Superchip-Larger Tires-Tranny Shifting
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Member
Joined: Apr 2001
Posts: 97
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From: Chicopee, MA, USA
Superchip-Larger Tires-Tranny Shifting
This message is for Mike, but I know the other members will benefit from this. I put a chip in my 2001 2wd Screw after installing larger diameter tires. The tires are 1.5" larger than the original. Seemingly not much but they threw off the computer tranny shifting something aweful. The SuperChip really helped this problem a lot. However...
The truck now wants to go into overdrive at 40mph. At highway speeds..let say 65-70 mph... the truck is doing about 1200-1400 rpm. Kind of a slug. If I turn off the OD, the RPM goes to about 2500. Much more responsive. So...I find I either turn off the OD at cruising speed around 65-70 or I drive 75-80 to get the RPM up to 2000. Now I know the chip can't do anything about the engine RPM at cruising speed, but can it be adjusted to delay the OD from engaging until I get to real highway cruising speeds...let say 55-60mph?
The truck now wants to go into overdrive at 40mph. At highway speeds..let say 65-70 mph... the truck is doing about 1200-1400 rpm. Kind of a slug. If I turn off the OD, the RPM goes to about 2500. Much more responsive. So...I find I either turn off the OD at cruising speed around 65-70 or I drive 75-80 to get the RPM up to 2000. Now I know the chip can't do anything about the engine RPM at cruising speed, but can it be adjusted to delay the OD from engaging until I get to real highway cruising speeds...let say 55-60mph?
Former Sponsor
Joined: Mar 1998
Posts: 13,385
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From: Virginia
Hi Dan,
That wouldn't be the way I would handle this. That would be a band-aid approach at best, and you can do that much just by turning your Overdrive off until you actually need it. We certainly *could* do that in a custom program if somebody wanted, but I don't advise it, it's not worth the expense when you can just turn the Overdrive off to me, but that's for you to decide, of course!
The real problem here is that you have installed taller tires, so you've lost torque multiplication and hurt driveability as a result, as always happens when installing taller tires and not changing gear ratios to match. Just how bad it is depends on what package you have from the factory & how much taller the new tires are. Those of us with ORP's (Offroad Package, which has the tallest factory tires available for the F-150 already and should have nothing less than 4.10 gears from the factory) & 3.55's *really* take a hit when installing even taller tires.
The Superchip, believe it or not, actually has *not* changed instructions to the transmission about what speed your vehicle shifts into Overdrive at on part-throttle. It only changes that setting at WOT (wide-open throttle). That bears repeating.........we do *not* change *any* part-throttle upshift points, they are still determined by the exact same factory algorithms that are vehicle speed & throttle position versus load dependant.
However, because of the increased torque from the Superchip, on the lighter throttle openings it will upshift sooner than it did before sometimes, simply because it has more power available now with the Superchip. What happens is the ECU senses that the vehicle can upshift without slowing down, and so it allows the upshift as soon as it realizes it can do so without immediately losing speed, that is it's fuel mileage strategy. That is not a change in the shift points from the Superchip, that is the factory algorithms responding to the increased power from the Superchip and allowing it to upshift sooner when you are using only light throttle.
Remember, it will only upshift into Overdrive at 40 mph on light throttle, and *you* control that with your right foot.
If you're using that little throttle, it will upshift as soon as it can do so without losing speed, as you haven't communicated to the vehicle that you require more performance, via your right foot.
Please feel free to give us a call if you'd like to go over this in more detail, ok? Thanks!
That wouldn't be the way I would handle this. That would be a band-aid approach at best, and you can do that much just by turning your Overdrive off until you actually need it. We certainly *could* do that in a custom program if somebody wanted, but I don't advise it, it's not worth the expense when you can just turn the Overdrive off to me, but that's for you to decide, of course!
The real problem here is that you have installed taller tires, so you've lost torque multiplication and hurt driveability as a result, as always happens when installing taller tires and not changing gear ratios to match. Just how bad it is depends on what package you have from the factory & how much taller the new tires are. Those of us with ORP's (Offroad Package, which has the tallest factory tires available for the F-150 already and should have nothing less than 4.10 gears from the factory) & 3.55's *really* take a hit when installing even taller tires.
The Superchip, believe it or not, actually has *not* changed instructions to the transmission about what speed your vehicle shifts into Overdrive at on part-throttle. It only changes that setting at WOT (wide-open throttle). That bears repeating.........we do *not* change *any* part-throttle upshift points, they are still determined by the exact same factory algorithms that are vehicle speed & throttle position versus load dependant.
However, because of the increased torque from the Superchip, on the lighter throttle openings it will upshift sooner than it did before sometimes, simply because it has more power available now with the Superchip. What happens is the ECU senses that the vehicle can upshift without slowing down, and so it allows the upshift as soon as it realizes it can do so without immediately losing speed, that is it's fuel mileage strategy. That is not a change in the shift points from the Superchip, that is the factory algorithms responding to the increased power from the Superchip and allowing it to upshift sooner when you are using only light throttle.
Remember, it will only upshift into Overdrive at 40 mph on light throttle, and *you* control that with your right foot.
If you're using that little throttle, it will upshift as soon as it can do so without losing speed, as you haven't communicated to the vehicle that you require more performance, via your right foot.Please feel free to give us a call if you'd like to go over this in more detail, ok? Thanks!
Last edited by Superchips_Distributor; Dec 23, 2001 at 08:21 PM.
Former Sponsor
Joined: Mar 1998
Posts: 13,385
Likes: 4
From: Virginia
Hi Dan,
What I would suggest is to give us a call & let's work that out over the phone. In general, I would usually lean towards 4.10's when looking at that basic choice, as the change from 3.55's to 3.73's is just not enough to be cost effective, generally speaking.
Since you have a 2WD, this is a lost less expensive proposition for you as compared to us 4X4 owners!
In our 2001 5.4 ORP F-150, at 81 mph, it's turning just 2100 rpm in Overdrive (as will any 5.4 F-150 w/ORP & 3.55's). That's just too tall for any F-150 in my opinion, but certainly for the heightened stance & aero profile of an ORP like ours.
Just give us a quick shout via phone when you can (we reopen from Christmas on the 26th) & we'll go over all your numbers & suggest your ratio for you.
What I would suggest is to give us a call & let's work that out over the phone. In general, I would usually lean towards 4.10's when looking at that basic choice, as the change from 3.55's to 3.73's is just not enough to be cost effective, generally speaking.
Since you have a 2WD, this is a lost less expensive proposition for you as compared to us 4X4 owners!
In our 2001 5.4 ORP F-150, at 81 mph, it's turning just 2100 rpm in Overdrive (as will any 5.4 F-150 w/ORP & 3.55's). That's just too tall for any F-150 in my opinion, but certainly for the heightened stance & aero profile of an ORP like ours.
Just give us a quick shout via phone when you can (we reopen from Christmas on the 26th) & we'll go over all your numbers & suggest your ratio for you.
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Member
Joined: Apr 2001
Posts: 97
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From: Chicopee, MA, USA
Gear ratio
Thanks Mike,
To those of you who are following this thread. I'll be out of the country for a few weeks. When I get back I'm going to install 4.10's and provide feedback and data.
Mike...I'm going to need your help on reprograming the chip if necessary.
To those of you who are following this thread. I'll be out of the country for a few weeks. When I get back I'm going to install 4.10's and provide feedback and data.
Mike...I'm going to need your help on reprograming the chip if necessary.
Senior Member
Joined: Jul 2001
Posts: 1,247
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From: El Cajon, CA
I have a SCREW and want larger tires, but before I do that I want the 4.10 gears on my truck. The SuperCrew (SCREW) only comes with the 3.55 rear end. I hae a 4x4 so this will be expensive for me but I think in the end worth it as I plan to keep my truck for a while.
I only want tires that would be about .7" taller (radius) but right now I can't spin my tires even will all my mods because of the 3.55 gears.
I can fly by cars on the freeway at over a 100MPH with no problem so with the taller gears your top end may go down a bit, but who really needs to be driving there truck at over 100MPH anyways!
I only want tires that would be about .7" taller (radius) but right now I can't spin my tires even will all my mods because of the 3.55 gears.
I can fly by cars on the freeway at over a 100MPH with no problem so with the taller gears your top end may go down a bit, but who really needs to be driving there truck at over 100MPH anyways!
