straight pipe losing power on TD? not enough back pressure

[Quinny34]

The D4D had the diesel version of the cat im pretty sure... not 100% on the non intercooled models...

At least my early 06 3l did and my 09

[wombat40]

Straight through exhaust = better flow but you don't have more fuel going in to take advantage.

If it was a carby then it would self adjust up its CFM flow limit but fuel injection is dumb - it needs to be told what to do.

The older diesil fuel pumps can be tweeked or if its the later electronic one get a chip.

Have to look at the whole package.

[Quinny34]

Have to look at the whole package.

Spot on.... It takes all the mods together to get results...

[bms]

About to do a new dump pipe on the young blokes 04 TD Lux and was going to make a 3" dump pipe then go into a 2.5" exhaust but after reading this thread are now wondering if we would be better off with a 2.5" dump pipe as well what do you guy's reckon .

[rwnslux]

in my opinion a 3" exhaust is too big for a 3L that can only rev to 4000rpm

2.5 or 2.75 would be fine

[wombat40]

in my opinion a 3" exhaust is too big for a 3L that can only rev to 4000rpm

2.5 or 2.75 would be fine

Depends on how much boost you are running!

Get a chip first then see about the exhaust - cheaper that way and more bang for your buck.

[Miller]

I just had the cat removed and replaced with a small hotdog, and the rear muffler removed and replaced with a straight through pipe. Yes it's not a hilux, but f$@#&% does it make a difference, much smoother and quicker now. Cheap mod, well worth it!

[brusa]

in my opinion a 3" exhaust is too big for a 3L that can only rev to 4000rpm

2.5 or 2.75 would be fine

There's a lot of us here that run full 3" mandrel exhaust including myself, for something that's no good it makes a big difference to performance.....

[Alby]

in my opinion a 3" exhaust is too big for a 3L that can only rev to 4000rpm

2.5 or 2.75 would be fine

There's a lot of us here that run full 3" mandrel exhaust including myself, for something that's no good it makes a big difference to performance.....

Brusa from what I have been told yes you get the increase in performance but the main gain is from the hi flo muffler not so much the 3 inch system. By having the hi flow muffler with a smaller diametre pipe you will get your performance in a lower rev band so it depend on where you are looking fro the power.
I personally know shite about this stuff other than a couple of weeks ago by accident I spent the day with a 4wd diesel performance specialist so I picked his brains for info.
Have no personal experience just repeating what I was told.

[Quinny34]

Why the mistress goes for a so hard...

[Skog07]

With a 124000 ks on the clock....
Found stock as a rock works the best......
Last service at Toyota was at 40000ks as far as I know not one plug was ever removed for a diagnostic...
The exhaust on mine was removed for a little while, ie dropped down to the main muffler and was removed from there back. Whilst it did sound alot better, performance dropped off. You got a little bit of turbo whistle around the 1800rpm mark, bolted it back on fairly quickly.
Cheers
Skog

[Jengel]

Now im rather afraid of getting a straight through

So say for an 04 3l Turbo diesel, getting a 3' is a bad idea?

I want it to sound like a Mac when im giving it the beans and a louder whistle from the turbo, but i want power gains too!!!

To get the noise, fit a snorkel and a Unifilter. It growls in your ear!!

[brusa]

Why the mistress goes for a so hard...

Posted at 8.34pm and your already not making sense mate.....must have been an early start on the leprechaun juice that day

[Quinny34]

Brusa from what I have been told yes you get the increase in performance but the main gain is from the hi flo muffler not so much the 3 inch system. By having the hi flow muffler with a smaller diametre pipe you will get your performance in a lower rev band so it depend on where you are looking fro the power.

Why the mistress goes for a so hard...

Posted at 8.34pm and your already not making sense mate.....must have been an early start on the leprechaun juice that day

For me or you.... Was agreeing with the "Albyman"...

[Fazz]

So by removing the muffler on a stock exaughst and using a straight pipe, there is a significant loss of power?

[boxhead55]

Yes form low rpm to about 2400. Then the turbo will recover.

[Fazz]

Thanks box head.

Would the loss be significant or not really?
Was planning on getting it done this afternoon :/

[boxhead55]

Some say they feel it some don't. But the extra noise always makes it feel as if it is better. And sometimes is can cause and over boost code to be logged and fail safe happen. But only sometimes
Try is you can always go
Back

[Fazz]

Yeh fair point. Thanks very much mate
Appreciate it!

[4sullima]

I had my muffler removed on my 2012 D4D, the shop I used replaced everything from the flange just before the muffler, so I still have the hump over the rear axle, but with a few shitty press bends in it, so a lot MORE back pressure than stock and I am absolutely certain that the engine is a lot more responsive and fuel economy has improved by about 50km per tank. No fault codes at all, but should I be worried about EGT if it isn't flowing as it was intended? Thanks guys