30 dollar Intake Manifold

[DjPantsSpecR]

You guys are gonna ahte me because i cant get any pictures up jsut yet. I have some on my phone, but this phone is from China and it uses some crazy chinese internet. I should be able to transfer them adn post them as soon as i get them.

Being a poor bastard i have added to my list of poor mans mods with the 30 dollar intake manifold. Its basically what i and others have been preaching, but i finally had some time to do it. It has to be able to be done by everyone and it has to be easy to manufacture.

Some might question the materials choice, but that is okay. As a future engineer i am very aware of the downsides of what i have choosen. However, i wanted to make something that could be built by everyone inside their own home.
The materials involved are:
22gauge weldable sheet steel a 24 x 24 inch sheet is all you need, adn mine was 9.98
JB Weld
Permatex Ultra Grey liquid gasket
36 nuts and bolts

Stock TB and gasket. Stock upper intake manifold (runners cut, SCV removed). No EGR, no IACV, no charcoal canister. two vacuum lines (one for FPR and one for brake booster). My battery is where the factory airbox used to be so the battery cable is not attached to the intake manifold

A sheet of steel is jb welded to the cut runners. Then a 3 walled box is gasketed and bolted to that sheet. this competes the plenum, and mine is water tight, so i imagine its airtight too. I am even able to use the stock throtle cable bracket, it bolts up to one of the 36 surrounding bolts.

36 bolts sounds unnecessary, but it was nice to have in order to insure a perfect seal on the plenum. it helps bend the sheet steel to the sheet steel which makes a nice and easy to seal surface for the liquid gasket.

i know this thread is useless without pics. And i havent installed the piece yet, because i keep blowing the ignition sw fuse on my other 240 and im not comfortable trying this on my only car. But now i have free time again and i hope to install this ASAP. I'll let you know if its worth anything

all this info right here is from my original design. i have already completed and run the second design for about two weeks now. i took it off and went back to stock last night for school and compareson.

finally heres your pics, bitches.



this is my pandas14 style shot.... i used to worship your ITBs/still do.



and this is my BigVinnie style shot... looks just like ya vin



Now that ive finally got the design down flat its time to ditch the JB weld mock-ups and start welding. Im trying to avoid machining a plate ala the xcessive unit. However, i can not see a better way to weld this together. if i could get a piece of thick sheet aluminum, i could do this, but im still looking for a great solution.

ive already got a lot of requests for write-ups of this, and i'd love to make the KA community a little faster for not much dough. however, i dont want anyone to profit off my research, my designs, and my ideas/creations. So if im not gonna be making any money, no one should be able to.

come on, Xcessive sells its manifold for 500 plus dollars, and unless youre a turbo KA you'll be losing power by having a peak torque at a lower than stock rpm.


Modified by DjPantsSpecR at 5:54 PM 9/5/2006


Modified by DjPantsSpecR at 5:57 PM 9/5/2006

[SeanC]

what did the internal volume come out to be? how long are the runners now?

[DjPantsSpecR]

volume is an issue here. On the race car at school we like to design for about twice the volume as the motor displaces.

On the KA you have many constraints. Hood clearance is one, but the throttle body also has to clear the coolant hose. The back of the plenum also is in very close contact to the firewall and the plenum comes near the strut towers. My plenum volume is 3670ccs which is close to 1.5 times the displacement of the motor, so im comfortable with it.

the runner length is about 9 inches. I only roughly measured it, adn that was a week ago. I am well aware that the runner length will determine where peak power is produced at. However, i wanted to get as much length as possible out of the stock upper manifold, so its cut right were the bend makes its 90 degree turn and cutting it vertically would involve cutting through a whole lot of aluminum.

i'm being very vague on purpose, because i dont want people to start trying this until im certain its good for us. But to summarize about 3.7 liters and about 9+ inches

[elgarvo616]

any butt-dyno numbers?

[DjPantsSpecR]

like i said, i havent put it on, because the first day i took my other 240 out of storage it developed a short somewhere about 40 miles into a drive, so im worried to do something crazy to my other car that might cause it to not make it back home.

for example if a weld breaks adn it develops a huge vac leak it will run lean as hell and idle at around redline......

however i do know one thing about the butt dyno in this situation. the low end loss associated with this design will make the top end gain seem much greater.

if you dont believe me unplug your coolant temp sensor adn warm the car up and take it for a ride. it will seem like a massive power spike at 5500 rpm. however dynos prove this massive increase is actual 8 less peak power and other areas are as great as a 30 whp loss.

so butt dyno can be misleading.

but im obviously hoping for positive results. Something like 8 hp would be nice. as soon as i can secure a job here i can get the exhaust i need and actual make power from my intake side

[3dKa24]

Any updates on the Manifold, sounds interesting well from a price perspective.

[DjPantsSpecR]

i always forgot to get back to this thread.

alright here's whats up. I had a serious amount of vacuum leaks, but this was easily solved with some liquid gasket. You have to keep in mind this was literally a piece of sheet steel JB welded to the runners, with a large box plenum bolted on over it. Ideally you would want a thicker aluminum plate welded to the runners (which you would have to have made), with a .050in thick 6061 t-6 plenum bolted up to it.

My plenum is one piece of sheet steel cut to be bent onto a box with tabs on the outside of all the walls to be bolted up to the plate on the runners. I simply jb welded the corners inside and out. Around the outside there is one fastener per inch, but thats mainly to make sure the seal is tight. liquid gasket is layed on the tabs and it is torqued. next, more gasket is layed around the edges. The throttle body alos has gasket around the outside of it, as well as astock TB gasket. I took the IACV's pipe off the stock intake, adn used that to run a coolant line to the heater core. I also cut and bent the stock throttle cable bracket adn bolted it to the corner of the plenum. My throttle opens sideways, but the throttle wheel is pointed to the sky, so i had to cut off the cruise control wheel and rethread the rod there. The hood support also needs to be cut out there for clearance. The plenum doesnt hit the firewall, but it has about an inch of clearance.

The car idles better than it did before, which is impressive as it only uses brake booster and fuel pressure regulator for vacuum.

Anywho, i swapped out my 240 intake for a 248, and i went back to 248/232. The car pulls much much better from 5000-on. There is definately a loss from 1000-2500, but that not an area you are usually in. It looks like i've done my homework, or i just cant rev high enough, but it seems to make peak power at 7k. thats probably something most people arent used to on KAs, this thing wants to keep going at revs. Maybe if i had a few hundred more revs i could see it dropping off, but there is no doubt in my mind that this car is quicker than what i've switched to...

I had to swap back to a stock manifold. I set up the stock manifold in a similar way, eliminating everything but BB and FPR vac. I hate the stock manifold, adn this is why. It causes peaky power, its not linear, especially with 248/232. its has humps and valleys, ups and downs. UNless you can keep it cookin above whatever RPM you might always notice a dip in power in certain rpm ranges. With my manifold the power just keeps stacking up, its much much more linear. However, i cant afford to give this intake mani what it needs to work right now. I've noticed that in mid RPMs it runns dangerously lean sometimes, so i still need to find a vac leak soemwhere i imagine. BUt if not i need something in an SAFC.... I also need a header adn exhaust. I've absolutely maxed out what i can do on the intake side without better exhasut flow. any power im making would be much more pronounced with an exhaust combination.

Otherwise, it works, it was dirt cheap and it makes power where i want it. It also looks incredibly bad ***, adn it makes wokring on the intake, or removing much easier. You can actually get to your starter, or your oil filter,a dn you eliminate a large amounf of weight from the lower intake manifold.

[s14 2510's]

header is sold you missed that boat. O well! ajax will pimp that sh*t.

[DjPantsSpecR]

ajax is in a whole different world of hurt. I came up witht he money to buy that header finally, adn then i realized that my girlsfriend's birthday is on the fifth.... so i was like ****.

How am i supposed to buy the s13 a header, my girlfriend some gifts, and satisfy my need to shoot roman candles at my friends all at the same time? well needless to say i didnt win at the casino, so i guess i only can do one of those options now...

Who do you love more? Fireworks, S13s, or girlfriends....

And driveshaft received

[s14 2510's]

I would have thrown in a few sets of free roman candles. But as far as pleasing your gf i'll leave that up to you. but you know how to use glue and you should have some mac and cheese. make her a pic. jk What ever. You could have used the header more seeing how you have no egr and your engine bay is no show stopper just peer performance. Right now I love my s14 more. jk That driveshaft has been in my trunk sence the day after I gave you all those parts. lol
I got ajax's squirter motors off too and they will be sent out wendsday. buy ajax's header for cheap and bend that pipe away from the steering.

[DjPantsSpecR]

well ****, we tried for two hours to get the steering knuckle outta the way so we could jsut pound it on his car, then at least i could still buy the DC from him. We couldnt get that ****er off for the life of us, adn all we need to do is clearance on of the secondaries by about 1/8th of an inch

when we went to unbolt the header, we found it was welded to the cat, which was welded to his 5zigen fireball exhaust. So its one piece from header back. So if i get his OBX im gonna have to have it welded on, which is okay i guess as i need to have a cutout welded on too....

stupid girlfriend, restricting me need to open up my exhaust....

[Ajax]

Yeah, what a pain that was. Sorry you came all the way out for that. Wished I had known it was welded beforehand. Once I get this whole thing worked out DJ- you get first dibs on what you want for cheap.

[DjPantsSpecR]

And we're gonna get you built back up for cheap.

763 537 9416 Motors By Gosh

[s14 2510's]

When I did my exhaust I welded 3/8 thick flanges on a universal 3" cat. So all the exhaust was a direct bolt in. All my egr and pair valve plugs were rusted into the old header so I just welded the egr and pair shut. but I could fix then in 20 minutes with a welder and grinder. I have a portable hobart welder I can bring and fix that if you dont have a welder. I just need to place the header in the car so I can tack the ends on then weld them back on off the car. I can get some more flat 3/8 steel for free from my budys junk yard and we can weld and make you exhaust normal again. I just need to know exhaust size so I can take drill press and cut the center holes. Too bad you cant drive down here i have a lift we could do this all on.

[DjPantsSpecR]

i now rock your header phil.

and i updated my first post. unfortunately all the information in the first post has little to nothing to do with the pictures. so hopefully i can confuse some folks

enjoy.

[neverlift]

I got what your doing and am planning a similar style. a bit smaller though. I probably will do it in different material and make runners as well. sohc motor I love the cheap power upgrade. Maybe I'll get to it soon and see what else I can make. Is that intake pvc? How did that butt dyno?

[DjPantsSpecR]

the intake is not PVC. its an off the shelf honda pipe thats been cut to a decent length.

that intake "tube" as it is so commonly refered to is generally called an intake "ram." the length of this ram, just like the length of runners can help influence where peak torque is developed. you can easily find this equation, but there is a general rule of thumb that i forgot. when i re-find it i will let you know. all i can say now is that the length of my tube, whatever it was is good for peak torque around 4-5k.

make a flange that bolts up, adn then make the runners and the plenum as well. it will make your life very easy welding if you know what you are dealing with. you could also cut the stock flange with little to no problem. i wanted to retain my injectors, plus i dont have the resources during the summer to make an entire intake mani.

ummmm, what else did i wanna say.... why did i type that, i could just as easily delete it.... anywho. i wouldnt make that plenum any smaller. and this is why

generally speaking plenum volume on an all-motor car is very important in where you produce peak torque. if this was for forced induction, make a plenum that is 2.4 liters. that is what i believe the xcessive unit must be.

however, my original plenum was 3.6 liters. ive already explained why this one sucked, adn throttle response was non-existant. dont do it.

the new plenum is 67% of 2.4 liters. it is generally agreed that for an all-motor app. a plenum volume of 60% will produce peak torque at 6k. if you decrease it to 50% youre making power at 7k. obviously these equations are completely non-exact as a motor that revs to 16k isnt gonna have a plenum volume of like 2% or something outrageous.

for every 10% of plenum volume you add, you will lower your peak torque 1thousand rpm. so for my plenum i should be making peak power at around 5-6k.

YOU NEED ONE OF THESE. hows the butt dyno? hows throttle response? insane.

i have a good amount fo stuff done to my 240, but with this manifold, me an Ajax personally witnessed that we could keep up with an almost stock 350z. I just installed a dc sports header, as you can see in the pics. i had the manifold on before the header.

the manifold has better throttle response than stock, easily. the kinda response that puts you back in your seat when you burp it in 3rd...

the intake manifold makes more power than the header does. the car with just an intake manifold and no header, has much more top end. after i removed the intake manifold and went to the stock one, i confirmed this. the intake manifold is a better power producer than the header. while this compareson is entirely bogus, we can at least agree that the header is good for about 7whp and 8ft/lbs of torque.

i would put the 6-7k gains at about twice that. i wanna say there is at least a 10-15 horsepower gain. this is with the manifold and header.

Mod list is as follows:
entirely stripped coupe. i still have a dashboard, passenger seat, and doors. No AC, no AIV, EGR, IACV, charcoal canister, or any purge solenoids. only brake booster ad FPR. custom short ram, with greddy arinx style filter. bypass TB coolant lines and the one line on the lower half of the intake manifold that everyone misses.... removed mechanical fan, relocated battery, 248/232 cams, dc sports header, gutted cat, SSAC n1 duals, xtd stage 3 clutch, 16 inch Borbets with Yokohama avs100.... im sure im missing something, oh yeah Trogen Engineering Intake Manifold.

[barcode]

your valve cover is badass dood, i was thinkin bout painting my whole engine some color since it is out of the car, and just got an acid bath, but i dont know what color, for some reasone i wanted do it either yellow, or lime green, and now your pic makes me wanna do both lol, so when you spose to get some numbers from you manifold, im anxious to see what it makes.

[neverlift]

thank you dj you are a smart man. I'd like to know more still though. I for some reason think that the ka can and should make power at around 5750 and start to fall off at about 6400 or so. The tune I'm running now seems to pull like a mofo at topend. I dont completely get the runner lengths and pipe length stuff, but would ove to know more :wink
any way forgot what the f*** I was saying keep up the hot homemade stuff man

[DjPantsSpecR]

i have links to all the ****. i'l even do the math for you.

i can aim for peak power numbers at 6k. and i shall, ill let you know what i come up with when i get a free minute tomorrow

[Florida240sx]

So what about turboed guys?? What % do we need???

[DjPantsSpecR]

i thought i covered that like three times, but i now realize im talking about this thing in like three of my threads....

anywho for forced induction the general rule of thumb is 100% displacement volume. so 2.4 liters. This, to me, is what the xcessive manifold's size must be. I say this in comparing it to my original 3.6 liter plenum.

forced induction wants to get as much air in the plenum as possible as it will actually gain a little pressure with the positive and negative pressure waves traveling up and down the runners. it literally works like a spring in packing the air in the plenum.

my 3.6 liter plenum was jsut a poor design based on a FSAE manifold. the breathe through such a tiny restirctor that it must be able to pack as much air in the plenum as possible to avoid starving under sudden WOT bursts. There is also extensive design done to gain as much power out of the restrictor, so helmholtz resonance can gain some ponies at a specified rpm level...

its more than you wanted to know.
again, its 100%

[neverlift]

hold on you will do the math for me. thats great.
But dont leave me in the dark send me those links my friend. sus2josh@peoplepc.com
I have always thought the ka just needed more air(tiny intake manifold). Thanks dj

[DjPantsSpecR]

alright, heres the link to some useful info.

go to http://www.grapeaperacing.com and go to the technical articles and then select inductions systems. you can ignore most of the info until you get to the helmholtz section. then there are equations for intake ram diamter, length, runners length as a function of diameter and rpm. and they have the nearly correct assumptions for plenum volume, as this is NOT an exact science yet.... check it out, adn i'll do your work for you later, ive already been working on it a lil, i just need to come up with a decent runner diameter for you if you are gonna be making your own runners.

[neverlift]

well I'm bout to go over to grapeape thank you so much +10 man
I was wondering about my intake earlier today,and took L/D long side is 6 5/8 short side is 4 3/4" inside dia. is 2 3/4" I also use a hacked maf tube with stock maf that is 2.75" inside dia. Any help with how it affected power band? Its a single 45* bend. I know I gained what feels like across the board but did no gteching to see for sure. I didnt because I dont know the exact weight of my car due to taking so much crap off and out. Maybe next trip to the junk yard I'll get her on them big a$$ scales they have. duh

[ddgsxr504]

Looks pretty ghetto but you might be onto something. Oh and I love that valve cover.... reminds me of Days Of Thunder...lol

[neverlift]

Man it might look hood rich, well thats because it is. But he made it for 30 dollars come on, were you looking to see cf or something more cosmetic? btw I also thought "D O T" . gimme fresh tires I'm going out!

[DjPantsSpecR]

lol its hood rich as ****.

you gotta understand this is just a prototype, something for me to get runners lengths and plenum volumes down.

now its time for the real-deal. its still going to a be a sheet steel plenum, but twice as this, and legitimately welded.

the biggest change is going to be the mounting of the plenum. thats where 100% of the failure is at, the connection. this is being replaced by 1/4 thick 6061 t-6 alum. unless i need to do more research because i cant tig 6061 to the runners.... all in due time.

days of thunder? lol actually i always thought it was a funny joke. Its a JUN auto rip-off. JUN would never touch a KA, so i just thought it was ridongulous.

[neverlift]

I like the prototype look myself man. Why does JUN ignore us so bad? Have they not heard of ka-t is wrong with them, money to be made. Oh well.

djpants whats up with my math work buddy? I have been kinda busy the past few days, no time to work on it myself. Also how long you think before the new hoodness is ready? You gonna dyno this one,seeing how it will be sealed better. Sorry if I'm rushing you just like the work.

[DjPantsSpecR]

yeah, dang ol man. im back in college now. Mechanical engineering sucks. im fairly certain im surrounded by virgins, male.

I'm getting my alum plate milled friday, and i will get the runners welded asap. i think i'll reuse the same plenum, before i design the new one.

but i might redesign the entire thing before friday. so you're put on hold for now, plus i gotta start up on the racecar teams, and hopefull that'll be a whole new manifold i get to design.

trust me JUN auto is way too baller to touch this little itty bitty four banger. and the only time ive ever heard of any major JDM company trying to develop a KA it was in a Yashio factory car. they bought a hatch and shipped it over, unfortunately for them and us someoen swapped in an SR20 before they got it, and no KA development was ever done.

i'll do your manifold after i finish my calc homework, but i have a lotta choices in the runner length and diameter. i need to fufill alot of requirements, but i'll be happy to see my design somewhere else, its no problem.

so, more time.

[neverlift]

its good they are virgins man, way more a$$ and tittie$ and big booty bitches.

not trying to rush man. I can wait it out. Get yours done first, work on mine in free free time. I know there isn't much of it these day.
I'll rock it and brag bout the **** too!

[mmm240]

so pants: how the production of the manifold coming?

[DjPantsSpecR]

pretty much on halt, as school just kept getting worse and worse and worse. Now its finals, i have one tomorrow one friday, and then only one more, then all my free time goes into a few places.

A lot of my time has to go into the FSAE car at school. if we dont have the frame done by winter break we're ****ed. i also have to finish my pedal box, but ive just designed it, i think you would be proud.

so enough of the bull****.

there is a shop that is just opening up north of me. it seems like its going to be run by a pretty young kid, but he personally worked with Ivan, and ive seen a one off supra manifold he fabricated. it was most impressive.

he's been TIGing aluminum for a while now, and he has way more of a capacity to do this than me. He wants to produce an N/A manifold and so do I.

so pending i dont get ****ed over, i might actually work with this guy.

differences in design im considering:

cut the runners just after the injector bosses. this would allow you to run an entirely straight set of runners. from the ricardo wave analysis ive seen of our university car's intake manifold, it makes a noticable difference in high end power if you have a curved plenum rather than curved runners.

so a straight shot for the runners could be added. the reason to not make a new manifold entirely is because it would be expensive to mill out the plate to bolt to the head and water jacket, and still keep the weird inlet port shape. its also not that fun to weld in injector bungs.

circular runners would make the adapter plate to the plenum that much easier to make. plus it could allow for the use of velocity stacks. we've made a nice set out of aluminum for the FSAE car, and its possibly something i could incorporate, if i do infact see that a radiused lip isnt the same effect as a stack.

i know for a fact that with this small plenum volume, filling air to the first and fourth stacks will become a problem. however, plenum design can always change.

well, of course, plenum design has changed.... a member on the team here has done a lot of carbon fiber work. our plenum is currently being made of carbon fiber, so i've included this as a possible way to make a plenum. it would raise cost slightly, but it's weight, heat, adn sexiness can't be beat.

otherwise, with the shop ive talked to, we would probably make it out of half a round peice and then triangle it down with aluminum, similar to my sheetmetal one. this would be entirely welded instead of being a bolt on plenum.

i'll also probably have to add adapter plate milled out of aluminum to accept he throttle bodies, and i rpobably need to come up with a better throttle cable system.

so it could really turn up as a lot of different things. i should do this simplest welded one, just to get some plenums out there. possibly use the straight runner design, radiused air inlets and a welded plenum. this should be more than sufficient.

it doesnt need to be too complicated, and thats the key. my craptastic JB weld and sheetmetal one gave me at least 10-15 wheel horsepower. it has been proven that a 3inch on an N/A KA with no supporting mods can net about an extra 12 wheel horsepower. there is no doubt in my mind, and both me and Ajax's butt dyno, that the intake manifold add's more power than that exhaust. i miss it.

so i guess time is the enemy.

[Bigvinnie]

and this is my BigVinnie style shot... looks just like ya vin

LOL Pretty similar. Good shout out. Anyways the progress looks good. But inorder for the system to be fully functional you need to keep in mind the IACV needs to run in conjunction. Taking a quick glance I couldn't see it mounted anywhere. IMO as long as you are using the stock ecu so you don't run into flow issues it would be nice to see use of all the stock parts bolted to it as well. I know a lot of people think it's just all worthless crap and to help with smog, but all that stuff serves with basic function. I did see the brake booster line being used though, but thats just common sense...LOL On the other hand who cares about the EGR/BPT system, unless you have a cali ecu throwing codes 32 it may cause more problems for the mani than it's worth.
Lookin good man, now all you need is an Lincln Electric ARC welder and use some gas to prevent bird droppings, stop using the J.B!!!!!
BTW what made you go with a tapered plenum design over abarrel design? MOst NA tuners choose to use a straight barrel for the plenum along with velocity rings used before each runner. What makes the tapered more effective IYO?





Modified by Bigvinnie at 5:47 PM 12/13/2006

[DjPantsSpecR]

lol, the JB weld was obviously for test mock-ups, and its not uncommon to use adhesives for test manifolds. However, it always fails. The manifold would twist at WOT and crack different places with time. i ran this for three weeks and repaired it once a week. the third time it didnt fail, but i had already removed it back for stock for school.

incorporating the IACV and the AAC is pretty easy to pull off, it just requires plumbing an additional hole in the plenum.

however, i havent used my IACV of AAC in over a year now with no problems until winter. i also have the butterflies and all water lines removed, so in the winter getting it to idle as it gets closer and closer to zero is hard. otherwise, my car idles great, although i agree, i'd rather have this stuff tuned out, rather then having it bandaged.

tapered plenum is for several reasons: its the easiest way to make a full size plenum 50% of its current volume. n/a motors want a smaller plenum volume for high rpm power and throttle response.

i've also seen some computer CFD showing that box type manifolds flow air in this tapered stream to the forth runner. there is a "bubble" of air circulating in the back corner of a box-type manifold. so i just eliminate the useless turbulence and introduce the air at the same angle to all of the runners.

the angled entry also flows air into the first runner much better, especially because the plenum size puts the first runner so close to the entry. angling the TB 30-45 degrees closer to the first runner helps bring turblence down a lot.

i couldnt really put velocity stacks into this plenum, because they would probably contact the plenum on the 3rd and 4th runners. there would be serious lean issues unfortunately.

i have an arc welder. i jsut didnt think i could arc weld aluminum

[neverlift]

I still have not found time to start mine yet. I have a few thoughts put together for it,but the wife and kid take all my time.

[DjPantsSpecR]

i just put down the last calc final i'll ever have to take, then one more tomorrow, and then one more next week then i have one month to complete as many projects as i can.

wouldn't that be sweet to just have a month to you and your car? it might be in below zero temp's but i usually have little space heaters right under the hood with me.

I have superchargeing in my eyes now. i wanna see the feasability of an M90 mounted around where the stock AC was. i'm looking into it.

but for this winter i should complete at least 1-2 manifolds, as well as a high compression build for myself. i might be able to afford a daughter-board now too, but i dont know where to get the best quality for a reasonable price.

so, i need to get to work clearly

[Bigvinnie]

l

tapered plenum is for several reasons: its the easiest way to make a full size plenum 50% of its current volume. n/a motors want a smaller plenum volume for high rpm power and throttle response.

i've also seen some computer CFD showing that box type manifolds flow air in this tapered stream to the forth runner. there is a "bubble" of air circulating in the back corner of a box-type manifold. so i just eliminate the useless turbulence and introduce the air at the same angle to all of the runners.

the angled entry also flows air into the first runner much better, especially because the plenum size puts the first runner so close to the entry. angling the TB 30-45 degrees closer to the first runner helps bring turblence down a lot.

i couldnt really put velocity stacks into this plenum, because they would probably contact the plenum on the 3rd and 4th runners. there would be serious lean issues unfortunately.

i have an arc welder. i jsut didnt think i could arc weld aluminum

Good explanation, but that isn't the same flow pattern at lower rpms. A full out barrel style allows each cylinder at lower RPM to grab atmospheric pressure even when the butterfly isn't open more than at idle, this only causes minor turbulence issues if the barrel is proportioned to it's correct diameter, if not then you start to get backfire and popping. This would allow for a much even combustion across all 4 cylinders when RPM and CFM are low below 3000RPM. This would actually raise low end torque, and it wouldn't effect high end response either since as you say it delivers a tapered stream already, which is only created by it's own vacuum.
As far as streetability it has always been common to use a barrel shaped plenum, almost every car manufacturer uses that basic characteristic. In all this conception you should just make it as simple as the plenum design of the KA24e , or the FJ20e, I think that is where you will find a good margin of power. The KA24e had almost every flawless characteristic to it's manifold accept for the fact that it used SCV's in every engine model, and it literally hinders high RPM HP...

[neverlift]

thread ninja

dj whats what about high c/r lmk about the high part,I'm wondering how high it can go(streetable,pump gas)

[DjPantsSpecR]

well, im on a budget, so obviously its going to be SOHC pistons, and hopefully iron ITM rings.

thats going to be about 11.2:1, which is just barely streetable. its not too hard to keep knock back with retarding timing and 93 octane, but im already trying to get some deals on an SAFC. its not like an SAFC wont still be useful with a daughterboard.

i dun know exactly what you mean by "lmk about the high part" but 11.2: is pretty high for the street. however, people that actually have it will say its jsut fine. Granted they're tuned for it, but celicas have stupidly high compression ratios.

i always wonder how high you can physically take a KA until the piston design can no longer gain compression over the amount that has to be removed for the valves, plug and squish areas. 15:1 is probably around there.