Well some of you may have already seen me mention in other sections that I am working on designing an intake manifold for our platform. So far I've spent a decent amount of money on learning ram theory, how airflow works, sound waves and a bunch of other stuff. I want to design something that I could possily mass produce and be able to start selling in the next year or so. But I need some input from some of you guys so I can come up with something that can work for a broad range of set-ups and still have exceptional power gains. So far I have come to the conclusion that there will have to be two different models, one for N/A and one for F/I. because the charecteristics of either rely on two totally different principalls and numerous variables. I'm starting with the F/I one because thats how my car is set up. So...after months of learning and planning I have come up with this: I am going to first make a flange with short stubs of tube comming of of it to give me a place to mount the injectors and fuel rail. This is going to remain constant throughout the testing as it will have very little affect of the end outcome. It is going to look similiar to this ITB setup I built last sumer for my friends D-series civic:

<a href="http://www.ringo.com/photos/photo.html?photoId=232984510"><img src="" border="0"/></a>

Next I plan to build a variety of upper pieces that I will use silicon hose connectors to clamp the two halfs together. This will allow me to make changes in runner lenght and size and taper quickly and easily on the dyno to compare results. Dyno testing will go as fallows: All variables will be recorded including ambient air temp, humidity, elevation, compression will be tested and verified before every session to asses any variances in the motor itself and anything in the enviroment that could influence the out come. Dyno sessions will be conducted as follows. Comparrison tests will be conducted at Beeyond engineering (http://www.beeyondeng.com/) in milwaukee WI utilizing their Dynocom dynomometer as me and my friends are regulars there and its easy access. There will be a 20 minute warm up session followed by a base pull to establish numbers for the day and compare to any previous runs made. Then there will be a second pull that will be recorded as the official base pull. A third pull will be made with the modified design in place to observe and record any changes that occure in power out put and location of the torque curve. A fourth pull will be made to verify these results. I decided that the initial testing will be done on a stock motor with 8lbs of boost and tuned with MS as I want this to be something the vast majority of us can benefit from. From what I have seen on here most ppl run a stock head with forged internals in the bottom end, therefore the characteristics of the intake should be good for anyone running any amount of boost as long as they have a stock head/valve train (I'm going to work on a race model when this one is complete). When I change out the plenums or adjust the length of the runners I will not be changing any part of the initial tune because I am looking for results that show how the motor is influenced. If any displayed information says that the motor is in danger of failure the pull will be aborted and the cause will be determined.

What I need from you guys is input of any and all information that any of you might have or know to help with the designing of this mani. I would also like suggestions as to how it should be designed and the layout for expample; Stock or 60mm tb option? stock location of Tb or relocate to a more preferable power producing location with a smoth transition. Vacuum ports? factory Map sensor mounting location with included block off plates? EGR or not, Includes blockoff plate for the head? and anything else you guys might think of. I want to build it to utilize the stock fuel rail but in the future I might build something with a bore of about 5/8" that would fit the stock location(still up in the air). And any other suggestions would be great.

This is what I have for an initial design:

Typical single runner single plenum side inlet design.

2.3 liter tapered plenum designed to distribute equal airflow to each of the runners.

8.65" long tapered runners making an equal smoot transition from 1.687 I.D round velocity stacks to the stock oval ports.

TB currently in the factory location.

Injectors and fuel rail utilizing stock location and design(direct fit).

The test piece will probably be made out of light gauge mild or stanless steel as both are easily welded and easily available to me.

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

Sounds like you have about everything already planned on what your going to do. I would def. have options for the 60mm tb and map sensor etc. People with ms don't need a map sensor on the mani, but also maybe relocate some of the vaccuume ports to a better location or something. I don't know it sounds pretty good right now, maybe you can get with Mark and test out an N/A version too.

Are the runners going to be straight like Magnus on the 4g63. If so i cant see how you are going to fit 8 or almost 9 inch runners and then the plenum in the engine bay. I measured an extra stocker that i have and from the front of the flange to the back of the curved runners is about 9 inches. From the back of the manifold to the firewall is only about 3 inches.

As far as your questions i would try to make it as close to a bolt on as possible making it accecpt all of the stock sensors. I would produce it accepting a stock TB but have a 56 or 57mm opening for the majority of people with ported TBs. As far as the TB location i dont know how you could keep it in the stock location if want those length runners. Personally i think that most people that are changing manifolds probably wont mind changing their piping to accomadate the new TB location.

Simply put i think if you have the proof that it makes more power versus stock then people would buy it.

at this point the runners will curve up to resemble the stock design, the length is mesured on the centerline of the passage from the valve to the end of the velovity stack wich will protrude into the plenum by about 1 inch from what I have figured now. I'm going to build a jig for this that allows me to place everything in the stock location. where would you guys like to see the vaccum port locations? on top if there is enough clearance? on the end opposite the TB? for now I am only goin to have a -10 line comming off to a vaccum/boost bar to accomodate the ease of changing it out. I want to create a race bred manifold that would help out the turbo guys that are runnin modified heads and valve train, these will prob resemble the magnus intakes as the runners will have to be substantially shorter to accomodate high rpm ranges. N/A wont be to far behind this first one. I'm going to need some specs from somebody building an N/A motor for high performance such as cam profiles, any head work and flow bench results, Rpm range of the motor, compression, and a few other things. If anyone would want to help out with this in the next few months it would make things work out alot better. I'd like to have a few ppl on here test out some designs in a few months after Iv'e had time to do some substantial testing. both N/A and Turbo, so When I have something ready I'll be looking for volunteers to bolt one on and get some dyno results

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

I will be more than willing to test out a manifold for you. If you are interested in this hit me up with a PM or better yet email me at Crab1092@yahoo.com and i will give you a complete run down of my car. As of now the only thing that is bone stock on my car is the damn intake manifold and thats only because my aluminum welding skills go far below sucking.

I would like one vacuum source near the TB side for the BOV and the rest on the other end all on the back . I would like to see the holes just tapped as 1/8 or 1/4 NPT so that it would be easy to plug if not wanted and barbed fittings would be easy to come by. I dont partically like the idea of them on top because half of my vacuum lines wide up going through my firewall.

I'll consider that as an option and an email will be sent shortly. But I would like more suggestions. Yours is great, but like I said I want this to accomodate a large range of types of builds, and I want it to be a Bolt-on instalation that wont require to many modifications except those that may be required to accomodate the end design fitting on your car. Wich will be determined by power output characteristics. So the more input I have the better.

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

Hmm.....one of the problems you will run into (obviously) is accomodating all kinds of different set-ups. As poor as the OBX design is, that seems like what they tried to do. It's shiney ,
people seem to like that. They shortened the runners a little and smoothed out the turn. They have a smooth interior with the injector humps pretty much not there. But plenum size, fitment, runner alignment etc. owns them.

For NA, you could shorten up the runners a little (obviously, finding the right length will require the R+D that you speak of)and use of velocity stacks for runners would be ideal.....

Eh, now that I re-read your post, I get the idea that you are looking for what would help sell your intake. Shiney works good I would think to make it as "bolt on" as possible; so you would probably want to maintain the positioning of all the sensors (including map). Be real sure that the bolts/nuts to the head are easily accessible. Designing a little bit easier access to the fuel rail bolt-on/off would be handy. I would recomend making the throttle body opening (sheetmetal I presume) at 60 mm (and in the stock spot). If someone has a smaller TB, there would be no (discernable) effect as the flow would not be interfered with. But if the hole was smaller than 60mm, then there would be interference (or the buyer would have to port it out a little. Yeah, normally no big deal for a basic modder, but more work nonetheless).

I believe that you would be able to make an intake that could cover both NA and Turbo (obviously, to the buyer, two specific intakes would be ideal, but now you are raising costs etc. Maybe have the option of a different "big turbo" intake). Most of the turbo guys are going to be below the "60 to 1" size turbo. I'm thinking that the intake you generate will have enough of the flow characteristics to take on modded NA or "smaller" turbo.

One of the biggest problems you will get for the NA is having the support for the intake on the customers vehicle. You'll probably get nothing (or maybe even worse results) using stock internals with a stock ecu (which is what many will want to do). You're really going to want some kind of tuner to take advantage of the intake. But that will be up to you as a seller to make that point clear (though, who knows, it may add power in some weird quirk of the ecu reading sensors etc. More for your R + D).

One more point you might want to think about; change the entrance angle. I really dislike the angle that the stocker enters at.

Just IMO. I know there are others on here who are much more informed on air flow characteristics, matching resonaces and the Bourne Identity effect on air (crap that I skimmed over in HS/College but I couldn't recall a bit now). They would have much more of a technical position to add. I do all my porting and air flow info through just practicality (the way I see air flow) and old man experience.

Oh yeah, and giving them away free to anyone over 30 would also help (well, would help me). But I would think your price range should land in the $350 to $400 range.

Again, just IMO.

Captain Caveman

96 RS Turbo 11.414 @ 119.62 MSNS, Crower 2 NA cams, BW366, 10.5 comp, UDP, 60mm TB, W/A intercooler, 3.55 tranny 567.9whp 430tq
97 RS NA 13.188 @ 103.87 MSnS powered 12.5 comp, Crower 3's and 219.4whp with 175tq
98 RS DD 12.5 comp on stock ECU, LTH, Crower 2's, Koni, GC, Hypercoil, DG hats
99 OZ 5sp Stocker 15.856 @ 85.97
99 GS stocker auto 17.7@77mph!

wiki home page:http://www.2gnt.com/index.php?d=bullettdsm

im 32 ill take one

We will build you bigger and stronger


Wake up and drive my ass... More like wake up and fix it.

If the opposite of Pro is Con
then the opposite of Progress is Congress

Thanks for the input! I'm not just looking for what would make it sell... well sort of... I just know that there haven't been many sucessful attempts at making a largely available intake manifold for our platform. I just want some input from some of you that actually understand some of the concepts involved in such a thing and some pointers as to how things should be put together. I know there are fitment issues with the OBX along with other design flaws... I want to come up with something that will fit as well as the stock but give the power gains that we all wish for. And I understand that there will probably be minimal gains with a stock ECU, but as always there are going to be greater results with some sort of tuning device, MS for example. Only R and D will tell what can be achieved. bullet, What do you mean by the enrance angle? Are you refering to the TB?

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

Captain Caveman

96 RS Turbo 11.414 @ 119.62 MSNS, Crower 2 NA cams, BW366, 10.5 comp, UDP, 60mm TB, W/A intercooler, 3.55 tranny 567.9whp 430tq
97 RS NA 13.188 @ 103.87 MSnS powered 12.5 comp, Crower 3's and 219.4whp with 175tq
98 RS DD 12.5 comp on stock ECU, LTH, Crower 2's, Koni, GC, Hypercoil, DG hats
99 OZ 5sp Stocker 15.856 @ 85.97
99 GS stocker auto 17.7@77mph!

wiki home page:http://www.2gnt.com/index.php?d=bullettdsm

ok, now I got ya. Yeah, the ports do sweep downward towards the valves. And I can see how the factory intake would cause a bit of turbulance in the entrance to the port. I believe the exhaust ports made somewhere around a 18 degree downward slope when I measured for my turbo mani. I'll have to measure the intake ports angle in relation to the flange surface when I get back from utah. Unless someone else could do it by chance I won't be back till the 11th... any way great point. This is the kind of ideas I'm looking for. I think the hardest part of all this is going to be determining an RPM range that works well for most. If I design using the third wave I would have to make the runners somewhat long to accomodate most looking for anything below 4000 Rpm. And a rough Idea of what kind of HP numbers people would be looking to achieve with such a manifold would be needed too. That way I can carefully consider the runners's cross-sectional surface area and the degree of taper to try to keep the theoretical velocity of the ariflow within a reasonable range when designing the initial test piece. Any one have any ideas for any of the above?

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

imo, the runner section of our manifolds are fuckin sweet with a nice port job, and then you slap a phenolic spacer in there for obvious reasons... then all u need is a nice plenum section and the 60mm tb for the boosted motors. i wanted to make something similar to the fast fabs plenum but with a slightly larger volume to support the 2.4...

I'm actually considering This as an option for the "stage 1" Once I get a chance to get the rest of the parts made so I can Start welding things together I'll be able to finally start testing things out. What do you guys think about a replacement for the upper half of the intake? If your running stock head and valvetrain that is. I still plan on making a complete manifold for The guys interested in making maximum HP, But I'm still working out the design of the test model. I've been talking to an old friend of mine that now owns and runs a laser cutting shop, and I think that there could be a few options available. Essesntially every thing is theoretically going to land in the stock location, but I could have different end plates cut out to accomodate a stock or jeep TB. I have also found after about 70 hours of playin around with a flowbench, burnin pencils on calculations, and a couple few late night drinks, That the difference between an N/A and a F/I manifold could possibly be left to the plenum alone. The diameter of the runners would have to alow for sufficient airflow but keep good velocity. And the length will determine the location and duration of peak torque. Here's what I have come up for this...

Stock head/valvetrain:
do to its limits in RPM I was thinking that the 3rd wave should alow for maximun torque around 4500 Rpms and carry to 7500 Rpm. Airflow limits would dictate maximum achieved power to be around 400 Bhp.

With head modifications(P-n-P, aftermarket Camshafts, valves, ect.):
Maximun torque to occur around 6000 RPM, but start around 4500 rpm's and carry to at least 9000rpm's. A Cross-sectional area of 3.1 square-inchs, and the final runner lengths are still TBD.

Any suggestions on the above?

I've been talking to a local company that does extrusion and anodizing so when I have a final plenum design i am hoping to have the runner and plenum pieces made be them. As far as forming the runners and the shape of the tube, I have called a couple of company's about custom dies for my mandrel bender but don't know if they will be oval. Or if I will use round tube and hydro-form the transitions to the head. For everybody thats interested, I am expecting a few test pieces available by the upcomming February. I know it's a ways out, but like always this takes time and money.

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

Just wanted to show what porogress I've made in the last few weeks. I built some dies for my press and a rig for my lathe that lets me make my own velocity stacks, and I cut out the materials for the plenum (turbo). I figured the plenum should be about 64% larger than the displacement of the motor to allow for maximum airflow yet still have good throttle response. So any way... here's some pics of the stuff so far, keep in mind that this plenum is going to be connected to the flange with silicon couplers so I can tune the length.

<a href="http://www.ringo.com/photos/photo.html?photoId=240233585"><img src="" border="0"/></a>

<a href="http://www.ringo.com/photos/photo.html?photoId=240233549"><img src="" border="0"/></a>

<a href="http://www.ringo.com/photos/photo.html?photoId=240233745"><img src="" border="0"/></a>

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

wow! keep going, if you can build something better than the obx (not hard) that would be awesome

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!

Haha. We've set our standards pretty low if our only goal is to build something better than OBX.

-----------------------------------------

-Paul

Service Manuals and Guides

Erik P.
Official 2GNT thread Hijacker
Some say that he's driven over more Covenant than he's shot, and that his grenades aren't where you'd expect them to be...
All we know is, He's not The Stig... But he is The Stig's Spartan cousin!

A car came into work today, an older Toyota( I can't remember what) but I saw the intake manifold and thought would could the 2gnt use something like this. It has the same basic shap as the 1 plenum 4 runner design as far as space goes but has better entrance angles to the ports on the head and I think would produce better VE in each cylinder. Check it out...
http://www.putfile.com/pic.php?img=6933731>
http://www.putfile.com/pic.php?img=6933732>http://img2.putfile.com/thumb/10<;a href="http://www.putfile.com/pic.php?img=6933733" target="_blank"><img src="" alt="Click to enlarge."></a>/29518112437.jpg
What do you guys think?

Those intake manifolds are from the 1998 - 2002 Toyota Corolla's. They're nice, and they definitely give the little Corolla engine some pep, but they lack a proper plenum. Due to that fact, I bet they would starve any engine pushing high horsepower.

I did like the concept though. Those manifolds were sort of my inspiration when sketching this:

-----------------------------------------

-Paul

Service Manuals and Guides

Also looks a bit like the intake manifolds off the early Old's Quad-4 engines. I had an '88 Grand Am, and it was that style - shortly after they modified it to a funny hump-looking thing...

/>

'95 GS w/ t3/t4b
FMIC, diy piping & RFL BOV
MS2-Extra Fuel&Spark
50 lb/hr Holley injectors w/ 1:1 RRFPR
JE 8.8:1 dish w/ Hastings Rings
Eagle Rods w/ ARP bolts
ARP Head studs
Mild port/polish head
3" custom DP/cat section, 3" PIT catback
dual MBC - 12 psi / 20psi

I looked at design's similiar to those in the past, they look cool, and give ton's of room for runner lenght. But like said above, there's no plenum volume. They make great low end torque and make for some great gas mileage but lack severly in the top end. Notice how you don't see anything like that around anymore? Any way...as far as the progress goes for this week, we tried to hydroform some aluminium tubing and came to the conclusion that it's probably not gonna happen... it seems that the mateial wants to split open wherever there are any defects in the material. We tried extruded and welded tube, along with trying to polish the inside and out of the tube to prevent any surface imperfections causing a crack on 30, 50, and 60 series materials with no sucess. So it looks like I'm goin to be makin a die set for the oval end of the tube also. Anything new happens this week I'll let everyone know.

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

My experience (V8's) it's been the other way around - the short runners are great low-end torque while the long runners are more beneficial top-end, directing the higher-speed airflow better.
Would plenum volume have much affect on a turbo vs. an N/A? I'd guess that in boost, since the air is basically pushed in instead of pulled in, then medium-long runners would benefit to direct the flow instead of forcing into a short tube in multi-directions just before getting to the valve.

/>

'95 GS w/ t3/t4b
FMIC, diy piping & RFL BOV
MS2-Extra Fuel&Spark
50 lb/hr Holley injectors w/ 1:1 RRFPR
JE 8.8:1 dish w/ Hastings Rings
Eagle Rods w/ ARP bolts
ARP Head studs
Mild port/polish head
3" custom DP/cat section, 3" PIT catback
dual MBC - 12 psi / 20psi

You're right in that the medium-long runners are probably better at directing flow into the combustion chamber. However, they also tend to be narrower, and thus restrictive in terms of volume. Shorter runners, on the other hand, can afford the luxury of being very wide. The wider cross section allows more air volume to enter the combustion chamber.

Don't get me wrong, laminar flow is still important, but when the air is so highly pressurized, volume takes precedence.

-----------------------------------------

-Paul

Service Manuals and Guides

well here's the thing... you can have long small diameter tubes on one intake and short fat ones on another and still see the same torque curve on a dyno. Especially when it comes to low end torque. There are a large number of combinations that will work great with a particular motor at a given speed. And if tuned properly you could put any one of those manifolds on the given motor and achieve the same exact results. That is if the motor only operated at that particular exact rpm throughout it's entire lifetime. But the fact of the matter is that in a car the engine operates at any number of speeds at any point in time. Therefore the intake has to support the vast range of operating speeds it will see. It needs to provide lowend grunt while still support enough airflow to handle high revs without choking the motor. And to top it off you need to be close enough in length and cross-sectional area to support the sound waves reflecting inside that we are trying to take advantage of. The idea is to have the sound wave hit the back of the valve as it opens and in effect "supercharge" the cylinder in question. The traveling sound wave push's the air as it bounces back and forth in the runner. It is created everytime the valve opens, travels to the end of the runner, and then reflects back down towards the valve. And thanks to harmonics and everything else I don't feel like describing right now, these multiple waves can co-exhist in the same air mass without interfearing with eachother. If you read this and understood what I was trying to describe, then congradulations, you now know the basics of ram theory!



But to the point... In the last two weeks I started with the adaptations necessary to fit a 420A to the superflow dyno at work. Have to fab up a bellhousing and mate our flexplate to a borg-warner drive disc. Some welding, some machine work, and a portable air-to-water intercooler and I'll have a very accurrate testbed. The dyno is outfitted with a Depac. Enough said there. Once I start actually building the parts I'll get some pics up of this also. The only prob I'm going to have with this is getting some time to myself with it. I already have the go-ahead to do this as long as it doesn't interfear with normal testing. Unfortunatly we do about 4 or 5 small block chevy's a week. I'll try to keep all those who have followed this so far up to date as I go. I generally don't get on more than once a week but I'll do what I can.

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...

If you're dealing with a turbocharged system, what's the point of fussing over few points above 100% VE via Helmholtz if the turbocharger is already doing that for you? Granted, it'd be nice to tune the manifold for resonance in the low end, but if you do that, the runners will be so elongated you're now hurting performance post-turbo spool.

I agree 100% that a manifold needs to be designed with an RPM range in mind; not just one point. At the same time, the entire design process is a system of compromises. In my opinion, it'd be better to have something open and able to support power up top, than something only capable of adding a little extra power down low.

-----------------------------------------

-Paul

Service Manuals and Guides

Ram-theory (ram-induction thoery) is pretty well-known, and, agree with above, it does and doesn't apply. Like quicksilver said, an N/A and an F/I engine require vary differnt styles. On an N/A engine ram is everything for tuning if you're honing on a power point, in which just the basic design is beneficial to turbo motors (just as port/polishing, even though air is pressurized it will still flow 'faster' with lower sidewall friction), but it can inhibit them after a point. So really there comes the 3 sets of perfomance, ecomony, all-out power, and somewhere in between - to determine how the design should be taylored.
Lookin forward to the flow-dyno results, wish like hell i had a setup like that to tinker on!! *slightly jealous*

/>

'95 GS w/ t3/t4b
FMIC, diy piping & RFL BOV
MS2-Extra Fuel&Spark
50 lb/hr Holley injectors w/ 1:1 RRFPR
JE 8.8:1 dish w/ Hastings Rings
Eagle Rods w/ ARP bolts
ARP Head studs
Mild port/polish head
3" custom DP/cat section, 3" PIT catback
dual MBC - 12 psi / 20psi

All valid points! Yes, the search for ultimate performance with a N/A engine requires the use of tuned intake and exhaust runners. In order to make use of the sound waves produced by the opening of the valves the lengths and diameters must be within a range that supports the travel of the sound in a manner that will promote better air movement within the engine. Now take into consideration a turbocharged internal combustion engine. It is true that before any positive pressure situations caused by the turbocharger the engine itself is nothing more than a N/A motor that has to deal with a hell of alot of back pressure. It is also true that if no reversion, or very little exhists at the time before the turbocharger positively pressurizes the intake passageways of the motor, then there is room for more power producing air and fuel to be forced into the cylinder prior to the valve closing again. Now we have to consider that the air within the intake runners, and the sound wave also traveling within, are moving at two different speeds. Air velocities may exceed 300 FPS. Sound on the other hand, travels at the speed of sound, wich is also controlled by the variable known as temperature. Knowing that sound travels at a great rate of speed we know that it will travel the length of the runner in a very short period of time. Faster than the air column that is trying to enter the low pressure area within the cylinder. And due to space, economics, and in some cases ethics... It is almost impossible to utiliize the sound wave the first time it makes its venture down the tube and back. In common practice the third wave is used. It travels the length three times before the valve opens again and is made usefull. Lets say that a runner is tuned to maximize airflow at 5000 RPM's utilizing the 3rd wave. Now lets say that we want to move peak torque down a step, to about 4500 RPM's. Theoretically we lengthen the tube a certian distance and have now achieved our goal. Now lets say we want to move power down to 2500 RPM's. We must lengthen the tube again. But at this point we have run out of space to place such a creation so we must shorten it again. But this time we are also going to change the cross-sectional area. Take the above example, peak at 5K RPM's using the third wave. The third wave is the key to our problem. If we could visually see the wave traveling through the runner at a lower RPM we would see that it has made its reflection and rarefraction more than three times and is no longer in sync with the valve. It may be on its way back toward the plenum, or reached it and is headed towards the valve again, but is not in a location optimal to utilizing its energy. Lower RPM's require more repitions of the afformentioned "wave" so at half of our theoretical 5000 RPM's we need twice as many travels. Or the 6th wave. This is how a manifold can support a vast range of operating ranges. A runner with 9 inchs length, plus 3.14 inchs port length(centerline) and an area of 3.7 square inchs could theoretically support a 7000 RPM peak of torque utilizing the 3rd wave. If un-tapered, and straight, we can use calculations to determine at wich point each of the succesive wave travels will align with valve opening events at lower RPM's. It is mostly a matter of time intervals between seperate events aligning with eachother. And using this information and the mentioned calculations, we can create a runner that will support ultra high rpm power and airflow, but still give significant and recordable results at lower RPM ranges. Lower RPM performance will boost the respose and output of a severly large turbocharger. But what happens if the lower range mentioned above doesn't fall into a usable timeframe of the engine design/turbo setup? Then we can taper the runners and alter the charecteristics of the sound travel and force it to work the way we would like it too. As the area increases the air velocity and the sound wave decrease in velocity. The air becomes more elastic and absorbes more sound than it transmits. And this also causes the frequency's within the air to change. Think of a guitar string. The tighter you stretch it the higher the pitch because it is forced to move within a smaller available space. So now that we have tapered our philisophical runner we have moved the 6th wave, wich would have normally occured at half of 7K RPMs, or 3500, to a more usable 3000 RPM's to where our turbo had originally started to create boost. We now have slowed the sound travel a small amount and helped our straining turbo achieve opperational RPM's sooner because we increased the power output of the engine enough to create more heat and velocity within the exhaust flow. It is true that the lengths mean little after the onset of boost. Airflow is the key at that point. But to be able to use otherwise wasted energy to help create more power in the long run, and still have a usable range of output, could mean that a once barely streetable car with say a large GT35R, could use something larger and not be restrained by the limits of the turbo. But still be able to function in a similiar manner to the previous layout. Ultimate power is the goal, but it does nothing if it's not practical or usable.

Creative thinking? Ingenuity? Hell, It's just an obsession!



99 Eclipse GS turbo: MSpowered, everything custom built, 223.8 HP-199.8 TQ @8psi through auto-tranny. The first time around...