Kingfish

I'm posting this for a friend who ran into an issue with his 2010 GT. Since he bought the car new a few months ago, he's put in a CAI, Flowmaster cat-back and Bama tune. He just swapped out the 3.31 gears for 3.55s but the acceleration in first gear now is not what is was before the gear swap. I drove the car last night, and it does seem like first gear doesn't wind out as quickly as it should. Second gear pulls like a mother, though.

I'd think a lower axle gear would mean first would wind out quicker, but that's not been the case. The only thing I could think of was a fueling or spark advance issue with the tune, but it doesn't explain why second gear is so strong. He's kinda bummed over this, but will try reloading the tune to see if there's any change. Anybody ever run into this after changing gearsets?

Will

Ltngdrvr

No offense but swapping 3.31's to 3.55's was a total waste of effort. Too little of a change for all that work and expense.

Why it is more sluggish on acceleration is strange.

Is it an automatic tranny or manual?

Kingfish

It's a 5M

AMChrisRose

I was all set on telling you "get a tune update, it affects MPH and will shift weird", but then saw it was a manual.

So it's definitely awkward for it to be sluggish after the gear install. You'd hear it if it was due to something in the rear.

Did he get an updated tune for the gear ratio that he loaded in? Maybe something else got accidentally changed? If yes, have Bama take a look at the file and see what happened. Also make sure that they sent over the same file (if we was running the Race tune, make sure they sent the Race file, etc.) They're available Monday-Friday 9AM-5:30PM EST at 888.226.9764

And if he didn't get a revised tune, try loading the tune again and see what happens. There's no reason for it to be sluggish out of nowhere.

Cusp

Maybe now your frying the tires and the traction control is holding you back. My guess anyway. Try it with the TC off.
On the 3.55s... Its a 7% increase in torque to the back wheels. Not a lot but should be noticeable. They were Ford's gear of choice in 05 and 06. Then Ford needed to eek out another MPG to compensate for the change the EPA made on how MPG was calculated. So we got 3.31s which is to high for this car. I read a study a few years back which reported that 3.55s will take the car to its highest top speed in 4th gear. The writer was of the conclusion that 3.31 left some power on the table and drag limited the top speed because of it. Where as the 3.73s ran out of RPM before Drag used up all the horsepower. The 3.55s were the best match. Note that the difference was only a few MPH plus and minus and all above 140 MPH. Pushing 150 in fact. I couldn't see a need to be operating at that edge and so opted for the 3.73s for its slight 5% increase in torque over the 3.55s. Helps with things like getting on the freeway.

Ltngdrvr

Disconnect the battery cable for a few minutes and clear the computer then reconnect and see what it does.

Bert

Yeah, has to be something weird going on with the tune or the computer, a computer reset might help like ltng suggested.

I have the 3.31 gears and I would not call it "sluggish" (though I've been driving Toyotas for too long so what do I know) and the 3.55 might not be a big difference but definitely should be better not worse.

KonaBlue5.0

You're in CT. Launching from a stop or flooring it from a slow roll in 1st gear is absolutely going to trigger the traction control, if not leave you spinning if it's turned off.

I have a similar issue, with my now-tuned '11 GT. There is so much power down low, and it's so cold out, that I can't put down any power in first or second gear. It's actually slower than it was prior to the tune because of this.

When it warms up, all will be well.

SteedaSupport

Definately sound like they may have used the tune options to correct for new gear ratio for speedometer, and may have messed up tuning the vehicle. The traction control should be dissabled while accelerated driving is being performed. If it engages, a light will illuminate on dash letting you know that it is cutting power to the wheels. This is most probable cause if engine light is not on and car performs well in all other gears.

wonger

I think you may just be used to putting your foot down to a point and waiting for the revs to match, and shifting before it ever reaches that point. More gear requires more throttle to get the same speed out of a gear. It makes sense that it 'feels' slower. Because unless you're flooring it or close in 1st; you are going slower or at least the same.