Hi All,
We are considering putting extractors on our Nissan Civillian with a 4.2 6cyl diesel motor to increase fuel economy.
Can you give any feedback on your experience, either good or bad?
Thanks
Extractors on a Diesel Motor
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Ian + Jan
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T1 Terry
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Re: Extractors on a Diesel Motor
A free flowing exhaust works wonders, but I'm not sure just how much improvement extractors would make over and above that. A long runner intake manifold makes a huge improvement in lower revs torque, but short interference flow headers make an improvement to torque, weird eh, short intake runners and long exhaust runners improve top end HP at high revs, so keep that in mind when looking at intake and exhaust modifications.
To improve fuel ecconomy yu need to improve torque so you can hold on to the higher gears for longer, removing exhaust back pressure with a free flowing exhaust reduces to piston effort required to push the waste gasses out. There is virtually no valve overlap in a diesel engine so the exhaust scavenging effect created by long runner extractors is of no benefit at all.
so, if the exhaust manifold is an old log design, fit short runner 2 in to one extractors, if the manifold has some reasonable flow design built in, save your $$ and spend it on a good free flowing exhaust, turbo flow mufflers are a good investment, Walker made some very good ones back when I had the workshop.
To improve fuel ecconomy yu need to improve torque so you can hold on to the higher gears for longer, removing exhaust back pressure with a free flowing exhaust reduces to piston effort required to push the waste gasses out. There is virtually no valve overlap in a diesel engine so the exhaust scavenging effect created by long runner extractors is of no benefit at all.
so, if the exhaust manifold is an old log design, fit short runner 2 in to one extractors, if the manifold has some reasonable flow design built in, save your $$ and spend it on a good free flowing exhaust, turbo flow mufflers are a good investment, Walker made some very good ones back when I had the workshop.
A person may fail many times, they only become a failure when they blame someone else John Burrows
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves
Those who struggle to become a leader, rarely know a clear direction forward for anyone but themselves
Re: Extractors on a Diesel Motor
I was talking to a motorhomer who had put extractors and straight thru exhaust and it was a 4 cylinder Coaster he was pulling more weight than me with a larger trailer full to the brim. He said changing made the bus breath easier and the straight thru got the gas away.
And a week ago at Fletchers creek Qld I was talking to another who had a Civilian the same as yours he put a turbo on and also a straight thru exhaust with a lukie muffler he also said it was a massive improvement on the old setup He bought the turbo for $3000 and fitted it himself, they wanted $2000 to fit.
These are their accounts of the changes to their motor homes.
Bernie
And a week ago at Fletchers creek Qld I was talking to another who had a Civilian the same as yours he put a turbo on and also a straight thru exhaust with a lukie muffler he also said it was a massive improvement on the old setup He bought the turbo for $3000 and fitted it himself, they wanted $2000 to fit.
These are their accounts of the changes to their motor homes.
Bernie