the old 3" exhaust debate..

[chapel gate]

yeah i know, but my old 2 1/4" stainless needs replacing. went to get a quote from a firm with an very good rep not far from me. the gist of the conversation was that i can have a 3" fitted if i want but i wont be getting any worth while gains over a 2 1/2".

bet they havnt got a 3" bender i hear you all cry, but they have..

what do you reckon?

 

[karl webster]

I recon let me know how much to have an extra one made

the he restriction is at the back end and also the boxes.

 

[clivehorridge]

Mine was made from 62mm internal ss and the box was made up in the workshop, but being a HZJ, I probably wouldn't have benefited from a 3".

Guessing the main restriction point on a HDJ will be the turbo dump pipe...

Mine came with a lifetime (of the truck) guarantee, so I'm reasonably well covered.

 

[Towpack]

To get full benefit from a 3" exhaust you need a matching 3" dump pipe as the OE dump pipe then becomes a restriction.
http://www.ebay.co.uk/itm/Toyota-La...HD-T-1HD-FT-/111730199706?hash=item1a03a38c9a

 

[Chris]

It's tha bend over the rear axle that loses the most
Get rid of that and you'll be flying regardless of the dia of the system

 

[chapel gate]

He says theres plenty of room to not need the squashed bit over the cross member. They make there own silencers. He did look at the dump pipe and concluded it wasnt too restrictive.

 

[StarCruiser]

the old 3" exhaust debate..

Even if there is a restriction, the losses in the pipe will be reduced by either increasing the diameter and/or decreasing the length. That's IF the capacity of the pipe is below the capacity of the restriction. If it's above that, then no decrease in pipe losses will have any appreciable effect.

I would say the pipe needs to be slightly bigger than the restriction of the turbo down pipe. After all, the turbo itself is a restriction in itself not just the down pipe.

 

[frank rabbets]

So what's the official power and or mpg improvement figures on an improved exhaust over the original?

 

[Shayne]

I got a 3" exhaust and was pleased as punch with it , but then i was told i should have had the turbo downpipe done as well so i did and i am very glad i did . Different truck of course but Chas has a 3" exhaust and is waiting for a bigger downpipe on his 80 .

 

[Towpack]

So what's the official power and or mpg improvement figures on an improved exhaust over the original?

There aren't any. Short of actually dyno testing before and after you've just got to make do with the fact that a bigger bore/free flowing exhaust makes the engine feel more torquey and responsive, probably due in no small amount to the tweaked fuelling and boost you can run. JMO

 

[chapel gate]

I got a 3" exhaust and was pleased as punch with it , but then i was told i should have had the turbo downpipe done as well so i did and i am very glad i did . Different truck of course but Chas has a 3" exhaust and is waiting for a bigger downpipe on his 80 .

In what way were you as pleased as punch with it? Why were you very glad you had the turbo down pipe done? In what way did they "do" the turbo down pipe?

 

[Shayne]

Mines a 1kz-te 90 series just so there's no confusion . It's hard to explain how a thing feels but anyone who has ever de-restricted a 125cc 2-stroke motorbike will know what i mean by pleased a punch . The turbo pipe flange must remain the same but tapers almost immediately up to a 3" diameter and it felt like it had been de-restricted again .

The 90 series drives like a car but changing the exhaust gave it a completely different character with power delivery more tractor like , less engine braking and lots more torque - more like the 80 engine i guess .

I imagine the 80 exhaust is less restrictive to begin with so the results might not be as obvious as mine were but what have you got to lose if your paying for a custom made job anyway .

 

[chapel gate]

Cheers shayne

 

[Yaro]

I have a custom 3 inch exhaust fitted in my 1hd-ft. This is one of the most meaningful upgrades that i have ever done on a 4x4 - my current 80 is my 10th truck and 4th 80 series in total up to now. I have changed entire exhaust piping from turbo going to the back of the vehicle, including down pipe. I very much recommend this upgrade for a turbo diesel 80.

 

[stumog]

On mine I have the oe first box then goes into 3" with a straight throw silencer and exits just in front of the osr wheel. This totally changed how my 80 would drive it just picked up so much quicker also was better on fuel. I try not to work out mpg when I am commuting in it though. I would use around £40 a week in fuel but once I did the exhaust I wouldn't have to put fuel in till Wednesday if I didn't use at weekends.
Best mod I have done so far.
Stu

 

[StarCruiser]

Nice job Yaro. Was that custom built from scratch as the down pipe looks really nicely crafted as does all of it?

 

[chapel gate]

Nice system there yaro.

is the general consensus the back box isnt needed, makes little difference to noise?

Still dont know what to go for tbh. Has anyone gone from a 2 1/4" to a 2 1/2" to a 3" and what were the incremental increases in performance please..... oh and before and after a free er flowing dump pipe was fitted to each different diameter system...

Anyone?

 

[Shayne]

http://beauexhausts.com.au/faqs/

 

[Sarmajornz]

I have a Rage Big Bore 3 inch mandrel bent pipe from the base of the turbo. It follows the oem route except for the very last section which I changed to exit out the side just behind the rear mud flap (kept squashing it). I feel like it allows the turbo to spool up quicker. It also sounds better.


Hedley Berge

 

[Ranger_ofthe_North]

I have a Rage Big Bore 3 inch mandrel bent pipe from the base of the turbo. It follows the oem route except for the very last section which I changed to exit out the side just behind the rear mud flap (kept squashing it). I feel like it allows the turbo to spool up quicker. It also sounds better.


Hedley Berge

I am new in here. So, Hi everyone. I have owned quite a few BJ60s and HDJ80s, but have not done anything to them. Now, I need to improve my currecnt 80 Series, an 1HD FT equipped off-roader.

Hedley, could you please post some pictures of your exhaust systems? Do we need to do anything with the sensors? I think there is one sensor in the first box? Do we need to do something to the electronics?

I need pictures, because I am in Pakistan, and the only way to have a bigger exhaust is to manually construct one.

Thanks a lot.
Irfan Khattak