1HZ exhaust (3 Viewers)

[Tennessee Jed]

My exhaust has a fair amount of surface rust on it and I'm considering getting it replaced. Is there anything to be gained by going to a 3" exhaust on a stock 1HZ instead of stock? I haven't measured the exhaust but I believe it's 2 1/2". Also, the right side of of the exhaust seems to cover most of the frame there below the door (troop carrier) and this seems to block welding on sliders which are also in the future. Can/should it be rerouted to miss this area (running inside the rail) or is this not really a concern?

 

[HZJ75 FARMER]

I have one with extractors and 3" exhaust. I don't think it has any more power than the others with the standard exhaust and manifold.
Possibly hard to tell, when comparing vehicles carrying slightly different weight, slightly different degrees of engine tiredness.
I didn't fit the bigger exhaust, it was on it already, so I didn't have a before and after comparison.

But if I was replacing a standard one, I would replace it with a new standard one. By going bigger, you really have to replace all the bits right through, and then it just makes life difficult in the future to find new bits that fit.

I also wouldn't replace an exhaust just because it has surface rust on it though. I would wait until it has holes in it.

 

[Tennessee Jed]

Thanks. It has an extractor on it now, but I agree probably nothing to be gained. Surface rust is rough in places but I'll wait a couple more years and see.

 

[HZJ75 FARMER]

Also something else worth mentioning, one of mine came with a Hi-clone fitted to it. I don't think that makes any difference to the performance either.

 

[Tennessee Jed]

Yeah mine came with an extractor, don't remember the brand, we call them headers here. The truck runs and starts perfectly and I understand there's no benefit to going back to the stock manifold there either. Truck's so reliable I'm looking for things to fix. Edit, not sure what a Hi Clone is, I assumed it was your extractor.

 

[HZJ75 FARMER]

A Hi-clone is a special piece of metal that fits into the intake hose, to swirl the air to get it to mix better with the fuel.

But I don't think it makes much or any difference.

 

[HZJ75 FARMER]

Welcome to Hiclone! - Hiclone Welcome to Hiclone! - Hiclone - https://share.google/ENqRrGk88t1djZ8px

 

[Tennessee Jed]

Yeah, won't be importing one of those. I remember that kind of thing from the gas crunch in the 70's. They didn't solve the crunch.

 

[PhillipJFrye]

For what it's worth, I'm super happy with my SS Manta exhaust. Evergreen Offroad hooked me up. It objectively increased the low end on my 25 year old 1HZ. I always had to shift down to first on a very steep hill near my house. Now I can cruise up in second gear. A surprising difference, and a cool purring noise out the back.

 

[bjowett]

The best in line six engines have a true dual exhaust. BMW is great example. Extended split manifold downpipes are the next best step… just look at the 3FE and early 1FZ in their respective models. Eliminating the interference between cylinders is key, and producing a system that simply eliminates the possibility is why the dual will work well. The cost to produce doesn’t need to be mentioned… it won’t be cheap.

I always though it would be fun to find out what the 1HZ could produce with a nice dual system and a ACIS variable intake.

 

[Tennessee Jed]

That's really interesting Bruce. I now have a nice humming exhaust leak after an event, probably hit a rock, and if I actually have to replace the exhaust I may look in to this. The Manta exhaust is pretty reasonable, about $800 from Australia through Evergreen OR, which I bet is about what a local shop would charge to build one, or maybe less.