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4.7onNO2
Dodge Dakota
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8/23/2005
23:25:52
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 Subject: RPM controled 2nd TB
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Not to steal credit from grapitedak (this was his idea)
but I have done some research on it and cant find a
reason why this wouldnt work friggin awesome. If you
go larger than a 68mm you lose your low end right? So
what if we designed a system using a 2nd Throttlebody
to only give you more air 3000 rpm and up.
Seems to me all you would need is to drill a 24-28 mm
(or start smaller) hole in your intake manifold which
would equal around the same cfm as a 72-74mm TB.
Now all we do is go to the junk yard and buy the
smallest cheapest tb that we can find and install that on
top of the hole. Then just set up an rpm window switch
and some type of silonoid or motor to open and close it
at 3000 rpms. seems like it should be worth some
serious gains for only $200 in parts. This should be
cheaper than a 72mm and the gains should be much
better.
To all those who I know are going to check my math TB
area = (3.14 x radius squared)
So what does everybody think. Does this sound great
or am I a friggin idiot?
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.boB
Dodge Dakota
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8/24/2005
00:41:31
| RE: RPM controled 2nd TB
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The theory is good, but the application is flawed. Remember the Taurus SHO? Same set up. Two sets of intake tracks - one for low rpm's, the 2nd kicks in with higher rpm's. It's a very complicated system, and requires gradual application of the second intake track. A simple on-off switch isn't going to work well at all.
Also, the computer has to read all the incoming air for the mass flow system to work properly. Simply bolting on a second throttle body would act like a giant vacume leak with disasterous results.
For a two track system to work, you'd have to have a computer with the ability to integrate both signals. Not something I would try.
OTOH, if you split the intake tracks before the TB, you wouldn't have to touch the computer at all. Buy the biggest TB you can get. Use two 2" or so pipes to feed the TB. One would be wide open all the time for slow speed operation. The second could have a butterfly blade with a progressive throttle linkage or vacume linkage. When the TB linkage is opened greater than 50%'ish, or the vacume drops below a certain point, the secondary track would start to open gradually to match the TB opening. Just like the secondary bores on a holley 4 barrell.
It would take a lot of experimenting to get the sizes and ratios right. But it might be fun trying.
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4.7onNO2
Dodge Dakota
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8/24/2005
01:18:13
| RE: RPM controled 2nd TB
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4.7 dont use mass air flow. We use map sensors and they are in the manifold I believe so that would not matter. I thought about using the vacume but I cant think of any easy cheap way to do it. I was thinking of using a electric exhaust cutout because they open more slowly. like 4 seconds until its fully open but with the 28mm hole underneath it would probobly reach its max in about 2 seconds after hitting 3000 rpms. only thing is once its open its open. doesnt matter if its 3000rpms or 6000. But i dont see how this would matter consitering thats what your throttle body is doing. Just to be sure does anybody else know where and how the incoming air is metered. Im pretty sure the only electronics before the bottom of the manifold is the TPS, IAC, and IAT
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GraphiteDak
GenIII
 
8/24/2005
02:11:50
| RE: RPM controled 2nd TB
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The "Holley" 4 barrel was what I was thinking.
I also was thinking more of the TWO sets of runners. Long runners and SHORT runners. Short runners for the 2nd TB. I wasn;t going to wire ANYTHING to the 2nd TB. I'd just connect it like a Holley where the 2nd one couldn't open unless you were going for the last 1/4 of throttle left. Not sure weather to make it electronically activated, or simple a mechanical connection like a Holley Double Pumper does.
Not being boosted, the PCM could very likely keep things in check. Not any more differences than changing altitude differences.
It's all in the "tuning" I'm sure. A certain intake tract would peak in a certain RPM range and drop off outside that. Our stock intake is designed somewhere for all around power I'm sure.
With a dual runner intake you could tweek some more TQ out of the bottom end and probably tweek some more high end as well.
It would take some experimenting, that's for sure.
I remember them SHO's. it looked like a tunnel ram intake, they were tall. But them little engines made some power at the time.
If I used some electronic control, I'd use a Parallax micro controller. That way it could be later adjusted with a simple re programming through a standard serial cable with it installed in the truck.
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4.7onNo2
Dodge Dakota
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8/24/2005
02:41:18
| RE: RPM controled 2nd TB
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Oh I see where you were going with that now. Guess i didnt understand that you meant making a dual runner intake. Wow that sounds complicated but sounds like it could be some killer gains for not alot of cash.
Never heared of this paralax microcontroler. You go robotics college or something :). Im more just trying to figure something out for cheap and easy so everybody can do it. If i could figure out a way to open the TB at 3000 rpms using vacume somehow it would probobly keep the price down but a holley def would make this project alot more expensive.
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N56629
Dodge Dakota
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8/24/2005
06:45:31
| RE: RPM controled 2nd TB
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Graphite has the right idea. It's not a matter of getting more air at 3000rpm or whatever it's a matter of varying the runner length. If you just wanted more air you would simply use a 4bbl and progressive linkage. Low vacuum would keep the secondaries closed until you acceleratate sufficiently to increase the vacuum and allow the secondaries to open.
Since you can't vary the length of the runners you could tap into the runners near the top of the manifold and add more air at that point. Not even sure if that is workable.
Hmm, three duces mounted sideways???
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Idano
Dodge Dakota
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8/24/2005
11:13:13
| RE: RPM controled 2nd TB
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Graphite,
The idea of a custom built intake sounds good.
As far as the "secondary" for your throttle body, a vacuum actuation set-up like the Holley and Carter spread bore carbs might be easier to get working than a mechanical set up like the double pumpers.
Don't know if you've had much experience with the spead bore set-ups? They had a mechanical "lock" tied into the throttle arm that would keep the butterflys closed until you reached a preset throttle position, once you reached that amount of throttle the likage would be released, however there was a spring loaded butterfly valve on the top that would open via vacuum. You could change the spring pressure to vary the amount of vacuum required to open the butterfly.
Since you're wanting to start using your secondary at the heigher RPMs, say 3500rpm and up, that might give you a smoother transition then a purely mechanical setup.
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Idano
Dodge Dakota
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8/24/2005
11:26:39
| RE: RPM controled 2nd TB
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Come to think of it, just to get your truck to sound like the old muscle cars with the vacuum activated secondary 4 barrels *might* be worth the trouble.
I've always loved that sound as the engine started coming up to revs and the secondaries opening. Pure music to us baby boomers.
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N56629
Dodge Dakota
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8/24/2005
16:26:18
| RE: RPM controled 2nd TB
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I have an M1 4bbl. coming and that's exactly what I intend to try.
How about hiding nitrous solenoids inside the fuel bowls of a double pumper? Heh heh
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GraphiteDak
GenIII
8/24/2005
21:44:03
| RE: RPM controled 2nd TB
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Idano. You mentioned Spread Bore, and you are describing the Rodchester Quadra Jet (Quadra Flush) exactly!
I prefer Holley over QuadraJet for carbed apps but I am also good at modifying them Quadra Jets doing exactly what you said.
First mod to a Quadra Jet. Remove that vacuum port and linkage that holds the top butterflies closed for the secondaries. Then you have to control timing of secondaries with your throttle but worth it to gain quicker responce.
2nd mod is then adjusting that hidden spring which regulates how easy them upper blades open.
And of course there's that choke linkage which holds the lower secondary butterflies closed if it's cold. Make sure it works freely or NO secondaries what so ever!
Then there is the jets and metering rods....
Yeah. I've played with Quadra Jets.
And having that LOUD intake howl of a 4BRL would be awesome!
I will most likely try the Dual Port intake idea. It should work. Eventually :p
The Parallax Micro Controller is an easy to program micro controller and the ones I have come with 16 input/output pins. Does calulations for counting pules (RPM's), and other neat stuff. I am not really good with them and once I played with it for a month they have sat here collecting dust!
Programming is easy and quick so once the circuit works, you just re program (flash) them.
Could get real technical with the TB it controls and use a Stepper motor or a geared actuated motor with feedback to control throttle position too.
I sometimes go to the Parallax user forum. Them guys make stuff a lot more challenging with them than controlling a TB.
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Idano
Dodge Dakota
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8/25/2005
09:50:45
| RE: RPM controled 2nd TB
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Graph,
Yup, Rochester Quadrajet, Carter Thermoquad, Holley SpreadBore, all three very similar. I forgot about the Quadrajet. Knew you were a Chevy guy, thought you'd know what I was talking about.
Electronics probably would work better, kinda outside of my experience, so I have a tendancy to overlook how much easier/better they have gotten. One of the reasons I visit these boards, need to come up to speed on how to hot-rod these newer engines.
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rgathright
Dodge Dakota
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8/26/2005
11:22:19
| RE: RPM controled 2nd TB
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Opening up the runners on the 4.7L sounds like a great idea. I would open up the front runners first though, these by design of the intake, have to be starved for more air at upper RPM's.
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GraphiteDak
GenIII
8/28/2005
02:06:24
| RE: RPM controled 2nd TB
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IDano. I'm not really a Chevy guy. I've HAD them Chevy's. Wont ever admit to being a CHEVY guy!
I've been a FORD guy for years. And a DODGE guy. Right now I have two Dodges. As of today THREE.
(Plymouth Duster).
I ran square bore Holleys though. They are more popular. And they kick a$$ over all.
rgathright. I don't think I'll OPEN my manifold at all. I'm thinking more the likes of MAKING a manifold. Not sure what I should use for material to mock the first one up. Steel would be easy to fabricate for testing. But not sure if it would expand, contracts, etc without leaking. But the HEADERS work. Why shouldn't a steel intake?
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N56629
Dodge Dakota
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8/28/2005
08:38:55
| RE: RPM controled 2nd TB
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GraphiteDak, use either aluminum or steel. You can get seamless tubing in either to make the runners. Use the gaskets to fab 3/8 thick flanges and sheet to fab the box. Stainless works too but it expands 50% more than carbon steel. However, unlike the exhaust headers it shouldn't be quite as much of a problem.
I've built two intakes and it was very interesting but it was a lot of work with little or no gain. They were far simpler than what you have planed so you really have your work cut out for you. Have fun.
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GraphiteDak
GenIII
8/28/2005
21:11:52
| RE: RPM controled 2nd TB
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Thanks. So steel sounds like the easiest for me to mock something up. I can cut, grind, and weld that quicker than using aluminum.
Does anyone have pix of what the 4.7 intake gasket looks like?
If I remember it is o-ringed. Are the o-rings held in place by a full gasket? Or are there 8 o-rings to attach???
I'd HATE to have to use Ultra Blue RTV on my 4.7 in place of the o-rings :p
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N56629
Dodge Dakota
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8/28/2005
22:40:48
| RE: RPM controled 2nd TB
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The orings seem to be the only thing sealing the manifold to the gasket. I don't know the proper procedure for installation.
Check this out for a parts list. Excellent referance source.
http://www.garyhedlin.com/nuke/modules.php?op=modload&name=Downloads&file=index&req=viewdownload&cid=1
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GraphiteDak
GenIII
8/29/2005
22:54:02
| RE: RPM controled 2nd TB
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Wow. Thanks. I saved that PDF. Should be similar to the 2003.
I see it has 8 seperate 0 rings. That kind of sucks. I was hoping something was retaining them together so I could more easily fabricate a manifold in place.
I may not mess with it once I start work on this Duster I just got. Got to get it into my garage first. The Dakota needs to be reliable. I just HAVE to wrench on something. The Duster may just save my Dakota from my un nessessary wrenching! 
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