Muffler or not?

[hotrats]

I'll be having a 3" exhaust installed on my '62 which has just recently had a 12H-T dropped in (the conversion is currently in process). Question is, should or should I not install a free-flow muffler? The turbo will dampen the exhaust note a bit so I wonder if the muffler is necessary. I'm not sure what to expect for sound either way since this will be a new experience for me.

Thoughts?

Thanks for your input!

 

[cruiser_guy]

Do you have smog checks in your area and do they do a visual check? If so, you need the muffler as it is generally a legal requirement. If not, I'd try without the muffler. Remember though that each bend in the pipe will help reduce noise but it will also slightly increase resistance.

Neither my '60 or my '55 have a muffler and it has never been an issue for me as far as I'm concerned.

 

[Marty Moose]

You will get alot more power with a diesel with out a muffler. There not that loud.

 

[jb BJ73]

if you can do it legally, go without i reckon! 12h-t with 3 inch pipe and no muffler would sound awesome being direct injected it will be louder than a 3b turbo, but still shouldn't be too loud. straight through muffler won't make any difference to power but will quiet in down a fair bit if you dicide its too loud without.

 

[inkpot]

Howdy! My son runs a 5 inch? straight pipe exhaust on his Dodge with a 6bt Cummins. It is noticeably louder, but not obnoxious. It is smog legal here in Arizona, don't know about Colorado. It made an obvious improvement in the power. Go without the muffler if at all possible. John

 

[Tapage]

if you can do it legally, go without i reckon! 12h-t with 3 inch pipe and no muffler would sound awesome being direct injected it will be louder than a 3b turbo, but still shouldn't be too loud. straight through muffler won't make any difference to power but will quiet in down a fair bit if you dicide its too loud without.

Interesting ... but seem's to be true .. the Sound in IDI Tencha it's much less than in DI Marilu ..

 

[hotrats]

Thanks for the input. I'll have to check the Colorado laws and see what's up. I suppose its mostly a noise issue, eh? Would be nice to save a coupla bucks as long as it doesn't sound like a big-rig with a straight pipe.

 

[mainlander]

I have a straight line magna flow muffler on my 2.5 exhaust. Now I've never run without the muffler so I don't know if it makes much of a difference.

One nice thing with the 12ht is that you'll be able to run the exhaust down the driver's side which you really won't care about that much and your passanger won't care either.

Go straight pipe if you want to or just get a magnaflow or something like I got. It wasn't much $ at summit racing.

 

[83bj60]

mainlander, do you have a sound file of the exhaust? Did the magnaflow really improve the engine output like they claim it does? I am looking at installing a magnaflow myself (3"), with exhaust in front of the rear wheel, but am not decided between that, a straight pipe and an aeroturbine (I can always sell the magnaflow to a buddy who needs one).

Thanks for your input.

 

[The Dude]

You will get alot more power with a diesel with out a muffler. There not that loud.

This simply is not the case. The restriction caused by your exhaust system will not "decrease" your power. What it does is restrict your air flow and has the potential to increase your EGTs. The lower the EGTs the better. You might find a slight decrease in turbo lag, but I have never experienced anything worth noting.

I have dropped 100*-225* on EGTs by cutting out the muffler and going up in exhaust size. My preference is 3" straight piped. Really, the bigger the better for geting that heat away from your engine, but it does cost $$$ for diminishing returns.

On the two dyno runs I have done on my diesels I have never experienced an increase in power with purely exhaust mods.

I like the straight pipe on my 61.

 

[Volcano cruiser]

mainlander, do you have a sound file of the exhaust? Did the magnaflow really improve the engine output like they claim it does? I am looking at installing a magnaflow myself (3"), with exhaust in front of the rear wheel, but am not decided between that, a straight pipe and an aeroturbine (I can always sell the magnaflow to a buddy who needs one).

Thanks for your input.

I was also trying to decide between running straight pipe and a Magnaflow muffler. Then I began to read about the Aeroturbine set up.

AEROTURBINE MUFFLER

Does anyone run the Aeroturbine setup and if so can they give their input to this discussion. If I follow the literature correctly, As the expanded exhaust gas rolls out of the manifold and into the pipe it hits a cone like device which then splits the flow of the exhaust and because of the shape of the split it causes that gas to spin and accelarate out of the pipe. The setup contains no restrictors and they say that it isn't any louder than stock in most cases. Anyone got any experience with this setup? Thanks.

 

[mainlander]

mainlander, do you have a sound file of the exhaust? Did the magnaflow really improve the engine output like they claim it does? I am looking at installing a magnaflow myself (3"), with exhaust in front of the rear wheel, but am not decided between that, a straight pipe and an aeroturbine (I can always sell the magnaflow to a buddy who needs one).

Thanks for your input.

First off I have to say that I went from a sort of stock (multi size pipes slapped together, rusted out sections, oval style muffler) exhaust system on a NA 3B to a turbo'd 3B with 2.5" exhaust which run from the engine bay to just infront of the rear passanger wheel.

So for me to say if the exhaust alone or even just the Magnaflow through muffler made any of the difference would be very difficult to say, of course I'd attribute 99% of the increase in performance to the turbo.

I think the "increase in power" as stated by Magnaflow for their through muffler is from a comparison from other mufflers of course, not compared to a straight pipe system. (I think that might be obvious but worth mentioning).

Really the straight pipe would be the least restrictive (depending on the number of bends in the system though) than a straight through style muffler, than a standard oval muffler all following the same path with the same number of bends in the system. My gut though tells me that my short relativly straight exhaust system with through style muffler offers about the same resistance as a no muffler system of the same size pipe following the stock run of the exhaust (more bends than mine).

As for the sound file, don't have one but I could just fire it up and record on my camera and post a video.

The says it actually sounds quieter with the new exhaust but has sort of a raspy sound to it .

The Magnaflow from summit was only $58 so that's really not much of the cost of the exhaust system and like you say, you could always sell it if you don't use it.

One thing with the through style mufflers is what they are packed with between the outer and inner tubes. Magnaflow boasts something different than straight fiberglass like a glasspack uses, and how tightly they are packed (who can really say without doing extensive research which are better though) would really be the difference in the sound deadening of the muffler and also the size of the perforations or design of the inner tube would also have alot to do with the performance of the muffler.

Pysics would say that the tighter the material is packed between the inner and outer tube, the better the sound deadening properties, and also the less restrictive to flow the muffler would be.

All of this is coming out my ass so take it with some salt please, but it sure makes sense to me

 

[mainlander]

This simply is not the case. The restriction caused by your exhaust system will not "decrease" your power. What it does is restrict your air flow and has the potential to increase your EGTs. The lower the EGTs the better. You might find a slight decrease in turbo lag, but I have never experienced anything worth noting.

I'm certainly not even close to an expert and admittedly know very little about engines and air flow vs power output but it would seem to me that a restriction in air flow would translate out to a loss in power. Of course there is some point in which there are diminishing returns but where that point is I don't know.

Maybe my above theory is just bunk when talking about a turbo'd engine vs a NA engine.

 

[cruiser_guy]

I will say that with my truck I went from a 100% stock exhaust (all OEM Toyota) and naturally aspirated to a 2 1/2" pipe following the original route and the AXT turbo and the sound level inside the truck did not change. The sound level from the rear is slightly higher and you get a throaty sound when passing near concrete barriers or other reflective surfaces that I did not get with the OEM exhaust and a naturally aspirated engine.

 

[lostworldexpedition]

Hotrats, what did you wind up going with? I am running straight pipes from my 12HT. I like the sound, but I must say it is a little on the loud side.

I am considering installing a muffler.

 

[R2HKS]

For the guys not running a muffler does the exhaust sound drone or resonate at all at certain revs? It'll be something I'll be trying myself but I can't stand an exhaust that drones and if it does I'll be fitting a resonator only.

 

[eleblanc]

Sorry not a 12HT, but a 3B with a turbo and no muffler

YouTube - Toyota Landcruiser BJ42 turbo straight pipe

 

[wesintl]

i have a straight pip on my 3b with turbo. If I had to do it again I would put in a small muffler. It's fine on the street and It's not bad but with all the windows down on my 70 it gets annoying on the trail.

 

[Diesel42]

Sorry fo rthe highjack but a friend was asking me the other day about the liability of not having any muffler and starting a fire somewhere on the trail. I know with dirtbikes, they require a (forrest service approved)spark arrester for off road use. I went with a 2-1/2" straight pipe w/turbo and no muffler. Not any louder at all, alittle throatier, and a impressive whistle. I am know pretty concerned about the not having any spark type arrester for liabilities sake. Any thoughts?