Roots intake manifold idea

[firebird_1995]

I like where you head is at. We do need some roots options with the ltx platform. A side mount is nice when you have the room for it but I know my system wouldn't fit on a 4th gen. As for casting a new manifold, there are a few issues I see.
1) strength of the casting. First, and along the lines of what meanta said, is the casting process. I have worked in a die cast foundry as a die service tech and the biggest issue I see with casting without any kind of pressure on the pour is getting a good and solid piece without voids, non-fill, or porosity. Also remember the casted intake is going to be subject to thermal heat cycles as well as vacuums as low as 20"hg to pressures up to 15psi. Any weakness in the casting is going to show up here. It doesn't mean it can't be done, its just going to take a lot of work.
2) machining the finished casting. After a successful casting is made, you are going to have to get the intake to head surface, intake to block surface, intake to supercharger base, and injector bosses machined. You also mentioned getting the ports touched up. These are all areas where having the entire base CNC machined would address anyway.
3) cost. I believe that for the cost of aluminum (even a junk set of heads to use for metal isn't free), the cost of having the piece machined after casting, and the amount of time involved, you would be money ahead to have a base completely CNC machined.
4) performance. The cost to HP gained factor of the kit has to be comparable to other options on the market. Trying to work within the available space the 4th gen has to offer is going to limit the size of blower you can fit under the cowl. The m112 is probably only going to yield 6-8# of boost in a 350ci engine. I'm only seeing 10-12# in my 355ci engine with an m122.
5) heat. These things put off a TON of heat. To run one without an intercooler is going to limit you to around 6# before you start to negate the benefits of more boost vs higher IAT. The tight space you have to work with is going to eliminate the ability of an in-manifold intercooler like the new gt500's use. Meth injection would be the only other option. That would have to be added to the overall cost of the system.
Now I said all of that not to discourage you from doing this, I think it would be great to see you do it. I'm just giving you some insight into my thought process because I've weighed it out in my own mind NUMEROUS times. I can tell you that to recreate my system, with everything needed to make it work, blower, bracket, pulley system, intercooler and piping would cost you 2k. If you added a manifold (whether cast and machined or full CNC) I couldn't see it costing less than 3k to reproduce on a commercial scale. At that point, as a consumer, you have to be able to justify the cost of your kit vs other commercially available kits, both new and used, and consider the power to cost ratio.

[shownomercy]

Now, a nice medium ground between a cast and a CNC product, is a rapid prototype piece.

You will still need a good CAD/CAM engineer to design the part, but you can have the intake made either with or without ports via a prototype shop for relaticly cheap. That will let you do fit check, bolt alignment checks, and pulley alignment verification. Most if not all places that do rapid prototype stuff will do limited run stuff, whereas a CNC shop will want a min order of 10+, otherwise you are paying a lot per piece.

Now, would a rapid prototype piece actually work on the engine... maybe, but I would say you will rip the bolt threads out or just crack the thing in half. I would a easy 40hr+ in design work for the intake.

[nateleduc]

I like where you head is at. We do need some roots options with the ltx platform. A side mount is nice when you have the room for it but I know my system wouldn't fit on a 4th gen. As for casting a new manifold, there are a few issues I see.
1) strength of the casting. First, and along the lines of what meanta said, is the casting process. I have worked in a die cast foundry as a die service tech and the biggest issue I see with casting without any kind of pressure on the pour is getting a good and solid piece without voids, non-fill, or porosity. Also remember the casted intake is going to be subject to thermal heat cycles as well as vacuums as low as 20"hg to pressures up to 15psi. Any weakness in the casting is going to show up here. It doesn't mean it can't be done, its just going to take a lot of work.
2) machining the finished casting. After a successful casting is made, you are going to have to get the intake to head surface, intake to block surface, intake to supercharger base, and injector bosses machined. You also mentioned getting the ports touched up. These are all areas where having the entire base CNC machined would address anyway.
3) cost. I believe that for the cost of aluminum (even a junk set of heads to use for metal isn't free), the cost of having the piece machined after casting, and the amount of time involved, you would be money ahead to have a base completely CNC machined.
4) performance. The cost to HP gained factor of the kit has to be comparable to other options on the market. Trying to work within the available space the 4th gen has to offer is going to limit the size of blower you can fit under the cowl. The m112 is probably only going to yield 6-8# of boost in a 350ci engine. I'm only seeing 10-12# in my 355ci engine with an m122.
5) heat. These things put off a TON of heat. To run one without an intercooler is going to limit you to around 6# before you start to negate the benefits of more boost vs higher IAT. The tight space you have to work with is going to eliminate the ability of an in-manifold intercooler like the new gt500's use. Meth injection would be the only other option. That would have to be added to the overall cost of the system.
Now I said all of that not to discourage you from doing this, I think it would be great to see you do it. I'm just giving you some insight into my thought process because I've weighed it out in my own mind NUMEROUS times. I can tell you that to recreate my system, with everything needed to make it work, blower, bracket, pulley system, intercooler and piping would cost you 2k. If you added a manifold (whether cast and machined or full CNC) I couldn't see it costing less than 3k to reproduce on a commercial scale. At that point, as a consumer, you have to be able to justify the cost of your kit vs other commercially available kits, both new and used, and consider the power to cost ratio.

I very much appreciate your response. A LOT of good information. A few things though,

1. I watched a video of a Porsche (and Edelbrock) engine being case, which is cast aluminum. In the video they didn't pressurize it at all, just poured the cast and let it dry. I'm thinking 1/4 thick minimum would suffice for strength. I assume that as long as the aluminum is relatively pure it should hold up.



2. Machining is a given. I do have a close friend who runs a machine shop who owes me a few favors. At least on my prototype I can get the base machined to match the block/heads. I'd also give it a straight mill across the top yo ensure complete flatness where it meets the plate for the SC. I planned on doing two peices for the manifold. One cast for the head match up, then a standard piece of 1/4" aluminum for the SC to mount too. Exactly like Cornell's build.

3. Cost. I can pull a set of LT1 heads from my Pick n pull for around $45 a head. I figure that one head should be close to what is needed for the intake. I've also got a buddy with a fabrication shop who has a bunch of old/cracked/warped heads I'm sure I can get by with. A quick bath and they would be a pretty good start for the aluminum supply.

4. I planned on a m112 as well, possibly one of the new GT superchargers I keep finding on craigslist. There is one on there now for $500. According to this I could theoretically pull 15#s of boost with a 2.4" pulley.

5. I don't really plan to put together a full kit, just a place for LTx owners to start. For me, when I was debating a 8.8, Hiltsy's torque arm mount was the key part. Yes there was a bunch of work that was needed, but I had a crucial part that I didn't have the skill/tools to make. The fact I was able to spend $40 on this mount made the build worth it to me. I'm hoping it could be the same way with this idea. I provide the intake manifold and maybe a few other things and you supply the rest. Yes, in a bolt on scenario, you could only attain 5-6#'s of boost, but that's not what FI is. If you wanted a full bolt on solution and not want any fab work, take it to a shop and have them sort out the details. I had already thought about the possibility of an intercooler, and like you said, ain't going to happen, unless it were some kind of crazy freon based coiling system. Meth is a given for any kind of high number build, but just like the original manifold, you still need to make some changes. My thought was a direct port (much like direct port nitrous system) on each port. I don't have any experience with meth injection, nor do I know if this would actually be feasible. And alternative to the direct port is a nozzle on the front and back of the intake.

I'm going to bet that you have quite a bit more experience that me when it comes to FI/fabrication. I personally don't think it would be unreasonable to pop out these manifolds for under $500 build cost, but again, I've never done anything like this I've got three sets LTX heads in my garage. My idea is to at least get a prototype and estimate the cost of producing them. As I already have the aluminum, and greensand isn't expensive. I figure why not create a rough casting, calculate the hours spend then see about machining cost. I agree the machining ill be the biggest killer on these, but again, I could always offer the rough casts for sale as well, for those who have the ability to do it them selves


I very much appreciate your response, as well as everyone else here for the positive attitude toward this. My main goal is to kinda get an idea of what everyone else thinks. I feel there would be a very good market for the manifolds (possibly the SC).

[firebird_1995]

As long as you are aware of what you are up against, I say go for it. When I was doing my side mount I caught a lot of flack from naysayers and guess what, it works. Pretty well I might add. Is it for everybody? no. Is it going to sell like oil and antifreeze? No, probably not. But if you can put one together for less than it would cost to buy a similar kit, you're money ahead. If you can sell a kit or two, maybe it will pay your r&d off. Do it.

[nateleduc]

As long as you are aware of what you are up against, I say go for it. When I was doing my side mount I caught a lot of flack from naysayers and guess what, it works. Pretty well I might add. Is it for everybody? no. Is it going to sell like oil and antifreeze? No, probably not. But if you can put one together for less than it would cost to buy a similar kit, you're money ahead. If you can sell a kit or two, maybe it will pay your r&d off. Do it.

Thanks for the support! I think that most people would be tuned off of the side mount kit because of the aesthetics of it. A roots/twin SC looks beautiful IMO. Once I finish the body work on my spoiler and the work on my computer case I'll think about working on a cast for one