Mufflers, resonators and post turbo exhaust design

[Volcano cruiser]

Ok I have been through at least five pages of threads that swim all around this subject and nibble at it in different ways. My turbo should go on next week. Here is where I am. While my 1HZ is quieter than my old B, it is still loud. Pre turbo install, everyone could tell over a block away that I was coming. While I get that the turbo (mine is CT26) is actually an exhaust flow "restrictor" and as such will muffle things a bit I am not comfortable with going with just 2.5 or 3 inch straight pipe. ( I am curently running 2.5 inch pipe) I want to have a U.S. noise compliant, read keep Virginia state troopers happy, exhaust system. I have long since passed the days of needing my rig´s sound to speak for me. If it can´t perform as I have designed it on the street and on the trail then the fact that my neighbors will hear me coming from a block away won´t be much consolation. At the same time any guy who looks at my rig just shakes his head an says it screams raw testosterone. It would be bad if after such high praise if I started it up and it sounded like a whiny three year old throwing a tantrum at Walmart.

From what I have been reading re: turbo exhaust system design, it seems that I want the following:

Resonator- which will to some degree reflect the exhaust sound back on itself thus canceling some of it out. An example that I found:

SLP Performance 31066 - SLP Performance Shotgun Race Resonators - Overview - SummitRacing.com

Reflective muffler- same theory as the resonator but with some sound absorbant material packed in as well. Some examples:

Hedman Hedders 25580 - Hedman Turbo Mufflers - Overview - SummitRacing.com

Dynomax Performance 17223 - Dynomax Ultra Flo Welded Mufflers - Overview - SummitRacing.com (doesn´t specify reflective or not)

Magnaflow 11219 Magnaflow Performance Satin Stainless Steel Mufflers

SLP Performance 31067 - SLP Performance Loud Mouth II Bullet Mufflers - Overview - SummitRacing.com

The goal is that sound that should be left should be just enough to be decent but not wake my neighbors up as I roll back home late at night after some shindig.

I have tried to avoid some of the hype "turbo" branded mufflers others that claim to "raise horse power". but there isn´t much detail from some of these manufacturers on how some of these mufflers are constructed.

Questions:
Resonators- how effective are they on a turbo diesel? Assuming that they are effective to some degree does anyone have any experience with any particular brand or other?

Reflective mufflers- Again how effective on a turbo diesel? assuming that they are effective any experience with any particular brand or other?

In responding to either of these if you have found either resonators or reflective mufflers to be ineffective, why not as best as you could tell.

Last question: Does anyone have any experience with the above brands, Hedman, Magnaflow, Dynomax or SLP? If so what was that experience?

Thanks in advance guys for the input.
John

 

[atlas78]

Hello,

this is a site of a serious supplier in France, they have almost everything for 4x4, from stock parts to performance parts.

Take a look you might find your answer

Toyota Landcruiser (série 4#) Parts - Euro4x4parts.com

 

[Adam B]

I have a 1HD-T, CT26, ~3.5" dump pipe off the turbo, home made 3" mandrel bent exhaust with a big flex joint close to the turbo, and the exact same Dynomax straight through style muffler you linked to (model # 17223).

I tried the same setup with no muffler and I can't stand the sound. It just sounds dirty to me. Adding the muffler didn't reduce performance in any way but it really cleaned up the sound and made it much less likely to offend anyone. I highly recommend it.

Incidentally, I have also tried the Aero Turbine (it was free) with built-in resonator with all other parts the same. As any thinking person will immediately guess, there is nothing special about it, it doesn't increase horsepower, it is larger than necessary, and mine was poorly constructed with several large chunks of glass rattling around inside. Yes, that's what I said. I cut it open after it drove me to the brink of insanity and that's what I found. POS and I wouldn't take another one for free.

 

[Volcano cruiser]

I have a 1HD-T, CT26, ~3.5" dump pipe off the turbo, home made 3" mandrel bent exhaust with a big flex joint close to the turbo, and the exact same Dynomax straight through style muffler you linked to (model # 17223).

I tried the same setup with no muffler and I can't stand the sound. It just sounds dirty to me. Adding the muffler didn't reduce performance in any way but it really cleaned up the sound and made it much less likely to offend anyone. I highly recommend it.

Incidentally, I have also tried the Aero Turbine (it was free) with built-in resonator with all other parts the same. As any thinking person will immediately guess, there is nothing special about it, it doesn't increase horsepower, it is larger than necessary, and mine was poorly constructed with several large chunks of glass rattling around inside. Yes, that's what I said. I cut it open after it drove me to the brink of insanity and that's what I found. POS and I wouldn't take another one for free.

Adam,
Thanks for the heads up on Aero Turbine. They weren´t on my list but good looking out just the same. Thanks also for the recommendation on the Dynomax. It was also recommended by a write up at overboost.com with references made to Gail Banks shop. I was also looking at SLP stuff as "supposedly" their mufflers and resonators are designed to work together. That could be complete BS to hype sales, hard to tell as again there is a lack of information out there on how they are designed to work together beter than say the Dynomax muffler with their resonator.

John

 

[Cruisin']

On my rig (1HD-T) I'm running a full 3" from turbo back. I also ran a straight pipe for a while and hated it. I redid it a while back and found a muffler that has no glass packing in it to blow out. What it looks like is an auger wrapped around a tube, within the housing of the muffler. You can actually see through the center part of it. The theory is that it disturbs the pulses and cuts the sound, and according to the parts guy it reduces sound output by about 8 decibels. That may not sound like much, but it makes a pretty good difference.

Moroso 94051 spiral flow racing muffler 3"

Having run stock exhaust, then straight pipe, then this muffler, I'm VERY happy with this one. Going from straight piped to the spiral I didn't notice any drop in power or response. There is no annoying resonance on the highway, and the sound is actually pretty nice. Louder than stock, but not loud.

Hope this helps, and good luck!
-Jason

 

[Tapage]

I'm the only one who's really happy with the 3" straight and short pipe ( ends in front of my rear pass tire ) in the 1HD-T .. ?

 

[Volcano cruiser]

On my rig (1HD-T) I'm running a full 3" from turbo back. I also ran a straight pipe for a while and hated it. I redid it a while back and found a muffler that has no glass packing in it to blow out. What it looks like is an auger wrapped around a tube, within the housing of the muffler. You can actually see through the center part of it. The theory is that it disturbs the pulses and cuts the sound, and according to the parts guy it reduces sound output by about 8 decibels. That may not sound like much, but it makes a pretty good difference.

Moroso 94051 spiral flow racing muffler 3"

Having run stock exhaust, then straight pipe, then this muffler, I'm VERY happy with this one. Going from straight piped to the spiral I didn't notice any drop in power or response. There is no annoying resonance on the highway, and the sound is actually pretty nice. Louder than stock, but not loud.

Hope this helps, and good luck!
-Jason

Jason,
Thanks. This is a design that I had not seen before. You´re right it looks just like an auger wrapped in a muffler housing. The key is that it is a reflective muffler, i.e. one that uses form to reflect back sound at the same frequency as it comes out of the exhaust, in effect cancelling the sound out and it seems to have been effective for you.
Thanks.

I'm the only one who's really happy with the 3" straight and short pipe ( ends in front of my rear pass tire ) in the 1HD-T .. ?

David,
I got quite used to the sound od both my old engine and the new one and didn´t think much of it until friends came down from the U.S. to visit. They couldn¨t stop talking about how loud it was and how they would all bt on how long it would take for the Virginia cops to pull me over once I got back. I blew that off after they left and kept rollng. Then recently my kids came down to visit and they both agree that as it is now that I would get pulled over in both New Jersey and New York, where they live, as well. As long as you don¨t have a problem with the police for making too much noise then the only consideration is what type of exhaust is best for the optimal performance of the rig.
John

 

[VTCDN]

Another Idea ?
: HIGH-PERFORMANCE MUFFLER - JCWhitney



Tapage (,'' I'm the only one who's really happy with the 3" straight and short pipe ( ends in front of my rear pass tire ) in the 1HD-T .. ? "" )

Hearing Aid turned off ? or the damage has been done ?? Kidding Sir.

Loud constant drones from exhaust noise are a real drain on driving , plus your hearing will be damaged .


I like the lack of glass , aluminized case and nipples , plus small in dia..

VT

 

[Volcano cruiser]

Another Idea ?
: HIGH-PERFORMANCE MUFFLER - JCWhitney



Tapage (,'' I'm the only one who's really happy with the 3" straight and short pipe ( ends in front of my rear pass tire ) in the 1HD-T .. ? "" )

Hearing Aid turned off ? or the damage has been done ?? Kidding Sir.

Loud constant drones from exhaust noise are a real drain on driving , plus your hearing will be damaged .


I like the lack of glass , aluminized case and nipples , plus small in dia..

VT

Interesting design. Thanks for the heads up.

 

[Cruisin']

I'm the only one who's really happy with the 3" straight and short pipe ( ends in front of my rear pass tire ) in the 1HD-T .. ?

Maybe it depends which side the steering wheel is on. My rig is RHD, and in the winter it was not really a big deal. I started hating it in the spring when I started driving with the windows down... The sound was always RIGHT THERE.

 

[Tapage]

Maybe it depends which side the steering wheel is on. My rig is RHD, and in the winter it was not really a big deal. I started hating it in the spring when I started driving with the windows down... The sound was always RIGHT THERE.

I can drive ear music talk to my wife open front windows without any problem or complain from her .. can cruise 65mh/p nice ..

If I push it hard .. yes that came a nice noise .. but isin't my case 99% of the time ..

LHD 80 series ..

 

[cruiser_guy]

John, do you have a muffler of any sort now?

Did you find the '55 to be noisy when I came by a year or two back? Did I ever come by with the '60 (I can't remember for sure)? Neither of my trucks have a muffler, just a 2 1/2" pipe that follows the factory route (not straight but a few bends to help restrict the noise but not the flow. They are noisy in an enclosed space or next to a building or divider but otherwise the '60 is no worse than stock.

When getting the exhaust done down south make SURE you tell them you want mandrel bent pipe NOT the typical Central American "bend the pipe with a torch" accordion look.

You can make sure there is a straight chunk of pipe long enough for a muffler and add one if needed. The BJ60 came with only a muffler from the factory. No resonator.

 

[Volcano cruiser]

John, do you have a muffler of any sort now?

Did you find the '55 to be noisy when I came by a year or two back? Did I ever come by with the '60 (I can't remember for sure)? Neither of my trucks have a muffler, just a 2 1/2" pipe that follows the factory route (not straight but a few bends to help restrict the noise but not the flow. They are noisy in an enclosed space or next to a building or divider but otherwise the '60 is no worse than stock.

When getting the exhaust done down south make SURE you tell them you want mandrel bent pipe NOT the typical Central American "bend the pipe with a torch" accordion look.

You can make sure there is a straight chunk of pipe long enough for a muffler and add one if needed. The BJ60 came with only a muffler from the factory. No resonator.

Charles,
Yes I run a stock looking muffler now, in the stock position. My plan is to run as straight a 3" pipe as possible with first the SLP resonantor and at the end the SLP muffler and have it all exit stright out back on the passenger side without the big 90 degree bend to exit out of the stock position. You will laugh but the muffler shop that I use proudly states that they only use Canadian SS and do mandrel bends.
John

 

[cruiser_guy]

have it all exit stright out back on the passenger side without the big 90 degree bend to exit out of the stock position.

You might want to reconsider this. The pipe straight out the back will end up getting squished when you're out wheeling (ask me how I know!!). I'd exit out the side.

 

[Volcano cruiser]

You might want to reconsider this. The pipe straight out the back will end up getting squished when you're out wheeling (ask me how I know!!). I'd exit out the side.

Charles,
Even if I can find a way to route it mostly through the frame rails. Wait, you mean just the actual exit point might get squished if it is straight out of the back. Got it. I'll have it make a slight turn to exit out of the passenger side at some point near the back corner.
Thanks again for the heads up,
John

 

[Adam B]

Mine takes an almost 90 degree turn right at the end and exits as high as possible just behind the rear wheel on my JDM driver's side. I did it to avoid mashing it on a rock but a convenient side effect is the fact that I can always monitor my exhaust smoke with the side view mirror. With tinted rear windows you can't see it very well if it's going straight out the back. Very helpful for tuning...

 

[Volcano cruiser]

Mine takes an almost 90 degree turn right at the end and exits as high as possible just behind the rear wheel on my JDM driver's side. I did it to avoid mashing it on a rock but a convenient side effect is the fact that I can always monitor my exhaust smoke with the side view mirror. With tinted rear windows you can't see it very well if it's going straight out the back. Very helpful for tuning...

I get that designing an exhaust system is an exersice in compromise. I was trying to avoid creating back pressure in my exhaust system design by keeping the pipe as straight as possible. You don't think that the 90 degree turn in the pipe causes back pressure to be present where it otherwise might not be if it was either no turn or less of a turn?

I do agree that if I had the exhaust exits out of the stock position I would be able to monitor smoke color better. Although how about a more mild 45 degree turn exiting out of almost the same position as stock but on the passenger side. That would give me a pretty straight run down the exhaust side of the engine, tucked up and away as much as possible, and then out. I could still monitor any smoke through the passenger side, side view mirror, avoid the sharper turn in the exhaust pipe and avoid the rock crushing scenario of a straight pipe exiting out of the rear. What do you guys think.
Thanks this is a big help guys,
John

 

[cruiser_guy]

John, you'll have way more back pressure from mufflers and resonators than from a bend or two in the pipe. The pipe on my '60 follows the factory route and so does the '55 so there are bends throughout the pipe. The bends help cut down on noise as well. When the sound needs to travel around corners then the sound waves start to cancel themselves out.

 

[Volcano cruiser]

John, you'll have way more back pressure from mufflers and resonators than from a bend or two in the pipe. The pipe on my '60 follows the factory route and so does the '55 so there are bends throughout the pipe. The bends help cut down on noise as well. When the sound needs to travel around corners then the sound waves start to cancel themselves out.

Charles,
You are definitely right, bending corners deflects the sound. I am hoping though that the straight through muffler and resonator that I ordered by their design won't be the source of back pressure. ( see below) It all could be hocus pocus only time will tell. As I said the whole issue of muffler or not, resonator or not, straight pipe or bent pipe, is full of compromises. Hopefully it all won't take too long to get here and I'll put it all together and see how it sounds and how it all performs.
Thanks,
John

 

[Adam B]

You'll get more back pressure from factory-style mufflers and resonators (I assume, never tore into a resonator) but I feel like the straight through design, perforated core or whatever is probably a fair compromise for the improvement in sound quality.

I also read somewhere relatively credible that a 90 degree mandrel bend is equal to about 10' of equal diameter straight pipe. Makes me almost reconsider my setup. Yikes...