BJ70 exhaust

[Devils Paw 80]

I've searched the archives on this subject and have found that some of you with turbos have evidently run a straight pipe down the right side. I've got a couple questions about this. First, a local exhaust shop told a former acquaintance of mine that his BJ70 needed a flexible pipe section in that short, straight run under the passenger door on the stock routing. That's BS, or true? It didn't sound very good, so the guy was dissapointed. One of the reasons I ask is that mine looks like it's been patched in this area, and the original doesn't appear to be flexible pipe. Second, for a non turboed 3B, would a straight 2.5 "routing out the right side with a muffler in there somewhere be a good setup? Would this require relocating the heat shield, and if so would it really be worth it changing the stock routing?

 

[silvercrusher]

I think alot of diesels are fitted with the flex piece. I know at work ours all have them. It takes up a huge jolt on start up and some expansion from heat which saves alot of grief.

 

[crushers]

the only Toyotat diesel i have come across with a "flex" is the 2LT,

all the rest are solid pipe,running straight pipe on a NA 3B is going to be LOUD, not recommended.
you can get free flowing 2 1/2" mufflers that do drop the noise and still lets the truck breath properly...
cheers

 

[beanz2]

One of my 1HZ engines which came from an HZJ80 has a flex stainless steel braided pipe. The one from an HZJ73 doesn't. The presence of a flexible section seems to vary with each application.

Dave

 

[Island Moose]

the only Toyotat diesel i have come across with a "flex" is the 2LT,

all the rest are solid pipe,running straight pipe on a NA 3B is going to be LOUD, not recommended.
you can get free flowing 2 1/2" mufflers that do drop the noise and still lets the truck breath properly...
cheers

My 88 BJ70 JDM has flex under the right door. It certainly looks factory. I have a straight pipe out back with no turbo, downshifting is invigorating.

 

[crushers]

invigorating can become irritating to others in very short time.
was the "flex" an actual flex or a resonator?

 

[dieseldog]

Both of my 7x series trucks have a flex pipe w/braided stainless from the factory on the short run just after the down pipe. It is definitely NOT a resonator but rather, a means of absorbing some of the shock load/vibration connected with the operation of a diesel. My BJ-42 never had one even though it has the same 3B, so it is my guess that it began factory use with the birth of the 7x series trucks. Both of my 70's had the bone stock exhaust systems when I got my hands on them.

 

[crushers]

now that is interesting...
so i looked on the EPC and it seems all the diesels from 1984 onward (in other parts of the world) received the flex piece. learn something new each day, eh?
it does make sense...

 

[wesintl]

I have a stock exhaust I got from sheldon. No flex pipe. Of course I really need to reroute the exhaust inside the frame rail. I was just out at Slee offroad for sliders but the exhaust is in the way. I really don't want to hack up a cherry OEM exhaust so I may consider selling this if someone is interested.

 

[silvercrusher]

My stock 85 bj60 has the braided expansion piece i watched it when my wife started the truck and it takes up a whopping load when started cold. I think i would install one even if it wasn't stock on the system just to prevent the cyclic loading that would occur in that section of the pipe. .02

 

[Devils Paw 80]

Thanks to all for the responses. I wouldn't consider running without a muffler, but I was wondering if re routing the exhaust straight out the right side would be worth considering.

 

[crushers]

iwould say that depends on how loud you want it for your passengers in the rear.
also how clean your engine runs, if it blows balck then you will have quite a mess to clean off your paint every once in a while...
cheers

 

[Koffer]

now that is interesting...
so i looked on the EPC and it seems all the diesels from 1984 onward (in other parts of the world) received the flex piece. learn something new each day, eh?
it does make sense...

When i had cruise4070 pipes run on his bj70 I had them put in a flex pipe about a foot or so off the manafold (thats where the old pipe was rotted off ) . I get a a lot of vibes from mine but im still running the stock pipes and a banging when started . I even replaced the motor and trans mounts (they were getting soft and the trans one was broke) and it still bangs when started ,so I say "flex pipe good" I also think it will cut down on the the abuse put on the exhast manifold flange when wheeling plus cut down on hanger/pipe replacement when rock surfing