Another HA intake cut-open and flowed

[SloGN]

I also want to throw is out there, because it's has me thinking quite a bit. When Pat and I were cleaning up the intake from his porting work, we took a water nozzle and placed in it the intake/turbo hole of the manifold. Water was gushing out of the 1 & 2 ports, some coming out of 3 & 4 and very little out of 5 & 6.

I hadn't finished reading the porting book that I bought (it's now in the hands of either Pat or Richard), but it mentions air flows like a liquid. If that's the case then it seems ports 1 & 2 would get the lions share of air and 5 & 6 would be deprived. I didn't mention this while we were working on the intake and putting it back on my car, because I really wanted to have my car back on the road the same day. Also it really didn't make a difference since that's the intake I was running with before I brought the car in and wasn't going to be much different from whatever intake I left with.

So air distribution is on my mind quite a bit at this point.

Eric

One thing you need to think about is about Volume. When we were cleaning the intake with the water hose. We were not able to flow the volume of water that the flow bench could flow in air.


Also when that water was just trickling out of the ports it was on the floor of the ports. In airflow in the ports of the intake and cylinder heads most of the air actually flows more in the roof area VS the floor. This is the reason for more modern intakes and heads using the catherdral ports.

 

[esinger]

Good point Pat and thanks for everything yesterday. The car does feel better and now I need to focus on tuning.

 

[fmster]

You guys are Great for taking the time to study and figure out how these things really work,for the benefit of all and not just for yourselves.

 

[Jerryl]

. . . .I hadn't finished reading the porting book that I bought (it's now in the hands of either Pat or Richard), but it mentions air flows like a liquid. . . . . . .

Air has much more mass than we realize.
Let’s say the mass flowing through the intake is 60lb/min of air (Arbitrary number).
On a 10 second run, that is 10lb of mass with some serious kinetic energy, that has to make all the correct turns.

 

[esinger]

The air takes far less bends in a gutted intake than the stocker, it's just not channeled as much as a stocker. I just wonder how air flows when boost is introduced, my thinking is that air is lined up ready to jump into a cylinder the moment the intake valve is open.

What I didn't realize is that a cylinder's intake valve pops open 50 times a second running at 6,000 RPM. Muliply that by 6 cylinders and you have 300 intake events happening a second on our motors at 6,000 RPM. So air really doesn't have a whole lot of time to sit around waiting to be moved into the cylinders.

 

[SloGN]

The air takes far less bends in a gutted intake than the stocker, it's just not channeled as much as a stocker. I just wonder how air flows when boost is introduced, my thinking is that air is lined up ready to jump into a cylinder the moment the intake valve is open.

What I didn't realize is that a cylinder's intake valve pops open 50 times a second running at 6,000 RPM. Muliply that by 6 cylinders and you have 300 intake events happening a second on our motors at 6,000 RPM. So air really doesn't have a whole lot of time to sit around waiting to be moved into the cylinders.

One thing you also need to remember that even though the valves are opening and closing at that rate the air is still starting and stopping during that time. But once the mass of air is moving it has inertia behind it so the air crashes and bounces back up the intake runner when the valve closes. Reversion. ( Kinda like how the boosted air comes back out thru the Turbo inlet when the butterfly slams shut on a I/C car).


One other thing to think about is that as the rpm increases the time to fill the cylinder actually decreases.




Jerryl your pm box is full.....

send your intake in to richard his addy is in the interesting numbers thread.

 

[Jerryl]

.............. Jerryl your pm box is full.....

send your intake in to richard his addy is in the interesting numbers thread.

Thanks Pat.
I will get it ready in the next week or two and keep you posted.

Edit:
Just located this. An interesting article.
http://www.waset.org/journals/ijeas/v6/v6-2-17.pdf

 

[jiho2]

The air takes far less bends in a gutted intake than the stocker, it's just not channeled as much as a stocker. I just wonder how air flows when boost is introduced, my thinking is that air is lined up ready to jump into a cylinder the moment the intake valve is open.

I think you're onto something.

When boost is introduced, the air doesn't flow, in the usual sense. The turbocharger crams the intake full of air at a rate faster than the air is pulled out by the cylinders, until the intake is packed with compressed (boosted) air.

In other words, those oddball channels and chambers that seem to restrict air flow aren't designed for air flow, they're designed to be crammed full of compressed air by the turbocharger.

 

[TurboRegal84]

Something else to keep in mind: with a boosted engine the easier the air can flow the less heat it will create which will then make the compressed air (boost) more efficient.

 

[SloGN]

I think you're onto something.

When boost is introduced, the air doesn't flow, in the usual sense. The turbocharger crams the intake full of air at a rate faster than the air is pulled out by the cylinders, until the intake is packed with compressed (boosted) air.

In other words, those oddball channels and chambers that seem to restrict air flow aren't designed for air flow, they're designed to be crammed full of compressed air by the turbocharger.

The channels and chambers are still a restriction even under boost. There is more volume of air in the intake when the air is compressed. But all of the port flows got up exponentional with the larger volume of air. So the port that is the least flowing will still be the least flowing even under boost/pressure.

The biggest issue with the stock intake is not only about increasing the volume/flow it's also about making sure all of the ports flow the same amount of air. in or out of boost.

 

[SloGN]

I flowed another varation of a hot-air intake

Howdy guys and gals


I flowed anopther varation of a hot-air intake that Jamie had in her collection of old aged hop up parts.........


I'm not sure who crafted this intake up. But the port work is awesome. The I/C neck on it is where the biggest restrction is.


The ports flowed from 155-160 cfm when flowed, The entire intake flowed 215 cfm with all the ports open. Like i mentioned before the small neck and the bend in it is where the restriction is. So i flowed the intake with just three ports open and it only flowed 202 cfm just a tad under what all six ports flowed when all open.


The stocker flows better than that. but the stock has very very uneven port flows.



Thanks to jamie for sending in her(paper weight) as she calls it.

 

[charlief1]

One thing that most don't understand is that by gutting a HA intake you do get more flow, but that it's always the best way to go. I eas discusing this with Brent the other day and if you do like Pat did by cutting the bottom off you get more flow but also restrict the total amount of air required to fill up the intake. This is one of the problems with gutting a HA intake. It opens it up so much that the turbo lags behind on filling things up. Just my .02 after all.

 

[SloGN]

One thing that most don't understand is that by gutting a HA intake you do get more flow, but that it's always the best way to go. I eas discusing this with Brent the other day and if you do like Pat did by cutting the bottom off you get more flow but also restrict the total amount of air required to fill up the intake. This is one of the problems with gutting a HA intake. It opens it up so much that the turbo lags behind on filling things up. Just my .02 after all.

well if there is lag in filling up a gutted intake VS a stock intake i'd like to see a comparison on this if it's even measurable. The actual volume of the intake is not changed very much at all by removing the zip tube walls and the center divider. ( this is one how i did my intakes. Not the one like jaime has...like pictured above...


So i guess porting the heads does the same thing too..........

I could maybe see the turbo lag when switching from a stock I/C to a front mount but porting a intake..................

 

[charlief1]

well if there is lag in filling up a gutted intake VS a stock intake i'd like to see a comparison on this if it's even measurable. The actual volume of the intake is not changed very much at all by removing the zip tube walls and the center divider. ( this is one how i did my intakes. Not the one like jaime has...like pictured above...

So i guess porting the heads does the same thing too..........

I could maybe see the turbo lag when switching from a stock I/C to a front mount but porting a intake..................

The best way I can explain this is to compare an IC intake, a HA intake, and an NA injected intake Pat. Each will flow differently but the restriction at the inlet makes all the difference. If you just gut and put the bottom back on a HA then you have that much more area you have to fill and the split that you have to get around. If you cut the bottom off, gut, and them shorten up the bottom you reduce the total volume which means the turbo has a better ability to keep up with the intake with out lag. The HA cars have less lag than the IC cars ,stock. because the intake tract is less in volume from the turbo to the ports, but if all you do is gut it you increase the total volume so the air has to catch up so to speak.

The C/T cars have an issue with lag but that's because of the way the turbo was designed and the poor understanding of the way the system can work. They also suffer from restrictions in the intake which cuts down on how much they can flow. The original TTA intake is much better than the C/T Buicks because the intake is open all the way through to the ports. They got better with the lag on the 84-85 design and made them less prone to detonation with the IC design.

 

[SloGN]

The best way I can explain this is to compare an IC intake, a HA intake, and an NA injected intake Pat. Each will flow differently but the restriction at the inlet makes all the difference. If you just gut and put the bottom back on a HA then you have that much more area you have to fill and the split that you have to get around. If you cut the bottom off, gut, and them shorten up the bottom you reduce the total volume which means the turbo has a better ability to keep up with the intake with out lag. The HA cars have less lag than the IC cars ,stock. because the intake tract is less in volume from the turbo to the ports, but if all you do is gut it you increase the total volume so the air has to catch up so to speak.

The C/T cars have an issue with lag but that's because of the way the turbo was designed and the poor understanding of the way the system can work. They also suffer from restrictions in the intake which cuts down on how much they can flow. The original TTA intake is much better than the C/T Buicks because the intake is open all the way through to the ports. They got better with the lag on the 84-85 design and made them less prone to detonation with the IC design.

The volume didn't change much at all. So by me simply removing a wall thats 3/8 thick (center divider) and two 1/4 inch thick walls(zip tube). Those are taking up so much space that the turbo can't keep up? and creates lag. ( i think your spliting hairs here)

I will agree that those walls did take up space in the plenum area. But did it really increase the area so much the turbo now has lag? I disagree.


I guess the same thing could be said about a power plate in a I/C car then. by simply adding the plate the turbo should build boost faster since the plate is now displacing some of the area in the plenum.



One more thing if the spilit in the intake was a restiction ( area under turbo nozzle/egr) why did the intake flow go up? If that was such a restriction the flow should be the exact same after gutting the zip tubes and center wall. They are after the said restriction.

 

[charlief1]

The volume didn't change much at all. So by me simply removing a wall thats 3/8 thick (center divider) and two 1/4 inch thick walls(zip tube). Those are taking up so much space that the turbo can't keep up? and creates lag. ( i think your spliting hairs here)

I will agree that those walls did take up space in the plenum area. But did it really increase the area so much the turbo now has lag? I disagree.


I guess the same thing could be said about a power plate in a I/C car then. by simply adding the plate the turbo should build boost faster since the plate is now displacing some of the area in the plenum.

You have to think of this with hydrolic flow theory in mind Pat. Just like a stream flowing into a pond if you will. Once the pond is full then the water will flow out at the same rate, but before it fills the water will flow in at a faster rate and the pond will fill up slowly because of the volume it has in it. If you suck some of the water out it will take a larger volume to fill it up again before the flow at the outlet will resume.

Once you remove the flow passeges in the intake and open it up the directional flow is removed and there's more overall volume and less resistance to flow. If you reduce the total volume by shortening up the bottom of the intake then the flow will move faster. Water and air flow in a simular manor even though air can be compressed. I'd almost bet money if you did this as a wet flow using pressure timed from the inlet to the ports you'd see what I was talking about.

 

[jiho2]

SloGN is having trouble accepting that a turbo intake manifold behaves differently than NA.

With NA, air flow is all pull-through, caused by vacuum in a cylinder, one cylinder at a time. With turbo it is large blow-in, little pull-out.

New air blown in by the turbo meets back pressure from air crammed in ahead of it. This is what builds boost. It also changes the routing of the new air to wherever there is less boost (less prior flow), so it tends to be self-balancing. The stock HA manifold's chambers and channels are designed for this blow-in routing, while isolating cylinders so one cylinder pulling air out doesn't bleed all the boost waiting on the other cylinders.

 

[SloGN]

SloGN is having trouble accepting that a turbo intake manifold behaves differently than NA.

With NA, air flow is all pull-through, caused by vacuum in a cylinder, one cylinder at a time. With turbo it is large blow-in, little pull-out.

New air blown in by the turbo meets back pressure from air crammed in ahead of it. This is what builds boost. It also changes the routing of the new air to wherever there is less boost (less prior flow), so it tends to be self-balancing. The stock HA manifold's chambers and channels are designed for this blow-in routing, while isolating cylinders so one cylinder pulling air out doesn't bleed all the boost waiting on the other cylinders.

No, I have a pretty good understanding on how intakes work. The intake still work the exact same. The only thing that changes is the atmosphere is which the intake is under is different. If that was the case all these NA cars that gets supercharged/turboed would have all kinds of issues. But they simply don't.


Taking that a tad bit further here, There are old ass carbed 4 barrel wet flow intakes that have had injectors added and a 90 degree elbow for a larger TB for turboed/supercharged applications. Now you know that wet flow intakes like those were never desingned for boost/dry flow applications. But they get used all the time with no issues. hell think about the guys that are doing blow thru the carb set ups and tell me if a NA vs boost make a intake work any different. The only thing that changes is simply the pressure at which it works under.


Actually for a true understanding the amosphere pressure is what fills the cylinders in a na engine.





Charlie. I think i grasp what your tring to point out. But don't you think that really spliting hairs........... I changed out my stock I/C to a front mount that changed the volume alot. But i didn't noticed any lag. This is due since i removed the restriction the air was about to flow faster with less pressure to do it. Thats the same thing going on in the HA intake.

 

[charlief1]

Charlie. I think i grasp what your trying to point out. But don't you think that really spliting hairs........... I changed out my stock I/C to a front mount that changed the volume alot. But i didn't noticed any lag. This is due since i removed the restriction the air was about to flow faster with less pressure to do it. Thats the same thing going on in the HA intake.

I agree that you're removing a large amount of restriction but you're leaving one piece there at the inlet of the intake. To really make it work better you'd need to remove the splitter where the turbo blows in. Once you do that then you'd get rid of a lot of issues. It's one of the reasons I think using the injected NA FWD intake would work better than the stock HA or moded HA intake. There's no restriction where the throttle body mounts so it should make a much better design, and the plenum is up off the bottom so it won't transfer heat as much.

 

[jiho2]

The only thing that changes is simply the pressure at which it works under.

Ahem, but I agree, that's exactly what I'm saying. The stock HA intake was designed to work under boost.

Where we disagree is whether that makes any difference in how it works.

The stock intake would make a horrible NA intake, nobody would want to use it for that. So the fact that it works at all under boost proves that it works differently with boost than without.