Muffler Tech

[Truenotch]

3 hours ago, yoeddynz said:

Not really any room for me to attach any unsightly proboscis (probosci?) off my secondary pipes. But maybe off the box itself? 

Packaging will be a problem for you eh... One of those links I posted earlier talked about the difference between a helmholtz chamber and 1/4 wave resonator.

The 1/4 wave reso seems easier to install and set up because it's more about length, so you don't need as much math to figure out wave timing etc... And you can easily cut and shorten a pipe to get it just right .

Helmholtz chambers are a lot more compact, but you'll need to do more calculations or revisions to get it just right. They also have the added bonus of looking more like a willy.

[Kiwibirdman]

17 hours ago, JustHarry said:

Anyone got a good recipe for v8 exhaust? @cletus @Valiant maybe? 

Kinda over the ponti sounding like a hairdryer.  

Current has a wee resonator just before the crossover then a big stainless muffler before the axle and then another resonator before the tailpipes. 

It's small pipe like 2.25" spec

If I just whip the middle muffler out will it go droney? 

My Firebird with a 350 Ponti has dual 2.5 exhausts with a crossover under the gearbox, so it is fairly long. I have dual flow master mufflers and tail pipes that drop down behind the back wheels. This sounds like a real V8 and not too loud. 

I have always done a balance pipe, not an x pipe. The one car I had with an x pipe sounded crap. Unless the x has a join hole of 20mm you are just creating a 2 pipe single system.

The other thing is tail pipes can make a huge difference, down to number of bends, where they are pointed and how far apart they are. The original tail pipes on my Silverado rusted out so I though I would do something different. The originals went out the back and were about a metre apart. They sounded good and were reasonably loud. Change to dual side pipes, both out the same side and close together. To save moving the mufflers I put a 130 degree bend out of the mufflers and the a 45 degree bend back. I thought it would be louder than before, with the tail pipes being a lot shorter, it is quieter. 

Interestingly before I did the tail pipes I had replaced the original flow masters baffle type mufflers with some straight through but same sized mufflers. Much quieter at idle, loud as when giving it hell.  

I got a quiet warning from my WOF guy that the front of the exhaust is getting close to 'its going to fail' so thinking of trying one of those dual 2.5 in 3 inch out mufflers with a short tail pipe. Since most of the exhaust is going in the bin, I can move the muffler well forward and get rid of all the tight bends in the tail pipe.

[440bbm]

35 minutes ago, Kiwibirdman said:

 

 I thought it would be louder than before, with the tail pipes being a lot shorter, it is quieter. 

 

this is extremely interesting. would never've guessed that. 
mine are short. well, its not that short cos the cars long, but it ends in front of diff, where the flowmasters are, and essentially has a tip straight out and its loud and droney at certain speed. 
When i put the rear half of exhaust system back on, which only goes up n over the diff and comes out behind the rear wheel ( not allllllllllllllllllllllllllllllllll  the way out the back which is like another 43m long ) its fucking quiet, loses a bitta hp, and runs too rich, had to re-jet it and still doesn't make the same power..   so illegal short pipes it is

which follows all other previous experiences ive always had. so yeah, curious asf about that one

[Kiwibirdman]

4 hours ago, 440bbm said:

this is extremely interesting. would never've guessed that. 
mine are short. well, its not that short cos the cars long, but it ends in front of diff, where the flowmasters are, and essentially has a tip straight out and its loud and droney at certain speed. 
When i put the rear half of exhaust system back on, which only goes up n over the diff and comes out behind the rear wheel ( not allllllllllllllllllllllllllllllllll  the way out the back which is like another 43m long ) its fucking quiet, loses a bitta hp, and runs too rich, had to re-jet it and still doesn't make the same power..   so illegal short pipes it is

which follows all other previous experiences ive always had. so yeah, curious asf about that one

Strange how it works. Sometime small changes make a big difference, my sons HSV Statesman had exhaust cutouts under the drivers seat. Electric and switched from the drivers seat, highly illegal. We cut them off and welded a patch over the hole. The car is noticeably louder at the tail pipe. It must be the turbulence that made the difference. 

I have never been a fan of the dump under the car exhaust. Can you run short tail pipes out in front of the rear wheels?

[440bbm]

not really a fan of it either, but havent spent the money on that, as its just as illegal as its current issue - so just leaving it till i come up with a more suitable soultion. which entails getting my shed build anda  hoist installed, then i can tackle it. LOL

 

i have turned the tips to point the exhaust out the wheels.. so if im cruising slowly with a few revs on, it actually gets a chop sound from the sharp edge of the rim spoke LOL.  but when doing a skiddy it plumes it out nicely  for dramatic affect LOL

[Kiwibirdman]

Yes a hoist, I am sick to death of lying under cars

Keep up the good work.

[Tiger Tamer]

Confession time, I also have a 77 Pontiac Firebird with a E headed stroked 400 to 462ci with Hooker headers and 3" X pipe exhaust through Exlerator mufflers ( may have been recommended in Jim Hands book). I took the tail pipes out the rear of the car instead of behind the rear wheels as the Firebirds have.

I love the sound it makes (when it goes). Sounds very busy very quickly. Owned it now for over 30 years.

 

[Yowzer]

11 hours ago, yoeddynz said:

Since id been shown them by a mate ages ago on his 20v carib thing I have since noticed lots of cars have them on the Inlet box. We had a serena in for work the other day and it had two on the inlet tract, different sizes I guess to cancel out different frequencies. 

Mate reckoned he'd removed the one on his 20v but it affected the smoothness of the engine enough that he put it back on. I think on those engines it's possibly fitted to create extra plenum volume before the itbs rather than just than a sound thing?

I think they're to stop reversion back through the MAF sensor, which would otherwise read the same air twice. The later 20Vs don't run a MAF sensor so I dunno what they do in that case, but normally ya rip the airbox off altogether and run open ITBs so it doesn't matter.

[cletus]

 

[yoeddynz]

@Valiant the above video might help explain the j pipe thing. 

[mjrstar]

On 21/08/2024 at 11:42, Truenotch said:

Another interesting one is the Mugen loop muffler for DC5 Integras. This passes through the chamber twice, so is a cheat code for getting extra exhaust length and muffler length in one hit. 

I had the cat back mugen exhaust with twin loop on my honda, it was spectacularly quiet.. 

I think I still have some bits and pieces of it lying around.. the muffler itself is ugly and bulky.

I think the loop is designed to kind of cancel out the sound waves on the second pass through.

The system was thin walled 2 1/4 dia (maybe .8mm) and pretty lightweight,  and unfortunately worn out from too many ditch cuts..

Has a 3 inch system now, can still hear the induction noise so that's the main thing.

[anglia4]

For ford V8’s are we still just doing dual 2.5” with a balance pipe and a pair of flow master 40 series?

[Tiger Tamer]

I have 2.5” twin exhaust with a balance pipe with AdrenalinR mufflers  on the Tiger.  The car has a 5.0 ho engine. Sounds great, very happy with the sound but they seem to be quite expensive now days.

[440bbm]

On 14/09/2024 at 11:24, anglia4 said:

For ford V8’s are we still just doing dual 2.5” with a balance pipe and a pair of flow master 40 series?

that will be fine.

the flowmasters are a bit droney but sound better than a kick in the nads. will def give it some noise. 
wouldnt go any bigger on that 390. most gains you will find will be in header design, untill you give it more comp and cam then you may wanna go 3" but depends on your overall plans for the car. if just a cruiser then be good as wood.

[anglia4]

Sweet. Yeah just a cruiser and the 390 will likely get binned for a 302 at some point.

I used to have a 302W with that exhaust setup, it sounded great.

[440bbm]

yeah the 390 is a slug unfortunately compared to the spritely windsor.  but all things being equal should move a larger car around with more torque. whats it in?

head design makes a massive difference in the sound with those fords

alos, have  a look up the engine masters muffler dyno results, was the frieburger dulcich combo. interesting results that show the flowmasters suck haha.

[anglia4]

I'm not gonna post what it is yet, as the car isn't yet in my control or posession... But I have got to be in a position to hit go on some parts orders quickly if the eagle takes flight.

Also, not at all concerned about power. It just has to sound good

[440bbm]

Understand the mission LOL.

i mean, who's gunna change the flowmasters out because of that result. I havent and they're on my thing, would i think about something else becasue of it, yes. BUT, nz sucks for supply and chances of going wrong because of it.... high. sooooo would go again yes.