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is it worth puttung a 2.5" exhaust on 4.2 efi

Tech Talk for Nissan owners.

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is it worth puttung a 2.5" exhaust on 4.2 efi

Post by MUNGA GQ »

is it worth puttung a 2.5" exhaust on 4.2 efi. Welding a pipe straight through the cat and fitting 2 new hi flow mufflers ?

Now the floor on the pasagers side heats up a lot, and i was thinking the cat may be blocked and over heating it as well as heating up the floor.

Any help.
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Post by 76patrol »

bud a bigger exhaust is always a worthy mod. i'd go a 3" myself. on my 3l i run a 2.5". no cat just a straight thru muffler and dump pipe. prob should have a cat though. haha just my opinion. cheers ray
that f***n hippy in that f*"*""n g60

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Post by BigrigCQ »

I ran 3" too extravagant used to much fuel and too noisy!

Went back to 2 1/2 and got better fuel economy and heaps more torque bak when towing the boat!

Ditch the cat!

I only run 1 hooker 2 1/2 muffler with dumped before diff!
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Post by 76patrol »

i hadn't even considered fuel. listen to bigrig i reckon. bigrig im with ya on the donkeys. 3 truck will be interesting again.
that f***n hippy in that f*"*""n g60

76 troll rockin a rb30 gq driveline, rollin on 37's and flexin with a 4 link.

buildup at downunder4x4.net
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Post by GAS-747 »

You want some back pressure to produce power.
Non turbo I would look at 2.5, and for turbo 3" JMO...
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Post by PGS 4WD »

The bigger exhaust is better however it also means devation from stock and therefore the stock tune may be an issue, large modifications from stock can present less benefit than expected due to them not suiting the standard tune. Larger gains are often acheived by the tuning process than the mechanical change.

Joel
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Post by wilsy »

PGS 4WD wrote:The bigger exhaust is better however it also means devation from stock and therefore the stock tune may be an issue, large modifications from stock can present less benefit than expected due to them not suiting the standard tune. Larger gains are often acheived by the tuning process than the mechanical change.

Joel
Joel, so what mods would you recommend to a 4.2efi, already with extractors and 2.5"exhaust, for those of us wanting a power upgrade without the use of forced induction??
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Post by create »

I installed a 2.5' mandrel bent system with 3-2-1 extractors. I went for straight through no muffers or cat. It was far too noisey and attracted too much attention. It popped and banged and droned really badly. I have now put a redback hi-flo muffler and its much better. Well worth the change.
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Post by BigrigCQ »

bigrig im with ya on the donkeys. 3 truck will be interesting again


Bloody oath the 3 car is going to be very interesting!

The donkees have got a real good crew this year!

If they dont right off there vehicles at tamworth!

Stay only with 2 1/2! you will regret going to 3"
Dont hold back, Limiter is there for a reason!!!
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Post by MUNGA GQ »

thanks guys i will be going for a 2 1/5 inch.
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