Hi gang, I just had my dealer install 4:10's (my only mod so far) in my '07 GT/CS automatic and took it for a drive! Car has come alive on low end, but the speedo is way out of wack. Dealer mechanic said that speedo wood be off about 7 1/2 % but in reality its of over 20%. as I check it in radar zone at 120 kmph it was actually doing 97-98 kmph. I realize that a retune is in order, but can the speedo be recalibrated with tune or does this only happen with new speedo cog?. When I took car to track the car ran 14.0084/98.46 mph best as compared to 14.118/97.33 (3:31's). I made several passes on car with tranny in drive but car would always shift to early on its own. If I left in first gear and shifted it would shut down on the rev limiter at top of first and second. I would appreciate any help on what tuner to go with and/or tuner shop I could call to trouble shoot. My goal is to get this puppy into the high 12's and would welcome advise to do so. Thanks

Bryan C

 

Bryan,
Welcome to the fun zone. I did just what you did and had dealer install 4.10 gears, and I also have an automatic. That's just the start of what you began. GET A TUNE. I think any hand held tuner will help you and let you program in your new gears to get the speedo right. But, I went with Brenspeed for my tuner and they will set it up (custom tune) it for your car. There are other reputal dealers/tuners out there, this was my choice and I have no regrets and have already recommened a few friends to Brenspeed. Every call I make there I talk to someone and I've done tune changes and they are right on top of it. What you get with a tune, what you need for speedo anyway, and a sore neck. That is until you get used to the car you just awoke into a new life. The response and torque will blow your socks and rubber right off. As they say, Just do it!!!!
Tune, tune, tune = fun, fun, fun

 

+1 on the tune first. It will do wonders and correct the speedo issue. Also, a torque converter would be HUGE now that you have 4.10 gears. The gears by themselves make the car feel alive, but a TC by itself will lower your times more, especially in the 60ft. The combo of the two is amazing for lowering your time for not adding any hp's. Both myself and a friend of mine each have auto's. He has the gears/tc combo and he needed to get better tires to keep from spinning them on the line. When he did it was a huge difference.

Of course there is always a CIA with a tune as well. One of the cheapest and best mods for hp per dollar.

 

If you do end up getting a tune, if funds are available, definitely jump on a CAI along with it. It will make a world of difference!

 

Yes with the CAI along with the tune. I forgot that part.

 

Your trans is being told by the computer to shift at certain speeds that were appropriate for the 3.31 gears. The 4.10's have confused the factory tune with respect to shift speeds, and you absolutely must correct the speedometer or you're heading for trouble. Get a handheld tuner (SCT, hypertech, Diablosport Predator, etc.) and you can correct the speedometer electronically - no new speedo cog needed (those days are long gone).

Simple fix and you'll be on your way to a faster car!

 

First mod I did was tuner, then 4.10's, then a big stall converter. The stall converter dropped my 60' time by 3 tenths of a second (2.1's down to 1.8's). My 330' and 1/8 mile ET's dropped the same, as well. Definitely a great mod for a street car that sees some drag racing action. Like Zip34 said, the 4.10/TC combo is a great way to go a lot faster without adding any power, and traction will become an issue, so get some stickier tires. My car ran a best of 13.09 @ 103+ mph in the 1/4 mile with just those mods above. Car is supercharged now, and I highly recommend forced induction, but even without a blower, our cars can be made to go very fast.

 

Thanks guys, onward we go..... Are tuners restricted to preprogramed tunes or can you make adjustments with certain things? ie shift points / torque converter etc.

does anybody have preference ie Predator / SCT / Hypertech ???


Thanks again....much appreciated


Bryan

 

Call Brenspeed and they'll answer all you questions. I should say most will, I can just speak for them since that's whom I chose to go with. But, yes to your question. And these tuners will give you custom tunes in your tuner for made your car. I love my gears but, the tune woke it all up. Carzy fun now!!

 

Once you get the tune you will be set for the mod you made. I have 4.10s now also.Just installed today. Have not nailed it yet but I will over the next couple of days.However I notice the additional pull just driving around at normal speeds. I also have a JLT II CIA, o/r x pipe, american thunder flows, and a 93 octane custom tune done by wheels direct in stockbridge, ga. These are other mods you can try to help get you in the high 12s along with a higher stall converter which is my next project.The car feels very diffrent now. So on to the next project. Good luck on your tune and future mods man!!

 

Nice install. check out bamachips.com for a tune and intake combo.I went the C&L racer intake with SCT III and with dougs race tune I went from a 14.00 stock to 13.70`s in warm weather all the way down to 13.30`s in cooler weather. I would love to see what 4.10`s would do... but then I would have to spring for Drag Radials. What did the dealer charge for this install... Something I might consider after driveshaft....

 

Gear change at a dealership should be in the $700-$900 range, which should include all parts & labor. Aftermarket stall converter is an awesome mod for our automatics. Drag radials are a big plus - especially at the dragstrip. And I highly recommend boost, as well.

 

+100 on CAI and tune. Might as well do CAI with the retune

 

I'm going to reccomend our 93 Octane Street Race tune and C&L Racer Intake.

Give me a call, we have a package that includes C&L Racer Intake assembly as well as SCT X3 Powerflash programmer preloaded with 3 of our custom tunes for your specific vehicle and modifications in stock ready to ship same-day!

$634.99

We also have the JLT series 2 intake and SCT X3 Powerflash programmer preloaded with 3 of our custom tunes for your specific vehicle and modifications in stock ready to ship same-day!

$525.99

Both packages will get you a HUGE increase in throttle response, power all across the RPM range, correction of speedometer, better gas mileage, all around 100 times better driveability. Because you have an automatic you'll also get better shift points, firmness, and quicker shift. You really get what you paid for!

Chris Rose
Tillman Speed Inc.
www.TillmanSpeed.com
610-497-5776

 

The dealer should be able to set the computer for the new gear set. but.....

We had gears installed by the dealer in my wife's '09 automatic. The Speedometer was off at least 10% (reads too high). The dealer made the computer adjustment, verified it, but the speedometer is still off the same amount.
Ford is claiming the ECM needs to be replaced. They also hint that this speedometer difference is 'acceptable'. I think not.

I hope a custom tune will correct the problem, but if the Ford scan tool changing the gear ratio setting doesn't work, how will a custom tune work?

 

It works. They can recalibrate it. Don't let them tell you otherwise. Or go to a new dealership.

You're going to want the CAI/Tune anyway. It makes 15x the difference that the gears did, guaranteed.

Chris Rose
Tillman Speed Inc.
www.TillmanSpeed.com
610-497-5776

 

 

Here is the latest from Ford on the '09 Mustang. Ford declares these settings are no longer adjustable by the Ford scan tool the dealers have. Ford has done this to maintain 'as built' emissions. The parameter is only changeable using an aftermarket tuner.
Apparently if a parameter is followed by an asterisk when viewed in the Ford scan tool that parameter is no longer adjustable through a Ford dealer!

 

Good info, I can believe that......


Get a cai and tuner- they should be the first mod on these cars IMO.