Finally, we are back on topic.

The issue with the throttle by wire is that it seems to require more gas pedal effort to "free-rev" the engine...moreso than what would seem to be required based off cruising throttle position. This is very noticeable if you go from a car without TBW (ie-an SN95), then try driving the S197.

The TBW seems to have some type of safety built in, where you have to PUSH on the gas to rev it in neutral/clutch depressed, as compared to just the light effort to accelerate when in gear.

 

Mike

Bear with me here. When you declutch, the transmission is disengaged from the engine. How can it be stressed (or loaded)? There is some drag between the clutch disk flywheel and pressure plate, but its ever so light. When you pull out of 5th (declutched), the input section of the trans is then freewheeling , the output section of the trans is coupled to the rear wheels and effectively stays at the same RPM (unless you are breaking). If you goose the throttle (enough) at this moment (between gears), the input side will spool up because of the little bit of drag on the clutch disk (even the air in the gap causes friction). if you do it just right, the RPM will match as you begin to apply some pressure to the shifter towards 4th. Ideally, as you goose the throttle, the input RPM overshoots the output slightly and as you execute the engagement part of the shift the blocker ring does its job in getting the input and output sides of the trans RPM matched.

I have experienced the 'blocked' feeling you are describing (not to be confused with constipation), but its always attributed to not declutching properly or foot and hand coordination out of sync slightly), and I believe what happens is the blocker ring gets hung and then the slider will not engage the gear you are trying to get into (there is nothing else in the transmission to block a shift). Pulling the shifter back out and into another gear always clears it.

I know both you and metroplex have messed with this alot and are very frustrated with it. And I am not suggesting either of you don't know how to drive a manual transmission, but try an experiment. Next time you are on the freeway at 65 MPH in 5th, no traffic around to worry about, push the clutch to the floor, put it out of 5th and simultaneously raise the RPM to about 3100 RPM, simultaneously pull into 4th with just a little relaxation on the throttle . It should slip into gear like a hot knife thru butter. Engage the clutch and it should be a smooth transition. With practice you can do it a blink of an eye.

At 65 in 5th you can also pull down into 3rd with the same technique, except the engine RPM will need to be raised to over 4000 at that speed.

This is a very clunky transmission and from shifting smoothness does not even come close to the old Ford top loader of the 60's. They just don't make them like they used to.

 

I guess I am not noticing that characteristic, this car (05 Mustang GT) along with my wifes S60 are the only two TBW vehicles I have driven. To me its not any different than cable throttle on the turbo Merkur or holley carbureted BOSS. Though at light throttle the 05 Ford I would say its a little fuzzy. When I declutch for a brisk downshift it only takes a light tap to goose the engine ... and I find the RPM snap to be very responsive. The Volvo on the other hand is ready to burn rubber at the slightest touch ... but that is less than 1000 RPM.

 

I've driven a couple 'o ten thousand or so vehicles, and the TBW is definately a little numb in neutral, and is a little noticeable in the .25-.50 or so durring a shift if you are trying to blip the throttle. I don't think the 3650 is clunky at all and under full accelleration I can get it to 'surge' into the next gear with only the slightest sense of a shift dropoff(typically only lifting about 1/2 from WOT for a split second going for broke). In gear I don't notice any real 'lag', only that it takes more then an average touch to get it to 'blip'. 1/4" in a miata=about 1"+ of travel in the Mustang's gas pedal.

The gas pedal travel is a little long, as is the clutch travel from the engagement point, so I would think most downshift 'problems' are more or less timing problems in the footwork. If it were like a Miata, with about 3" of total travel for the gas and 4" for the clutch its a lot easier to nail the downshifts. The hydraulic clutch is more or less finding the engagement point by memory then feel(i.e. on a cable clutch, the variable spring tension is discernable to the touch after a few miles with a car you 'know' how much pressure there is around the engagement point). To really get the timing better you do have to put a little pressure on the clutch(in the rather large zone where its doing nothing) prior to the shift so its a shorter foot movement to time it out better. Again, I think all the 'clunkiness' or resistance to a shift is all from a bad timing/coordination issue in a shift. You do have to 'slow' it down a bit and use slightly broader strokes with your feet and hand to get a positive shift every time. Its easy to outpace the footwork with the shifter.

 

Thats why I like the Long Style clutch so much more than these non linear diaphram clutches. The latter style require pedal to the floor for complete disengagement, while the Long style disengages with much less pedal travel.

These tremecs use a non bronze (brass) blocker ring with a composite material on the taper. And IMO results is less smooth engagements (syncronization) than a 40 year old design top loader.

 

This is exactly the issue I'm talkin' about... and I know I sound like the paenut gallery just trying to get my 2 cents in.. so I'll say once again, and then let it lie.... But I used to now have any trouble with throttle response, and now it seems like it takes more time on the pedal, and more pressure on the pedal to get the amount of fuel I want to rev up the motor, in particular to rev match, or whatever. I'm convinced that it's because the fuel pump has gone south... otherwise it would have been this way right out of the box. Instead... it took about 6000 miles to deteriorate....
So, I'll go get the fuel pump swapped out on the TSB (06-09-09) and let you all know if that has any effect on the problem we're talkin' about.. and I don't mean double clutching .. I mean slow throttle response, causing jerky shifting...
I know it's not because I'm bad with a clutch.. I have always taken pride that I can get a manual to shift smoother than an auto.... and I used to be able to in this one.... up until about 6 months ago.
to be continued.....

 

I can hear something whirring at the gate if I am lucky. If I hear that sound, it means it's ready to downshift. If I don't hear that sound it means I'm SOL and have to blip the throttle.

It's using the factory ATF.

RadBoss: That usually works if I can manage to blip the throttle properly. According to Steve (theedge67), my 3650 is FUBAR'd if I havve to rely on rev-matching or double-clutching to downshift.

And yes, the drive-by-wire seems non-responsive for the first part of the throttle travel. I'm used to the cable throttle where the weight of my foot is usually enough to open the throttle for cruising on local roads.

 

Lets think about this. The fuel pump is running flat out all the time and at more pressure than the injectors require. There is a pressure regulator at the engine that dumps off excess fuel pressure back to the tank so the injectors always see the required 35 or 45 lbs (or what ever it is for this engine). No load throttle response requires very little fuel. So why would the fuel pump be to blame? Going on what you described I would thnink either:

a) injectors are dirty

b) the control software is causing the characteristic

c) there are deposts built up behind the throttle plate at the idel position and the computer has the idle bypass near wide open to compensate.

If the pump was toast, you would see significant probelms at WOT acceleration.

Unless you get a tune to the parameters that control throttle action, the throttle hang problem while shifting will not go away. It bugs me too.

 

If double clutching became an all the time necessity, then I would agree. Just should not be necessary for a synchronized gear box.

 

I was just saying that double clutching or rev-matching should not be necessary to downshift from or to nearly any rpm. Sure, the tranny might whirr a bit and it might require a little bit more force to push the shifter into gear. It should NOT be impossible, or even difficult though.

 

I tried virtually every possible downshift combination today and noted nothing strange Also ran through a bunch of out-of-sequence upshifts like 1st to 3rd or 2nd to 5th. Piece 'o cake

 

I ran through the downshift scenarios and revmatching was required to make it go smoothly. Upshifts have never been a problem for my 3650. I've tried WOT 6k speedshifting, normal shifting, etc... and it shifts like butter.

 

I do all of these things all the time;- especially on the freeway. I agree, time it all out right and the downshift is like a "hot knife through butter". There is no pressure on the clutch as the revvs are subsequently matched. Almost like a sweet spot in the rpm range for the ger you are going in to. Consider also, that I am a spirited driver and a bit heavy on the clutch too.

Yes, if I am off on the judgement in the foot with the shifter timing, there will be some movement of the car upon shifting.

When the clutch is depressed, the car is essentially in Neutral and everything is spinning with the gear selected, but not touching. A slight friction against the flywheel, but it allows time to go back in the gear before the revvs drop;- if you get out of the gear and decide you need to go back in;- Watch the revvs so they don't drop, and go back in gear and it is still like the hot knife through butter. If the revvs drop, then goosing the throttle a bit in between takes care of it. I can feel the revvs of the engine change through the shifter handle. It is made of billet and so is the Aftermarket beam. Helps a lot.

 

That's why I had the Clutch adjusted to come an inch off the floor in the Roush. It is a light clutch and had far travel;-it was difficult for me to use. Like One would keep pulling it off the floor and wondering "where is it at". lol

Shelby is about 1 1/2 inches off the floor with the heavier dual disk unit in.

 

No rev matching required, but it is easier on the tranny.

With a healthy dual syncroed transmission, double clutching is not a necessity.

 

So the Shelby GT has a dual disk set up? Still Diaphram type?

 

metroplex

Well if you can upshift w/o problem, then you should be able to down shift w/o problem. The only difference between the two operations is on upshift, the input side of the trans has to slow down, on the downshift, the input side has to speed up to match the output side. The syncro blocker ring does the same job in either case: from the output shaft side it clutches the input side of the trans and speeds it up or slows it down to match the rev's to the output shaft in that selected gear.

 

I think that the shifter you have will make a diffrence in the way you shift. I thought the stock shifter was OK but I recently switched over to the MGW shifter and it's night and day. See if you can find some others with diffrent type of shifters and then try them out. Also your clutch will have a huge impact on how smooth you shift. How many miles on your clutch? I can tell you that if your having problems on a stock clutch your going to hate a high performace aftermarket clutch.

 

I think it is mainly my technique for downshifting. There's no way for me to do any type of heel-toe downshifting until I figure out how to rotate my knee. Otherwise, with some more practice on the hydraulic clutch and with the drive by wire, it feels like the 3650 is working properly. My clutch has less than 100 miles on it, and I have the stock shifter.

 

I don't think that's exactly true. A slightly different situation than what we've been talking about, but *may* make my case:

If you are REALLY good and know your car, you can theoretically upshift without the clutch (and without grinding). Once again, you have to be good enough to know what rpm to do this at where everything will be matched and meshed.

Downshifting, on the other hand, REQUIRES the clutch in order to avoid grinding gears.

I'm not trying to start another back and forth "discussion"...This is just what I've been told by other people, and I don't have the guts, nor the skill, to attempt this personally. So, it may be untrue, but my sources were pretty reliable.