Type S

what is Dual Stage Induction System and Free Flow Dual Exhaust System?and how is it works??is it only avaliable on acura type s cl or it is also avaliable on the other car manufactures..??

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Red CL Type S
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GoldTypeS_RENAMED

Here's a brief answer....

The dual stage induction system works like this:
There are metal plates in the intake that are normally closed until about 3800rpm when a control module signals them to open. They open letting more air in and hence making more power. It's only on the Type S as far as I know. Not sure if any other manufacturer has a similar system.

Lots of cars have "free flow dual exhaust" so they say, but it depends upon just how free flowing it is and compared to what. The Type S has a less restrictive exhaust system than the premium model, hence Acura marketing a "free flow exhaust" for the car. Most aftermarket exhausts are also pretty free flowing.

Type S

thank u for reply my question..so much

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mrdeeno

the dual stage induction system switches between a long airpath (below 3800rpm) and a short airpath (above 3800), to simulate a supercharging effect (resonance effect, i'm too drunk to explain it). that' show that owrks.

several other makes have it, bmw, benz, the prowler has it (i did a study of this on the prowler in school). some have more than 2 stages too.

the freeflow exhaust is just that, freer flowing and reduces backpressure (the faster waste air can get out, the faster fresh air can get in).

Achance

Well I'm hoping that it is better designed then the integra GSR. With it's dual stage system the butterfly plate actually causes too much wind drag and decreases power. A lot of the guys take them out competley, and Skunk2 even makes a new manifold that gets rid of them. It helps for lower torque but thats it. I think you can see about 7 hp gain by taking them out somehow. I know the type R doesn't have the dual stage, so that must tell ya something.

Type S

m........... kind of confuse now...it is good or not??

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2001 Acura Red CL Type S.
1997 Honda Civic EX.
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typescl@yahoo.com

EricL

Automatics without low end torque are a real pain. You probably would gain top end horsepower with the runners gone, but automatics like low-end torque. Until someone puts a manual in, keep the 2-stage system. Acura made this trade off to keep the CL/TL low-end punch along with the 2nd cam's lift/duration/etc (good high end).

Find a book on Weber carbs -- one per cylinder. There was always an optimum length stack for a given RPM. Honda has done a good job of doing the same. Too bad the gas has to curve (it looses energy) but there isn't infinite room...

mrdeeno

you guys must be talkiing about something totally different.

the integra does not have the dual stage intake system...the cl-s is the first acura to have this.

under low rpms (under 3800rpm), it routes the airflow (after the airbox and filter) thru a long path before it enters the combustion chambers. because there is a slight pulsating-like suction, the long runners create a resonating effect which sucks more air in (ie like a supercharger w/o moving parts).

above 3800rpm, it switches to a shorter path 'cuz the engine speed causes the pulsation intervals to approach infinity (constant suck, no pulsing/resonating) and the shorter path allows for less restriction, so again, more air goes through.

there is no butterfly valve in this system, it's another type of valve that switches between the two runners, either one or the other.

that is why there is MORE torque at low rpms and MORE torque at higher rpms, as well as more high end power. cars without this rely on the natural sucking of the engine for airflow, with more sucking at higher rpms and less at lower rpms...this solves the problem for more air at lower rpms (long runners=supercharging effect) without sacrificing more air at higher rpms (short runners=less friction/pressure drops).

[This message has been edited by mrdeeno (edited 01-09-2001).]

scalbert

The intake runner legths are constant. Either open the plenum up or look at the engineering drawings to see this.

There IS a butterfly valve seperating the two halfs of the upper intake manifold. The flow works as follows:

In through the TB and then splits 90 degrees out to two plenum end tanks. From each end tank there are constant length runners that travel in and down to the lower intake manifold and the heads. But also in these end tanks are paths to a center chamber. This center chamber has two halfs that is seperated by a butterfly valve. When it opens at 3800 revs a resonance does occur as mentioned and the proclaimed 'natural supercharging effect'.

The Type-S dual stage intake manifold is too often being confused with other uneven length dual stage runners.

EricL

I'm starting to not be able to tell who is talking to who.

All I know is there has been a lot of research on short intakes vs. long intakes.

I have a very old book (1965) (I guess I'm showing my age). It is called, "The Sports Car Engine", by Colin Cambell. Page 239 has a graph of engine RPM vs 'Induction Pipe length for maximum ram'. At 4000 rpm the graph shows 24 inches for max ram. At 6000 rpm it shows 10 inches for max ram. The curve is asymptotic, so someone has there physics down (as far as the infinity thing goes) -- the graph shows the pipe length going down to 9" @ 10,000 rpm.

Finally an excerpt:

"When designing an induction system for an unsupercharged racing engine or a competition sports car engine it is customary to design for maximum ram to occur at maximum power rpm..." It then goes on to suggest that twisty tracks with their need for low-end punch needs to extend the induction length accordingly...

1. Didn't Acura accomplish this?


2. I don't know dick about the Acura Integrals' induction system/etc..

3. Since I'm still waiting for my bloody service manual, could someone here save me the trouble of ripping my engine apart *and* verify the exact operation, info regarding the CLR Type-S induction schema with pictures/diagrams?



[This message has been edited by EricL (edited 01-10-2001).]

mrdeeno

the supercharging effect happens UNDER 3800 rpm (longer path). above that the engine speed creates enough suction to not require it (shorter path).

trust me on this. i did a study on this in college on the prowler for chrsyler. it has the same type of system...i know what this is!

yes, i did look at the acura site on the 'type-s' enhancements...it's not techincally right. if it is, then every one else that uses the system (the prowler, mb, bmw) is wrong, as well as physics.

it's right in the fact that the first stage (under 3800rpm) is a smaller volume of air, but the airflow path can be longer yet still maintin a smaller volume, and the 2nd stage is a larger volume as it just sucks in air.

but it's techincally wrong in that the supercharging effect happens at higher rpms...at higher rpms, any car can suck a lot of air, all it needs is more of it to suck.

it's at the lower rpm that creates the "resonating" effect that's considered the supercharging effect (it sucks more air in than if it wasn't there).

and if you tell me acura can't be wrong, then i guess they were right also when they introduced the cl as "being built on a totally different platform than the accord."

[This message has been edited by mrdeeno (edited 01-09-2001).]

EricL

Well, your previous data sure seems correct. I'm at the, "I'm from Missouri stage". Yep, I posted the intake length data (in harmony with yours) so are you saying that the induction paths are switched for best ram/pulse/pressure wave effects. For example:

Up to 3800, only the long pipe is open.
After 3800, only the short pipe is open.

Yes,No,Something else?

mrdeeno

my study was based on theory as well as experimenting on an engine we had and different intake "paths", with specs taken from the prowler (provided by chrysler).

at low rpms with a standard intake, the engine creates suction in a pulsating manner (very fast pulses though, but still pulsing). with a longer airpath, the pulsations create a resonating effect, so at the opening of the path, the airflow in was pretty constant (very light pulse), and the volume was higher (we measured airflow and used the volume of the intake)...this is in fact the supercharging effect, it's sucking more air in than it normally would.

at higher rpms with the same long intake, the pulses were theoretically present, but were so close together that it can be considered a constant suction. this is a characterisitc of any engine at high rpms. it just sucks air in. with a longer path, there's more friction creating a lower velocity which creates a lower volume flowing into the engine. that's why there's now a short path for this.

that is why acura confuses me...every other manufacturer that uses this type of system considers the supercharger effect at LOWER rpms, 'cuz that's where the system effects it the most. every engine can suck as much as the cl-s engine, that's why people replace their throttle bodies (larger volume) and manifolds (larger volume as well), so the engine can suck in more air. is this a supercharging effect? NO! supercharging is basically putting more air in than there would be under normal aspiration, and this happens at LOWER rpms with this system.

mrdeeno

so yes, longer runners at lower rpms create the resonating effect=supercharging effect.

the shorter runners are just the same as putting in a freer flowing intake system on a car...gives more high end power 'cuz it can suck more volume.

acura's site is inaccurate! (hey, it says that the nav. is only available for the tl and rl...so how did i get one on my cl?)

EricL

Well, according to my book's graph, it shows a change in pipe length happening up to 10,000 rpm+ (Graph stops at 10,000 rpm, but you can see it flattening-out [obvious asymptotic behavior]). The rpm, horizontal limiting line would have been at about 9 inches of runner.

There are about 5 pages with pictures of wave reflections etc from the induction pulse and their reflections (yep, I get that).

When I was running 4 barrel Weber side drafts (1 barrel per cylinder, I still needed an extra inch of velocity stack (for each carb) to get max output on a number of dyno tests (car had 8000 redline). So, while the ram charge effect isn't as great, it is still active at 8000 rpm (and that is higher than our Acura CLS).

I'd still like to see a diagram. But I guess I'll have to be patient or figure out where my manual is...


[This message has been edited by EricL (edited 01-10-2001).]

scalbert

Geez, people like to discuss on theory and principal enough. But what about actually getting into the engine...

From the funnel to the heads in the CL-S engine, the intake runner length never changes. EricL, I understand you don't have the manuals yet, but when you do the engineering drawings do show the exploded veiws of the induction path.

Or if you really want to get into it, take the engine cover off, then the manifold cover and the front end tank. You will easily be able to see the paths then.

In fact, the actual volume never changes in a sense. But it could also be said that when the plates open the appereant volume to either side is doubled. This does promote the concept high rpm resonance bewteen end tanks. This cycling through the center of the manifold will help to fill the end tanks from the TB.

I've been tossing around the idea of mounting a pressure transducer to one of the end tanks and do some high speen analysis of the readings, i.e. 1kHz continuous stream. If only time permitted...

EricL

You are right about one thing. Looking at this post I've seen about 3 different descriptions of length/volume: different length = yes/no, both on = yes/no, etc, etc. I know one thing: one of you is wrong and I can't tell who. Both of you guys speak with total authority.

ATTENTION: Please look over the posts. I've got one of you, a post later saying the runners are different length, but no high speed resonance. Then you come along with the changing volume explanation. But not one of you will spend the time to post a drawing or reference to back up your info (and your on my but, give me a break). At least you can look at my posts here and see were I gleaned the info. Then, there is the issue of spelling. I looked over your profile and you are the frickin director of engineering, but can't communicate and spell correctly. Hmmm, wonder why I can't tell who is the authority here?

Mrdeeno and scalbart seem to have different opinions on what is happening. Did both you guys stare at the same diagram? Or stare at the same engine? I wonder if this is like witnesses at the scene of an accident describing completely different events. AS I SAID, I don't have the manuals to look at yet!!!!

So, one says "different length", the other "changing volume."

Next time I read your stuff, I'll know to wait to get my manuals and decide for myself.

The NOISE is much higher that the SIGNAL. < END >

BTW -- there is a spell checker built in to the board.


[This message has been edited by EricL (edited 01-11-2001).]

EricL

"If only time permitted", yep, I know what you mean. That is why I am not ripping the engine apart..."

scalbert

You surely like to get upset quickly. Not knowing my general attitude towards this discussion, how would you know that my intention was to be 'your on my but' (BTW, typically spelled with two 'ts' when referencing someone's back side, JK).

Try and understand that this is a board for discussion and debate. I entered this as a friendly debate. I even stated that I know you don't have manuals yet. But when you do get them you can see the parts breakdown, which was all I was stating.

When discussing this issue I do speak with some authority as you mentioned, I do have the manuals (have had them since summer), but am I going to bring them to the office, scan them and post the pics to satisfy this discussion when, according to your own statements, you will soon be receiving them. Obviously that would be a waste of time.

By your statements I assume clarification is needed. I never once stated the lengths change, I solely stated that there is a single runner length. This means exactly that, no dual un-equal length runners per cylinder as alluded to (not necessarily meaning you).

Now can the perceived volume in the plenum change, yes. This is irrelevant to the runners, a separate issue completely. Why was this issue brought up, because this is where the IMRC plates are located, in the intake manifold, not the runners.

So, under closed condition the intake manifold is basically split into two sides separated by the initial split after the TB and then by the IMRC plates in the center of the manifold. When the plates open, the perceived volume available to each bank could be looked upon as doubled since there is an opening to the other side after the initial path from the TB.

Now how can this cause a resonance (and this is debatable as to if it is isolated to higher revs only)?? My assumption, here is where the theory comes in and hasn't been discussed, is that due to pulses of airflow entering the end tank a shifting low pressure would be caused in the center manifold (with the plates open). This low pressure may help overly fill the end tanks creating high pressure there thus filling the cylinders better. But again, this is just my idea. But the fact does remain, there are no dual un-equal length runners in the CL-S, but there is a plate that separates the two halves of the intake manifold. Which is what I thought the initial discussion was about.

BTW, check with Helms and verify they didn't screw up your order. I got mine within a week of ordering it, single book unlike other makes (my GTP and Typhoon had three manual sets).

Also, please try and understand I was not attacking you; I do not do that on boards. I simply entered a discussion of which I do have knowledge and conveyed my opinion. I apologize if you took it has being harsh, it was never intended that way. Secondly, I do appreciate you taking the time to point out my 4 spelling mistakes, my wife and employees typically inform me of my mistakes, it's good to know there are others out there (not to mention spell check in Word and Outlook...). And yes, I am Director of Engineering for an Industrial Test, Measurement and Controls Sales company. We also do system work in implementing test and control systems in the industrial process and manufacturing environment. But this has nothing to do with my quick posts to this board...

Take Care,
Steve

scalbert

The point of opening up the engine was not meant to be taken literally. Again I am sorry that the point was missed.

gavriil

About if supercharging is happening at low or high rpm:

Supercharging is "pushing more air into the engine". More meaning, more than the atmospheric pressure which is about 14,7 psi.

Also, what Acura is doing is considered passive supercharging not active for obvious reasons.

The dual stage manifold system by Acura is trying to be optimal at both high and low rpm. So one could say that supercharging is happening at both stages. We can only be certain if we had proof that more than 14,7 psi of air was entering the cylinders under whatever rpm range/s.

Acura is stating that supercharging is happening at high rpm because the engine needs and sucks much more air at high rpm than at low so although scientifiaclly, probably, inaccurate they are trying to make a point in a very simplistic way to say that we dont need to play with active forced induction, we found a way to achieve that without any moving parts which compromise reliability and in a very inexpensive way. So here is your 260HP from 3,2 liters in a cheap reliable package.

Who do you think will go on Acura's site? The super scientists and super engineers of the world. Everyday people will go and check out the car because they are interested in buying it.

So dont be so harsh on Acura, they made the engine, I am sure there is a team of people that know exactly how the intake works and why it does what it does. This is not the team that will be involved in building the site and have to do with the content on that site. Marketing people are the ones that take the jargon from engineering and try to convey it to the general public.

Gabriel

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Gabriel
CL Type S

[This message has been edited by gavriil (edited 01-11-2001).]

EricL

Guns stop. We meet at DMZ. Sign peace treaty.

mrdeeno

ok, to clear some things up and to defend scalbert some, what i meant by differen't length "paths", i was talking about the intake manifold. i may have confused people when i said "runners" in my one post.

after scalberts last post, we're pretty much on the same wavelength (if i change the word "runners" to "airpath" instead in some posts).

in the intake manifold,
under closed conditions, the air takes a longer path before it gets to the runners and combustion chamber, etc.

under open conditions, the air doesn't have to take that path. the volume doesnt' change much as there is the same amount of air in there at one time, but each cylinder has access to more of it at once.


gabe,
when the engine is running, there is always LESS than 14.7 psi of air in the cylinders (suction), because if there wasn't there would be no airflow into the cylinder and therefore no combustion. if there was more than atmospheric, it would be blowing air out.

but by your definition of supercharging, under normal circumstances, air is being sucked into the engine (or pushed in, whatever your pleasure)...but under supercharging "more" air is sucked in (pushed in).

at low rpms, "more" air is pushed in because of this system, compared to the normal "air is pushed in" which happens in all engines.

at high rpms, air is being pushed in relativly faster than at low rpms, but not moreso than any normal engine would at higher rpms. there's just more available than normal 'cuz the intake manifold makes it freer flowing 'cuz of volume available.

that's why i techincally consider the supercharging at lower rpms...it's sucking more in than usual.

EricL

Ok, I don't know if this is worth anything, but the link talks about various induction power boosting technologies at the following link. They mention the Porche's VarioRam and say that the Honda (Acura) NSX is another rare applicant for that intake system. (I saw on another page that the Integra uses 2 different length pipes [different thing from what you guys said -- got it].)

So, here is the link, to the page with the blather and some diagrams. Let me know if it is anything close, or totally confusing:

Link to Power Boosting Technology page

You will need to look down the page, below the section on, "Variable length intake manifolds" for the section on "Resonance intake systems."

(I figure that this is not exactly the same, but let me know if this is close enough?)

Finally, there is an excerpt from one other page (again the Porche, with reference to the Acura):

"...The alternating intake cycles in the left-hand and right-hand cylinder banks force the air column in the intake manifold to oscillate. These oscillations or resonances are used to achieve optimum torque at the top end of the engine speed range. Resonance charging achieves optimum effect over a narrow rpm range."

There is also some info on some other types of systems etc.

Hey, if it is bunk, I'll just delete it...


[This message has been edited by EricL (edited 01-12-2001).]

scalbert

That was an interesting article. Although I found the refernce to the CL-S incorrect, it was a good description.

Anyway, I decided to go ahead and bring my manual in and make a copy of the diagram. I didn't post the image due to size, just the link. It's about 550k, when I shrunk it the details got bad.

But in it you can clearly see that there is a single runner per cylinder. You can also see the center manifold seperated by the IMRC plates. I do think this makes it Resonance intake system as described in the article.

http://www.flwsoutheast.com/images/s...32A2Engine.jpg

EricL

Thank you very much!