Gear ratio help

[sqidd]

I just picked up a 07 GT and I am now starting the mod process. I put exhaust on front to back yestaerday, Kenne Bell Blower goes on next week. Wheels will be here today......big brake, etc.

I am thinking of changing out the rear end gear, but I don't want to loose much top speed. I google'd some sites this moring to find the tranny ratios, etc and calculated it out. But I want to check with you guys and make sure my math is right.

I show the TR3650 tranny as having a .62 fith gear. The car has a 3.55 in it and the tires are 25.75" tall. With this rear end gear it showas a top speed of 209MPH at 6000 RPM's (yeah right:rolling: ).

If I chuck a 4.10 in it shows I'll have a 181 MPH top speed, which is more like it:rockon:

Can you guys check my math for me and give me any input you may have?

thanks
jason

 

[WPGFORDGUY]

we saw 176 with 4.10 in the dyno in my car at 6250 rpm

 

[YardSpecial]

With a roots blower more then 3.73 is a BAD idea.

With a Vortech 4.10 would be safe

SO for now stick with the 3,55 gears with the blower, car would be slower 4,10 geas IMOP.

 

[03MUSCLE]

do 05-07 gt's come with 3:55 gearing?

 

[sqidd]

do 05-07 gt's come with 3:55 gearing?

Thats what I was told, can anyone confirm?:shrug:

 

[sqidd]

With a roots blower more then 3.73 is a BAD idea.

With a Vortech 4.10 would be safe

SO for now stick with the 3,55 gears with the blower, car would be slower 4,10 geas IMOP.

I was kind wondering that myself. My 03 Cobra was just fine with the 3.55, I never even thought about changing it. Maybe I will just throw the blower on and then see what I think

 

[sqidd]

we saw 176 with 4.10 in the dyno in my car at 6250 rpm

Thats plenty fast. I doubt I will get the car up much higher than that, but it looks like if I gear it I will be going with the 3.73, which will put me at about 190MPH. That should give me the breathing room I need if I race any motorcycles:rockon:

I see in your sig that you run two different wheel/tire combos. Are you doing any solo (I don't know what that means) racing? What is that? Do you have any brake mods? I am thinking of doing some sort of brake mods to my car, but I am not looking to go overboard. I like the Powerslot Rotor Hawk pad idea, that looks like about $565.

But I talked to the Bear brake guys today and I think it was something like $2200 for the front and rear with full floating 14" front rotors, yada, yada, yada. That seems like a bit much, I won't be taking this to the track, thats what the bikes in my sig are for

It sounds like if you are doing some sort of racing you will have some input on the brakes? Got any?

thanks
jason

 

[BigRick]

Kenne Bell's own website claims that the 3.73 ratio is the best for 1/4 mile times.
As far as top speed goes do you really plan on going 180MPH?

BTW, can I borrow that money tree of yours?epper:

 

[sqidd]

As far as top speed goes do you really plan on going 180MPH?

BTW, can I borrow that money tree of yours?epper:

Yes;-) See the bikes in my sig? Thats me. I kinda have a speed problemepper:

Sorry, currently all the money on my tree is gone, try me next spring

 

[sqidd]

Thats what I was told, can anyone confirm?:shrug:

I just checked my 07 GT and it has a 3.31 in it:cuss:

Crap, I didn't want to change that. I hate the smell of gear lube:fm:

Now what to get 3.55's or 3.73's?????????