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[Betsy1969]

I read on one of the Landrover forums on FB today that someone had fitted a petrol exhaust system to a diesel as they are bigger bore and thus should provide an improvement in power.

Is there any truth or evidence to support this ?

Regards
Andy

[Old Hywel]

Different length downpipes.

[oilstain]

I've found if you want a bigger bore it may be best to either go to a company that does the conversions for the engine your fitting or a old school exhaust company that looks under your land rover, look at the engine and makes one up to suit your Land Rover and your budget in mild or SS steel. We have such a company on Anglesey, but a long way from you

[rustynuts]

It is a misconception that a larger diameter exhaust will necessarily give an increase in power. For every engine (and state of tune of that engine) there is an optimal diameter, which if exceeded will result in lower gas velocity such that the pressure wave travelling along from one exhaust pulse will restrict the flow of the next.
I don't know whether the original exhaust is under, optimally or oversized, but you could be going to a lot of effort to end up with a reduction in power.

[Wittsend]

If you have a standard engine (petrol or diesel) then stick with a standard exhaust system.

As mentioned ^^^ diesel downpipes are different as they have a different manifold. There after the system is the same.

The problem you have is that you do not know what a PO may have fitted cobbled together.

If you have a bored-out high comp petrol (ACR upgrade for example) or a 200/300 Tdi fitted then fitting a big bore exhaust is a waste of time/money and power. For a 200/300 Tdi you will benefit from a 2" diameter bore all the way through.

Whether you go for a mild steel replacement or a s/s system - you have to do the maths.
A standard OE system should last you 4/5 years and they are dirt cheap and not that difficult to replace.


 

[Betsy1969]

Maybe I should qualify my original post . I am and intend to continue , running a standard 2 1/4  Diesel with a recently fitted new bog standard exhaust system which hasn’t driven much over 20 miles in the last 2 or 3 years . I realise that lack of use is not the best way to preserve a mild steel exhaust but it is garaged full time so I hope that will help.

My original post was purely a question based on information from a Facebook group which suggested that petrol exhausts had a larger bore than diesels.
I have neither the intention or funds to fit a tuned engine at any time , I’m happy to stay original.

Thanks

Andy

[diffwhine]

I'll stand corrected, but if the standard 2.25 exhaust for petrol is a wider bore than the equivalent diesel, I've certainly never noticed it. Probably explains why I don't use Facebook - too much confusion on there for my liking.

[George1990]

Yes I've noticed the the Land Rover groups on Facebook to be full of rubbish, and I can't bring myself to correct them. On the forum people generally only comment if that have the answer or quality experience on the subject, while facebook gets all the verbal diarrhoea and the 'my mate said this' kind of advice.

[GHOBHW]

i thought the later series 3 diesel engines also have a 3 stud exhaust, to bring it in line with the petrol route, no idea if the bore is different or not, also never noticed
on the facebook subject...
not to mention the mocking posts and the same jokes everytime
i see people trying to sell things, people say "not worth owt", next week that person is selling the same thing but its now worth a fortune
it does have its good times sometimes though, for sharing or finding land rovers or previous owners

[biloxi]

Many years ago I bought this odd L/R engine pipe cheaply. I knew it wasn't S1. I thought I could cut it up and use the various bends.
It turned out to be a pipe that was only used for a very short period, according to an Australian parts supplier. Picture also shows a
 2.25 pet. engine downpipe.
.W.

[biloxi]

Please ignore the above post. Completely irrelevant to the original question.
.W.