I think the key here is the size of the exhaust piping ...37 mm O.D. ( 1 7/16") smaller I.D. which will raise the pitch but at the expense of performance and the resonator certainly plays a big role. I would like to know what brand it is. My Alfa has no muffler but has a resonator and it sounds like this car but even better
[This message has been edited by Erik (edited 07-22-2010).]
There is a remote mount filter installed. I will have to ask Tom if it is necessary for exhaust clearance. While his English is not great, he has been really going out of his way to send us info. His current car is a Ferrari 348! However he still likes Fieros.
I have a friend in Shanghai who I sent this link to. The blog says that the exhaust were hand-made 7-8 years ago by a small shop owner. The current owner found the shop again and to have another set made would cost around $600 (and I seriously doubt that he means Taiwan dollars...that would equate to about $18 US dollars).
I had my friend interprete what he is saying at the end of the first clip. He listened to it repeatedly, but could not catch the whole thing due to the background noise. Basically though, he is saying something like "they're still heavy ---- sound, right? And the two-in-one combined still has the "huuu-huuu-huuu" sound."
Tom
$600 eh? how about without the resonators? I am genuinelyinterested in looking into this. I'm doing a 3.4L set up on my 88 fiero. and have 2 sets of manifolds...I could very easily make this same set up if I had a diagram with measurements of the bends andpipe lengths. if anyone has info or is interested in an exhaust system like this I'd be interested in making them. I'd have no clue on finally cost until I make a complete one first on my own engine. then I can copy it. also having 37mm (1 7/16") piping isn't bad at all. especially if it's for just 2 cylinders.so total pipe size if compared to stock style fiero exhaust would be over 4"...just thinking outloud.
[This message has been edited by gtxbullet (edited 11-09-2011).]
I am commenting on the OP link to the Fiero in Taiwan, I think it sounds like any other Honda on the road that the teens and twenty-something year old's drive to be "cool". However, I think the environment is affecting the sound in the video as well, as parking garages do that. I drove a 4-cyl mustang through a parking garage with an exhaust leak and it went from sounding like crap to sounding like a little prop-plan spooling up. (Like the Cessna's we have here in AK). Just my opinion. lol. Other then that, interesting exhaust system routing! lol.
I seen that guys, he does 1+4, 2+5, 3+6 which is just basically pairing the cylinders that are furthest apart. Makes sense, but the guy in the original video appearently paired 1+5, 2+6, 3+4. I don't know why he did this and why it sounds the way it does.
quote
Originally posted by ericjon262:
FWIW, someone made an exhaust similar to this Fiero's on 60*V6
Sounded like he was shifting, i'd say fake. Listen to it, revs a bit then it sounds like he shifts.
If you mean in the second vid (where the car actually moves), the car does slow down for a second, and it seems like there was probably some other issue involved at that time. If you look at the pictures, you can see that it looks like a flood victim, and there is quite a bit of rust coloring and other grime, underneath.
I doubt it's a fake. There is way too much work in that exhaust, and it's a Fiero, in Taiwan, so there isn't anything to gain by faking it.
I seen that guys, he does 1+4, 2+5, 3+6 which is just basically pairing the cylinders that are furthest apart. Makes sense, but the guy in the original video appearently paired 1+5, 2+6, 3+4. I don't know why he did this and why it sounds the way it does.
Cylinders 3 and 4 are not connected at the primaries. 1 and 5 are, with 3 merging back in after; and 2 and 6 are connected, with 4 merging back in after. This is similar to the Tri-Y or 4-2-1 design on a V8 or 4-cylinder, and given the firing order of 1-2-3-4-5-6, and the engine is a 60 degree V instead of 90, the design makes some sense, and is the reason it sounds the way it does. I can't find (and don't have) a video to show the rotation, cam timing, and firing, to show how this would work, though. Having it would help, but hopefully you can visualize it in your head a bit.
I seen that guys, he does 1+4, 2+5, 3+6 which is just basically pairing the cylinders that are furthest apart. Makes sense, but the guy in the original video appearently paired 1+5, 2+6, 3+4. I don't know why he did this and why it sounds the way it does.
After hearing this sound I decided I HAVE to try this. And the timing couldn't be better. I'm in the process of finishing up my 3900 swap.
The guy in the video used 1-5, 2-6, 3-4 because it puts the firing order one piston out of sequence (still working on the math). But basically #5 fires, then #6 and then #1 so if 1 & 6 are 360 degrees crankshaft out of phase that means that 1 & 5 are 240 degrees crankshaft rotation out of phase. 2-6 is 480 degrees crankshaft out of phase, 3-4 is 120 degrees out of phase. If you then bring those 2-1 pulses into a 3-1 collector you have an even firing. I think it may be more important to look at how this effects tube length than the actual order. Below I detail the firing order of the 60 degree V6.
When I first started this build I wanted a flat plane crank. But after researching I found out that even Ferrari V12s are not flat plane.
Only the V8s are because of the 90 degree bank angle. The reason is due to exhaust sequencing and of course lowering rotating mass. What ferrari does though is have two 6 cylinders on the crankshaft with no correction for bank angle. With 6 extra cylinders the math works out that things are relatively balanced. Since it is impossible to have a smooth running 60 degree engine with a flat plane crank you'll see that each pair of crank throws are set 60 degrees to the next such that they run two 6 cylinder engines in the same block. If you compare the 60 degree GM V6 to the V12 crank, what you'll see is that GM essentially reduced the length of the crank throws (compared to the ferrari) so that each throw only has one cylinder with two cylinders close together (1 & 2; 3 & 4; 5 & 6). Thus the firing order on a 60 degree engine is basically 1-2-3-4-5-6 or if you look at each bank as its own engine 1-3-5; 2-4-6.
After setting out to design my own crank to have made, I noticed that the GM 60 degree engines are basically two 3 cylinder engines set at 60 degrees to one another and that with a 60 degree engine there is no way to get an even fire with a flat plane crank. This basically forces the design to be two 3 cylinders and creates two well balanced engines in one block.
Here's where the firing orders come into play. A quick look at a 60 degree crank (3.1L casting in this case) reveals that #1 & #2, #3 & #4 and #5 & #6, cylinders are offset on the crank shaft by 60 degrees (not 120 degrees). BUT when you add (subtract) the bank angle to the offset this means cylinder 1 is 180 degrees out of firing order from cylinder 6.
When people talk about a 180 degree exhaust its the firing of the pulses that is 180 degrees in time, and even this is misleading as the engine has to rotate 2 complete times for every piston to fire. If you view the complete firing of pistons as 180 degree exhaust timing, it is actually 360 degrees of crankshaft rotation (half the complete cycle it takes the engine to fire two cylinders offset by half a combustion cycle, or 360 degrees crankshaft rotation).
If you draw a picture of the 60 degree V6 block with the 60 degree included V angle then draw the positions of the crankshaft throws (1,2; 3,4; 5,6) with each separated by 60 degrees. You'll see the following pistons at top dead center at any given time:
1 & 6 3 & 2 5 & 4
This means that when spark plug #1 fires (combustion downstroke for #1) that cylinder #6 is on the intake stroke. Or 180 degrees out of phase from opening the exhaust valve ( but not crankshaft angles).
Of course 5 & 4 follow suit as do 3 & 2.
So if you group the above cylinders into their own collectors you will effectively have 180 degree exhaust for a V6. Interestingly if you put ALL of them from even or odd into one manifold you'll see the the firing order 1,2,3,4,5,6 means each manifold has only one pulse at a time. So a set of equal length headers should develop the same sound using a 3-1 2-1 setup as (3) 2-1 into a 2-1.
Anyone with a 60 degree engine on the engine stand with no heads on should be able to validate what I've said above. In the mean time I'll see if I can double check everything and figure out whether I need 2-1 or 3-1 collectors.
Anyone have a sound clip of a set of odd and even banked equal length headers? Perhaps like West Coast Fiero sells?
[This message has been edited by FieroNate (edited 11-20-2013).]
My guess is that it is fake. But I am no expert. IF you get it working to sound like that my hat goes off to you One reason I think it is fake is because it sounds like it revs much higher than a Fiero 2.8 V6 or has twice the cyliders. You can fake the sound a little with tube size and length and fireing order by collector phasing but you cant make it echo in such a way to make it sound like it revs higher than it realy is.
[This message has been edited by Rickady88GT (edited 11-21-2013).]
I'm a big nut for the perfect exhaust sound and upgraded the exhausts on most of the cars I've owned and will be following this project closely. An engine sound can be changed a lot with the proper exhaust design and muffler choice and our little Fieros deserve a proper high tech exhaust sound.
The 3.9 is as much a PIA as any swap. Mounts are simpler though. Wiring and computer are basically the same as an LS7... My swap is a but more unique. I've got a 3.9 block with 2.87" stroke and 6.125" rods. Should make for a screamer. Now it needs the right exhaust....
My guess is that it is fake. But I am no expert. IF you get it working to sound like that my hat goes off to you One reason I think it is fake is because it sounds like it revs much higher than a Fiero 2.8 V6 or has twice the cyliders. You can fake the sound a little with tube size and length and fireing order by collector phasing but you cant make it echo in such a way to make it sound like it revs higher than it realy is.
It's not fake, but the routing isn't exactly what people think it is. 3-4 don't connect separately and then merge back in. They are merged back on their same sides, after the 1-5 and 2-6 splits merge. It's not actually revving that high. It just sounds like it is, because the Fiero is a bit loud already anyway, and the car is inside a parking garage structure, with the ceiling probably right around 8 feet.
The small tubing, length, and lack of cat or mufflers, also accentuates the tone, and makes it a bit louder, and at a higher pitch, than would normally be heard with a Fiero and typical V6 exhaust designs.
The 3.9 is as much a PIA as any swap. Mounts are simpler though. Wiring and computer are basically the same as an LS7... My swap is a but more unique. I've got a 3.9 block with 2.87" stroke and 6.125" rods. Should make for a screamer. Now it needs the right exhaust....
Custom crank? I thought the 2.8 and VVT 3500 used 2.992 stroke...
My opinion is that you should have kept the displacement. The real impediment to revving a pushrod engine out is the valvetrain, not the rotating assembly. The 3900 heads have plenty of airflow to feed the machine.
Yep billet crank from Crower. Has a 2.827" stroke. It's a billet crank with a SBC flange. I bought it thinking it was a stock 2.99 or 3.31" stroke... But it allows me to run some long rods giving a really nice rod to stroke ratio. It's going to be a turbo engine so flow isn't an issue. The flow math says I'll need to turn 7800 RPM to get the same flow as the sock 3.9L did. So that's what I'm going to do.... Plus a turbo. I'm curious to see how it runs and even more curious to see how my equal length headers perform. I'm trying to get the same sound as the video. I like the high pitch sound rather than the low rumble... Maybe I'll get both??
I've heard a Ferrari 599 and at idle it sounds just like my fiero with stock exhaust at a 2000 RPM high idle.
Maybe consider a 1/4 wave resonator or helmholz resonator to get the sound you are looking for. Maybe a resident engineer can chime in with some rough calcs?
Yep billet crank from Crower. Has a 2.827" stroke. It's a billet crank with a SBC flange. I bought it thinking it was a stock 2.99 or 3.31" stroke... But it allows me to run some long rods giving a really nice rod to stroke ratio. It's going to be a turbo engine so flow isn't an issue. The flow math says I'll need to turn 7800 RPM to get the same flow as the sock 3.9L did. So that's what I'm going to do.... Plus a turbo. I'm curious to see how it runs and even more curious to see how my equal length headers perform. I'm trying to get the same sound as the video. I like the high pitch sound rather than the low rumble... Maybe I'll get both??
I've heard a Ferrari 599 and at idle it sounds just like my fiero with stock exhaust at a 2000 RPM high idle.
You're going to need pretty serious valvetrain to do that. Nothing will be direct fit, but with enough effort and investigation, you can do it. My concern, however, is that the stock rocker bosses in the heads won't be strong enough...
Originally posted by FieroNate: After hearing this sound I decided I HAVE to try this. And the timing couldn't be better. I'm in the process of finishing up my 3900 swap. [...] Anyone with a 60 degree engine on the engine stand with no heads on should be able to validate what I've said above. In the mean time I'll see if I can double check everything and figure out whether I need 2-1 or 3-1 collectors.
Move any further with this? I'm sure I and many others would enjoy continuing reading about your project. Do you want someone to validate your claims?
I just want to see the header's design. its all in the headers... he's basically running a glasspack muffler somewheres...
Who is? The Taiwan Fiero? It is not using a glasspack, and I don't know why you'd say that, as it doesn't really sound like it is. It's not all in the headers either. The exhaust primaries are only a part of the system, and thus, only part of what causes the sound to be a certain way.
Move any further with this? I'm sure I and many others would enjoy continuing reading about your project. Do you want someone to validate your claims?
Sure someone can validate my claim. I simply drew each of the journals in a circle at 60 degrees to each other and numbered them. Then I drew a 60 degree V and figured out which was the odd and even bank. Then I figured out which way the crank rotates. When the crank is inline with the cylinder bore you are at top dead center. Turns out two cylinders are at top dead center at the same time. Which means they are on opposite strokes.
Someone can validate the direction of rotation and cylinder numbering.
beyond that the only thing to really look at is how valve size and exhaust tube size effects the sound.
I've noticed that even with a nice muffler the 3.5L has a deep rumble, I suspect it is due to the large valve sizes. Compared to the 3.6L DOHC which has smaller valves and most likely variable cam overlap which is not possible on a pushrod engine.
Someone can validate the direction of rotation and cylinder numbering.
Engine rotates clockwise when viewed from the pulley end.
Firing order is 1-2-3-4-5-6, so 1 & 4, 2 & 5, 3 & 6 are at TDC at the same time. The bank that's forward (CLOSEST TO THE PULLEYS) has cylinder #1, 3 & 5, the bank that's back has 2, 4 & 6.
Will is correct. The cylinder pairings on the 60-degree V6 are 1&4, 2&5, and 3&6. To verify this, just look at the distributer. Cylinder #4 is opposite cylinder #1. Taking the heads off and turning the crank will also reveal cylinders #1 and #4 rising and falling in synchrony. Same goes for the other cylinders.
But you're right about one thing. The 60-degree V6 is essentially two 3-cylinder engines joined at the hip, with the timing staggered a half-step.
Could be I sort of quickly looked at the 3.4L (3.1L) crank I have sitting around.
However when I looked at the firing order since each bank is essentially its own 3 cylinder the routing of the manifolds should largely be irrelevant. I'll double check hopefully this week if I get some time.
I should soon be digging back into the car and making my headers....
