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Just a curiosity as I forgot... did we have a flow of the siamese runner modeled? I'd think a CFD model of what is happening in the runner would show what's causing the... "weirdness" per say. Or a siamese runner made of clear bits and some smoke... I'd think there would be a very interesting velocity profile going on in there...
Just a curiosity as I forgot... did we have a flow of the siamese runner modeled? I'd think a CFD model of what is happening in the runner would show what's causing the... "weirdness" per say. Or a siamese runner made of clear bits and some smoke... I'd think there would be a very interesting velocity profile going on in there...
No CFD that I could find.
The only hard data I have is from my flow bench tests.
The Siamese runner had 1/4 to 1/3 the velocity of the Large Tube runner at the same flow rate.
That would imply the intake manifold runner IS pulling air from the whole Siamese portion of the runners and not some localized "high speed flow area".
So much in these past posts I've already forgotten what I've done ...
but it looks like I did smoke test the Siamese runners with the plenum.
You can see some of what happens in the inlet, but not down the runner.
Maybe I could spend more time on this during the winter
The only hard data I have is from my flow bench tests.
The Siamese runner had 1/4 to 1/3 the velocity of the Large Tube runner at the same flow rate.
That would imply the intake manifold runner IS pulling air from the whole Siamese portion of the runners and not some localized "high speed flow area".
So much in these past posts I've already forgotten what I've done ...
but it looks like I did smoke test the Siamese runners with the plenum.
You can see some of what happens in the inlet, but not down the runner.
Maybe I could spend more time on this during the winter
cheap bore scope could see down the runner but could affect the results.
The only hard data I have is from my flow bench tests.
The Siamese runner had 1/4 to 1/3 the velocity of the Large Tube runner at the same flow rate.
That would imply the intake manifold runner IS pulling air from the whole Siamese portion of the runners and not some localized "high speed flow area".
So much in these past posts I've already forgotten what I've done ...
but it looks like I did smoke test the Siamese runners with the plenum.
You can see some of what happens in the inlet, but not down the runner.
Maybe I could spend more time on this during the winter
interesting. Depending on the measurement location though, I suppose there could be a pinch point on the air flow pattern within the runner. I'm picturing almost like a venturi flow pattern just due to inlet/outlet shape. It'd be nice to build a model out of acrylic or something translucent to see inside what is going on. The smoke isn't revealing anything too odd.
The timing of this is funny...kind of. I'm about to dyno the ASM siamesed runner and ported plenum on a hi flo base. I the owner is pumped for the results, I think he thinks it'lll match the Super Ram. I think the test is a waste of time, it won't match the Super Ram, and your data is adding to my doubts about it's effectiveness. BUT, it's another intake option data point so I'll do it anyway and we'll see how the dyno compares, relatively speaking, to your flow bench results.
The timing of this is funny...kind of. I'm about to dyno the ASM siamesed runner and ported plenum on a hi flo base. I the owner is pumped for the results, I think he thinks it'lll match the Super Ram. I think the test is a waste of time, it won't match the Super Ram, and your data is adding to my doubts about it's effectiveness. BUT, it's another intake option data point so I'll do it anyway and we'll see how the dyno compares, relatively speaking, to your flow bench results.
I have been watching over there
This is why understanding everything we can about a design is important.
On your STOCK engine, the heads and cam lift are the air flow/rpm restriction.
Like the TPIS 350 dyno test I posted earlier, you will probably see a good bump in power, over the stock runners, around 5000 rpm ... but it should fall off quickly.
If he has a bigger motor, better heads and cam, it's going to hurt him a lot more.
The numbers say the Siamese can't keep up with the Super Ram in a situation when the intake manifold is the largest restriction to the air flow.
The only hard data I have is from my flow bench tests.
The Siamese runner had 1/4 to 1/3 the velocity of the Large Tube runner at the same flow rate.
That would imply the intake manifold runner IS pulling air from the whole Siamese portion of the runners and not some localized "high speed flow area".
Well, thanks for that – it kills the theory that a portion of the siamesed area is acting like adding runner length. Looking into it more, I found the AZ siamesed runners are a lot shorted than I had originally thought. When entering the “correct” measured divider length and runner diameter, and increasing the flow a few CFM over the AZ long runners, the curve matches up fairly well to the actual results everywhere except for the higher RPM estimates. This is the same thing that is happening with the sims to a lesser degree with the TPiS full-length large runners and to a larger degree with the SuperRam. All the other sims of the “short runner” intakes tested in the 10xTQ article compared to actual results matched up really close throughout the entire RPM band.
With that, I’ve mentioned in other posts over the years how bad the runner-to-base and base-to-head transitions are with the stock and aftermarket “GM” style TPI intakes. I’ve never gone into details, but I think those transition points are “the issue” with these intakes not being able to make the higher RPM power they should with the reduced runner length.
As seen below, the aftermarket intake improved a little on the runner to base transition compared to the stock base. However, the stock and even the larger tube aftermarket runners at best come at the base straight on or even worse at the opposite angle of what it should. Flow bench testing with an aftermarket base and runners shows a 14% drop in flow with stock runners (216 cfm vs 252 cfm) and a 4.5% drop with the SuperRam runners (240 cfm vs 252cfm) even though the SuperRam runners flow more than the base (289 cfm). The SuperRam’s runners come at the base at a slightly improved angle, but it's still bad enough to reduce the base's flow. Flow numbers aside, I think that transition point also causes enough turbulence in that area, that the effective port area decreases with increasing RPM and port velocities.
However, I believe the base to head transition for the GM style TPI base causes more harm than the runner to base transition. The stock and aftermarket TPI base is a “Low Port” design and under higher RPM and increasing port velocity, I believe the effective port area decreases (as the Low vs High Port example posted earlier shows) and subsequently causes the "additional" reduction in upper RPM capability. I included the FIRST as an example of a “High-er Port” design that better holds its effective port area as RPM and port velocity increases.
The reason I bring up the FIRST is because I ran a fully ported TPI base and siamesed SLP runners (a little before the halfway point) on my old IROC (355 capable of making around 415 FWHP with a short runner intake). I considered that to be an optimized TPI/SLP combination for that engine/car combination. When I swapped over to a box-stock, full-length, FIRST it dropped almost 4-tenths off the ETs and added 3 mph. Shift points went from 5500/5300 with the TPI/SLP combo to 5800/5600 with the FIRST. The TPI/SLP combo fell off a quickly past 5500 rpm, while the FIRST ran within a few hundredths shifting as high as 6200/6000. While the FIRST does flow a lot better and has a larger minimal cross sectional area, I’m going to attribute the higher RPM capability of the FIRST mainly to the higher port design - better holding the native/effective port area at the head. The runner to base transition of the FIRST is a lot better as well – flow bench testing done by the 3rdGen guys in CA, showed flow numbers of the base (slightly opened up to a 1205 gasket) dropped very little with the runners connected (IIRC 297 cfm vs 301 cfm).
So, that’s why I believe the actual power drops off so quickly with the combinations running the GM style TPI base compared to the sims. The sims assume a constant port area, as opposed to a variable port area (reducing as RPM increases). All the shorter runner intakes in the 10xTQ article have a “High Port” design and as mentioned earlier, the sims matched up well to the actual dyno results.
Anyway, the stock based TPI style intakes are not capable of making power at high RPM and it’s not just the runner length. The SuperRam with its revised plenum and shorter runners is about as good as you can get and even then the base intake won’t allow it to take full advantage of the “potential” RPM capability of the shorter runners - especially the more modified the engine is.
It might sound like I’m knocking the GM based TPI, but I'm not. They can perform great as long as you concentrate making power within its capabilities – people just need to stop trying to make it do something it can’t do. That is unless you do like the CA guys and weld up the base and relocate the injectors to make it a "High Port" intake.
With that, I’ve mentioned in other posts over the years how bad the runner-to-base and base-to-head transitions are with the stock and aftermarket “GM” style TPI intakes. I’ve never gone into details, but I think those transition points are “the issue” with these intakes not being able to make the higher RPM power they should with the reduced runner length.
However, I believe the base to head transition for the GM style TPI base causes more harm than the runner to base transition. The stock and aftermarket TPI base is a “Low Port” design and under higher RPM and increasing port velocity, I believe the effective port area decreases (as the Low vs High Port example posted earlier shows) and subsequently causes the "additional" reduction in upper RPM capability. I included the FIRST as an example of a “High-er Port” design that better holds its effective port area as RPM and port velocity increases.
I pretty much agree ....
I made the decision to flow bench test just the intake manifolds and not flow through a set of cylinder heads, for most of my tests.
Wanted to be able to compare intakes "cross platform" and I have seen to many people bench test a 300cfm intake bolted to a 250cfm head and claim the intake flows 250cfm.
You always need to know where the restriction is in the system, valve, heads, intake runner, plenum etc.
Once you flow the individual components, than you should put them all together and see what happens.
As you probably know, EA-PRO has an intake manifold flow coefficient which should help differentiate between a poor flowing runner (low rise) and a good flowing one (high rise) that share the same dimensions.
If you have head flow data with and without the intake, it can calculate the flow coefficient for you.
The flow bench data should capture some (but not all) the effects of the runners restrictions and curves, without flowing through the cylinder heads.
A curved runner is a curved runner and will hurt the flow, but I agree that "High Rise" would flow better in the "Full" system.
I bought a BIG converted Super Victor single plane intake from someone on this forum.
Knew it was way to big for my mild 350.
I potted the floor up to give me 300 fps intake velocity at 6000 rpm and it runs great low and higher rpm on the small motor.
One benefit of the potting is that it fills the dead space on the runner floor and gives me a real "High Rise" runner into the head ports.
Doesn't leave much hood clearance though
I've been taking a break from design and testing intakes to look at materials.
Is it possible to 3D print a real part that can survive under the hood on a home 3D printer?
I would really like to print an intake elbow to replace the aluminum plenum box I have now, but I think it's smarter to start with a less critical part.
The default air filter location on most supercharger installs is to stick it right on the blower next to the hot exhaust manifold, size limited by the master cylinder.
There just isn't a good way out to open air, up, forward, down, or back.
I use to run two Callaway style hood scoops, but I don't want to cut holes in my new painted hood.
Going down the highway on an August day, the air at the filter is around 190 degF.
The air over around the battery is about 100-120 degF.
For now I fixed the fender well in place and used some silicone elbows to move a bigger K&N filter in the battery area.
Couple of DataMaster Dyno runs show I picked up a little over 10 horsepower and 10 ft-lbs of torque.
I think this air filter tube would be a good less critical part to work on.
The most common base material people print with is PLA (polylactic acid).
It's cheap ($35 a spool), tough and easy to print with.
The problem is it isn't very chemical resistant and has a very low deflection temperature around 140-149 degrees F.
I designed a quick version and printed it out to get started, but it's not a viable material.
Was designing air filter tubes from scratched and realized, why not just copy the hose setup that already fits ... measured and modeled it.
The next possible material up the food chain is ABS (acrylonitrile, butadiene, and styrene).
It's relatively cheap ($45 a spool) super strong and hard material, with a borderline deflection temperature around 190-192 degrees F.
Not to good with gasoline.
I've been warned that it is a bear to print with and I should have listened.
I won't waste much time talking about it but ... some highlights (low lights)
-Took me forever to figure out how to get it to stick to the printing surface.
-A lot of dimensional shrinking as it cools which leads to the part cracking along the print lines.
-To get the print layers to not crack and stick together as it cooled, I had to run such a high print head temperature that the printer nozzle failed and plugged 50 hours into a print. Had to take the printer head apart to clear out the plastic.
I don't like to give up ... but after a dozen parts ... I did
Next material, quite a few steps up the ladder and usable in my printer without modifications, is either a Carbon Filled Nylon or Polypropylene.
They both have high deflection temperatures around 315 degree F and very chemical resistant.
Nylon absorbs H20 and need to be oven dried before use, Polypropylene doesn't.
In the end Nylon may make a stiffer part, but I started with the Poly.
Braskem FL900PP-CF Polypropylene Carbon Fiber ($75 a spool).
I used the printer settings suggested by some the "Experts" that I've been bothering, and man ... the parts just came out beautiful, first try
They are a little "fuzzy" when they first some out of the printer, from the carbon fiber, but I was told to flash over the parts with a propane torch and it leaves a nice flat uniform surface.
Designed a two piece slip fit and the parts welded together real easy.
They don't look or feel like printed parts, reminds my of any air filter housing on a production car.
You can squeeze and deflect them without any cracking.
Fits nice and so far they have survived a few 30 minute test drives without issue.
Started to look at what a throttle elbow might look like.
The Super Victor intake only leaves me with three inches of clearance to the hood to work with.
Don't think I can get it designed and printed quickly enough to test this year ... might be a winter project
Worried that the Poly might be to flexible and may buy some Carbon Filled Nylon to try.
Rainy day here today ... so laid out the first throttle elbow design.
Has to be in two parts to fit on the printer, an elbow and a throttle spacer.
The three inch height is very limiting.
Don't know if a compact smooth and straight design will flow better than one with a "Big Butt" on the rear.
Have to flow test on the bench to find out.
New elbow compared to the old one I tested previous.
I want it to be a drop in replacement for the aluminum box plenum I have, so it has to fit within the design box.
Decided that clamping the throttle and EGR valve with a flange and bolts is better than risking inserts pulling out if the plastic softens ... for now.
Also put two big ribs under the curve to help support the throttle body.
Going to print out a the model in cheap PLA plastic to flow test and test fit on the engine instead of using the final expensive polypropylene.
I can print faster with the PLA 41 hours verse maybe 81 hours for the poly, on the larger elbow part
[QUOTE=SuperL98;1607058740]Rainy day here today ... so laid out the first throttle elbow design.
Has to be in two parts to fit on the printer, an elbow and a throttle spacer.
The three inch height is very limiting.
Don't know if a compact smooth and straight design will flow better than one with a "Big Butt" on the rear.
Have to flow test on the bench to find out.
New elbow compared to the old one I tested previous.
I want it to be a drop in replacement for the aluminum box plenum I have, so it has to fit within the design box.
Decided that clamping the throttle and EGR valve with a flange and bolts is better than risking inserts pulling out if the plastic softens ... for now.
Also put two big ribs under the curve to help support the throttle body.
Going to print out a the model in cheap PLA plastic to flow test and test fit on the engine instead of using the final expensive polypropylene.
I can print faster with the PLA 41 hours verse maybe 81 hours for the poly, on the larger elbow part
[/QUOTE
makes sense to me to prototype the cheapest way until finding a design your satisfied with. the freedom of design compared to fabricating these designs out of flat sheet is amazing to me. I was in the metal fabricating industry for over 40 years. The cost to have one of your elbows fabricated, would be too high to be practical. Would have to makes design compromises to keep cost down. from my perspective 3d printing is dirt cheap. 3d printed parts look better and cost less
makes sense to me to prototype the cheapest way until finding a design your satisfied with. the freedom of design compared to fabricating these designs out of flat sheet is amazing to me. I was in the metal fabricating industry for over 40 years. The cost to have one of your elbows fabricated, would be too high to be practical. Would have to makes design compromises to keep cost down. from my perspective 3d printing is dirt cheap. 3d printed parts look better and cost less
The money I have spent on prototype parts over the years, is staggering
Hand made models, CNC machined from blocks, stereo lithography, soft pre-production tooling, plaster mold casting ..... etc.
Luckily was someone else's cash
I retired long before 3D printing was a thing.
It doesn't mater if it's a $10 part or the first pieces from million dollar tooling ...
You always feel like a kid at Christmas when you get to hold a part you designed for the first time
How does your thermostat clearance look? That was the issue I had with the Accel Pro Ram. I wish more carb style intakes had their waters passages to the thermostat housing not raised.
How does your thermostat clearance look? That was the issue I had with the Accel Pro Ram. I wish more carb style intakes had their waters passages to the thermostat housing not raised.
The manifold shown with my prototype elbow on it isn't the one on my engine.
The one installed was fabricated by Jeb Burnett a long time back specifically to fit under the C4 hood and has the water crossover cut down and welded.
My design fits within his plenum box design, and if I measured right should fit.
I'm trying to have the patience to test fit the final white plastic model before printing the final $$$$$ piece.
You get a unique perspective on a part watching it print layer by layer.
I could tell right away, watching Version #2 printing, that the throat area where the elbow turns was going to be to small. (I'm calling the old orange elbow Version #1).
I'm knew I had a busy appointment week coming so went ahead a designed Version #3 and set it printing ... make good use of the time.
Version #3 has the smooth bottom curve of Version #2 but the big behind of Version #1.
Not to complain about SketchUp again, but I couldn't extrude one curve for the elbow
To get what I wanted, I had to extrude separate bottom and top curves and stitch them together manually ... but I got there.
I also widened it right out to the carburetor bolt pattern to get the maximum throat area possible.
Added details, captured the throttle stud nuts, bigger throttle bosses for inserts, more room around the back vacuum fittings.
Another day of printing for Version #3 and I'll try to find time this week to flow bench test all three elbows and the box plenum together
You get a unique perspective on a part watching it print layer by layer.
I could tell right away, watching Version #2 printing, that the throat area where the elbow turns was going to be to small. (I'm calling the old orange elbow Version #1).
I'm knew I had a busy appointment week coming so went ahead a designed Version #3 and set it printing ... make good use of the time.
Version #3 has the smooth bottom curve of Version #2 but the big behind of Version #1.
Not to complain about SketchUp again, but I couldn't extrude one curve for the elbow
To get what I wanted, I had to extrude separate bottom and top curves and stitch them together manually ... but I got there.
I also widened it right out to the carburetor bolt pattern to get the maximum throat area possible.
Added details, captured the throttle stud nuts, bigger throttle bosses for inserts, more room around the back vacuum fittings.
Another day of printing for Version #3 and I'll try to find time this week to flow bench test all three elbows and the box plenum together
curious to see flow result difference between throat side runners and heel side runners.
08-31-2023, 08:30 AM
