Will 3.55 gears hurt or help with a whipple or VMP set up

[bsb318]

There is a 2017 Lightning blue standard GT auto on a local dealer lot I plan on buying.
One of the options it has is 3.55 gears.
Should I steer clear and find one with 3.15's or order one with 3.15's if I plan on going with a whipple or VMP set up ?
I heard 3.55's may hurt me.
Is that true ?

Whats the opinion here of VMP vs Whipple for my choice.
I am leaning towards Whipple because of the fact there is no need to cut the K brace or cut or grind anything on the timing cover or under the intake manifold.

I have seen the torque at launch and some sick ET's at the track from VMP's.
I never saw a Whipple in action at the track as of yet.

My goal is to break into the 9.90's on a 50 degree dry air kind of night.

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[smokinzx14r]

I have 3.55 gears ... seems to work fine with my procharger making 561 foot pounds of TQ .. Can't say about a PD blower..

 

[Terminator2]

There is a 2017 Lightning blue standard GT auto on a local dealer lot I plan on buying.
One of the options it has is 3.55 gears.
Should I steer clear and find one with 3.15's or order one with 3.15's if I plan on going with a whipple or VMP set up ?
I heard 3.55's may hurt me.
Is that true ?

Whats the opinion here of VMP vs Whipple for my choice.
I am leaning towards Whipple because of the fact there is no need to cut the K brace or cut or grind anything on the timing cover or under the intake manifold.

I have seen the torque at launch and some sick ET's at the track from VMP's.
I never saw a Whipple in action at the track as of yet.

My goal is to break into the 9.90's on a 50 degree dry air kind of night.

It can hurt traction mostly (especially on street tires) and depending on tire size and shifts points it could mean the car will have to make an extra shift right before the traps which could hurt ET in some cases. There isn't a definite answer unless you know your entire setup and cars trap speed.

 

[bsb318]

I have 3.55 gears ... seems to work fine with my procharger making 561 foot pounds of TQ .. Can't say about a PD blower..

Your car stats are impressive.
Judging by your 1/8th your car should be a mid 10 sec. car.
Did you do that 1/8th on 93 ?
What was your 60 foot and tire size ?

I just saw the article on SVT about Sarasota Ford offering procharger stage 2 set ups new from the dealer.
Is that like what you have ?

 

[JasinEdward]

If you're looking to go 9's you might wanna consider 3.15's. At those power levels you might be shifting to 5th. A PD blower with 3.15's can light em up whenever it wants...

 

[smokinzx14r]

Your car stats are impressive.
Judging by your 1/8th your car should be a mid 10 sec. car.
Did you do that 1/8th on 93 ?
What was your 60 foot and tire size ?

I just saw the article on SVT about Sarasota Ford offering procharger stage 2 set ups new from the dealer.
Is that like what you have ?

Yes 93 Shell pump gas ..60 foot was 1.50 with just a bit of wheel spin .. The tires are M/T 305/45/17R drag radials .. Based on my 1/8 numbers mid 10s @ 133 sounds about right.. I'll find out for sure later this year when I can get to our 1/4 track ..

 

[Burnin4]

Here...

You're gonna need 140+ traps to crack into the 9's. 3.15's on a 28.8 at 7800 rpms will get you to 140 at the end of 3rd, which means you'll need to go to 4th. 3.55 goes into 4th at 124 till 164mph (same tire diameter/rpms). In this case, a 3.55 will be just fine, both gears will need to be in 4th for 140+ traps, which is what you'll need for 9's.

I'd go 3.55's anyway if you plan on going 9's, cause you'll be launching with a lot of power and the stock rear clutch packs eventually start slipping after enough burn outs/drag pass's. The 3.55's will come with the cast iron diff housing, which is stronger and it gives you options to upgrade differentials (Weltrac). No options to upgrade differentials for the aluminum 3.15 housing, so if you burn up a 3.15 you'll only be able to replace with another oem unit.

My TVS setup began to "peg leg" after about 30-35 line-lock burn outs at the strip, but I was still cutting 1.4's on 20's, stock stall/shocks. My rear diff's days were numbered, went ahead and made the entire swap, Weltrac rear differential, new OEM housing, 3.55 r&p, axles, gonna be hitting it harder on a stall with a 2 step now.

If you plan on going 9's then work with Ken Bjonnes, he has several TVs and Whippled customers already there, you'd be a flash away from your goals. Whipple's tune isn't going to get you there if you buy one of their tunes, a 10sec pass isn't even guaranteed. Gonna need 15psi+ on e85 as well, and I wouldn't run more then 12/13psi on 93. Good luck!

 

[bsb318]

Yes 93 Shell pump gas ..60 foot was 1.50 with just a bit of wheel spin .. The tires are M/T 305/45/17R drag radials .. Based on my 1/8 numbers mid 10s @ 133 sounds about right.. I'll find out for sure later this year when I can get to our 1/4 track ..

Which 1/4 mile track you going too go to ?

Bradenton or Orlando ?

Bradenton is awesome...Been there a bunch of times.

Thats a pretty impressive 60 foot time you did.

What gear and converter you running ?

My last stang was a 2013 with a stock 3.15 gear stock converter and Roush TVS with 82mm pulley custom 93 tune an aluminum 1 piece driveshaft and magnaflow cat backs.

That set up did a best 1.59 60 ft time , 6.99 at 101.21mph 1/8th ending with a 10.83 at 129.13 mph 1/4.

 

[bsb318]

Here...

You're gonna need 140+ traps to crack into the 9's. 3.15's on a 28.8 at 7800 rpms will get you to 140 at the end of 3rd, which means you'll need to go to 4th. 3.55 goes into 4th at 124 till 164mph (same tire diameter/rpms). In this case, a 3.55 will be just fine, both gears will need to be in 4th for 140+ traps, which is what you'll need for 9's.

I'd go 3.55's anyway if you plan on going 9's, cause you'll be launching with a lot of power and the stock rear clutch packs eventually start slipping after enough burn outs/drag pass's. The 3.55's will come with the cast iron diff housing, which is stronger and it gives you options to upgrade differentials (Weltrac). No options to upgrade differentials for the aluminum 3.15 housing, so if you burn up a 3.15 you'll only be able to replace with another oem unit.

My TVS setup began to "peg leg" after about 30-35 line-lock burn outs at the strip, but I was still cutting 1.4's on 20's, stock stall/shocks. My rear diff's days were numbered, went ahead and made the entire swap, Weltrac rear differential, new OEM housing, 3.55 r&p, axles, gonna be hitting it harder on a stall with a 2 step now.

If you plan on going 9's then work with Ken Bjonnes, he has several TVs and Whippled customers already there, you'd be a flash away from your goals. Whipple's tune isn't going to get you there if you buy one of their tunes, a 10sec pass isn't even guaranteed. Gonna need 15psi+ on e85 as well, and I wouldn't run more then 12/13psi on 93. Good luck!

I did not know the 3.55 option came with a different housing than the 3.15.
Good to know.
I actually met Ken a couple months ago at Bradenton during the NMRA.
I would go to him anyway just for the fact he was a really cool guy.
Sounds like you have a bad ass car.
What are you running ?

 

[Burnin4]

I did not know the 3.55 option came with a different housing than the 3.15.
Good to know.
I actually met Ken a couple months ago at Bradenton during the NMRA.
I would go to him anyway just for the fact he was a really cool guy.
Sounds like you have a bad ass car.
What are you running ?

MPR forged/sleeved longblock, Hellion twin 62's, Fore/ID1300's, finishing the build this week, 1000+ on e85 will be no problem. I previously had a VMP TVS setup that went mid 10's at 134 on 20's/pump gas/cats, tuned by Ken.

 

[v8440]

140+ trap speeds aren't necessarily required to go 9's. I made quite a few high 9 passes in my '91 notchback, and my highest trap speed was a little over 138. My best ET was 9.76, and I think that was at 137 and some change. Some of my very high 9 second passes were at 136 and change.

 

[Burnin4]

140+ trap speeds aren't necessarily required to go 9's. I made quite a few high 9 passes in my '91 notchback, and my highest trap speed was a little over 138. My best ET was 9.76, and I think that was at 137 and some change. Some of my very high 9 second passes were at 136 and change.

It's possible for him to go 9's at 139 but I'd go 3.55's for the other reasons I mentioned above. 3.15's are still going to top out at 136-139 depending on the rear tire 28.1-29/7800rpms.

 

[Dntalman]

3.55 gears are perfect! I love mine!! Think of it this way TQ gets you moving a car with 3.55 gears will move out great!

 

[bsb318]

3.55 gears are perfect! I love mine!! Think of it this way TQ gets you moving a car with 3.55 gears will move out great!

You have a nice set up too.
You ever run it yet ?
What made you get the Roush over a Whipple ?

Nice hellcat prayer...I don't think it was answered.

 

[olaosunt]

Pretty sure all the auto cars come with aluminum diff housing regardless of rear end gear ratios.
I swapped the the entire pumpkin with 3.55's to the iron diff housing with 3.31's(donor from a manual car) in my Hellion car.
I run a 28 inch tire .
Car has done a PB of 9.5@147 (1.47 60ft and 6.2@114 in the 1/8)

I think it would have been quicker in the 1/8 with the 3.55's(may be 60 better?)
but I did the swap mostly for strength .Not sure what the diff in the 1/4 would be since I never ran with the 3.55's at this power level .

I still have the pumpkin with the 3.55's and if it turns out I am wrong about the diff housing I may try it agan or swap the gears into an iron diff housing.
I could get a new one for convenience and go back and forth .

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