300tdi 3inch exhaust required

[redrovertdi]

Does anybody know/reccomend some body to make an exhaust in brisbane or selling kits for a 300tdi 110, was quoted $800 today from turbo back.

[Blknight.aus]

theres an exhaust shop near here that will make up what you want custom to your vehicle and not charge you umpty million dollars for the privilege of doing so.

Havent had a complaint about them yet.

[LowRanger]

A 300Tdi,unless you are doing something outlandish to it,doesn't require anything more than 2 1/2" exhaust.And that will save you a considerable amount.

[james_foster]

you could always just put a 3" tip on it!:D

[weeds]

i had my 2.5 fitted normal bend at redcliffe, straight through no exhaust with flexi joint for $200 from memory

[redrovertdi]

-With out starting an arguement those that i have spoken to with the 3in exhaust all reccomended it, my defender runs a full front allard intercooler and a water cooled MTQ mitsubishi turbo, i dont have a centre muffler but the exhaust is tired and i have been patching up holes around the rear muffler so if i am going to replace now would be the time to upsize

[CraigE]

-With out starting an arguement those that i have spoken to with the 3in exhaust all reccomended it, my defender runs a full front allard intercooler and a water cooled MTQ mitsubishi turbo, i dont have a centre muffler but the exhaust is tired and i have been patching up holes around the rear muffler so if i am going to replace now would be the time to upsize
Yeah, fair enough, but the question you need to ask yourself is have any of these people produced quantifiable positive results from running a 3" system that have been doccumented and compared to a 2.5" or 2.75" or do they just not know any better? Most opinion is a 3" is too big and can actually cause issues.

[LowRanger]

What CraigE said is exactly correct.
A 2.5" exhaust will flow over 500 CFM which is approx. what an engine putting out just over 230H.P. will flow.
This is more than enough for a 300Tdi no matter how big the intercooler and size of the turbo,without some serious internal work done to the engine.
There are a number of reasons you don't want to go too large with the exhaust,such as loss of scavenging and accoustic resonance.There is a lot more involved than just picking a big pipe.Just look at the doof doof brigade,all noise and no go,but they usually have a nice big pipe and chrome resonator.

[rick130]

Yeah, fair enough, but the question you need to ask yourself is have any of these people produced quantifiable positive results from running a 3" system that have been doccumented and compared to a 2.5" or 2.75" or do they just not know any better? Most opinion is a 3" is too big and can actually cause issues.


IMO 2.75" would be about ideal, but there's no problem with a 3" system, plenty of us use them and have done for a very long time now without any known overspeed issues.

When I built my system (too many years ago now) 2.75" tube was prohibitively expensive here in Australia and for the overall length of a 130 system I couldn't see any sense in 'just' going to 2.5" tube, although in hindsight it probably would have been fine.

In comparison the standard OE exhaust is 60mm OD, (2.375") all bends are mandrel bent with the main muffler and resonator straight through perforated tube, so it is nicely made.

Before making the big pipe system I had ground out the large mig weld bead inside the throat of the dump pipe, it encroached into the pipe by a large amount, (close to 5mm all the way around) but my sensitive bum dyno couldn't feel any improvement, nor was there on my test roads and hills.
Having noted that, I still ground out/throated and matched the cast dump section to the flange and pipe and made sure the transition to 3" was at a 15* taper to minimise turbulence....:angel:

Going to a 3" exhaust several things were immediately apparent.

Maximum EGT's dropped by about 25*C.

The rev range through the gears was extended significantly.

With the OE system 3rd gear was good for about 75km/h, then the engine just stopped accelerating, it hit a wall so you had to change gears. (255/85-16's)
With the big pipe 95km/h was easily within reach, and the first test run I hit 100km/h in third.
The engine has done 300,000km now and the improvement there is still useful, I hit about 95km/h in third yesterday overtaking a car, so nothing untoward has happened to the turbo or the engine over all those years either.

Apart from that, the performance increase was pretty minor (no pump fuel adjustments had been made, everything else was stock)

I have no doubt a 2.75" pipe would have enabled exactly the same improvements, although I'm not sure a 2.5" pipe would, taking into account the length of a 130 system. A 90 or 100" (RRC/Disco) could probably utilise a 2.5" system well but I think a 110 could leave something on the table, but we'll never know unless someone does a back to back dyno run and it's only a 300Tdi on a Landy, so why would you ?

One thing I must point out, the noise increase, drone and resonance was terrible. (and I'm an ex-racer)

Don't listen to anyone that says a turbo alone muffles an exhaust adequately, a muffler and particularly a resonator is a must with a 3" pipe.

[rick130]

What CraigE said is exactly correct.
A 2.5" exhaust will flow over 500 CFM which is approx. what an engine putting out just over 230H.P. will flow.
This is more than enough for a 300Tdi no matter how big the intercooler and size of the turbo,without some serious internal work done to the engine.
There are a number of reasons you don't want to go too large with the exhaust,such as loss of scavenging and accoustic resonance.There is a lot more involved than just picking a big pipe.Just look at the doof doof brigade,all noise and no go,but they usually have a nice big pipe and chrome resonator.

I disagree Wayne, with a turbocharger the only thing stopping you going too large is turbo overspeed, scavenging losses are (mostly) a non issue but back pressure is, unlike a naturally aspirated engine.

One place where maintaining heat and therefore velocity (scavenging) seems to help is in the first couple of feet of the dump pipe.
Back when I built my system I had a good long chat to one of the blokes from Queensland who was making 3" Patrol and Cruiser systems and they'd found that HPC coating the dump picked up 4-5lb/ft of torque and HP over an uninsulated system.
I header wrapped mine from the cast dump to the back of the t/case and can't say it actually did anything, no one is sensitive enough to pick up that type of minor improvement, but it dramatically cut down the temp inside the cabin.


Also the longer a system the lower the flow as you have higher duct losses, even on a straight length of tube.

[LowRanger]

I disagree Wayne, with a turbocharger the only thing stopping you going too large is turbo overspeed, scavenging losses are (mostly) a non issue but back pressure is, unlike a naturally aspirated engine.

One place where maintaining heat and therefore velocity (scavenging) seems to help is in the first couple of feet of the dump pipe.
Back when I built my system I had a good long chat to one of the blokes from Queensland who was making 3" Patrol and Cruiser systems and they'd found that HPC coating the dump picked up 4-5lb/ft of torque and HP over an uninsulated system.
I header wrapped mine from the cast dump to the back of the t/case and can't say it actually did anything, no one is sensitive enough to pick up that type of minor improvement, but it dramatically cut down the temp inside the cabin.



Also the longer a system the lower the flow as you have higher duct losses, even on a straight length of tube.

Rick

The size of the turbo,will come down to the physical and mechanical inefficiencies of having a Turbo that is too large for the engine.And we are talking about a nearly stock 300Tdi.
As far a coating or not coating to give possible increases,this has been a debated point for many years,some swear by it,others deny it.It has to do with Helmholtz law regarding pressure wave resonance in an exhaust allowing better scavenging and efficiencies.Some say that by changing the frequency of resonance by adding a coating (similar to a tuning fork effect)that greater efficiencies can be had.
Backpressure on a typical Turbo Diesel engine is around 3"Hg
I have done a couple more calculations regarding Intake airflow(CFM) and exhaust flow(CFM) on a 300Tdi.Which is dependent on maximum engine temp. and the volumetric efficiency of the engine,and a 2.75" exhaust will do the job nicely.The diameter of the pipe is I.D. as I noticed you were referring to O.D..
These specs could be changed up or down by either increases/decreases in engine temp and changes in engine volumetric efficiency.

And I agree that you need to run a muffler/resonator as it can become very annoying after a while.
I have a 2.5" I.D exhaust on one of my Defenders,and it borders on uncomfortable,even with a muffler.The vehicle is stock apart from this,I haven't got around to turning things up like my other truck,which runs the standard exhaust.

[ugu80]

Performance tuning a 300tdi. Sort of like sprint training a snail.

[rick130]

Hi Wayne,

I'm aware of the theory on gas temp and pipe tuning, I was surprised when this bloke told me his results with the TD42T and the HPC coating.
(and for the life of me I can't remember his name, he rang me to discuss an online query I had re TD42T systems and we ended up talking for about 15-20 minutes)
They backed to backed it and it was repeatable, which doesn't mean you'll get the same result on a slightly different combination either.

It's definitely OD on exhaust too.

I still have 4m of 3" aluminised pipe plus a few mandrel bends, about 1m of 2.5" in black and 2m of 1.5" (from modifying headers and making a couple of merge collectors) and it all measures OD.

[rick130]

Performance tuning a 300tdi. Sort of like sprint training a snail.

Yep ! :D

[LowRanger]

Hi Wayne,



It's definitely OD on exhaust too.

I still have 4m of 3" aluminised pipe plus a few mandrel bends, about 1m of 2.5" in black and 2m of 1.5" (from modifying headers and making a couple of merge collectors) and it all measures OD.

Hi Rick

I just meant that we were referring to 2 different measurements,you to O.D and me to I.D:D

[Didge]

get some side pipes and use em as fancy rock sliders - go onnnnn!
Oh, and then post the pics :)