where are the exhaust scientists

I've been working with rip raps drawing too.
Don't think I can make it up to 6" but I just finished some 2.25 to 3" over 12 cones.
Pretty cool , reminds me of rocket nozzles

 

Bought some Goerlich Xcelerator mufflers to try, I think those qualify as real mufflers.
100.00 on the shelf now.

The rear "x" pipe with no mufflers sounds so much better.

Next

 

Put the 2.25 to 3" cones on and it started really pounding. You could start to feel it in your chest a little bit.

 

Excellent choice. i dont give a rats ass how they sound, but I know those mufflers work well.

 

I'm going to try the goerlichs at the end with a 3" cone turn down. I can hide quite bit under that bumper. Maybe I can get up to a 4" cone.
I'll let you know what happens

 

OK, ran the Goerlich Xcelerator mufflers at the vary end of the pipe. Very nice low mellow rumble. Sounds really nice back there, much better than forward 5' or so. Lots of pounding too. The cab was vibrating greatly the dust was jumping off of it, definitely feel it in your chest , and it would shake some sand on a table. That might turn into some really bad drone but I don't know yet.

The rear mounted "x" pipe still sounds the best.

I also did a running compression test with the mufflers and then with the X pipe.
On the snap I got 100 with the mufflers and 110 with the x pipe.
Not sure what to make of that yet.

 

That would make me think you have some serious back pressure. But really just plain don't make any sence.
The Wizzard

 

Or that the mufflers offer less back pressure?
Welding up a splitter as the research continues!

 

I haven't fired my engine yet so I'm still wondering what it will sound like. I'm running a Chevy 4.3 V6 with stock exhaust manifolds into 2" pipes, H crossover under the cab and 2 Flowmaster 40 series at the end with 12" long polished stainless 2" dia tips. The guy @ Flowmaster said keeping the pipes small was key to keep the engine from being "boggy" when you blip the throttle and he said the crossover pipe was essential. All this experimenting you guys have done is very interesting. While I'm concerned about how loud my setup could be. My major concern is drone in the cab. I had an OT truck that ran a Y pipe into a single Borla stainless turbo muffler that dumped out at the end of the cab on the drivers side. What A freakin mistake! I ended up adding a DynoMax Turbo tube straight through muffler in line with the Borla and dumped it out ahead of the back tire. Much improved sound but still not a truly engineered exhaust. It's great to see you guys experimenting and filling us in on what type of results you get. Not all of us can experiment like that!

 

Well they say they promote scavenge, and falcongeorge says they work.
I still don't know what to make of that test.

I'm going to redo it, all cylinders and make sure what I'm seeing is directly related to the muffler and not some other phenomenon associated with the new motor.

Now on another note ( pun intended) , I made up some 3" to 4" cones incorporated into the turn Downs. The exhauste note dropped several octaves and sort of makes everything in tge building buzz with a really low bass note. Its really kind of cool for a while then it starts to drive me nuts.

 

anybody got any sound audio with small block chevy x pipe configuration?

 

This is already used in OT luxury cars to quiet the interior. Some cars also play "exhaust notes" through the sound system (along with other engine noises that have been picked up by sensors) to give the car the "perfect" performance sound inside.

It's interesting what can be done via audio engineering, but I prefer the old methods of HP+a good set of pipes.

 

www.headerdesign.com has more exhaust science than you need. If it's still around, that's where I designed my O/T car's system and it's very nice. Also Ed Hamd wrote a book on building Pontiac engines that had a giant chapter on this. There's a lot to know.....

 

I didn't get my nick name "RapRap" for nothing!

 

Is this the one.

 

Lmao !

 

OK I redid the dynamic compression test on all 8 cylinders with the xcelerators.
My method was flawed previously

Cranking - 168 average
Idle ------- 89.3 avg
Snap WOT. 125 avg.

According to what I can find the intake is a tinsy winsy restriction. Its a '73 quadrajet on a factory 305 aluminum manifold with 305 heads. I could play with the cam timing, maybe different induction, or bigger intake valves 1.84 in there now. Not going to do any of that so that's that.

Now with the X pipe I redid the test Again but only on the easy cylinders.
The results were identical - no difference.

Had it out in the parking lot under its own power.
All I can say is WOW!!
This thing runs so nice. Really responsive on the throttle, Revs up FAST and back down to idle almost as fast as you move your foot. It sounds awesome and just flat outbad ass with either system
Its extremely powerful for its cubes. Just a little throttle will slip the tires, a little more and up they go. 150' burnout and I wasn't even trying.
Very happy.

The xcelerator mufflers sounded great especially with the cones. Very nice low pitch mellow performance sound, very nice.

The rear "X" pipe with no mufflers sounded 10x better. Then I put the turn down 3-4" cones on and that was an auditory orgasm for any gear head!!!

If somebody can explain it - that would be great !
but after all the experiments I've done, different configurations I've tried, parts I've made, parts I've bought, that sounds the best for a hotrod.

Hope this helps a bunch of you guys.


I have to get a you tube up but I've never done that. If I have time to figure it out I will, us there a help for YouTube?

 

Isn't this the Tuner Car "Coffee Can Exhaust" theory?. No offence implied.

 

Not really, it sounds like sound wave theory.
The larger diameter tips do lower the pitch and increase that low rumble that you can feel.
100% truth to that.

Now those tuner fart cans are nowhere near whats going on here/hear.

 

i heard a drag car,sbc that had the x pipe right after the collectors and then about one foot of pipe after that. it sounded different than any car at the track. it got my attention! my stude is running a solid lift fairly rumpity cam 383 sbc. i want to run x pipe right after the collector, then cutout pipes with caps, then cherrybombs,then get bigger gradually as i go back up and over the rearend to say 3 inch tailpipes. please one of you exhaust scientist tell me if this will sound good or not. help me take the guess work out of this. x pipe in front or in the rear? the car is a 53 studebaker coupe street/ strip car.oh yea, does it make a difference if the tailpipes are close together or far apart? thank yall...ed

 

btt

 

The one thing I can answer for sure is that the exiting pipes closer together sounds different than far apart. Now "sound good" is a matter of personal preference.

The thought of rear X pipe is probably unheard of and was a complete fluke of chance i tried that works about perfectly (for me) without mufflers. Theres been about 6 different gearheads that say it sounds great, my girl likes the way it sounds.

Rap Raps drawing explains alot and the cones I built produced the exact results that he explains. Bigger pipe, lower note, bigger again and lower still. A 4'' cone vibrates my chest like if I was humming low and softly. It starts to vibrate the ground and everything around it.

The futher back the muffler, the shorter the tailpipes, lower (octave wise) the note. The sound is cleaner - think of talking thru a taper towel roll, it sounds funny right. now maybe that "funny" maybe helps or hurts. in my case it hurt in my opinion and every one else. Not that it sounded bad, just that rearxpipe sounded so much better.

also remember to size your pipes correctly, for you engine-going too big kills your velosity and power.

I posted a link for rob a few pages back, theres some really good info there.

 

thanks for that info. i would want the xpipe so that even with the open headers, i would benefit from it. so the xpipe would have to be right after the collector.does that make sense?

 

Sure that makes sense.

I can tell you that when I moved the x 5-6 feet forward towards the engine it sounded shity out of the tailpipes with no mufflers. Adding mufflers produced a sound nobody cared for compared to the rear x no mufflers.

X pipes are supposed to go towards the engine for the benefit.
I still haven't gotten a definitive answer as to why it sounds so damn good at the end.

 

where at the end? how far from the tailpipes?sorry i'm asking so many questions, but i only want to do this once . thanks for all the great info

 

Once huh ? I lost track of how many times I built or changed this system and I have 1/2 a pickup truck full of parts. I'll say its more than 20 times. Spend a few hours to build a part then say " nope don't like it " throw it on the pile and try again.

When I say at the end or at the rear bumper that's what it is.
From the rear bumper forward …
4"to3" cone over 8" ,,,
3"pipe by 6" @ 30 degrees…
Bassani x pipe - pic is in the link I posted and the narrow side to the rear.
10 feet or so of dual 2.25" pipe
Headers

 

heres a pic

 

Anymore thoughts on this ?

 

no. i think i know what i gotta do. we'll see how it turns out. thanks for the valuable info.

 

I'm not a expert tuner but I do have actual exhaust tuning experience on Triumph cycles. The old ones with a Hemi two valve head.
Typical modifications were camming the engine,more compression and straight pipes,sometimes with open megaphonesone pipe per cylinder,not a collector header. More often than not this lead to what was called "Megaphonitis", an annoying flat spot in the power band just at the RPM when torque was coming on,maybe at 4000 rpm,maximum torque was around 5000.Hillbilly tuners like me really didn't understand what was going on,but I believe the exhaust and cam leaned out the fuel mixture. Over scavenging I suppose. Enrichening up the carbs helped a bit but then you were too rich on top end.
What I did was a balance tube between the exhaust pipes.this mellowed out the power band with a very slight loss of top end power.This worked out nicely on the street.The Brit cycle manufacturers did this for a different reason,sound reduction to pass noise standards.