is this a modification for larger turbos only, or only for a car with head work?

 

Well yes and no...

The intake manifold will be designed for top end power so you would see the best gains with a turbo that could flow enough at high RPM. It would still give benifits to any turbo by raising the powerband.

The exhaust manifold I am not exactly sure. I am still doing alot of research regarding the design, benefits and drawbacks. I think the exhaust would help regardless of what turbo you are using.

Headwork would not be needed but you would see bigger gains with a well ported head to allow more flow.

The CFD modelling helps out with seeing the flow in the intake manifold and ensuring proper filling, distribution and keeping the flow as unrestricted as possible. The exhaust portion can utilize the CFD stuff much better because you can actually see the TQ being exerted on the turbine at different RPMs as well as pressure, velocity, etc. Im not an expert at this stuff but I am getting much better with it.

Another thing I have been toying with is Finite Element Analysis stuff. All of this engineering stuff gets very interesting and really cuts down on prototyping time. Instead of creating 5 products and getting close to what is good you can get it close without even making one test item.

 

From what I've seen, the intake manifold for the Saab Viggen hillclimb car is almost identical. Same cone/plenum/runner setup. I haven't had a close enough look to be sure, but it looks pretty dang similar. The exception is that the injectors are mounted on the plenum and shoot the streams of fuel straight down the runners. Pretty neat.

Still not sure why you're worried about the length of the runners in relation to flow. The length of the runners serves primarily to pulse-tune the intake setup. There's a good formula on this borrowed from the book I mentioned previously:

Runner length (from valve to plenum) = (90 * 1,100)/RPM

The value of 1,100 will be loosely dependant on intake temperature. (IE: speed of sound) The RPM is the approximate RPM at which peak pulsetuning effect should result. There will also be a significant change in the effect when different camshafts are used; a longer duration cam will require a longer runner tube to create the same pulsetuning effect. (Though the "same effect" may not be desirable.)

For an engine running peak torque at saaay 6,000 RPM, you get a value of about ~16.5 inches, give or take a couple.

Sometimes people tune to the second pulsewave, which reduces the requisite length by quite a bit. (Not exactly half, IIRC, but somewhere in the vicinity.) In either case, it's worth thinking about.

 

The original design concept was taken from a 24 hour race car designed by HKS. It has changed a decent amount in me trying to get it to be perfect. Not an easy task at all

About the runner length yes, there are a few different ways to measure the pulsing. I am assuming the one you mentioned is a helmholtz equation broken down to be simple. Similair to this:


The problem I have found with this equation is it gets less and less accurate at higher RPMs. There are a few other equations that do pretty well. Using sound wave design/emulator programs seems to be the best and most efficient way so far (And it works for companies like Ferrari). The other advantage of using the sound wave programs is it can also tell you the volume of the plenum as well as the lengths/volume of the runners.

It just becomes a serious pain trying to first get a design done, then testing it to ensure the best possible flow and then trying to fit that design into a sound wave type program. All this takes an extreme amount of time but its something to do

The good news is I dont actually have to make anything to test the designs. I couldnt imagine if I just starting making things with no idea of how well they actually worked. Im sure after 5 designs that take a while to fabricate, bolt up and dyno I would get close but I will never know how well they actually do work compared to what is possible.

 

And the cam duration is not as significant as people think. I suppose if you had a 220 compared to a 270 it would be but considering we would only be interested in the 272 to 280 range it really isnt much of a difference.

 

Here is a short movie of what is not acceptable in my books flow wise:

http://www.thedrunken.com/downloads/badflow.avi

 

No doubt. A PITA, to say the least. Hopefully it will make you at least enough cash to make your time spent worthwhile!

Not even that complicated. It's just a basic open-pipe oscillation equation. A CFD approach would be infinitely better, especially in the case of building a single engine with as few unknown variables as possible. But, since so many Evo's will have so many intake/cam/turbo/porting/valve arrangements with this manifold, there will be no way to predict any sort of exact pulsetuning, making the precision of a particular equation less and less valuable.

The Achilles Heel of my previously mentioned equation is that it doesn't consider the iterative effects of the previous engines cycles. As you pointed out, at high RPM, the wavefronts from the previous few engines cycles are still not completely damped. In reality, you'd need to compute the viscosity of the air, the effects of the shape on sound damping, the local mach number (to test for compressibility), and you'd need to take into account the linear movement of the air into the engine and its effect on pulsetuning: IE you'd need either 1) a GOOD sound-wave emulator program or, 2) a variable-length test manifold onto which you could put pressure probes.

Talk about a PITA! I wonder if the design of all those sheet metal manifolds involved any of that ... (maybe one or two of em? )

Truth be told, I was just curious why I hadn't even seen you mention pulsetuning thus far. No offense, but it kinda seemed like you were missing the most important aspect of the manifold! (Otherwise you'd just park the plenum at the runners with some horns to smooth the flow. You'd get badass flow numbers, but the powerband would suck.)

But, as long as you are at least considering the pulsetuning effect, I've certainly no objection! I'm sure you'll do a fine job with all the computational and mathematical tools at your disposal!

That's the beauty of designing in the computer.

Also +1 for cams not being a huge deal in this case. I just mentioned it because, hey it does matter in some cases, people may as well at least be aware of it!

-Adrian

 

I have an extremely good sound wave program. I wont say exactly what it is but plenty of companies that are not exactly small use it with very good success.

As for how many sheetmetal intakes use CFD modelling... I dont think any for us Evo guys do. When you actually plug in the dimensions of many manifolds it becomes apparent that they were not modelled with CFD but more on the "It looks like it would flow good".

As for the tuning of the manifolds yes, the programs I am using do crap out pretty much everything and now that I have this sound wave one it does show compression and decompression of the waves. The mach numbers and viscosity results can only do so much because CFD does not take into account of reversal of flow or blockage of flow. It is more designed towards straight flow, going in one way and out another. That is why I needed the sound wave stuff.

About making me enough money to make it worthwhile I wont. I never planned to nor think I will. I started the project for my own cars and once it became apparent that to use some sort of molding to make it happen because sheetmetal most likely wont work out for the final design I decided I my as well sell it at near my cost if anyone would want it. Im not in the business of designing and manufacturing. I like to make things that work well for myself... it just happens that some other people might also

 

Groovy. We could use more people like you in the performance aftermarket scene.

 

any news

 

Well the design is pretty much done. I need to do some minor fixes for the injector bosses / fuel rail mounts and I am making another one so it can fit a DSM but now Im mainly just finding a good place I want to do both the casting and machining. Im still not sure what type of casting I will use either.

Im also lazy and wont try to hide it This should have been done a while ago. Ill see if I can actually get some stuff done and have at least a proto-type by next week.

 

Neat stuff here, dropped yah a PM

 

Trina, what do you need to know in order to put other intakes into your your flow software?

It'd be interesting to see how all the available intakes look. I'm especially interested because I was about to have one fab'ed up.

 

Measurements. I use Solidworks for the modelling which could import files from another modelling software if needed. I was going to try not to bring in other peoples manifolds in a public view because for some reason I could see a little fire start if I start doing that but I may decide to do so anyways.

With the CFD software you can make every measurement at any space in the manifold (Pressure, Pressure drop, Velocity, Mach #, mass airflow, temperature, force, etc). You can also enter in how well the exterior will withstand high pressures, dissipate heat, etc...

I can also use my CFD modelling to create 3D samples from a plastic and use the plastic to create molds which makes it pretty easy to get them made. Using that I can easily make most any custom part I want. Currently I am thinking of starting with the intake manifolds, then move on to exhaust manifolds, 02 housings, custom hubs (Probably just for DSMs), possibly control arms for DSMs, etc....

 

[QUOTE=TrinaBabe] Im mainly just finding a good place I want to do both the casting and machining. Im still not sure what type of casting I will use either.
QUOTE]


I know of a few places you could have the casting made. Bremer Manufacturing, Scholten Pattern, or Rapid Cast. I don't know if you need / want to have the patterns made but if you do Bremer or Scholten would be able to help you out there as well as having the casting made. Rapid cast would be able to create a rapid prototype part and have a casting made from that which should save you from investing in a pattern for your prototypes. I have had good luck with Bremer and Scholten. Bremer made front covers, valve covers, and intake manidfolds for us.