Gollum

Except he didn't ask which one had more mass. He asked which one "weighed more" which is directly dependent of the gravitational field it's in. What creates gravity? Mass. Hence my answer - The one with more mass INSIDE it's gravitational field being polorized to a single side. The reason I mention the polarity is that in theory if the object was suspended in a hollow sphere it can theoretically weigh nothing, even though it obviously has mass in it's gravitational field. This post isn't nearly funny enough for this thread, and I can't figure out how to fix it.

I was just thinking a fun car to do this with would be the SC400/LS400. I bet it could easily hit 13's.

Yea I've been thinking about that. I could easily make the bend near the hood a few less degrees, then add the same amount to the last one before the injectors, and add any length between the two bends, or after if needed. I'm waiting to get some more dimension estimates to revise the drawings. Once I have a better Idea of how much space needs to be given I'll be able to adjust accordingly. Astral Ace ~ I don't think I'll be making these to sell, unless someone want to pay me $600+ for it, as time isn't something I have a ton of lately. I'll gladly make any plans and blueprints availible though, even links to suppliers I go through for the metal. And as far as the strut bar goes, I'm not sure what conflicts there will be yet. I know there will probably guarenteed be SOME issues with most bars, and I just have to figure out where to see what can be done. No worries though, I HAVE thought about that.

In my first version I had the injectors up there, but I'm not exactly liking the idea. It really complicates things having them out there. If I just use the stock location it'll be that much less I'd have to fabricate and make sure I engineered correctly. No harm no foul.

I think that's backwards actually. Trucks and other heavy vehicles tend to have long runners to provide strong low end torque, while small displacement engines with high redlines have very short runners. And lengthing the runner lowers the RPM at which the 2nd, 3rd, 4th, and so on waves occure. Though if someone wants to explain why I'm wrong, feel free. The real benefit to this design is that you'll be able to get as much as intake as possible away from the turbo AND it REALLY simplifies the intercooler plumbing. If I'm going to make an intake from scratch (which I wanted to anyways, just for the fabrication explerience) then why not do something different than most people and see how my theories work? This isn't going to be a race oriented manifold. I'm not increasing the runner diameter much (I'd leave it stock if I could, just so I didn't have to mess with the head), so this is really just about an idea and what comes of it. I was kinda hoping someone would have some thoughts on well it'll actually work. A 15" runner isn't THAT long. I think it's not much longer than some of the long runners sceen on this site even (the long ones 1 fast Z/brian makes comes to mind). And on those engines they're going for peak HP numbers well beyond 6000 rpm, and I'm shooting for there or under. Where's braap? I was really hoping he'd comment on what I've got thus far.

One quick update before the insane business of the weekend comes. This is starting to look really good to me. If the hood clearence is good enough I don't think I'll change this too much from here on out, except maybe some plenum design. Runner length = 15.532" 2nd wave = 10250 RPM (way too high to be seen... EVER) 3rd wave = 6820 RPM 4th wave = 5115 RPM 5th wave = 4093 RPM 6th wave = 3410 RPM I must admit... I don't know how much each resonate wave will help power. I'd assume that the lower waves, like 2nd and 3rd will show much stronger peaks, but I'm completely uneducated in this field... Just a wild guess on my part. I figure the numbers might still mean something though. You can't see it in the picture, but I've also radiused the inside of the plenum/runner transition to .50. Looks pretty neat.

The one with more mass within its immediate gravitational field depending upon the polarity of the mass to said field.

Sorry man, just been moving REALLY slow. Money has become a bit tighter as I'm going to school come september. So i'm in the middle of trying to find another job that will work with my schedule, so most car projects are kinda on hold. Main limitation is time. I only have about 2 week nights that I'm home at a decent time, and due to the crazyness of summer my weekends are booked solid. By winter I should be driving my 280ZX as a daily driver, and I'll have more free time to work on the car. I already have 10+ worth of cans that want to be sprayed onto my panels.

I don't know how it took me this long, but this is why I'm glad I've started modeling this NOW, instead of just a month or less before I plan on building it... But my current idea of how to build it to clear the hood is wrong. The engine is angled, so while I'm trying to wrap around the valve cover I have to make the lowest point off axis from the valve cover. Here's my latest attempt to get it to a dimension that looks like it might clear:

Latest Render. I checked the dimensions of the valve cover last night so my guess would be a bit more accurate. Front height = 5" Overal Length = 26.6" Distance down to intake port from lower portion = 7" The new render reflects those changes. I have a bar shown that's where the intake port should be. The tube in the render ends about .5" away from the bar to give room for grafting into the stock intake. My estimated overall length is 17.98". (that's with the extra .5" added to get to the head). Should I be adding some distance for the actual head port? Well, at 17.98" my peaks are as follows 2 waves - 8880 RPM 3 waves - 5920 RPM 4 waves - 4440 RPM 5 waves - 3550 RPM Cam duration is 240 (stock L28ET cam) and runner diameter is 1.37", or 34.8mm. This is slightly larger than stock, but I don't have much of an option when you're shopping by price. Maybe I'll port the head a taste when I do this. I don't think I'd be removing that much material to get it to match. Today after work I'm going to go buy some play-doh at the $1 store and check my hood clearences. EDIT: 14 guage 1.5" OD comes out to 1.334", which is much closer. It would cost about $130 before shipping. I think I could manage that. I'll be changing my drawings to reflect that change.

That turbo motor your dad has should push a S30 Z (240Z, 260Z, 280Z) well into the 14's stock. Lots of guys out there are going 12's without ever opening up the longblock, some on the stock turbo. That alone doesn't make it a great choice though. If his car was unmodified, then the tranny is a T-5. Stronger than the nissan unit, but not very fun to shift.

You know, I don't leave my car in gear half the time, but you know what? I still always check it before starting, even when the clutch is down. It's called habbit.

2.5" Radius bends which are tight, but I think it'd be alright. I'm liking the look of it.

I need to measure my valve cover, but I think these specs are close: I'd changed the radius of the 180 degree bend to 4", just to find that the metal suppliers websites I have bookmarked don't carry that radius for the pipe size range I'm looking at. So it'll have to be changed back to 6" for all of it.

Yea, I cut slightly into the journals on that first slice. On the last one I did I made sure not to. I really wish I had a crank in my hands to work off of. I've been basing my work on pictures and basic part specs on the parts availible. Through the parts catalog on summit I can get: Main Journal Diameter Rod Journal Diameter Rod Width Rod Big and Small end Diameter Rod Length And I know the bore spacing for the motor, so it becomes a guess work of the thickness of the main journal.... It's an educated guess, but still a guess. If I was going to be working on a "final" mockup before having it made I'd make sure to have the block in hand so my specs were perfect.

Yea I thought that number was fishy too... guess that's what I get for just doing a basic mm to inch conversion... wooops. Ok, I just checked my other crank (not seen in this thread) and I've got this: "1876.846 (square millimeters) = 2.90911712 square inch" That inch figure makes a bit more sense. Still not as much area as yours, but I'll try to figure out how much stress it'll take. Quick question though... in your picture there's quite a bit of material from the main journal in the critical plane. Am I wrong? Is this being calculated? Are you cheating me? Ok, I'm off to try to figure this stuff out.

That thought hadn't crossed my mind... sounds extremely complicated if you ask me. You'd end up with the manifolds crossing and things might get messy. Not much space to cross them. If you're trying to move the turbo... you could move it to the wheel well... I'm on a tight budget though, so a custom exhaust manifold hasn't been in the budget from the get go. As soon as I started learning about the torchable aluminum solder ideas started racing through my head....

I'm not exactly sure that car still classifies as a daily drive. I suspect it's not still legal...

Here's another mockup/new design. This is probably a bit closer in design to what would actually get built for these reasons: 1: Easier to work with assembling panels vs round plenum 2: Multi curve runners to keep the runners close to the valve cover without making contact. My runner length is 29.0465, darn close to 2nd wave calculations for 5500rpm 1st bend is 4" radius, 2nd is 6" radius.

OTM Here's a cut like you were saying. Inventor is calculating an area on this plane of 1503mm^2, which is 59.1732 square inches.

Awesome, I found the pictures. I'm going to post them here as well. Thanks for the heads up tony. Some good reading in that thread. It's a nice and compact little manifold. I'm amazed at how sharp those bends are though!

Thanks for the link. I'm getting a result of 19.44". My design is 21.7" in the last picture if I've made my calculations right.

Here's the plenum after some slight revisions. Shorter straight length, a bit more radius added. I added the fuel rail for visual purposes, just to get an idea of what it'd look like. I'm wondering what it would take to use a stock manifold as a base for this.... Would bring down costs. Wouldn't have to buy one of blake's flanges, or make my own. The clamp idea seems pretty cool tim, but I'm wondering if I might end up with sealing issues if I go too cheap on them. That's a lot of clamps that will need to make pretty good seals.

Wow, I'd forgotten about that commercial. Man that's funny. OTM - This will be turbo, so I'm not sure how much runner length affects power, other than throttle responce. And no I havn't calculated the helmholtz yet... Not even sure how honestly.

They look good. There's quite a bit of wasted space on the inside though I bet. -69 with a 8" wide rim is only going to be around 2" of backspacing, when the car can handle 5" of backspacing EASILY, and possible around 5.75" of backspacing without rub in the front. That's easily an extra 30mm of tire you could be running. What tires are on there, 225? 215? Even if they're 205 wide tires, you could be running 245 easily with a 9" rim. With a +10 9" rim you'd have 5.4" of backspacing, which I'm pretty sure would clear just fine. And it'd actually bring the tire IN about 1.8", and your currently setup looks like it might rub under extreme shock compression. I'm not trying to be a jerk, just letting you know in case you didn't.