Mustang lost power after 4.10

[Snake-Eye]

Hi Guys,

So here is my story: I installed my FRPP 4.10 gears about 3 weeks ago after 1-2 days of installing it the car lost alot of power it feels that im driving a stock mustang !!!!

Car specs :

-05 Mustang Gt has around 93,000 miles on (150K Km)
-FR cold air intake
-SLP muffler delete
-4.10 FRPP Gears
- DS custom tune
- 305/45/18 drag radials


What I've done right after the Gear installation

- Changed the axle ratio on the tuner from a 3.55 to 4.10 (Didn't add or change any premeters except for the axle ratio, the fuel to air ratio is the same )
- Cleaned TB

Please dont tell me your tires are too big,

i ran the same tires on the 3.55 and frankly speaking i don't see or feel much difference with 4.10

Is it possible that my engine is loosing its compression ??
or do i need to retune ?? or what ???


One more thing anyone has access to a DS tuner in case i need to retune ??


Thank you in advance guys

 

[ct07gt]

When you changed the axle ratio on the tuner did it upload the stock tune instead of the custom tune? I know you said it did not change the A/F ratio, but it is the only thing I can think of. There should not be any mechanical reason you would feel a decrease in performance, so it has to be a tune issue I would think. If you can't get it figured out, call VMP or JDM to see if they can send you a tune.

 

[klaw]

Are you driving with the traction control on or off? Is it possible that you break the rear loose easier with the 4.10's and therefore the TCS kicks in and "modulates" the power?

 

[Snake-Eye]

I don't think it uploaded the stock tune cause I edit the performance tune

And I always drive with the traction off !

I thought of taking it back to the dyno and retune the whole thing over

Let's just hope it's not the engine

Thanx guys !

 

[mjk]

maybe its the tb? just throwing out ideas... but "Id re-load the tune just to be sure about the tune, also make sure you dont have any air leaks in your intake.

 

[Redfire281]

If it didn't act up until 1 or 2 days after the gears/modified tune install, I would not think it's in the tune.

 

[mrdeath2000]

are the gears new? or used from a 3rd party?
if they are used, are you sure its a 4.10 and not a 3.31?

try switching the tune back to 3.55 and see if there is a difference.

 

[SpartaPerformance]

Is it an automatic? If so it may be a tune the parameter you cahnge on the hand held only re calibrates the speedo it does not change the shift points for the new gears. My $0.02

 

[gmantheman]

If he had 3.55s before, I doubt it's an auto. Something doesn't seem right. Last week I drove my friend's 05 with a dyno tune and 3.55s. The car was fast but it didn't have the acceleration of my car with the 4.10s.

 

[DarkFireGT]

Have you tried reflashing your tune? Sometimes tunes just don't "take" and require a second reflash. It doesn't happen often, but I have experienced it before.

 

[SpartaPerformance]

Have you tried reflashing your tune? Sometimes tunes just don't "take" and require a second reflash. It doesn't happen often, but I have experienced it before.

Brain farts!! Gotta love 'em!

 

[chefalan25]

this is just a shot in the dark, but try disconnecting your battery cable for a few minutes, then try to reinstall the tune. maybe something wierd happened with your ecu and its pulling timing.

 

[Snake-Eye]

Heeey Guys,

Thank you all for the wonderful feedback,

I haven't really found the time to do all that,

As DarkFireGT's said...i will be reloading the tune, and also checking my engine's compression,


@ mrdeath2000 : Nope dude it's a brand new FRPP 4.10

@ SpartaPerformance : It a manual .


Thanx again guys !!

 

[Snake-Eye]

Heeey Guys,

Thank you all for the wonderful feedback,

I haven't really found the time to do all that,

As DarkFireGT's said...i will be reloading the tune, and also checking my engine's compression,


@ mrdeath2000 : Nope dude it's a brand new FRPP 4.10

@ SpartaPerformance : It a manual .


Thanx again guys !!