180 Degree L28ET Intake

[Gollum]

Way wicked Gollum!

 

Have you considered putting the injectors on the final turn, on the outside, pointing toward the head?

Might be easier to get at and to fabricate?

 

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.

 

Oops, sorry was drinking last night. Yes got it backwards!

 

No harm no foul.

[Astral Ace]

Hey I was just out looking at my car and I realized that I have a strut bar... it got me thinking of how many other people have strut bars. I have the MSA adjustable one, but there are many others out there. Maybe you should take that into consideration as well.

 

Like I said, I'll buy one, but I don't want to have to lose my strut bar. So if you could design around that too, I'd be happy. LOL.

[Kevin.pk]

Is there going to be enough room for the injectors in the stock position. I understand you left room for the flange in your renderings. But an injector with (I'm guessing) a pallnet style fuel rail may be a tight fit.

 

 

 

 

Kevin

[Gollum]

Is there going to be enough room for the injectors in the stock position. I understand you left room for the flange in your renderings. But an injector with (I'm guessing) a pallnet style fuel rail may be a tight fit.

 

 

 

 

Kevin

 

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.

[Six_Shooter]

I'd place the injectors on the outside of the radius, you'll be surprised just how long the last part of the runner going to the head will need to be, to clear the injectors and fuel, along with actually being able to service the injectors.

Also the farther up the runner the injector is, the better the atomization can be, at higher RPM. Nearer the head for low RPM and idle. This also seems to efect low RPM emmisions as well.

 

This also seems a LOT more involved than just running that single 3" tube from one side of the car to the other, behind the rad, in front of, where ever. I don't see any real benefit to this other than building some great bottom end torque with the LONG runners. If you're trying to reduce heat soak, the plenum will have less heat soak, possibly, but again, I'm still not sure it would be that much benefit.

[Daeron]

Wait wait wait wait WAIT!!!

 

Center the TB flange on the plenum, facing down right in the middle, and make an A frame box tapering to smaller vloume out by cylinders 1 and 6. You want even distribution, there you go. You could PROBABLY even install some air combs similar to what monzter did in his intake plenum.

 

Ford Escort, mid 90's, the intake runners are long curves.. you MIGHT be able to get away with using those as stock, but looking at some of your later renderings I don't know. You HAVE seen images of the LD28 intake manifold, right?

 

EDIT Regarding the strut tower bar, I *think* theres a good chance that the spacing between #3 and 4 intake runners (in other words, the spot on the head where the 3&4 exhaust runners are) should provide a spot to run a strut tower brace bar through there. I need to find a picture of the bar I have in mind, but there is one with a C-shape mount, and an ear that comes up on the hind side of the mount. If the bar is mounted on the back side of the ear it should be kosher.. as long as the plenum sits low enough. END EDIT

 

 

 

Now, I have an interesting idea that I am curious to know the impact of....

 

What would the result be if one were to build a manifold along these lines, with a balance tube uniting all six runners near the head? I haven't got a clue, but it was one of my first thoughts when the subject of "how long those runners are!!" came up.. (the better to torque your n*ts off, my dear!!)

 

Me LIKEY this idear!!!! You could possibly even run a set of 45* tubes to a single flange pointing skywards, install the injectors on the fender side of that flange, and have it bolt together so it would be easily removed for valve cover (and spark plug) access.

[m4xwellmurd3r]

where's your oil cap though >_<

I'm can't remember the exact location, but wouldn't it be in the way?

[Gollum]

I've thought about all that's been brought up, so sorry if I don't adress every little comment.

 

Oil Cap ~ I think it'll be far enough forward to clear. I'm not positive on that yet, But it's a hope...

 

LD28 Intake ~ I've seen the marine one that enters in the middle. Is that what you're talking about Daeron?

 

I'd thought about having the TB flange in the middle, I just wonder if it was worth the extra inches of intercooler piping. Thinking more about it I think it is. Even distrobution will not just help keep the power smooth and safer, but should help low RPM driveability too.

 

Balance tubes ~ I'd thought about this idea too, but I'm hesitant as I'm not sure how that will affect the induction wave runing of the runner length.

 

Six Shooter ~ duh it's more involved. That was never the reason. I didn't think it would be LESS work, just a simpler, cleaner airflow design that reduces heat soak and makes the turbo easier to get to and work on.

 

Remember as I said before, that I think not only will the plenum have less heat, but the turbo will get more air to it. The stock setup leaves very little room for the turbo to breathe. Though some would argue (rightfully so) that a heat blanket on the turbo would see almost all the same benefits.

 

But where's the fun in that?

[Gollum]

Six shooter and others were right about space for the injectors, they just won't really work in the stock location. Oh well.

 

So I modeled an injector that's pretty close to spec I think (going off of specs I got from MSD's website), and also modeled an injector boss. The main reason I didn't want to go this route was cost, but it's cheaper than I thought. I found bosses at many websites for well under $20 a piece, most around $14-$16. Idealy I'd like to find them for less than $10, as even $60 on bosses really hurts the $300 budget.

 

I also modeled a clamp in there so I could get an idea of what clearence would look like. It's not bad. I'm still not sure I like the idea of clamps. Clamps mean that

 

A) More cost

 

I HAVE to make a braket to support the plenum side

 

C) One more thing for air to catch on

 

D) More cost!

 

If someone can point me in the direction of a good junkyard clamp around the right size I'll see what I can find. Otherwise I'll be searching the net for something affordable.

 

Oh, I almost forgot. The latest images:

 

[Six_Shooter]

You're going to need to modify the cam cover as well. I looked at my L28 in my car in the driveway, and the oil cap pretty much lines up with the #1 port.

 

Placing a "balance tube" near the head will destroy any resonance function that you are trying to get, essentially it becomes a plenum, a small one, but that's how you would need to think about it. I'm not sure what the purpose of that "balance tube" would be.

 

I would change the location of your TB flange in the last renedering. You would lilkely end up with the TB being VERY close to the engine mount, inner wheel well, wiring, etc. Probably also need a very tight bend to get and intake tubing to mate up. I would place it on the "top", basically 90 degrees from where it is, this will make IC tubing a little easier to connect to, probably also make throttle linkage a little easier as well.

 

I'm still thinking hood clearance is going to be an issue.

[Gollum]

I'll be able to verify clearence tomorrow. Stay tuned.

 

I didn't bring up the balance tube, if you noticed. I only addressed the issue since it was brought up. But thanks for confirming my suspision, that it would destroy resonance effects.

[Gollum]

Ok, I just measured while on my lunch break. I didn't have a tape measure handy, so I had to eyeball it, but It looks like just in front of the oil cal there's just less than 2" (maybe right at 2") and behind the oil cap there's at least 2.5" or more.

 

I'd already noticed the oil cap issue before, and I'm thinking the best route around that problem is to plug the hole and move it to somewhere else.

[Daeron]

I'm not sure what the purpose of that "balance tube" would be.

 

I wasn't suggesting it had a purpose; the concept occurred to me and I had no idea what effect it would have, so I asked. Thanks for confirming my suspicions. I just like to throw my wild-ass ideas out there because once in a great while, one of them actually makes sense. I would hate to discard an idea simply because my current knowledge level cant tell me whether it is a good one or not.

 

 

Gollum, I was seriously thinking that a stock FI intake flange might be weldable to your "primary" runners, and that takes car of both injector bosses and attaching the primaries and secondary runners.... (primary being head side, secondary being plenum side) Add a second flange minus injector bosses on the other side, and bolt them together. You are maintaining the spacing between the runners the same across your entire unit, so is there any reason why it wouldn't work like that? Plus, you can use half of a paper intake/exhaust manifold gasket to seal between these two flanges.

 

Oh, and regarding the LD28 manifold.. I was just wondering if you had seen the design of the runners that they used,,,

 

 

 

 

 

Clears the hood fine, and strut tower.

[Gollum]

As far as the flanges go, I was planning on cutting off a stock one and welding to it. But the injectors just wont' fit in the space I'm trying to maintain. I don't want the runners going way out to make space for the stock injector location. Any increase in runner length on the turbo side is added time the air gets put through hot aluminum.

 

That stock LD intake would be a GEM of a base to work off of if the lower portion was shorted in half, and regular injectors could be used without much work.

 

I have yet to ever see a LD28 in the junkyard though. Just not common around here.

[Daeron]

As far as the flanges go, I was planning on cutting off a stock one and welding to it. But the injectors just wont' fit in the space I'm trying to maintain.

 

You aren't getting what I am trying to describe.. Instead of welding injector bosses to the rails in the outside middle of the C-shape, I am trying to suggest welding a flange there from a stock EFI manifold.

 

Where you have pictured clamps in your rendering, cut the pipes. On either side of these runners, weld a flange from a stock EFI manifold. Retain the injector bosses on one of them (probably the top one but I would need the pieces in my hand to visualize it right) and use them rather than purchase any. This has the advantage of allowing you to maintain one set of injector bosses from the flange, (rather than buying them) and use those to inject the fuel essentially where you have it pictured in your most recent rendering.

 

It might not be doable; but just a little time and patience looking at the flanges on the stock manifold should tell you that in short order.

[Gollum]

Hey I get it!

 

I'm really tired right now, but I get what you're saying. That might work, but I'd have to make the joint closer down by where I currently have the injectors. Why? The injectors are already getting really far away from the head, and low RPM power and drivability will start to suffer. Remember, I'm going for that nice broad power band for street driving.

 

 

Ok, as far as valve cover clearence....

 

 

dun Dun DUNNN

 

Are you ready? I've measured. I'm quite sure this is an accurate measurement within a 1/10th of an inch or so.

 

If you remove the oil cap the clearence between the highest point on the valve cover at the cap and the hood is right at 2". From there clearence gets EASY as the engine slants backwards.

[ben280zx]

Any update nathan?

[Gollum]

Been a while, but I must say I'm most likely not going to do this intake idea. I found some intake "dynos" if you will, comparing various intake lengths. Shorter intakes did yield better flow at higher rpm, while long lengths did have a low RPM boost, but what was surprising was overall performance. If you're tuning for 1st order harmonics then you're going to get a huge sharp boost for where you're tuning it to, but that's exactly what it is, sharp. The rest of the range suffers from the length, even the RPMS bellow the boost.

 

The reality is that for good all around street performance it looks like you need to tune for 3rd or 4th harmonics.

 

I hope to still make an intake, if not only for the engineering aspect. If/when I do I'll make sure to document it well.

[Gollum]

So I'm back at it again!!!

 

I'm working in solidworks this time around, and might even be able to manage some ghetto flow analyses going (I'm not nearly as versed as some like MONZTER on here).

 

What got me back on this old idea of mine was that the more I learned about force induction systems the more I realize that runner length doesn't matter nearly as much as runner diameter. Sure in a NA trim length can have a huge impact, but when the intake is pressurized there isn't the same limitations when you're running on vacuum.

 

I'll have to scan or take a pic of the intake dyno I referred o earlier in my last post a year and a half ago, but it's amazing how much better a short runner tunned for the 4th or 5th wave actually works in practice. Sure the 4th or 5th wave might not be as strong, but it has a much more even response between the waves and allows a much broader range of flow. A long runner tuned for the 2nd or 3rd harmonic has VERY strong harmonics, but their overall performance gets sacrificed greatly. You can really "see" how long OEM runners kill top end power in truck V8's and similar applications.

 

 

Anyhoot, another reason I'm looking into this again is that I'm expecting to go E85 in the future, and plan on running NO intercooler. My plan is to actually find a way to run the intake piping from the compressor UNDER the engine and up towards the intake plenum, running a design similar to the last one posted with a throttle body in the middle. I'll probably have a similar air comb system as in that design but done a little differently.

 

My estimated costs this time around are probably a bit more realistic at around $500, and that's if I can get some next to free time on a mill. We'll see if I can pull that one off. As people like MONZTER have said in other threads, doing one off machine work without cheap CNC access just doesn't make financial sense. It really is the key in doing DIY stuff like manifold flanges if you're just making it for yourself alone.

 

Plans for the oil cap will be to move it between cylinders 3 and 4, and I will definitely be using a quick disconnect system, probably using heavy rubber with clamps. I figure if it's good enough for OEM's like BMW and Mercedes then it should be good enough for me if I engineer it right. This will require solid mounting on BOTH sides that basically get the runners within 1/16th of an inch or less and let the rubber at as a seal only, not a part of the runner. Same concept as quality intercooler piping really. Silicone couplers are NOT for getting pipes to meet to each other.

 

I'll have some renders probably in about a month or so. I'm gonna wait until I at least get to where I was at before, which will take some time to build back up to. So far I've got a rough sketch of the flange and the runner.

[sweetleaf]

Have you looked into TechShop? They have some pretty amazing equipment. Definatley worth the membership for just the CNC mill time not to mention their piles of other fancy toys. Like 3D printers, vacuum forming setups, (CNC mills, lathes, laser cutter, plasma cutters), MIG's, TIG's, etc, too much to list. The place is a tool junkies dream land.