I have been doing a lot of flow bench data on different intake designs over the past few days and this is what I have come up with so far.

Now the test subject was a totally stock 1G head. It still has the factory valve job and valves.

Here are the numbers that I have collected as of now.

Stock head with no intake and a ¾” radius entry. #3 intake runner. As you can see these are a good flowing head to begin with.

Lift CFM
.050 48.91
.100 94.21
.150 139.62
.200 181.24
.250 216.94
.300 241.11
.350 261.52
.400 271.14
.450 280.45


Stock head with a stock intake. No T.B. with a ¾” radius entry. #3 intake runner. You can see not only does the stock intake kill the upper lift flow like everyone knew, but it hurts low lift flow as well.
Lift CFM
.050 33.75
.100 88.70
.150 128.18
.200 169.87
.250 202.57
.300 223.95
.350 238.73
.400 245.79
.450 252.65


Stock head with a 4” tapered runner sheet metal intake and a 240 cubic inch plenum. No T.B. with a ¾” radius entry, and a 60mm opening. #3 intake runner. You can see were the stock intake out flows it until the .200 lift mark. It will hurt the lower end a bit, but make up for it in the mid to upper RPM range.

Lift CFM
.050 32.02
.100 76.92
.150 128.41
.200 169.54
.250 205.36
.300 233.91
.350 254.90
.400 267.98
.450 274.29



Stock head with 6” tapered runner sheet metal intake and a 240 cubic inch plenum. No T.B. with a ¾” radius entry, and a 60mm opening. #3 intake runner. You can see were this one kicks the crap out of both intakes tested in every lift. Makes for killer low end and top end charge.

Lift CFM
.050 45.28
.100 91.17
.150 140.12
.200 183.17
.250 221.39
.300 243.46
.350 261.52
.400 270.10
.450 278.41



Stock head with 4” tapered runner sheet metal intake and a 540 cubic inch plenum. No T.B. with a ¾” radius entry, and a 60mm opening. #3 intake runner. Now this test was done to see if a bigger plenum does have any effect on non force induction application. Remember the flow bench draws air threw the intake, not forcing air into it. That test will come later on to see the results as well. You can see were the two shorter runner intakes flow a lot alike.


Lift CFM
.050 35.12
.100 61.31
.150 121.32
.200 167.51
.250 205.36
.300 233.91
.350 254.90
.400 267.98
.450 280.45



Stock head with 6” nontapered runner sheet metal intake a 240 cubic inch plenum. No T.B. with a ¾” radius entry, and a 60mm opening. #3 intake runner. Now notice how not having a tapered runner does not fill the cylinder as well. It does out do the stock intake but not well enough.


Lift CFM
.050 35.40
.100 89.91
.150 128.62
.200 170.88
.250 205.36
.300 231.46
.350 252.65
.400 263.69
.450 270.10



I hope to do a complete stage test as above in the next few weeks. I will start with a level 1 head with stock sized valves and go up from there with all the same test shown as above. From what I have gathered so far. I do believe that a aftermarket intake even on a stock car that is tuned properly (intake) to the combination will make more power. Now I am not trying to say go out and buy something like this first, but I do see were it will help out long before a ported race head. I can see one thing for sure. If a stock intake hurts flow that bad on a stock head…..what is it going to do on one that has been worked over?

I would like to flow a stock Extrude Hone intake to compare it as well. If any of you guys have one and are not using it yet I would like to borrow it for a day. I will be happy to pay shipping to and from my shop.


All the test have been performed on a JKM 600 flow bench on the same day under the same conditions. Each intake tested had every runner (except #3) blocked off between the intake and head so that no bleed off air was involved. All vacuum ports blocked and injector hole plugged as well.

Now as you can see what time it is by my post. I am tired and heading for home.

Hope some of you learn something from this.

Polk

are the #'s for "Stock head with a 4” tapered runner sheet metal intake and a 240 cubic inch plenum" correct? they are exactly the same as the stock manifold..

are the #'s for "Stock head with a 4” tapered runner sheet metal intake and a 240 cubic inch plenum" correct? they are exactly the same as the stock manifold..

Click to expand...

Sorry for that. It was late when I posted the numbers. It is fixed now.

As for the 2G heads I will be doing some test on them as well. It may be a couple of weeks out on them.


Polk

OK everybody, I have some more flow data on the 1G head. Now this one is pretty much a race ported head. I will start off with everything that was done with the stock one has been done here as well. Example: ¾” radius entry. #3 intake runner and so on. All tested @ 28” of water

Now I want everyone to realize one thing…..WE ARE NOT RACING FLOW-BENCHES…. The numbers that I am posting just show the characteristics of different manifolds and how they react in different applications. Just because this intake shows to outdo another does not mean that it will be right with your combination. Many of DSMers have ran good times with stock intakes. Marco at Magnus ran a very low ten second pass with a stock head. But one thing you have to remember.. Efficiency means power.


4G63 level 4 head. 1mm over valves, no intake, ¾ radius entry

Lift CFM
.050 60.38
.100 106.30
.150 161.19
.200 187.97
.250 241.11
.300 270.10
.350 298.19
.400 309.45
.450 320.31
Now I kept on flowing it past this lift to just see what this thing could do.
.500 334.25
.550 345.98
.600 357.32
.650 365.21
.700 374.46 Now that should give some of the V8 guys nightmares.


Same head with 6” tapered runner 240 cubic inch plenum
Lift CFM
.050 55.46
.100 104.67
.150 152.47
.200 187.97
.250 236.33
.300 265.85
.350 288.47
.400 301.99
.450 313.11


Same head with 4” tapered runner 240 cubic inch plenum
Lift CFM
.050 58.46
.100 101.35
.150 147.94
.200 210.84
.250 226.48
.300 259.33
.350 282.48
.400 298.19
.450 307.60


Same head with stock intake
Lift CFM
.050 55.46
.100 101.35
.150 144.43
.200 189.94
.250 218.80
.300 243.46
.350 263.69
.400 270.10
.450 280.45


Same head with Cyclone intake. Now there will be two different numbers on this one. One were both short and long runners are open and one with just the long one in use.

Both runner in use.
Lift CFM
.050 52.29
.100 98.96
.150 142.05
.200 180.29
.250 210.84
.300 241.11
.350 261.52
.400 270.10
.450 280.45

Long runner only
Lift CFM
.050 52.29
.100 94.24
.150 133.36
.200 162.25
.250 183.12
.300 193.94
.350 205.36
.400 210.84
.450 213.53

Polk

Hey Don,
Someone had posted this thread on our little board here in Missouri. Things are still going slowly together. Which size plenum was used on my intake? Which stage head did you do for me? I assume its the 240 cu. in. plenum and the stage 4 head work. Currently< iam waiting on tubular manifold from Automotosports that will be dumping into split housing T-66 turbo. Everyone in St luois who knows about this build up on my spyder are very interested to see what happens with it. Whether its a big expensive turd or a powerhouse. To round out the airflow on the head Lowry and I are putting Hks 272 intake and exhaust with fidanza adj. sprockets. Whatever happens I will let you know offline what occurs.

Rob
(7 GST Spyder

Rob you have a 240 ci with 6" runners. Your head is a level 4 as well.

That thing should be a beast when it is done. I hope you have a standalone.

Good luck and if you have any questions give me a call.

Don Polk
www.PolkPerformance.com
501.847.RACE

if your pulling more air in , you have better vloumetric efficency...as is the case with the stock 1 g. the engine is not having to work as hard to pull in the charge. and if you understood finite amplitude wave dynamics, you would know that when tuning for outright power, a longer runner (when tuned to the second or third pulse length) is better with a 2- 4 degree taper, such as the old ramjet muscle cars. how would you say it increases the swirling effect? they both follow the same curved path, enter in the same location, and by the time they go past the intake valve, how much of that swirl do you think is left? ive seen swirl controlled by valve angle, valve shrouding and piston dome shape, rarely by intake runners, but i have seen it before, so im not saying it hasnt been done. then you have the problem with the secondary butterflys causing unwanted turbulence in the air stream, and if you are causing turbulance, you have to use energy to drag air over the obstacle (like drag on a car), again, reducing efficency.

how would you say it increases the swirling effect? they both follow the same curved path, enter in the same location, and by the time they go past the intake valve, how much of that swirl do you think is left? ive seen swirl controlled by valve angle, valve shrouding and piston dome shape, rarely by intake runners, but i have seen it before, so im not saying it hasnt been done.

Click to expand...

Because only one intake valve is being fed. Two runners, two valves. One runner closes and the majority of flow is going through the path of least resistance. Sure some air will go through the valve farther away, but there is still a majority of air entering at one corner of the cylinder. Am I missing something? This will favor swirling.

if your pulling more air in , you have better vloumetric efficency...as is the case with the stock 1 g. the engine is not having to work as hard to pull in the charge. and if you understood finite amplitude wave dynamics, you would know that when tuning for outright power, a longer runner (when tuned to the second or third pulse length) is better with a 2- 4 degree taper, such as the old ramjet muscle cars

Click to expand...

The stock 1G intake has its volumetric efficiency at higher rpm where short(er) runners and large runner areas are good for short wave pulses. I don't see anyone arguing this. The stock 1G intake is very good at high flow, venom intakes are better, etc. But in this case people want to tune for something in addition to outright power. A longer runner with a smaller cross-section will have more volumetric efficiency at a lower rpms. Some of us like low end torque.

then you have the problem with the secondary butterflys causing unwanted turbulence in the air stream, and if you are causing turbulance, you have to use energy to drag air over the obstacle (like drag on a car), again, reducing efficency.

Click to expand...

This is the tradeoff of "best of both worlds" intake tuning. You can't avoid the valves in this design. But those valves are no different than your throttle body valve, just more of them. Sure you'll reduce some efficiency, but that's what porting is for. There is still no evidence that this turbulance is significant on our cars, i.e. it is not the driving factor for flow.

im not arguing the point of long and short runners, i just believe that the two should be totaly independant from another, not one on and then the other, or even better is variable length venturies. you have to remember, at large airflow rates, air acts like a liquid, and if both intake valves are sucking air in the same vacum and rate, which they should be, not much more air is going to favor the most direct route. small runners were generally put on low revving vehicles to improve throttle response and to keep the fuel charge suspended while it was on its way to the ports, which is not needed with mpi, as it sprays right at the valve ports and doesnt linger in the runner to condense. then also the butterflies have to wreck havoc on the internal harmonics of the runner. also how do you port out the secondaries then fit the fly plates back in, you would have to buy new bigger ones correct, but you say that outright airflow is not your concern? that intake is twice as heavy as the 1g and i couldnt find aftermarket wires to reach the coils. that was actually the deciding factor in putting it in the scrap heap.

You have a lot of good things to say, and I want to reply to all of them, and get your input.

I'm betting that combining the 2 will be beneficial. There are some dsm'ers out there that have tuned the opening times and have seen very noticeable improvement. Posts have been on the dsmtalk.com forum, its about 7 pages long: Link

The way I ported the secondaries was easiest everywhere but the valves, but I was able to do the valve area because the valves are oval and not round. This requires the actuator travel to increase slightly, but enough to enlarge the openings. BTW, even without porting, the added area of the openings minus the open valve shade is more than the stock 1G. But yes, I agree about turbulence subtracting from that. Overall I don't believe there is significant reduction in top end flow. Head flow numbers support that, as do other people's track experience. It's the people that run the manifold with a simple plug to vacuum that causes the intake not to function right. It needs to be tuned to open right.

I wish I new more about what the air will do near the valves. You make a good point about the liquid, BUT remember that the valves are opening for very short intervals, and there is not much time for buildup to occur to equalize the flowrates through both valve ports. That is how I see it anyway. I'd like to talk about that more.

Outright airflow is definitely a big concern, I do like to go fast. But its not my only concern, and that's why I think a 2 runner approach favors both. It's heavier by maybe 5 lbs, but I can't say that frightens me. There's a guy on the above forum that can source the right length wires for $30. There's also other options for mounting the coil closer by an inch which is all that's needed for #4.

Ken

unfortunatly i have been unable to find any tech articles on the fluid dynamics of a dual runner setup, they always are just single stage runners. the amount of testing needed to "see" what the air is doing right before the valves and after is enormous, as the only people who can afford it is manufacturers and formula 1 teams come to mind.

if you picture yourself in the cylinder on the intak stroke looking at the valves, first, the cylinder pressure drop is the same through out pretty much, so you have to say it the same at and after the valves for the first millisecond, as that too experiences a pressure loss, then it will be the valve in the more direct path that gets favored a small amount. another thing to look at is the direction each runner takes, one comes from the bottom up the other top down, which may be your swirling effect/ turbulace. i have always read that 2 small holes flow more than one large one, thats why efficent engines use 2 and 3 intake valves, so i fought long and hard a while ago about the benefits of using a dual runner setup, but now im not so sure, i would love to see some definitive proof...

The only way someone could prove it is to run the stock manifold on a dyno, then swap in the cyclone and run it, then put the stock one back on, perhaps swapping yet another time back to the cyclone for more data points/batches. All this without changing any other variable. It's unlikely that anyone would go to the trouble of doing this because of how much a pain it is to swap them. Unless someone can gain financially on a manifold, but these are relatively cheap to get.

No matter how fast I go, someone will argue I could go faster top end with a stocker. It's very unlikely I can compare with anyone out there, because no one will have my combination.

I'll be running 2G heads fully ported and polished on a 1G intake, SS valves, crower springs, GVR cams, all on top of stock bottom end 6-bolt. I am interested to see what I will be flowing. Anyone else with this setup? Curious to see how they've been doing. I got a S-AFC on the way to help with some tuning.

What test pressure was used?

I would also like to see the difference between the 1g stock head and the 2g stock head. I was think about going with the 1g head swap on a 2g, but i would like to see if it was worth the time. Has anyone done the swap and how hard is it. What do you all have to swap over and what has to be done. I think it might alot easier that i have the dsmlink with the cas.

Yes, continue this, and this time post the 2g stock head with just a 1g intake manifold and 1g throttle body put on. I would seriously like to see if there are any improvments by doing this. I know they are different sizes, but without doing anything to the 2g head I would like to see if there is an improvement. Is there anything bad that can happen by just swapping on the 1g intake manifold and throttle body onto a completely stock 2g head?

Yeah, it would hurt performance because the the ports on the stock 2g head won't match the 1g Intake.

Originally posted by Beemer
I know, let's all petition one of the import rags like sport compact car to do an intake manifold shootout like the v8 guys always have! (like they would ever listen to us anyways) It's an idea though.
dave

Click to expand...

I agree.. but think the limited# of vendors and dependency by the mags would not be conducive to "unbiased" comparison testing (or cross-testing at all). Hence my reason for cancelling Turbo 7 years ago

Would also love to see dynos of Camshafts / Exhaust Systems / DPs / 2.25 vs 2.5 IC Piping..etc.

If I hit the Lotto.. I will buy my own Dynojet and do all said testing myself and publish it here.. though I'll still work my 8-5 job :laugh:

enjoy DSMers

more 2G pics

Hey Polk if your pockets are deep enough how about getting rid of the valves all together. http://www.coatesengine.com/ I know for a fact there are a few SBF mustangs running around with this technology and spin upwards of 9000 rpm. Seals need to be replaced often but well worth it IMHO. Also wouldent have to worry about breaking a timming belt as there are no more popet vavles.

Click to expand...

I had a chance to play with a set of those heads way back in 95. They are pretty trick. One of my good friends had a hand in helping design them. To bad the big three are in deep with the valve train people. We could have had this technology here on production cars by now.

Cody you can look at this site www.mondellotwister.com Joe has been around for some time and knows a good deal about heads.

Dave do you own a flow-bench or have one access to one? I know that they are not a make or break in porting, but they are a very useful aid in doing competition heads.

Thanks
Polk

Originally posted by Polk


I had a chance to play with a set of those heads way back in 95. They are pretty trick. One of my good friends had a hand in helping design them. To bad the big three are in deep with the valve train people. We could have had this technology here on production cars by now.


Polk

Click to expand...

Honda will probly be the first they suposidly have a 1.5L motor with a CRV head and the main issew is seal longevity. Same problem everyone is having. But your right if big three would jump in it would have been here by now. Imagine spinning any engine upwards of 12,000+ rpm. O well i can dream.

Hey moto, the only problem with soaring RPM's is the lack of torque. This is where the increased displacement comes in, to consume a larger volume of air, making more bottom end and mid range torque. Thanks, Dave

Originally posted by fiveliterfrenzy
Hey moto, the only problem with soaring RPM's is the lack of torque. This is where the increased displacement comes in, to consume a larger volume of air, making more bottom end and mid range torque. Thanks, Dave

Click to expand...

You are correct and i was thinkin more along the lines of a race only motor. But the CRV technology boost both HP and torque substancially. I did have (before my hard drive failed) dyno sheets showing the before and after of a stock SBF 5.0 with only the head changed and same bottom end making an instant 80 Ft lbs and 100 HP more at less than 7000rpm. And i am not talking peak here i mean perty much across the board above 1800 RPM. Could have done much more but was held back from very conservitive non-variable valve timming and stock bottom end at 9:1 commpresion. also if you read up on this technology and just look at how it works you can see its easly adaptable to variable valve timming. Now thats the kind of V-tec i could live with. If i ever have the money somday I would like to adapt this to a SBC 383 (destroked 400) or a nice very light and expencive bottom end 4g64. More overall power with less boost. And ya wouldent have to rev it to the moon. O and if your wondering the SBF heads start out at $5000 a peice!

Uhh, i guess you gotta be an old fart to remember this, but i know Polk has heard of Rhoades lifters. They pioneered the variable lift system in 68, with an oil pressure sensitive lifter pintle and seat, with progressive rate spring to cause the lifter pintle to raise and lower, depending on RPM (oil pressure). To further these ends, BMW (double VANOS), Porsche (VarioCam), and to an extent, Bosch aG all went a step further, incorporating a dual length intake runner system in to compliment the abilities of the variable lift system. All of the european companie were into the act well before the 70's were over. Now, the year is 1984, and honda introduces a motorcycle, the 400GS-R, (letter designation sound familiar to any import fans ?) wich was coined as "radical" and "amazing" when in fact it was just the first engine to use this design on such a small scale. So to this end, remember that all this ingenious variable valvetrain was invented and abandoned here before anyone else had even thought of a similar design. F.Y.I. the big 3 select what pace to move at, they're not spinning their wheels. No offense to import guys, or guys that drive cars made here, and designed overseas, but the USA still has this whole automotive industry thing under wraps