Thread: 300TDI Exhaust options?

hey mate,

i am not sure why people are still going for rear muffler and removing the centre one. as the exhaust guy that did mine and has a LR himself said, its better to have no box on the back and one in the centre where it is protected by the chassis. this improves the AoA on the rear and is less likely to get a hole smashed into it from a rock. i think it is a pretty awesome design this way. no one seems to take notice of me though

mine is basically straight through system all the way with a slight silencer in the middle section. the thing is 2 and 3/4 inch all the way through. i think that matches existing. not much gain making it bigger than that. the main problem is the resistance on the flow the original systems had.

as for mandrel bend, unless you are building this car to race in the dakar rally there is absloutely no point doing it as the difference is so marginal that you would only bother if you are trying to gain 1/1000s of a second from a bmw rival.

I think people are removing middle one bacause it creates more flow restriction, not because of it's position.

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Originally Posted by ROAMER_AUS

I think people are removing middle one bacause it creates more flow restriction, not because of it's position.

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Exactly. Quickest, easiest and cheapest way to get a good performance gain.

If you want to talk about the best possible design contact Rick130.

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Originally Posted by SSmith

Exactly. Quickest, easiest and cheapest way to get a good performance gain.

If you want to talk about the best possible design contact Rick130.

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well like i said, mine has less restriction. i removed the original centre (restrictive) one and replaced it with a straight through box (noise reduction) similar to what the one at the back does. this then removes the need to have the box in the back where it is punctured and damaged easily and puts it in the middle where it is protected.

that was the reasoning behind the guy that did mine and makes perfect sense to me.

my 300tdi breathes beautifully since. you can hear turbo spooling up nicely and runs much smoother. you are basically putting the back box in the centre and removing the centre box. i just have a bit of pipe sticking out the back of it which is very hard to damage and gives me much better clearance and AoA.

i did this at the same time as doing valve clearances and changing air intake filter. run very smooth now. can almost balance a 50c piece on it like my rb30. well, not quite.

You are right, shifting the remaining muffler to the middle protects it, but if others have not damaged the rear one because they use their car differently, that extra cost becomes entirely optional.

You asked why people do it that way and i gave an answer. Sorry if that was seen as an attack.

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I was going to remove the center muffler to try to optimise the gas flow, providing the noise penalty is not too much. I'm also considering fitting another straight through muffler in that place. ( probably end up as my final choice) . Though I'd like to hear from guys whop have replaced the center muffle with a pipe, and are very happy there's no extra noise.
The rear muffler and tail pipe is fairly well situated, inside the body line of the car, I would say the likleyhood of damage is very low, the most vulnerable part is the tail pipe witch you still have even if you remove the muffler.
Agree with the comments about the mandrel bent 3" exhaust, some of the prices I've seem are same as my VNT turbo and manifold, when you look at $ 2000 for an exhaust system, a VNT kit looks like a good deal. The VNT is a better value improvement even with a standard exhaust.

I'd like to optimize the exhaust and get performance but I'll probably stick to the standard diameter, and have two mufflers, my defer is noisy enough inside now.

Originally Posted by SSmith

You are right, shifting the remaining muffler to the middle protects it, but if others have not damaged the rear one because they use their car differently, that extra cost becomes entirely optional.

You asked why people do it that way and i gave an answer. Sorry if that was seen as an attack.

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hey mate,

i didnt think that sounded like an attack. sorry if my writing might have given the wrong tone i didnt mean for it to be like that. i was trying to explain my rationale but there was never any ill feeling or defensiveness etc.

take care.

Originally Posted by simmo

I was going to remove the center muffler to try to optimise the gas flow, providing the noise penalty is not too much. I'm also considering fitting another straight through muffler in that place. ( probably end up as my final choice) . Though I'd like to hear from guys whop have replaced the center muffle with a pipe, and are very happy there's no extra noise.
The rear muffler and tail pipe is fairly well situated, inside the body line of the car, I would say the likleyhood of damage is very low, the most vulnerable part is the tail pipe witch you still have even if you remove the muffler.
Agree with the comments about the mandrel bent 3" exhaust, some of the prices I've seem are same as my VNT turbo and manifold, when you look at $ 2000 for an exhaust system, a VNT kit looks like a good deal. The VNT is a better value improvement even with a standard exhaust.

I'd like to optimize the exhaust and get performance but I'll probably stick to the standard diameter, and have two mufflers, my defer is noisy enough inside now.

with my centre straight through muffler and pipe at the back the noise level has increased very slightly from the factory set up. you notice it when you first pick it up from exhaust shop but after a while you forget what it sounded like and get used to it.

with regards to having it at the back i cant remember what that looked like either so if it is protected as you say then i guess can just leave it there. i was upgrading my whole exhaust system so the guy would have pulled the rear muffler anyway to put a hi flow there which is why he put that in the centre and left the pipe at the back. if you are only looking to remove or modify the centre bit then yes, it would make sense to leave the back one as you would save some $. i think from memory mine was a whole new system from after the turbo all the way to the back and cost me around $600 using 2 and 3/4 inch normal bend.

i am currently fixing the clutch and leaks and installing an ems2 and silicone hoses for intercooler and cooling system. then upping the pump to suit. after that maybe an uprated intercooler. i will post it all on the what mods have you done thread once finished if you are interested and put pics of my exhaust there too.