Call us anytime as well
281 398 6666 Shop
832 455 9756 James/Louzee Cell
832 266 7525 Sam/Gretechen Cell

The cnc's get pretty loud sometimes so we might not hear the phones
We are here though typically 6 days a week sometimes 7

-James

my 15th post, now I can get pm's!

-James

Haven't forgotten this thread we have just been busy.
We will be working on our low budget manifold for the Honda guys next week, we will have enough material left over to get started on some miata stuff as well.

-James

Shipped that 1.6 mani out to you today. You get my PM with my #?
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No sir no pm's have been received.
You can email it to sales@bmcrace.com if you want

Thanks
-James

Email sent
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Thank you Sir.
Emailed you back

-James

...in for the ?!?! factor...

After working with a few more plenum designs for our production Billet B Series Manifold I think I am about to settle on this.

It starts out round in the front but tapers all the way to the back creating an oval. It has a constant volume through the entire manifold, even in the very back with full taper. This will maximize plenum overall volume and flow while keeping velocities high as well.

Here are pictures.

http://bmcrace.com/Manifolds/Intake-...ovalplenum.jpg
http://bmcrace.com/Manifolds/Intake-...valplenum2.jpg
http://bmcrace.com/Manifolds/Intake-...valplenum4.jpg
http://bmcrace.com/Manifolds/Intake-...valplenum5.jpg
http://bmcrace.com/Manifolds/Intake-...valplenum6.jpg
http://bmcrace.com/Manifolds/Intake-...valplenum7.jpg

This new plenum design will require a little more work for construction with the need of an added forming process that will involve us having to produce some press dies to form the pipe extrusion and then machine, however I believe the added work will be well worth the increase in performance due to the higher overall volume and greater velocities.

Physical construction should begin next week. So I will keep everyone posted with pictures as they come.



-James

Can't wait to see one for the Miata.
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Don't know why I didn't see the updates for this thread.....


I understand...I actually work in a fastener shop with about 10 big PUMAs and others, we also have some 3 story forges in the back.


I'm not out in Katy much, but will check ya'll out next time I'm there. Looks like you've already lined out some business, and if the results look good I can bring mine by, or pick up the new design.


If you search here there was a pretty good thread late last year where Braineack did some fluid flow analysis in Solid Works to come up with his BEGi modified manifold.

I understand what they did is different than your modular design, but it may give you an idea how well flow will be distributed through the plenum. We've seen a lot of problems in several iterations getting even flow to each runner, and I honestly would buy anything without seeing some pretty animations.

In all honesty you should use your modular setup to test several plenums and see what works best, and note which design suits different demands.

i might be interested in intake mani for 1.8L '99-00 head

The big fancy design that people posted the pictures of are not going to be an official design at all, I will leave similar things to that as custom one offs only leaving a much simpler log style plenum to be my production model. We are about to begin construction of the forming dies and hope to have a solid plenum formed by the end of the week.

As to my opinion on CFD... I believe CFD tests to only be good if the person also simulates the valves opening and closing and air flowing through the motor because that makes a HUGE difference as to how the air flows through a said intake manifold. Who cares it it flows "equally" through all 4 ports at the same time because all 4 ports are NEVER open at the same time.

Now don't get me wrong CFD has a place out there, but for anyone less than GM who can afford the real deal CFD testing that will simulate the entire workings of a motor just to design a intake manifold, well it is just pretty silly to inaccurately to simulate something that will never be.

so what testing ARE you gonna do on it? flow bench? flow bench with cylinder head with cams and ability to turn it at 0-5000 rpm?

Actually yes a customer of mine whom we build Lotus Elise parts for and sleeve blocks has a flow bench and the final product will receive full flow testing. After that's said the owner of Inline Racing just happens to be our best personal friend much less best business friend and I have 24/7 dyno access to really dial things in 100%.

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+1

Its all very good to say the normal testing is meaningless, but then you should come up with something else to replace it. If you can't come up with ANYTHING better, put a second set of cam gears on a stock motor, and drive the second head with that. :-) I was once on a project where we took a 4 cyl motor, bored a hole in the head, and used one cyl to drive a linear generator we were testing. :-)

Huh, does anyone have a feel for what kind of horsepower it takes to run cams at 7,000 rpm? I've got a couple air compressor motors I'm not using.

I'm going to take a guess and say around 10-15hp.

the cams turn at half the crank speed. I was hoping he'd test to 10k equivalent.

There's the issue with backpressure, though I guess pulling a constant vacuum on a chamber with enough volume would "fill" on each cylinder.

Yeah - I was thinking 7,000 rpm equivalent. 10,000 he'd need shim under bucket. :-) I'd love to know when one needs that since... my bottom end can handle it and I'd like to not trash the head.

if you've got enough flow capacity for an improved intake manifold, you'd presumably want to use that capacity, no?

Estimated plenum volume is going to be 4Liters so I don't think anyone is going to run into a lack of volume for high rpm, or big boost... I received the 1.6L intake manifold and things look very promising for coming up with something that will produce ALOT more power.

I have some questions that need to be determined by the majority rule now,
What throttle body should this be standard to use, also how bolt on does this need to be?

The way I typically make intake manifolds is to use a more or less universal throttle body bolt pattern being the ford which allows for a large selection of throttle bodies to be ran, after that is said I don't typically put factory iacv and stuff like that on the plenums, I just have 4 1/4" npt fittings at the end cap and allow people to run those to what they need.

My goal here is not to satisfy 1 single person but instead the majority of people as I have learned that business is best ran by covering a group rather than a select few.

So now it is time for the suggestions to pure in...

Also any houston guys please get in contact with me as when I have a finished piece I would love to do so dyno testing before I release it, as stated before I get 24/7 dyno access from my best friends shop and he just so happens to be well known for tuning 800+ hp cars so I am sure he can handle the job.

-James

IIRC 70 mm Mustang throttle bodies seem to be the favorite. I wouldn't worry to much about a IAC. If you can't find anyone local to dyno ID be more then happy to bolt one on and run to the dyno. I just dyno'd a month ago and don't plan to make any changes until I get a new intake mani.
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I noticed there is a passage on the head flange, it looks like a water port, is this something I can block off (I am assuming it is throttle body heater)?

Also how high rpm do the 1.6L rev to? This will determine runner lengths.

Yeah you can block that port off, Most of us guys do. 7200 rpm is the rev limiter.
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When you come up with Miata intake drawings id suggest starting a new thread in the engine section so there less to scroll through.
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Ok

More questions..

Where do you want the manifold tuned to?
Low RPM
Mid Range
High RPM?

Do yall want a bracket to hold the throttle cable or no?

Obviously the less of these little nitpicky things the quicker the construction and the lesser the price. I just need to know if people would be happy with the barest minimum or will I need to include everything including a set of instructions?

All of the above if possible, but mid to high since most of us do suffer from serious torque drops up top with stock intake manifolds. Yes, we definitely would want a bracket for the throttle cable. If anyone needs instructions they need to start taking the bus.
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Well you never know, on the instructions thing lol I have had some pretty crazy phone calls on how to do the simplest of things.

I will go ahead and do the throttle bracket.

By the way you said the powerband drops on the high end it sounds like I should try to help out there the most so I will keep things in the mid-high end range for post part.

You might find some folks would prefer the IAC - though isn't that built into any of the throttle bodies?

Also, not saying you shouldn't make a 1.6 version, but the 1.8 version would support 10 years of car, the 1.6 only a couple. If I were in it MERELY to sell as many units as possible, that's what I'd make.

Then again, selfishly, I'd say practice on the 1.6 and when you have it down make a 1.8 version. :-)

Ohh got a important one here,

What is the distnace between the intake valve seat and the port flange surface?

This is calculated into the overall primary length and to get things accurate I need an accurate measurement here as well.

As to injectors what do yall want here?

Factory style injectors or bosch style are the options.

If factory style is preferred I will need to get hold a 1 injector for pulling measurements.

-James

Just putting it out there, the lancer evo injectors are both very cheap and readily available (550 or more cc take offs) and work well... And are compatible with the miata stockers. So I'd vote for that.

I have a head at the shop I can measure on for you tomorrow. Call me when you get in, you should have my number in your email.
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Stock injector, I can send you one tomorrow.
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If someone wants to send him a 1.8 mani I'm sure he'd make it.
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I would prefer either sticking to stack miata or bosch type instead of mixing in other injectors.

I have your number I am at home right now I will call you tomorrow from the shop.
I dont really need the head itself just the measurement, however if port sizing on the head is very different from the manifold then it might not hurt for me to measure off the head because that is what it is important that we match the ports to. However if most people like to resize the stock ports I would need some idea of what to size the ports to so that we can machine them to that instead.

sti injectors are the best for low budget setups, the honda guys take them from their factory form (550cc) and cut the nozzles and boom they are 900cc lol

Some ghetto honda fab there for yo! lol

ok, stock injectors is best.
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Huh. Well, there's a guy on here who wants one of my spare mani's to try gutting. But I could send it, with or without stock injectors, if you cover shipping. :-) I will someday be in the market for an upgraded mani, but not yet. If you get serious about 1.8's let me know.

Digitizing the head flange and working up a program today, hope to be finished getting the programs written for the head flange on monday

If someone could help out I need the exact measurements for the ports at the head just to verify their size against the intake manifolds ports, also if most people port match to the gasket let me know so that I can just go pickup a gasket in town and shape the ports to that so that it is a completely matched setup.

-James

I'd prefer port matched to gasket personally. Although there isn't much difference, enough none the less.

I've got a few late model heads. Are you doing a 1.6?

I hope so, its the best of all the miata motors!

We are still working on this, Sam has nearly finished writing the program for the head flange and hopes to be cutting metal on the mill around this weekend or sometime next week.

good to know

Will this be useful for NA applications as well?

It should be just as beneficial there as it would be in a turbo setup so yes it should be just fine.

I would be in for a 1.8L one if it had even flow to each cylinder

The design and program has been finalized for the 1.6L intake manifold flange.
We are currently pushing to have our production Honda B Series intake manifold finalized by next weekend and once that is accomplished we will be 100% full focus on Finishing up the Miata intake manifolds.

Just finished off polishing
http://bmcrace.com/Manifolds/Intake-...d/DSC01927.JPG
http://bmcrace.com/Manifolds/Intake-...d/DSC01928.JPG
http://bmcrace.com/Manifolds/Intake-...d/DSC01929.JPG
http://bmcrace.com/Manifolds/Intake-...d/DSC01931.JPG
http://bmcrace.com/Manifolds/Intake-...d/DSC01933.JPG
http://bmcrace.com/Manifolds/Intake-...d/DSC01939.JPG
http://bmcrace.com/Manifolds/Intake-...t/DSC01917.JPG
This is our High Production Plenum in the works, the end cap will be billet as well and have 4 large npt ports to be ran to needed accessories

Here are a few pictures of the throttlebody flange in the works (still needs to have profile machined and holes drilled and tapped)
http://bmcrace.com/Manifolds/Intake-...t/DSC01912.JPG
http://bmcrace.com/Manifolds/Intake-...t/DSC01913.JPG
http://bmcrace.com/Manifolds/Intake-...t/DSC01914.JPG
http://bmcrace.com/Manifolds/Intake-...t/DSC01915.JPG

Unfortunately we will not be able to produce a modular manifold for the Miatas as the powerband is to low to get away with a straight primary, you would run into major clearance issues with the shock tower and other items because the runners would need to be so long.

I will have several pre made options though that will be to accommodate certain boost/rpm powerbands so that you may pick one that best matches your setup.

-James

The plenum keeps a constant volume throughout, it will also be ~4 liters in volume once end cap and throttlebody flange are attached.

did you mean constant cross-sectional area instead of constant volume?

because not many people are cool enough to run a variable volume plenum.

The variation in volume at the front of the plenum is within 10% of the volume at the back of the plenum, that is what I meant.
Or what you said is another way of saying that^

Here are a few pictures of another in the works (being built for the owner of Inline Racing, this one is a bit more on the back burner though, the Miata manifold will be finished and ready for production before this manifold is finished)
Pictured below is what will be known as our Pro Street style, this one is being built for an all motor s2k and we will be dynoing it soon.

http://bmcrace.com/Manifolds/Intake-...t/DSC01940.JPG
http://bmcrace.com/Manifolds/Intake-...t/DSC01942.JPG
http://bmcrace.com/Manifolds/Intake-...t/DSC01944.JPG

-James

Pretty slick, again. Nice job James!

Lets get going on the 1.8L. If the price is right im sure you would sell 3-5 right off the bat.

In the interest of helping out the 1.8 guys, James would you like me to send you a 1.8 mani?
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You could but I would really like to finish off the 1.6 First before getting started on something else.

I can do the fabrication work quite quickly but development work on new products take a while because it is going through my dad then and he really has to work on Paid orders first as if he doesn't we would go out of business. I really appreciate the patience you guys are having with us.

I am estimating it to still take another 1-2 months before we have a finished product for the Miata 1.6L at the moment however I will do all I can to get my old man to press a little harder and get something done sooner if at all possible.

-James

Alot of time had gone into construction of the forming tools for producing the plenum, many of the parts will be interchangeable as this plenum I have designed is to be for both my hondas, the miatas, as well as my upcoming Cellica and Elise intakes

The idea is that we will build and form the plenums all at one time (like 10 to 20 at a time) and cut out the bottom section for the plenum plates to be welded to. We will keep these in stock on the shelve and then as we get an order we will just weld the appropriate plenum base plate, as well as the selected throttle body flange and end cap profile. After that is the all other parts are just pulled off the shelf and the manifold is bolted/assembled together fully and sent to the customer (we will include all proper o rings, fuel rail, manifold bolts and standoffs, etc)

-James

No problem. I have it sitting here, so when the 1.6 is done I cloud send it to you.
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So I still haven't had the time to make it out to Katy...but I might be more motivated as a customer instead of just a forum member poking around.

I would really like one of these...but haven't seen price mentioned anywhere...

Can you give me an idea so I can stop daydreaming about it...or start saving?