3 inch exhaust - how much benefit for an N/A 1HZ? (1 Viewer)

[JDM Journeys]

I'm still in the early stages of assessment, and parts acquisition, but my original exhaust with 240k kms on it has some pinholes that I can see (wheel-well) and probably more holes that I can't see. If I'm not planning to turbo it (I like the simplicity of it as is), will I see much benefit to a 3" exhaust, or would I be better off just getting the factory pieces and bolting on a brand new OEM system? If I went 3", I'd have to have a shop custom make it. Bolt on - I could do myself.

I'm at 1100m, so not super high altitude. My use will be mainly soft-roading, and long trips on back roads... I'm also less accepting of droning noises than I used to be. Opinions from those who've driven both?

 

[GTSSportCoupe]

I've read that 1HZ's respond well to quality headers (extractors as some call them) and a free flowing exhaust. Improves the top end a bit. Fella in our local club has headers and stainless exhaust in his HZJ73, and goes good. 3" might be a bit big for non-turbo application? 2.5" (mandrel bent) might be best? Do a bit of reading and see what others have done.

 

[SKULLYOTA]

I tried this topic awhile back, asking for exhaust opinions with an NA 1HZ. didn't get much back

1HZ non-turbo, what are you guys running for exhaust


I was going to replace mine with 2.5" and a basic welded turbo muffler at somepoint.

 

[Indestructible 47]

Most Aussies that turbo the 1hz mildly go with a 2.5" exhaust. Reason is that 2.5" flows more than enough whilst still maintaining decent back pressure.

A 3" exhaust is not going to benefit a N/A 1hz. Certantly not seat if the pants. Extractors yes, a little, but the 1hz is a total slug unless many thousands are poured into it. Stock for stock, a 2f makes similar power, and I garentee it will go better to put perspective on it.

 

[AussieHJCruza]

There's no need for a 3" exhaust on an N/A 1HZ. Extractors pick up a few horses on the dyno but she'll still be slow

 

[AndrewHadji]

i had extractors, and 2.5. No difference on teh butt dyno, but she did sound better. I didnt see an increase in mpg either. I went 3 in when i turboed

 

[JDM Journeys]

Thanks for all the feedback folks. Much appreciated. Sounds like 3 inch isn't worth the cost/hassle. Still weighing OEM versus exhaust shop bent 2.5". But holes in the body will get fixed before holes in the exhaust.

 

[ForealBoreal]

You do not need back pressure for a diesel. You need to evacuate as much heat as possible. I wouldn’t think twice about going with 3” on a NA 1HZ and probably will in the figure as I have a bunch of the stuff laying around opposed to 2.5”