D2 Fuel Economy

[Redback]

A couple of weeks ago i did this modification to my exhaust manifold
http://inlinethumb13.webshots.com/3916/2854013550101313710S425x425Q85.jpg

Since then the fuel economy has improved dramaticly, our towing economy has gone from averaging 15l/100k to low 13s per 100k and the non towing tank is on it's way to being the best ever, so far with 260ks on the clock the needle has only got to a 1/4, this is for us, amazing.

Factor in larger tyres, roof racks with an awning, pole carrier, shovel, drawers and this is amazing, the biggest killer to fuel economy are the bigger tyres and roof rack.

I think it is a number of things that has improved our economy, the heat at the manifold has been reduced, all the gaskets are new, the manifold is finally attached properly with no leaks and is not warped, something i feel that the standard size studs weren't doing the job and were braking soon after being replaced and over time the manifold was warping, i think the bigger studs i had put in are doing a far better job than the standard TD5 manifold studs, because after replacing the studs before we never noticed this big of an improvement, there was a slight improvement but that soon dropped off over the first week.

Not only has our economy improved but also the power has too, it is pulling right off the bottom at around 1400rpm, instead of 1900rpm when the turbo kicks in, no more slipping the clutch while keeping the revs up around 3000rpm:D

So from this i would recommend that all owners of chipped TD5s do this mod if your having problems with the exhaust manifold warping and broken studs on a regular basis, which for ours was evry 6mths or so.

Baz.

[WildOne]

G'day Baz,

Does your D2 also have the Catalytic converter? Mine does but apparently some D2's don't. By all accounts this is also a major restriction that should be removed? Unsure of the legalities though?

[Ken]

G'day Baz,

Does your D2 also have the Catalytic converter? Mine does but apparently some D2's don't. By all accounts this is also a major restriction that should be removed? Unsure of the legalities though?

Totally illegal to remove catalytic converters as far as emission laws go although you can get a High Flow Cat to reduce back pressure which helps greatly as far as turboed engines go

[Franz]

Baz,

Forgive my ignorance :blush:(I'm not very technical) - what exactly did you do? :confused: Don'y know what the manifold looked like b4 so it's hard to comprehend what you did.

[Redback]

G'day Baz,

Does your D2 also have the Catalytic converter? Mine does but apparently some D2's don't. By all accounts this is also a major restriction that should be removed? Unsure of the legalities though?

It's a TD5 not a V8


Totally illegal to remove catalytic converters as far as emission laws go although you can get a High Flow Cat to reduce back pressure which helps greatly as far as turboed engines go

AS ABOVE


Baz,

Forgive my ignorance :blush:(I'm not very technical) - what exactly did you do? :confused: Don'y know what the manifold looked like b4 so it's hard to comprehend what you did.

Franz it looks like this
https://www.aulro.com/afvb/images/imported/2008/02/306.jpg

Baz.

[feral]

Franz,

Baz has removed the webbing from the manifold. The manifold is cast and during manufacture there are webs between the ports. Baz has circled the shiny bits.

The fuel economy most likely would have come from all the new gaskets and the proper sealing of the exhaust manifold.

P.S.....stuff you Baz :p I must not let work get in the way when on this forum :eek:

Cheers.

[Franz]

Franz,

Baz has removed the webbing from the manifold. The manifold is cast and during manufacture there are webs between the ports. Baz has circled the shiny bits.

The fuel economy most likely would have come from all the new gaskets and the proper sealing of the exhaust manifold.

P.S.....stuff you Baz :p I must not let work get in the way when on this forum :eek:

Cheers.
Thanks Feral.

Would removing the webbing make for a better (non leaky) fit? I did see the shiny bits but did not know there was webbibg there - Baz's b4 picture explained that.

If that's what it takes to improve fuel economy, I was going to break out the angle grinder (although that looks more like a die grinder job!)

[Franz]

Franz,

Baz has removed the webbing from the manifold. The manifold is cast and during manufacture there are webs between the ports. Baz has circled the shiny bits.

The fuel economy most likely would have come from all the new gaskets and the proper sealing of the exhaust manifold.

P.S.....stuff you Baz :p I must not let work get in the way when on this forum :eek:

Cheers.
Baz,

I haver no noticeable increase in fuel consumption when running the 265/75's - There might be a difference in the hard stuff but I never use my standard tyres off road and therefore have no basis for comparison.

On road, I have no discernable difference in my fuel consumption when running 265/75's.

[WildOne]

It's a TD5 not a V8



AS ABOVE



Franz it looks like this
http://inlinethumb11.webshots.com/6922/2448125340101313710S425x425Q85.jpg

Baz.

Baz, my D2 is a TD5 also mate, a 2001 model like yours i believe, and mine has a catalytic converter just after the banjo joint on the exhaust.

[BigJon]

Some Disco II TD5s have the convertor, some don't. As a matter of interest, the non convertor engine pipe is a direct bolt in replacement for the convertor type, and is a LOT cheaper. I think the TD5 would pass the relevant emission tests regardless of whether it had the convertor or not (but that is my opinion, not a fact). As far as I know, the Australian standard of the day was a lot less strict than the Euro equivelant.

[WildOne]

Some Disco II TD5s have the convertor, some don't. As a matter of interest, the non convertor engine pipe is a direct bolt in replacement for the convertor type, and is a LOT cheaper. I think the TD5 would pass the relevant emission tests regardless of whether it had the convertor or not (but that is my opinion, not a fact). As far as I know, the Australian standard of the day was a lot less strict than the Euro equivelant.

I forget which site i was reading about this, but it was relating to the differant mods to be done to the TD5 exhaust which included, as Baz has done, grinding the webs out of the manifold, slotting some of the bolt holes in the manifold, removing the cat conv. all together, and removing the middle muffler.
Even the rave cd does'nt show a cat on it's exhaust diagrams. Mine might fall off one day:angel: so i can see if there is any differance without it.

Baz, if you rekon your changes have made a noticeable differance i may give it a go too.
I want my Beast to inhale and exhale as well as possible.

[Redback]

If your having trouble with broken studs, then yes go right ahead, it's a big job and not cheap if you don't do it yourself, i had to get a mechanic to do the studs as i don't have good quality thread taps.

Grinding the manifold is the easy part, i did that with a 4" angle grinder, it's the rest that's makes it expensive, wait till you have the broken studs and do it then.

Baz.

[BradM]

Hi,
I have one of these fitted, the 25" one and it took my Deisel back to 10l 100klms after it was ECU remapped by TombRaider (on his advice) and doing 12l 100 klms.

I am one happy Disco owner. 30 - 40% more power with the same fuel economy. I did not even bother to remove the Cat converter after fitting one of these. "They Work" :D

Vortex High Performance Exhausts (http://www.vortexexhausts.com.au/products.html)

BradM