loudnlow

This isnt another "OMG tell me what to get" thread. I just have a few questions.

Okay I have a 05 GT with an Auto tranny in it with just basic stuff (tune, cai, exhaust) and I am going to be purchasing gears with my tax returns and I really have my heart set on FRPP 4:10s.

I am running stock tire size and will probably stay the same size, also and the car will see some track use maybe 3-5 times a year but not too much.

Later on I will be buying a vortech or paxton s/c and I want to get the right gears now for the blower. I am heart set on a centri so please dont suggest staying with stock gears and getting a twin screw. I am looking for some extra acceleration until I can afford the supercharger and I believe gears are the answer.

Are 4:10s going to ideal for a centri s/c?
What rpms am I going to be at around 67 mph and 75 mph?
Is traction impossible with these?
Are these gears great from a roll compared to 3:73s?
And seat of the pants feel, how noticeable are they?

Thanks MFers!

SLPstang03

i had 4.10's on my mustang gas is going to kill you. RPM's are around 2500-2600 at 65 and 2900-3000 at 70-75. They are really good at a roll and start. As for traction thats outs the question unless you run like 335's with some nitto invos then you might but top end power sucks bad

loudnlow

Those rpms are a bit higher than I thought

SirKnightTG

Those RPMs are too high for the 5R55S. At 70mph, you should be around 2500-2600 in O/D (0.71)

Also, I can get with my mods at 80 mph w/ 3.31 doing about 2500 rpm 25.5 MPG (I get the same doing 70mph @ 2000 rpm). These engines like RPMs.

For me, since I do 50/50 city/highway with the highway being littered with steep hills, I'd be surprised if I saw a change in MPG. These hills really put a load on the engine and same for city. There are times where I can turn O/D off and run in 4th (1:1 ratio) and while the RPMs are very high I'm getting BETTER than when I was in O/D doing much lower RPM.

loudnlow

Thats exactly the same with me I often drive 80-85 to get better mileage but thats one reason I am wanting gears as well to get my car in that sweet spot of RPM's at a lower speed.

bigblue15

hey man i dont mean to like pollute your thread with questions or what not, but with getting these new gears do you have to get your tuner 're-tuned'? i've always wondered if you have to do that when you get any new performance because when i got my tuner bamachips asked me to list all my mods (i know i should probly know this, but i dont lol)

kingsofcrunk

With gears you use the tuner itself, not the loaded tune file, to change the gear ratio.

bigblue15

ahhhh ok, that makes sense haha idk why i didnt think of that, but i guess thats why they have forums lol...thanks man...what about if you get parts like headers or something?

deekum1627

4.10 rock they are noticalbe. also i think im at 2700 rpms at 70 ill check tomorrow i should be taking the car out.

Riptide

@ 75mph with a 27.0" overall diameter tire and 4.10 gears you are looking at approx. 2600rpm.