reach. Just. You'll have to re-route the harness side pigtail for the rear O2s. Please use cats. No matter what your beliefs are on global warming, it still kills people's lungs and greatly increases risk of cancer. On top of that, whether your locality has emissions testing or inspections or if they don't have either, you can still be issued a ticket by any cop in the US for $10,000 for removing catalytic converters based on either a smell test or a visual inspection.

Now, you will probably have room to mount a resonator if you want to but it's not completely necessary. Route the 3" pipe up and over the axle then make a hard 90* turn to go between the gas tank and the frame mount for the drivers side watts link. Make another hard 90* turn and put your muffler in place of the factory resonator.

As for Flowmaster... You will greatly regret it. I had a Flowmaster 40 on my Disco for a while. It sounded pretty good, but the drone was TERRIBLE and it was all the time. Like seriously deafening.

I've had various glasspacks of various lengths, both louvered and non-louvered. They sound decent and they're cheap. If you go this route try to find one that's perforated core (non louvered) because they flow a million times better. The longer you go the quieter it will be.

Magnaflow makes good mufflers. Never used one myself, but I hear and see a lot of good.

Thrush/Dyno-something turbo style mufflers. This is a little more tame sound, but will give you a good rumble. Kinda a muscle car sound I think. I like them both for sound and because they're dirt cheap. Thrush Turbo 3" muffler is like $36 on Amazon.

My personal favorite, Borla. I have a Borla Pro XS on my Silverado right now that was originally on my Disco and I will be moving it back to my Disco. A little more pricey at around $100, but top quality. Plus you're supporting sorta local business. They're designed and manufactured in Johnson City, TN. Beautiful sound. Plus, $100 isn't that bad for a muffler, just more than the other options presented.

Lastly, no, this won't cause any engine codes. There's a nice little power increase across the board; even at the lower RPMs no matter what anyone says. I would recommend matching it with an intake. If you want a write up, check out the link in my signature. I did one when I made an intake for my Disco. Again, nice little power bump.

I will say, these Rover V8s are really great sounding engines. I mean, they're classic American push rod V8s. They were originally designed by Buick in the 60s. I honestly prefer the sound 10 times to an LS engine or the Modular V8 in my Mustang. If you've got any questions I've probably got an answer for you on this topic.