Lets talk about the optimal exhaust for a 3.4 DOHC. I am interested in doing all custom exhaust from headers back. Now, i have alot fo 2.5" exhaust pieces, but im thinking that I should maybe even be going larger than that. Who knows, well thats what were here to find out. I want to go with just a single cat/resonator tip setup. I have all of these pieces, im thinking that the cat will be bolt in with an equal length resonator piece that i can put in there in its place for when I dont need to take emissions or when i go to the track or whatever. Anyhow, as for headers, Im still undecided about the best design as far as primary size and length goes, or even if it is worth it to go with the equal length headers. You tell me! From the headers it is going to go into a custom crossover that exits out the rear side of the motor to keep the engine bay heat down to a minimum and also to keep it short as possible. All bends will be mandrel up untill the split for the dual exhaust, in which case it wont really matter anymore.
So, suggestions/comments?
------------------ REMEMBER: If you cant win the race you loose the argument!! 3.4 DOHC Motor Swap-14.7 in the 1/4 mile with no hook-up, crumby exhaust and automatic chip. Better exhaust, chip, cam retarding, and driver to come... I'm feeling lucky! www.geocities.com/j_depies
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01:11 AM
PFF
System Bot
FieroReinke Member
Posts: 1065 From: St James, MO Registered: Feb 2003
how are you going to run the exhaust down the backside of the engine and still run a cat/resonator? The only way i see to run a cat is to route it stock style. I have always wanted to put a resonator in place of my cat since i dont have to pass emissions. But as far as header design goes I have no clue. I am sure Aaron will jump in here in let us know what would work best.
------------------ Chris 3.4 TDC SWAP COMPLETED...this is going to be a fun car
how are you going to run the exhaust down the backside of the engine and still run a cat/resonator? The only way i see to run a cat is to route it stock style. I have always wanted to put a resonator in place of my cat since i dont have to pass emissions. But as far as header design goes I have no clue. I am sure Aaron will jump in here in let us know what would work best.
like this
i'm about to do my setup using a shorty cat its 9" long
well I'll be interested in what you do here; what year engine do you have? Of course, that dictates port shape and thus difficulty in making headers - altho none of them really lend themselves to a nice, easy connection at the head anyway.....
Do you think you might come out 'across' the transmission (sort of 'stock' routing) near the shifter or try to go under or some other route? Are you going to use stainless or mild steel? Do you intend to insulate it? You're not turbo'ing are you?
One thing that is a little factor; we have a pretty short system on the fieros so a 2.5" pipe may not be as bad as people think. Especially if it means you can put it 'nicer' bends than a bigger 3" pipe would require. In conjunction with that, if you are using conventional mild steel, with its 'pretty good' thermal characteristics - it transfers heat fairly well - then the exhaust piping is going to 'give up' heat. That means the gases inside are cooling and thus contracting in size. And that means that a slightly smaller pipe might not be so bad. However that means the engine compartment is going to get warm which is something that a lot of people don't want, of course.
Decisions decisions. What way do you think you'll go? gp
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08:33 AM
wetpoop Member
Posts: 921 From: Baltimore Maryland USA Registered: Feb 2004
Having built and installed a few exhaust systems on 3.4L TDC vehicles, and 1 trick set of headers, I can give what dimensions I'd use for a stock-near stock engine (anywhere form 200hp-250hp crank). 2.5" is fine. You know a perfect exhaust size when after install, the power curve is not at all affected, just higher right across the board, with the most gains being up high. Although I don't have a dyno sheet yet, my 3.4 liked the 2.5 mandrel bent exhaust. My white car how it sits, after 96+ intakes, could probably use a 3" system, with dual 2.5" inch header collectors, but I am also expecting over 300hp out of it.
As for the headers, it is worth it. OH MY GOD is it worth it. My car CAME ALIVE with the equal length headers, and the engine intake roar was exagerrated like 200%. THe car breathes so well now. Anyways, IMHO the perfect primary size is 1 5/8", and 34" length. Go 36 if you want more midrange power, but drop off after 6500rpm. I am using 30", and I wish I would've gone longer, as the car really doesn't pick up until 4500rpm. These dimensions are the same for the 91-95 ehads, or the 96-97. Use dual 2.25" collectors, and make sure they are good ones, like more than 4" long, mine are 6". Then run the dual 2.25" pipes for whatever length, keeping them equal if possible, then Y into a single 2.5", and run that back. Mine on my white car are equal until right after the collectors, where the fronts have another 3' of 2.25" mandrel bent downpipe. Pics below.
As for the headers I'll be making for DOHC Fieros, if I ever get the ball rolling...I'll sell them with or without a complete exhaust, and you can buy it with true dual setup or a single split into duals (factory setup). I'd go true dual, but the sound will not be as good. The true dual will also be 100% equal length, all primaries, the downpipes to the X pipe, and the downpipes to mufflers, and the mufflers to tips. So if the front has 6" before a muffler, so will the back. True tuned equal length dual exhaust. The headers will be made for any year, and will also be equal length. I will run the back set over the tranny, the front set will wind around like crazy to pick up length. When someone orders, they can specify if they want just headers or headers and an exhaust, and they can change primary size or length if desired, or any other dimension (I will not reccomend doing this unless you have a modded engine). Prices will be high, but expect around 40 wheel horsepower, if not more. All this available when I get around to it, so about a year...lol
Pics-Equal length headers, 1 5/8" X 30" primaries, collecting into dual 2.25" downpipes, Y-ed into a single 2.5", which runs mandrel bent back using all Magnaflow components.
And a few videos, mine is the REALLY loud one that sounds like a buzz saw. It is not nearly this loud when it is at part throttle and not wide open at 7200rpm
------------------ 1992 Lumina Z34 5-speed 14.78 @ 92.688, high 13s at sea level 1992 Lumina Z34 5-speed Stock, new crate engine and trannsmission 3.4L TDC V6 getting built with a Whipple 3300AX supercharger for a 88GT
[This message has been edited by AaronZ34 (edited 02-23-2005).]
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05:28 PM
crzyone Member
Posts: 3571 From: Alberta, Canada Registered: Dec 2000
Aaron, hurry up! I have cash for headers burning a hole in my pocket.
Exhaust, intake and cams, and maybe a little head decking and the motor will be well over 300hp. If you take that into account, a 3" system would be better right?
Anyone know off hand what kind of hp a single 3" pipe can support? Or a single 2.5"?
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07:07 PM
AaronZ34 Member
Posts: 2322 From: Colorado Springs, CO Registered: Oct 2004
I took a video before the tranny slave exploded again. Its no good quality but you get the idea. I went 60% throttle in 1st and 75% in second and third. But had to shut down because already reached the traffic.
well this thread seems appropriate, so anyhow, some of you arnt getting my plan for exhaust, so ill try and simplify... details on headers are not worked out yet. So what are you all thinking about the headers in this page? http://www.custom-speed.com/fiero.htm Ill try and sketch a drawing of the exhaust and how i want it soon. Lets keep the info rolling in. Aaron, whats your price?
Is there anyone who will do headers for the TDC in a Fiero? I know Aaron said he will but that's in the future and I'm wondering about now. Anyone? Anyone? Echo.
------------------
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12:34 AM
fieromadman Member
Posts: 2217 From: Oconomowoc WI, USA Registered: Jan 2003
Hey Josh, lets get together and talk sometime. You dont happened to have a welder, do ya? Right now im considering either trying to get ahold of a welder or else buying one and making some headers/ exhaust myself. My fabricator quoted me 800ish-1400ish for headers. I've seen his work, its excellent, but that is ALOT of money. Sure they be built to proper specs and perfect equal length headers and all but I just dunno. I think that it would be good experiance doing some myself anyhow, and besides, Im pretty sure i could copy them and sell them if i come up with some good designs. We should get together so i can check out the project Josh. Let me know what yer up to sometime.
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12:38 AM
AaronZ34 Member
Posts: 2322 From: Colorado Springs, CO Registered: Oct 2004
well this thread seems appropriate, so anyhow, some of you arnt getting my plan for exhaust, so ill try and simplify... details on headers are not worked out yet. So what are you all thinking about the headers in this page? http://www.custom-speed.com/fiero.htm Ill try and sketch a drawing of the exhaust and how i want it soon. Lets keep the info rolling in. Aaron, whats your price?
Those aren't headers, they are exagerrated manifolds. IMHO, headers aren't headers unless they are a good set that is worth the money. This is why I don't build crappy headers. They are nice, probably pretty cheap, but you will realistically see DOUBLE the gains with a well-dimenshioned set. But that is how I'd like mine to be routed sort of.
As for pricing, it will be around $600 a set, including any crossover pieces, and I will be working with JetCoat to get discounts on their coatings. But prices aren't set in stone yet, and they depend on a lot of things. I will be buying my Fiero over spring break, MAYBE early summer if the oens I'm looking at fall through. If at that time I have an extra 3.4L long block, I may throw it in for the express purpose of building a set of headers. But this is risky, and a pain to do.
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10:20 AM
joshua riedl Member
Posts: 1426 From: watertown wi USA Registered: Jan 2004
well I have put this comment up in a number of places and I don't know if people don't believe it or just don't know what to make of it, (which is what I expect) but ALL the talk about equal length headers is pretty much wishful thinking. Sorry but it is. Please understand that this is NOT a flame; just trying to get a "physics" point across. Any guys here involved in the piping or (fluid/gas) flow business will support this 100%. "Equal length" headers will ONLY be equal length - FROM THE POINT OF VIEW OF THE EXHAUST GASES FLOWING THRU IT - (which is what it is all about, right?) if and ONLY if they are all identical OR equivalent in LENGTH, SHAPE and NUMBER and TYPE of bends. Ie, 6 perfectly straight pipes or 6 that have exactly ONE 90* bend, etc etc. Of course, that is impossible; you are bringing them from different points to a single point.
As soon as you start bending one pipe more than another, you have changed its "EQUIVALENT" length. In other words, the exhaust gases flowing thru it suddenly experience a lot more "difficulty" in getting thru one piece as compared to another. So just because you START with 6 tubes that were all (ie) 32" long doesn't mean much anymore when 3 have a bunch of tight bends and the others are a single 90 etc. The pressure drops through two pretty tight 90's or 180's are significant when you compare that tube to one farther along the engine that has only (for sake of argument) two 45's. All the 'bundle of snakes" headers you see look really mean and are a tribute to fabrication etc but unless they were designed and tested tube by tube (a HUGE time and material consuming task!!) then they are just a tubular exhaust. No doubt (!!) they are better than stock and I think that is why they always pay off, but in a fiero especially, with its cramped quarters and available (or NON available!) space you will be into the 'snakes' situation, no doubt. So here I am with a 'problem' and not proposing a solution. Not good. I guess all I want to bring up is to be aware of this fact and situation and IF possible take it into account. I expect that what happens in the real world is that EVERY set of headers will end up being "Proper" for its application at a certain rpm range, and that helps. It WILL result in some scavenging effect somewhere along the line, so it is still a good exercise. This might be where the ability to play with collector lengths will be important; if you can build in that kind of feature. I say this after doing a few calcs (about a yr ago now so it is a memory item :rolleyes but IIRC exhaust gases can flow in the 10,000 feet per minute PLUS range in an exhaust system at high rpms. (I think I used a SBC for a base) At idle of course it is a small fraction, so you see the kind of HUGE latitude you are trying to accommodate with a single size header tube!?!?! It has to be a compromise and there is no way around it unless...... well, never mind. Dual pipes? Extra sensors/controls/dampers/actuators etc etc? nahhhhhh...... anyway. So I guess the bottom line is don't be extremely concerned about the 'equal length' item; you won't be able to do it (no, I wouldn't be able to either) unless you have nothing else to do with the rest of your life AND a lot of materials/equipment at your disposal. Where you have the flexibility and space, use 2 - 45's instead of a single 90*. Make EVERY bend as smooth and long-radius as possible. Pay a LOT of attention at the header flange; I mean the bend and fitting. Try to get the gas out of the head into the tube as smoothly as possible; this is where it is hottest and where the velocity is highest, so friction losses are most critical. Try to make all the 'transitions' as smooth as possible; you get the picture. Imagine yourself screaming down that tube at an extremely high rate of spd; then you hit a pothole. Potholes aren't good in the exhaust; we want that stuff out of there as quickly and efficiently as possible. I hope nobody takes this the wrong way; it is like I said just some facts about fluid flow, and exhaust gases are a fluid. It does make an interesting problem and yes, someday I will be working on a set for myself and they will be a compromise too. They gotta fit the space...... But it does maybe open up a bit of understanding about the situation I hope.
whatever you do will be beneficial. Anything is better than stock. All the exhaust gases dump into a 'log' manifold and find their way out. But there are the little things you can do to make it better.....
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11:36 AM
soloyosh Member
Posts: 192 From: Queen Creek, AZ Registered: Jun 2003
well I have put this comment up in a number of places and I don't know if people don't believe it or just don't know what to make of it, (which is what I expect) but ALL the talk about equal length headers is pretty much wishful thinking. Sorry but it is. Please understand that this is NOT a flame; just trying to get a "physics" point across. Any guys here involved in the piping or (fluid/gas) flow business will support this 100%. .....
A TRUE header system for a V6 Fiero is a project I’ve had in the computer for over 2 years now. Being able to model it in the computer is a huge help, but even with this amazing tool available, it’s still a daunting task. Correct me if I’m wrong, but to my knowledge, no one has done one in real life for a Fiero. Understanding the difficulty and benifits in building a TRUE header system, even $1600 would be VERY well worth it.
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01:10 PM
joshua riedl Member
Posts: 1426 From: watertown wi USA Registered: Jan 2004
my knowlege might be a little dated but i remember FOCOA having a set of headers. i think they were 91-95 tdc heaqds buy not sure. a also don't know if they actually take request or if it was a one off job. some1 plz enlighten me on this for my knowlege.
aaron, that will work out great then. it will be about a year be4 i get my tdc into a fiero. after which you gotta hook me up. i am worse tha you though i want an 88 gt 5spd t-top. that sux b/c the cheapest one i seen was 6,500 and that is in the land of cheap cars.
[This message has been edited by dohcfiend (edited 02-24-2005).]
my knowlege might be a little dated but i remember FOCOA having a set of headers. i think they were 91-95 tdc heaqds buy not sure. a also don't know if they actually take request or if it was a one off job. some1 plz enlighten me on this for my knowlege.
aaron, that will work out great then. it will be about a year be4 i get my tdc into a fiero. after which you gotta hook me up. i am worse tha you though i want an 88 gt 5spd t-top. that sux b/c the cheapest one i seen was 6,500 and that is in the land of cheap cars.
probably easier and cheaper to buy an 88 coupe t-top or formula and swap gt panels on
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02:27 PM
fieromadman Member
Posts: 2217 From: Oconomowoc WI, USA Registered: Jan 2003
Josh, how about making two sets, we can just make em as idntical as possible, granted our ideas are simular, and then tack them together. I know of a fabricator, like i said, that would prolly weld them for really cheap. Like he told me last night, there is nothing with welding time compared to the time it takes to design them. I dont really care to have perfect headers, mandrel bends with 1.75" primaries going into a 2.5 " collector then a 2.5" y pipe outta do it for now. I drew up some designs but i dont know how im gonna post them online, maybe ill re-install photoshop on my computer today. Equal length can be a goal but it doesnt have to be made possible. What are your plans for headers Josh, just an imporvement over stock? I dont know when ill have time this weekend to stop over, maybe ill call, i dont know if i still have your number or not but i can look. I gotta get my car fixed first, its acting up a little bit, misfiring/weak fire at high rpms and it feels un-even. Fixed all of my motor mounts tho.
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02:42 PM
WHEELIE Member
Posts: 267 From: ROBBINSVILLE NC USA Registered: Mar 2002
Alright!! Got my header flanges coming for my 96 3.4 dohc. Now all I need to find is the 3/1 collectors.I want nice smooth long ones.anybody know where? thanks ken (wheelie) wheeler
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03:01 PM
joshua riedl Member
Posts: 1426 From: watertown wi USA Registered: Jan 2004
Well to the trained eye, an equal length set, that seems to have all the correct measurements, will look much better than a shorty style, or WCF style. Plus the WCF, and most other companies, use REALLY bad collectors, basically merge type.
Fiero308, I respect your opinion, and you are right and wrong. I love a good discussion that uses technical aspects, yet with no bashing. It helps everyone involved, and the Fiero community and aftermarket. The exhaust is under pressure, low, but still pressure. The bends, unless rediculous, do not affect flow too much. The main "problem" is that the gas pressure will not be equal at one point around a corner. The gas/liquid will want to flow to the outside. The creates swirling once they go straight, which isn't good, but doesn't hurt too much. When I design a set, I try to make them as smooth as possible. Dyno results have proven that equal length headers have the potential to outpower shorty headers, by triple if not more, depending on application, and I have seen first hand how much a decent set can help a car. And although your definition of perfect is true, it is impossible. So I do my best to make them smooth, I use large radius turns, and don't normally bend a pipe more than 90*. But some apps make this hard to do, my Z34 in peticular. My rear set, although equal length, is definately not smooth. So I agree that equal length doesn't mean perfect, but it is as perfect as it will get. I mean I have the time and skills to make them truly perfect, but it just isn't possible to take these pipes and do that. You need to also have distances the same. 2" off head to the first curve, which is 90*, then 8" to the next, blah blah blah. Not possible. As for off the head, it isn't too bad ont he early heads, although they are big outlets. I used a bell, which I heated up and shaped to the port , that bells from 2" to 1 5/8". It is a really smooth outlet design, I am happy with it.
As for you all making your own. Please, follow my advice, I've done all this before. Use 1 5/8" primaries, and dual 2.25" collectors. Mine are this way, and they are already too high end oriented, but it is mainly due to primary length. My gains don't come till about 4,000, and the motor really doesn't start pulling until 4500, where the stock engine comes on strong at 3500. Run the 2.25" crossover/downpipe, then Y it into a single 2.5". This is a great setup, good sound, much better than stock, cheap, and easy to install. Plus you have the perfect dimensions to support up to 300hp. As for collectors, I am using ones from HeadersByEd. They are about 6" long, and very smooth. I liek them, and any shorter and my power curve would be almost rediculous (5000+).
Progress is being made, I just ordered about $300 worth of flanges for headers and intake manifolds...lol
------------------ 1992 Lumina Z34 5-speed 14.78 @ 92.688, high 13s at sea level 1992 Lumina Z34 5-speed Stock, new crate engine and trannsmission 3.4L TDC V6 getting built with a Whipple 3300AX supercharger for a 88GT
hi Aaron naw I dont believe in bashing etc. Working with air/liquid flows and piping etc is what I do for a living so it is just something I've given some thought to I suppose. The only point i am trying to make here is not about 'absolute' pressures, values or anything else; it is simply that each of the header tubes be as 'identical' as possible: so keep the number of bends PLUS the total tube length in mind. The key is to realize that a single 90 degree bend can be "equivalent" to QUITE a lot of 'straight' piping....... The pressure drop thru that 90 bend will be the same as if the exh gases passed thru (who knows how many) several FEET of piping..... I say who knows because it will vary by engine type and size, rpm being considered, primary pipe dia; total length and pressure drop of the system; even whether or not it has header wrap.... and more.
But it is always going to be a compromise of course in that (for you and me) the system has to fit inside an engine compartment. HOWEVER, if there is any flexibility or choice, then try to make them all the same. I just had a quick scan of some popular header mfrs products and it would be easy to show some good examples of bad examples........ but again, they have to FIT. I looked at SBC headers and one of the big items they have to work around it the engine mounts (I have struggled installing them in the past ...) and you don't see those considerations of course in the pix. And fender liners and frame rails and spark plug placement and alternators and other peripheral items all affect the final shape and length.
Anyway, the only way to be sure that the 'design' is right is to test each tube with a manometer and see what the actual pressure drop is across each one. Ideally, you take the 'worst case' tube and ADD bends and/or length to the other tubes to make them 'equal' to it. And do the same to both sides of the engine. Not impossible but very very time (and money and material) consuming. Higher end race cars etc and those with the budgets and manpower would invest in this. It makes sense. Why have 3 (ie of 8) cylinders 'fighting' to push out the exhaust while the others have an easy time of it? Sounds like a good cause for a miss, uneven idle and mostly, poorer performance at WOT. The gases won't flow as easily as they should. 3/8ths of the motor won't be able to 'scavenge and stuff' their cylinders as well as the other 5.... Anyway making the tubes all similar is all I was trying to get across; I will make a set someday too and run into all these same practical limits to a perfect set.... But I will try to compare them using a simple manometer (you only need a shop vac and some plastic tube!) and be as scientific as I can.
So doing this, my question for anyone on headers and exhausts is: When bringing all the primary tubes together in the collector, why not use the collector as the equalizer? What I mean is IF one did do the simple manometer comparo and tirmmed all the tubes so that, bends and all, they were all very close to the same pressure drops but the ends didn't 'line up'....... why can't those ends all be gathered in the collector (leaving the ends 'staggered')? What if they were all within, say 8" of each other (I'm guessing but maybe). Any reason? gp
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09:20 AM
Yellow-88 Member
Posts: 819 From: Coventry CT. Registered: Feb 2005
On equal length: Any primary tube is “perfect” for only one RPM. Engines change RPM constantly, so if not all tubes flow exactly the same, slight differences will not be noticed. In fact the unavoidable slight differances may help to smooth the responce curve.
On equal length: Any primary tube is “perfect” for only one RPM. Engines change RPM constantly, so if not all tubes flow exactly the same, slight differences will not be noticed. In fact the unavoidable slight differances may help to smooth the responce curve.
yup; no doubt! And the tube diameter and length and 'complexity' of the shape and all of that: same thing applies. The nice thing is that almost anything we can concoct will be better than the stock setup.
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10:03 AM
AaronZ34 Member
Posts: 2322 From: Colorado Springs, CO Registered: Oct 2004
I understand you, and agree 100%. But it isn't practical when designing a set for a 200, maybe 300hp street car. For Nascars and such yah, but here, having them fit without cutting is a big concern.
As for your idea ont he collector, elt me get it striaght. You get the 3 to everything deisred, and they ar ein the triangular shape, but one pipe is longer than the others correct? What I do in this case is redesign them. When I design them, I pick a place that I want all 3 to end at, and then I design them accordingly. But if they are clos,e within 1" MAX, then you can just wrap the colelctor around them. But most of the time the collectors don't wrap too much of the piping. IE on most of my sets, the piping only goes into the collector about 1/8" or so. But generally it is best to have all 3 end at the same place, just for smoothness.
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11:35 AM
Yellow-88 Member
Posts: 819 From: Coventry CT. Registered: Feb 2005
It’s my understanding that the collector is a critical place. It seems that one of the big new realizations in header design, is that the collector is far more important than previously understood. I agree with Aaron. With out super high tech lab to work in, just keep them very smooth and clean.
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11:44 AM
joshua riedl Member
Posts: 1426 From: watertown wi USA Registered: Jan 2004
does anyone know where to get bends other than 180 degrees? i'm just thinking in my head right now and i think a few 90's and 45's would be nice. i know you can cut and piece the u-bends but honestly that seems a little crappy and allows more places for leaks and cracks. also some tubes with some good wall thickness. i saw headersbyed has 16 gauge but is limited in bend radius. he mostly has 18 gauge. really the thicker the better. i've fought with crappy headers on my truck and won't be going cheap again. a 3/8 flange is already as thin as i would go. plus they will be quieter and this engine needs all the help it can get.
Let me correct your errors here.
headers will not make a car quieter, in fact most will make sound quality go down, overall note a tad louder, and you hear the engine more. It almost sounds like my engine is knocking form the front because of the headers.
As long as they are built and supported ocrrectly, you shouldn't have a problem with durability. I learned to weld 1/2 hour before building my first set, and 1.5 years, a lot of miles, and a lot of track runs later I have only had one primary crack, of which was becuz I stressed it into the collector. As for leaking, mine leak, but not considerably at any welds. It is rumored that a welded joint is actually stronger than the formed pipe itself. My only leaks are at the head due to worping that came from me using WAY too much heat when welding the bell to it, and small pinholes that my welding skills didn't fill...I agree with 3/8" flange being the minimum.
180* U-bends are the cheapest, plus you will need to cut the 45s and 90s to make them fit anyways. Headers don't use perfect bends, they use weird angles a lot. And I had a few places where I needed to run a bend larger than 90*, and on a Fiero you surely will too.
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11:21 PM
joshua riedl Member
Posts: 1426 From: watertown wi USA Registered: Jan 2004
Anyhow, im glad that people with experiance have come forward in this thread. Drex, i know its hard for you to tell since you never ran the motor with the stock manifolds on, but do you think that they have made a difference?
Right now im considering either trying to get ahold of a welder or else buying one and making some headers/ exhaust myself. My fabricator quoted me 800ish-1400ish for headers. I've seen his work, its excellent, but that is ALOT of money. Sure they be built to proper specs and perfect equal length headers and all but I just dunno. I think that it would be good experiance doing some myself anyhow, and besides, Im pretty sure i could copy them and sell them if i come up with some good designs. We should get together so i can check out the project Josh. Let me know what yer up to sometime.
but IIRC exhaust gases can flow in the 10,000 feet per minute PLUS range in an exhaust system at high rpms. (I think I used a SBC for a base) At idle of course it is a small fraction, so you see the kind of HUGE latitude you are trying to accommodate with a single size header tube!?!?! It has to be a compromise and there is no way around it unless...... well, never mind. Dual pipes? Extra sensors/controls/dampers/actuators etc etc? nahhhhhh......
But I will try to compare them using a simple manometer (you only need a shop vac and some plastic tube!) and be as scientific as I can.
