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Post by holden on Sept 26, 2008 14:25:56 GMT 11
Hi all, Im thinking getting a 2.5"/3" exhaust for my mu but would like to know if these is much power gain from haveing the exhaust on the back of the turbo then have it bolt onto the dump pipe?? how much power gain would a 2.8 get from a 2.5" exhaust? Is it worth doing??  kane |
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Post by geeves on Sept 26, 2008 14:37:10 GMT 11
It is better to go all the way but that front section of pipe costs nearly as much as the rest of the system as it has the expansion joint and has to be made very accuratly to clear everything. My system is only from the end of the dump pipe and still gives very usefull gains over standard.
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Post by Jimmu on Sept 27, 2008 14:05:15 GMT 11
This has been asked a few times before and there have been some arguments as to if it is worth it. On my 4JB1T it made a massive difference over just having the exhaust done. I would say more difference than the rest of the exhaust did. If you want maximum performance from it get the dump.
Jimmy
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Post by holden on Oct 1, 2008 15:26:46 GMT 11
Got a quote today at Midas Whangarei for a 2.5" press bent (Didnt want it press bent but thats what they had) exhaust from the back of the turbo, flex, muffler to the end. $962.53 NZD. Mandrel exaust sound like the way to go. Got some more places to go get quotes from and will go with the cheapest. There is a guy on trademe that does mandrel exhaust in whangarei and not to dear ill try get a quote from him. www.trademe.co.nz/Browse/Listing.aspx?id=177733228  kane |
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Post by geeves on Oct 1, 2008 15:54:10 GMT 11
A little off topic but thats a monster turbo
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Post by holden on Oct 1, 2008 16:14:03 GMT 11
A little off topic but thats a monster turbo LOL Yeah makes the Isuzu one look like a little toy. |
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Post by holden on Oct 2, 2008 6:41:34 GMT 11
Got a internet qoute to day for a mandrel 2.5" exhaust from back of the turbo. $800. $162.53 cheaper then midas and should be a better exhaust.
kane
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Post by holden on Oct 4, 2008 16:17:18 GMT 11
Going to get the 2.5" exhaust fited some time next week. But would like to know the fuel and timing tuning side of things what needs to be done??
kane
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Post by geeves on Oct 5, 2008 6:52:22 GMT 11
exhaust on its own makes a sizeable gain. Fuel can be increased a tiny bit at a time till full throttle between 2000 and 3000 makes a noticable smoke then back it back to the smoke stops. timing is advanced till you hear the diesel knock then backed back so this is virtualy gone. These are not standard settings and every one is a little different.
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Post by holden on Oct 8, 2008 14:28:45 GMT 11
Has anyone done a 2.5" press bent exhaust from the the dump pipe. If so did you get alot of gain over standed. As standed 2" is press bent aswell. So 2.5" press bent should go better then standed.  ?? kane |
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Post by geeves on Oct 8, 2008 14:43:24 GMT 11
Thats how my lwb bighorn is. The difference is noticeable with power coming on earlier and smoother. Also slight economy improvement (will never pay for the exhaust from the saveings)
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Post by holden on Oct 15, 2008 7:49:30 GMT 11
exhaust on its own makes a sizeable gain. Fuel can be increased a tiny bit at a time till full throttle between 2000 and 3000 makes a noticable smoke then back it back to the smoke stops. timing is advanced till you hear the diesel knock then backed back so this is virtualy gone. These are not standard settings and every one is a little different. How do you get the the cap off the fuel ajustment screw? and is there only one screw with a metel cap?? so then I know its the right one as have have found one but cant get the cap off. |
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Post by holden on Oct 15, 2008 14:45:07 GMT 11
Will ajusting the fuel wash the bore's??
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Post by geeves on Oct 15, 2008 15:08:02 GMT 11
Bore washing does happen on diesels but is less of a problem esspecialy on isuzu engines with chrome bores. It only happens if you are seriously overfueling or have injector problems causeing lots of smoke. Chances are you would fix these problems before they caused harm
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Post by holden on Oct 20, 2008 16:24:16 GMT 11
exhaust on its own makes a sizeable gain. Fuel can be increased a tiny bit at a time till full throttle between 2000 and 3000 makes a noticable smoke then back it back to the smoke stops. timing is advanced till you hear the diesel knock then backed back so this is virtualy gone. These are not standard settings and every one is a little different. How much somke should there be?? a little or heavy? should there a little bit of smoke after tuning?? |
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Post by geeves on Oct 20, 2008 17:45:14 GMT 11
Starting from the usual amount of smoke at full throttle before adjustment it hardly changes as you tweak it up untill you reach the point that theres more diesel than can be burnt You will notice a big change in smoke and drop in power. Then back it back till the smoke returns to normal. This test requires full throttle. If you have significant smoke at other throttle positions you have an injector issue that needs to be fixed before tweaking
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Post by holden on Oct 20, 2008 17:47:16 GMT 11
Starting from the usual amount of smoke at full throttle before adjustment it hardly changes as you tweak it up untill you reach the point that theres more diesel than can be burnt You will notice a big change in smoke and drop in power. Then back it back till the smoke returns to normal. This test requires full throttle. If you have significant smoke at other throttle positions you have an injector issue that needs to be fixed before tweaking thanks for that geeves |
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