Dead spots?

[guinnessman]

Hey guys, if you have 4.XX gears are there any dead spots in acceleration??

What i mean is this, right now i still have the stock LSC gears (3.27) and i notice 2 huge dead spots. The first, flooring it while i'm doing 40...it downshifts to 2nd at around 3800rpm and you have to wait for it to hit the sweet spot at around 4600 to take off. The second big dead spot is flooring it at around 55, it again shifts to 2nd at around the same 3800rpm, and it's a waiting game till it hits 4600 etc.

Any dead spots like that with say, 4.10 gears? Now lets say i didn't want put in gears, what mods should i look at that give you good power increases UNDER the (peaky) powerband, more torque and horsepower from 2500-4000 etc.

I actually love the stock, wide gearing, this car is so fast when you romp it around 25mph or 70mph.

 

[bryantaylor]

sounds like sticking IMRCs

 

[guinnessman]

Not really, it's just that the programming (i might be wrong) says to the engine/tranny "this speed we will downshift to 2nd gear cause if we downshift to 1st, it would waste gas"......making the driver go :-(

LOL.

PS I've had many Ford's, and all of them have had these "lazy shifting" transmissions, at a certain speed, they WILL NOT downshift to the preferred gear for optimal acceleration.

 

[NateRW21]

I'll throw my $0.02 in...

going 50mph in 2nd gear should net you somewhere in the 4000 RPM ballpark; I'm not going to take the time to do the math and give you exact figures.

Either way, this "dead spot" may actually be a slow down shift.

If that isn't the case, I'd have a serious look at your off the line, low-end power and the IMRC's. There shouldn't be a "dead spot". Of course, you must also keep in mind that the car will accelerate faster as it moves further into it's powerband, and there really is nothing which will eliminate that; a transmission with three forward gears and one overdrive cannot possibly keep the engine 100% in the sweet spot at all times. Changing your final drive will allow for stronger acceleration across the board at any given speed because you are already higher in the powerband... but you will still feel it come on stronger as it gains RPM's.

Anyhow, your description makes it sort of difficult to determine where your problems might be; how long is this "deadspot" What are your initial RPM's after the downshift? Also, what you perceive to be a dead spot, could as I said before... be perfectly normal shifting and acceleration behavior for the given RPM.

 

[LI LSC 98]

Guinness- I understand what you mean- right around 40 mph, when you try and go WOT in drive you dont get that downshift and hard "snap". When you floor it around 40 it just stays in that gear and climbs into the powerband without the hard downshift you get anywhere before that.

 

[guinnessman]

I made the mistake of saying deadspot. Nate, it's just that certain times it doesn't shift into the "sweet spot" as you said.

You're also correct about the fact that it is after all a 3 speed, so it cannot always be in the sweet spot.

With 4.10 gears, are there as many "non-sweet spot" downsifts as stock 3.27 gearing?

I just want to know before i blow $500+ etc

 

[NateRW21]

Have you installed a shift kit or J-mod yet? I'd look at doing that first; it's relatively cheap to do and your shifts (both up and down) will improve a lot. I put a B&M Kit into my 98 F-150 w/ 4R70W and it made a huge improvement (which I still own- It's a reliable mod so don't worry about that).

Anyhow, I don't own a mark yet (I have an LS right now), so someone who's already done the gear swap might be able to tell you better how the car responded in the shift RPMs. But generally speaking, transmissions use a combination of throttle position, RPMs and Line pressure to determine shift points; long story short, yes, the rear gears should have some affect on your RPM's after downshift, but I wouldn't expect it to be monumental. The real money maker for shifts comes from work on the tranny.

I'd throw in gears, limited slip, B&M shift kit w/aluminum pan (if it will clear) and upgraded cooler. However, I'd look at 3.73 or 3.90 gears; you'll get a different story from everyone you talk to; some swear 4.10 is the only way to go, some say 4.10 minimum or 4.56. Some say don't do gears at all. From experience, in a car, highway RPMs are a touch high on 4.10 gears when paired with an AODE or 4R70W for my taste.

Anyhow, if you've not touched your tranny, look into that first, then maybe worry about your gears

 

[kustomizingkid]

4.10's will help the car accelerate quicker under any circumstance....

I don't think 4.10's are too deep at all... I'm going 4.30's with no worries.

 

[Rich88LSC]

PS I've had many Ford's, and all of them have had these "lazy shifting" transmissions, at a certain speed, they WILL NOT downshift to the preferred gear for optimal acceleration.

You think that's bad test drive an LS

4.10's will help the car accelerate quicker under any circumstance....

I don't think 4.10's are too deep at all... I'm going 4.30's with no worries.

+1

I can still downshift into second at 55mph and your in the better part of the powerband when it does. And I can cruise at 80 and still be a hair under 3k rpms

I do agree with Nate about doing the jmod and then get a tune. The jmod will help with the sloppy lincoln shifts and the tune will change when the car shifts. Even with stock gears changing the shift schedule in the computer will make the car a lot more enjoyable to drive.

 

[Kraze]

I would definitely go with a tune first. My car will downshift into first at 40, even 45 mph after the tune. And the increased line pressure really makes the shifts fast and precise. Plus you can always go with the jmod if the shifts still aren't firm enough for you.

 

[NateRW21]

4.10's will help the car accelerate quicker under any circumstance....

I don't think 4.10's are too deep at all... I'm going 4.30's with no worries.

My point on different opinions for gears has now been illustrated!

 

[kustomizingkid]

Cheers!

To each their own.