Which gear ratio will do me best in the long run

PinkieT

Well-Known Member
Joined
Jun 22, 2015
Messages
2,522
Reaction score
989
Location
Cleveland
98 GT, manual trans, 3.27 rear. I bought a set of Cobra brakes and snagged the 3.73 geared rear axle with it. Engine mods right now are BBK CAI, performance coils and wires, Flowmaster muffs. Phase I of the build will add PI heads and intake, larger throttle body and plenum. However, Phase II will be a mild turbo or blower setup. Should I keep the 3.27s in there knowing the power adder is in the future, or just go with the 3.73 rear?
 

the5.ohh

Legend
Joined
Oct 15, 2012
Messages
9,561
Reaction score
129
Location
Shaolin, NY
Unless you're running stupid high boost and racing it 24/7, I'd go 3.55 and call it a day.
 

Rob04Mach1

New Member
Joined
Dec 1, 2015
Messages
74
Reaction score
2
I've had Stangs with 4.1 & 3.7 Gears but I was running tall over height Street Slicks so it was a good combo
For the normal (short tires) most Stangs run (and I run on my Mach 1) I have to admit the 3.5 Gear is perfect for big power :headbang:
 

07GtS197

Well-Known Member
Joined
Mar 16, 2015
Messages
2,635
Reaction score
996
Location
Fort Myers, Fl
Since you plan on boosting your stang I wouldnt do the pi head swap. It raises your compression so the amount of boost you can on pump gas is limited.
 
OP
OP
PinkieT

PinkieT

Well-Known Member
Joined
Jun 22, 2015
Messages
2,522
Reaction score
989
Location
Cleveland
Thanks for the input. I already have two axles, one with 3.21 in the car and the Cobra axle with 3.73 sitting in the garage, so swapping gears to 3.55 is not something I really want to do.
 
OP
OP
PinkieT

PinkieT

Well-Known Member
Joined
Jun 22, 2015
Messages
2,522
Reaction score
989
Location
Cleveland
Unless you're running stupid high boost and racing it 24/7, I'd go 3.55 and call it a day.

Thanks for the input. I already have two axles, one with 3.27 in the car and the Cobra axle with 3.73 sitting in the garage, so swapping gears to 3.55 is not something I really want to do. Boost would be low, racing not on the radar.
 
Joined
Sep 8, 2013
Messages
3,620
Reaction score
957
Location
Pleasanton/Hayward, CA
Fun street cruiser that won't get spanked too badly by newer cars.

I'm going with 355s after I swap out the 410s in my car but I'm also tracking the car. But I still use it for a daily so having 373s in 2 previous sn95s I'd vouche for them. They're fun and not too aggressive. Especially if you have different rear ends and they're already in then just go to the 373s, you'll enjoy them
 
Joined
Sep 8, 2013
Messages
3,620
Reaction score
957
Location
Pleasanton/Hayward, CA
Also...you're gonna get spanked....learn to live with it. I don't ever try to worry if I'm gonna get spanked or not because I know my car doesnt compete. I do however know for the year and generation of cars put out in that Era that it's one of the faster cars so I hold my car up to others from the 1990-2000 time because that's roughly what it could "compete" with
 
OP
OP
PinkieT

PinkieT

Well-Known Member
Joined
Jun 22, 2015
Messages
2,522
Reaction score
989
Location
Cleveland
Since you plan on boosting your stang I wouldnt do the pi head swap. It raises your compression so the amount of boost you can on pump gas is limited.

Good point. I read though that the power added to a motor by a blower or turbo is based on the power of the engine you start with, so a power adder PI motor with 260 hp stock would have more power at the end than a NPI motor starting with 225 hp. Maybe I should just do the PI swap, headers, throttle body and plenum, and a tune and call it a 300 hp day.
 

the5.ohh

Legend
Joined
Oct 15, 2012
Messages
9,561
Reaction score
129
Location
Shaolin, NY
Thanks for the input. I already have two axles, one with 3.27 in the car and the Cobra axle with 3.73 sitting in the garage, so swapping gears to 3.55 is not something I really want to do. Boost would be low, racing not on the radar.


Hmmmmmm fair enough. Go 3.73!
 
OP
OP
PinkieT

PinkieT

Well-Known Member
Joined
Jun 22, 2015
Messages
2,522
Reaction score
989
Location
Cleveland
Also...you're gonna get spanked....learn to live with it. I don't ever try to worry if I'm gonna get spanked or not because I know my car doesnt compete. I do however know for the year and generation of cars put out in that Era that it's one of the faster cars so I hold my car up to others from the 1990-2000 time because that's roughly what it could "compete" with

My 500 hp 440 six pack did a lot of spanking. I'm at the age that now I just wanna have a fun drive. I was actually thinking of a Miata - great handling fun cars - but I had to go with a rumbling V8.
 
Joined
Sep 8, 2013
Messages
3,620
Reaction score
957
Location
Pleasanton/Hayward, CA
My 500 hp 440 six pack did a lot of spanking. I'm at the age that now I just wanna have a fun drive. I was actually thinking of a Miata - great handling fun cars - but I had to go with a rumbling V8.

lol well a 500hp isnt a stock or era correct number for our cars hahah, with that much power by all means my friend do all the walking over fire kittens and vetties you want
 

Witzy0070

Active Member
Joined
Dec 10, 2009
Messages
836
Reaction score
2
Location
Montana
After running multiple power adders and 3.55s, 3.73s, and 4.30s in less than a 4 year span... On your build I would personally recommend the 3.73s. I miss my 3.73s because of the way the T-45 has ratios in 3rd. However, you're running a T-5 from what I gather. The 3.73s will be happy with future mods and current and give you a beyond good balance for drivability, acceleration, and highway comfort in fuel economy and noise.
 

07GtS197

Well-Known Member
Joined
Mar 16, 2015
Messages
2,635
Reaction score
996
Location
Fort Myers, Fl
Good point. I read though that the power added to a motor by a blower or turbo is based on the power of the engine you start with, so a power adder PI motor with 260 hp stock would have more power at the end than a NPI motor starting with 225 hp. Maybe I should just do the PI swap, headers, throttle body and plenum, and a tune and call it a 300 hp day.

Yes and no. Im not saying to skip the blower because using to stock npi heads will limit you. They wont flow like pi's but you can still make good power with npi heads and will keep the stock compression ratio. Doing a pi swap minus the heads wont give you gains like that of a full pi swap but youre not losing out on much.

My recommendation, 3.73's, turbo, npi heads, pi intake, either pi or blower cams and an aftermarket throttle body and plenum. A pi swap and full bolt ons would give you a good bump in power but what if you want more? The compression will necessitate either lower boost or race gas/e85.
 

Thomas_W

Well-Known Member
Joined
Jan 25, 2007
Messages
1,485
Reaction score
62
Location
Capon Bridge, WV
Speaking from a having an all motor car on 4.10's (both NPI, PI head swapped and Pi'd motor) roots blower with 4.10's and a turbo PI'd motor with 3:55's...

either go 3.55 or 3.27. 3.55's even with a fully built motor on 12psi (about 550rwhp) was stupidly fun and would knock the tires off in every gear (including fifth!).
With a turbo you benefit more with a numerically lower gear like a 3.27 or 3.55 because the engine stays loaded longer so get the turbo to spool and stay within its power band longer. To Tall of a gear and your constantly shifting, to low and you never get to shift, so its really a balancing act.

If it was me, i'd stick with the 3.27's.
 

rz5.0

Legend
Joined
Mar 26, 2010
Messages
5,853
Reaction score
131
Location
Great state of TEXAS
Turbo 3.27, centri blower, 3.73.. Don't worry about the high compression.. It will be more fun with a high compression low boost set up

Sent from my LGLS991 using Tapatalk
 

Latest posts

Forum statistics

Threads
77,492
Messages
1,503,740
Members
14,965
Latest member
wbarter

Members online

Top