Offroad-Express

my exhaust seems very restricting on my 4.2 diesel lwb daily driver, its a non turbo, i was just wondering if anyone has changed theres and had good results?? just thinking of changing pipework from the manifold to the back. dont want to turbo this one, its not worth the expense and i would rather turbo my offroad truck at some stage.

I think the general consensus is no bigger than 2 1/2" on a N/A and it gives a noticeable difference but is not always an increase thats worth the cost.

Did read on patrol4x4 that one guy did the bigger exhaust with headers as well and decided he might not need a turbo.

muskie wrote:my exhaust seems very restricting on my 4.2 diesel lwb daily driver, its a non turbo, i was just wondering if anyone has changed theres and had good results?? just thinking of changing pipework from the manifold to the back. dont want to turbo this one, its not worth the expense and i would rather turbo my offroad truck at some stage.

DieselBoy is prob the one to talk to about performance gains from the N/A td42, When i had my Safari's and was researching mods etc I recall Pete (DieselBoy) was modding his and getting ok gains using a Holley Blue inline pump etc.

Cheers

we ran a straight 3" with extractors on our 2003, 4.2 GQ with just a small quietner, did help with the notorious heating problems.

2003? i think youl find that is a gu, and turbo

Taz wrote:I think the general consensus is no bigger than 2 1/2" on a N/A and it gives a noticeable difference but is not always an increase thats worth the cost.

Did read on patrol4x4 that one guy did the bigger exhaust with headers as well and decided he might not need a turbo.

That's a coment from someone who has never driven a turboed TD42!
My one was NA and had 2.5" exhuast better inlet etc witht he fuel turned up a wee bit accordingly and the difference between that and after turboing it is incredible! I say save your money on NA mods and just turbo it. The factory TD42 manifold is actually quite a good design so going to extracts doesn't make that much difference but it does sound better!!!!!
With a huge amount of mds you might gain about 20% on a TD42 which will give you about 120kw. A fatory turbo that is really small and apthetic will give you with all the emission crap. Sort it out a bit with a decent exhuast etc and you'll probably gain 20% on that eg 145kw. Fit a decent turbo and you'll be quite a bit more again.
Diesels love turbo's and to say modding it NA is almost as good is just fooling yourself.

PS Porting the head on a TD42 will gain about 28 to 30% increased flow but you need to know what you are doing so cheaper to do a turbo, ( or maybe turbo, ported head, inlet, exhuast, fuel pump, intercooler and go for over 200rwkw would be an idea!!!)

Safari Swb wrote:2003? i think youl find that is a gu, and turbo

Originally a 2002 but, chassis was replaced and now classed as 2003 GQ/s2 with the black top motor,with a/m turbo.

are lumpier/turbo cams available for the td42? I've searched and cant find shiet.

I put a mandrel 3" on mine late last year (no turbo yet), it made a big difference. Sounds better and it responds and opens up much better.

flyingbrick wrote:are lumpier/turbo cams available for the td42? I've searched and cant find shiet.

Yeah there is alsorts available. Depends what you want but the turbo cams are a bit better an they can also be improved upon.