So, my Head unit blew up a couple days ago and I had an hour drive to visit inlaws.. Well without the radio i was jammin to the symphonic melody of my valvetrain and cam and I noticed something..

Does the 2002 3.0 Motor have some kind of secondary injector or secondary intake runner like the SOHC focus SPI motor???

The reason I ask is cause before I heard it, I noticed on my data logger that around 3000 rpm @ greater then 75% TPS up to 5800 Rpm with maybe a little more T/P,, there was a surge in Air Flow pressure that was not consistant with the throttle position since there was little to no deviation, along with the air surge, the truck felt like someone cracked VTEC in a honda, that feeling of being pushed back in the seat with no extra "EFFORT" required.. Now with the radio not working I noticed that at that same RPM range the truck began to make a high pitched whine that increased as RPM increased and became more pronounced with greater throttle position. The only exception would be if I pushed past 100% to kickdown cause the trans would shift and it would go away...

Has anyone else had this occur? At first I thought it was just me, but then other people would ask me if I had VVT cause with my Straight Pipe exhuast it's "from what I am told" a noticble change as RPM increases. Thats when I decided to check the data logger for any anomolies, and found that surge.. Which is not a random occurance either, it's acutaly consistant.. But the data is simliar to the Split-Port Induction system on the SOHC Focus motor which does infact employ a dual intake-runner manifold.
SPLIT PORT INDUCTION EXPLAINED HERE

I sure hope someone can help here, unless the 3.0 does have this setup, if so then it needs no further explanation..

(PS.. Merry Christmas / Happy Holidays to all!!)

 

No, it's just the "resonance" or whatever in the intake system. All 3.0's are like that, and there is not secondary control of runner length or anything.

What I think happens is the intake impulse frequency just starts the air getting out of it's own way, lol. Don't know why since there is no other effect. It could partially be an exhaust effect also, I suppose.

 

Well I have one of those AMSOIL EAA filters and I modded the airbox for more flow.. Plus I kept the 3 cat's and cut the muffler out so it's just a straight pipe back to the rear from the cats.

Maybe those two things combined just made it more pronounced then most others or even then before I did the mods..

But if there is no secondary runners or what have you then it must just be one of those Ford perks.. It's cool with me cause like I said the truck does sound cool going from 3-5 grand cause people really wonder whats under the hood. .

Thanks for the info!!

 

Mine is very pronounced with the airbox mod, MAF mod, TS-122 Amsoil foam filter, and a 1/2 shafted throttle body. When you hit a certain RPM (like you it's at 3K+) it's like a kick in the pants -- the only thing close to "power" you will feel in the 3.0, lol.

Ford knows this. The locked wheel stall speed of the 3.0's auto tranny torque converter is about 3000 RPM! They KNOW you don't have any torque to speak of in the low RPM's, lol.

 

Okay, dumb question I know.. But perhaps asking in this envrioment will get me an answer to this that I understand....


What "exactly" does Stall speed mean in a torque convertor?? And does it matter if it's a Lockup-Type or not?? What's the real point of a Lockup Convertor??

 

First the easy part: a lockup converter is there for highway mileage and reducing tranny temp at highway cruising. It's a "locker" that locks the input and output shafts of the torque converter together, completely eliminating "slip" and resultant waste of power as heat.

Second, the stall speed comes in many "flavors" to someone engineering a torque converter, but the one specified is the one with the output shaft immobilized.

Basically, when you put the vehicle in gear and lock the brakes, then apply power, you will note the engine gets to a certain RPM and doesn't want to go higher even with more power. This is the "stall speed" or "stall RPM".

The stall speed is generally designed to work with the motor's torque curve vs. driveability concerns. In racing, high stall converters are used to get the motor into the maximum power band more effectively. But higher stalls are also used on motor with poor torque curves in the lower RPM's -- like the 3.0.

Now, this does not mean your engine goes right to 3K whenever you punch it. When the output converter vane is rotating, that is taking power from the input vane, the "stall speed" changes DOWNWARD -- that is to say, the input to output shaft RPM ratios are different than when the output is locked. Most converters still run around a 2:1 ratio for high power transfer. The input shaft can turn twice as fast as the output +/- some factor I'm not qualified to discuss. In the process, torque is multiplied with the output shaft turning slower, but with more torque than the input shaft.

Too high a stall speed can make a vehicle seem unresponsive in normal driving, and too low a one makes it feel sluggish. And all that is relative to the motor's torque curve, vehicle weight, and gear ratios. Something a powertrain engineer could possibly quantify for you. I'm familiar with the general theory, but have no training in the practice of calculating such things.

 

Wow.. It took a few times reading that but it explains a lot.. Although I am still a little fuzzy on how or why you would want to hold the brake hard and hit the gas.. Wouldn't you break something in the motor or snap a mount long before you hit this Stall speed anyway???

And as far as the lockup part goes, why couldnt someone make a switch where you can make that come on anytime you want?? Wouldn't the concept of no slippage in the trans be great on a hard launch where just after you start to hit the gas you could lock it so the motor didn't stall and have some serious power?? Of course the whole system would have to be pretty complex. you would need to be able to keep the motor from stalling when slowing down and on top of that have some sort of engine speed monitor that makes the system disarm when up shifting so you don't blow the tranny..

(I know, I know.. they already make this system it's called a standard trans,, But you know what I am getting at here. Right??)

 

That technique is used for "launching" an automatic when racing, lol. And you don't need to do it for long to get the stall speed.

You don't want it locked when you shift by the way, that's why it's not generally done. That would be a good recipe for breaking something in the transmission. Since there is no "clutching" like when a manual shifts, without the "cushion" of the torque converter, the shifts would be MUCH harder.

Part of the problem is the lockup clutch itself: it's magnetic. Now you may envision an electric clutch as being instantaneous, but it's not. In the real world there is time for the magnetic field to build and collapse, and time for the level to reach a point where the clutch disengages or engages. This time element makes cycling the clutch in and out problematic, I would think.

If you are cruising on the highway and you hit the gas to downshift, you will sometimes notice two events, and a slight delay.

1) The lockup converter unlocks, RPM's climb suddenly, but not a large amount.
2) After a brief delay to let the lock release, the transmission downshifts and RPM's climb a lot.

 

I never knew that it worked off of magnetics... I figured; "like you said" it was an electric clutch. I also figured that having the clutch locked while shifting would be a reciepe for TX BOOM!!

With regards to launching an Automatic.. I only did a few brake-stand burnouts.. I never tried to launch the truck using the brake then hitting the gas.. I only recently learned that burnouts were bad for the trans. I imagine using the brakes to launch the truck would cause irreversable damage to the motor and tranny. Plus having 4x4 and no weight in the rear-end, my guess is that launching the truck would just make the wheels spin anyway..

Since it's a 2002 with auto-hubs I would have better luck just launching in 4WD and switching back to 2WD before I hit 45.. Not that I have much call for racing but thats the only thing I can think of to do that would give you traction for a launch.

 

Well, I don't race anyway, lol. But guys on here do it for sure.

 

I wonder if that would work though?? Not good.. I hate getting ideas like this cause now I want to try it but I don't know what it would do to the truck or the transfer case.. I tried a search but only came up with this post and one about this huge argument over why manuals are better then auto's... I know the answer to that one.. Auto's suck!! I wish I had a standard trans but there were none on the lot when I got my truck..

 

I like auto's for the convenience factor. My hands are free to operate controls on radios and so forth. Also, less breakage with autos. It's surprising how many "real" offroaders are putting in automatics of some kind.

So, I know what you're saying -- but auto's don't suck so much as an absolute -- only in relation to what you're DOING. A manual is not always "better".

 

Well, that's true.. my wife can't drive standard and like you said the ability to just drive and not have to operate any extra features is a nice part.. It's just that I don't know what the trans can and can't handle.. I don't want to blow the thing up and I am afraid that if I add too many performance parts the trans won't be able to handle it. I don't know what actualy "slips" in an automatic like in a standard.. I know in the standard the clutch isn't able to handle the power and slips on the flywheel under heavy load cause it can't transfer the energy sent through it.. What the heck slips in an automatic??? How could the rotors in a torque convertor slip?? They aren't touching anything.. unless thats not what slips.

 

Ha ha! With a Ranger auto tranny that is a totally VALID fear, lol.

 

Can shifting your truck like a standard blow the tranny?? I mean can you turn overdrive off and just shift like it's a manu-matic??

 

I suppose, but you'll miss the "extra gear". The shifter gives you first gear in the "1" (or "L"?) position, with the coast clutch engaged for engine braking, then it gives you THIRD gear in the "2" position, again with engine braking, then the D position will allow you to upshift into 4th if the PCM thinks it's time. 5th (overdrive) would be disabled in your scenario.

So although you can, it would probably be slower than just flooring it a lot and letting the PCM learn to shift at high RPM's (which it will do if you're on your truck a lot).

 

If I disconnected the battery for a while to clear the computer, then beat the pee-waddling-pi$$ out of my truck just flooring and getting on it as often as possilbe it would make the tranny adjust itself??

Cause I am getting a new Kenwood H/U and I will have to disconnect it for that anyway.. I just thought I was supposed to take it easy for the first 500 miles after disconecting the battery.. In that case I will just whomp on it..

 

Yes, leave it disconnected for at least 15 minutes.

Whomp it hard and it'll learn to shift high.

 

Thanks for the help on this.. I checked UPS and the radio will be here tomarrow.. I will just unplug the battery while I solder the harness and install it.. That should be a least 30min..

Then since I have the day off....