Overall 4.10s are only going to help your top end acceleration and speed. There will be a brief moment when you would be in 5th with 4.10s but in 4th with a lower numerical gear ratio, which might hurt performance over a tiny range of speeds. Once both are in 5th, the 4.10s will eat up 3.55s. Top speed in our case is power limited, not gear limited.
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Steeda CAI&UDP/Bama Tune/FRPP 4.10 Steeda Sport Springs & HD Strut Mounts / D-Specs 2006 GT - 13.37@105.8
Overall 4.10s are only going to help your top end acceleration and speed. There will be a brief moment when you would be in 5th with 4.10s but in 4th with a lower numerical gear ratio, which might hurt performance over a tiny range of speeds. Once both are in 5th, the 4.10s will eat up 3.55s. Top speed in our case is power limited, not gear limited.
even with the auto and OD?
I notice that when with the OD off and in 5th I think@80-100 the rpms drop and sit at 4k or so though speed still picks up the tach barely moves or only gradually. So with the gears it would be in the higher rpm range- thus more pick up?
Also riding around town and in the city,I am kinda having second thoughts about 4.10s. I kinda like how the stock gears react to day to day city driving,worried about hitting the gas too hard either to pass or lane changes,don't want to either spin the tires too much or launch the car too hard in the wrong situations lol.
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2008 MUSTANG GT/CS 5 SPEED AUTO C&L RACER CAI BRENSPEED 90 OCT TUNE PYPES MUFFLER DELETE RACE PIPES
Posts: 384
Joined: 12/24/2006 From: New Orleans,, Louisiana Status: offline
Let me jump in if you all don't mind. I have a Whippled HO. SC'ed 07 with 3.55 gears and am thinking about a gear change. What are your opinions on this? I like the 3.55's but think I might rare up the power with the 4.10's. And the car is a standard 5 speed. Opinions please.
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2007 Mustang GT Premium Package. Alloy Gray with . CDC Hood supports, Dynamite Sticks sequencial brake lights. MGW shifter 18" Bullits, Cervini's C 300 Kit with side exhaust.. Prothane motor mounts, and OH YEAH, a WHIPPLE HO. 1 Bad ASS SC.
And remember although you will be using higher rpm, the engine has more mechanical advantage which means you won't need to step on the throttle as much when going up a hill
IN anauto you also have to have the shift schedule recalibrated to adjust for the fact that the engine will see more RPM's for the same road speed. The Lower the gear, the more important it is to rescale the shift schedule.. In extreme cases, without a rescale, I've seen cars that won't shift at all past second gear.
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"Vera" '07 GT. Manual, 3.55's, Spohn Adj LCA's, Hurst Shifter, GT 500 Rear and chin spoilers, GTA's, Steeda UDP, Roush rear springs, ProFab CAI #6, BBK Shorties
"Dyno's Rarely Lie, but E.T.'s and Trap speed say so much more."
Posts: 1543
Joined: 12/19/2006 From: Northern California Status: offline
If I had an SC and not a turbo I would get 3.90 instead of the 4.10s. With the 4.10s, depending on the tire you have, you will be close to redline or at it going across the line in the 1/4. I trapped in the mid 116-117 mph range with 4.10s and 265/40/18 DRs. I trap the same now with the 3.55s and can now leave it in 4th up to the stock 145ish. With the 3.90s I think you could get into the low 120's and still have plenty of low end grunt off the line to keep your ET low. Kind of a happy medium. Someone could probably do the math and give a better estimate.
I have the 4.10s...in a box. Hopefully next Saturday I will get them installed. According to this website http://www.wallaceracing.com/Calculators.htm my gears will actually be closer to 4.30 this is because of my tire height.
Overall 4.10s are only going to help your top end acceleration and speed. There will be a brief moment when you would be in 5th with 4.10s but in 4th with a lower numerical gear ratio, which might hurt performance over a tiny range of speeds. Once both are in 5th, the 4.10s will eat up 3.55s. Top speed in our case is power limited, not gear limited.
even with the auto and OD?
I notice that when with the OD off and in 5th I think@80-100 the rpms drop and sit at 4k or so though speed still picks up the tach barely moves or only gradually. So with the gears it would be in the higher rpm range- thus more pick up?
Also riding around town and in the city,I am kinda having second thoughts about 4.10s. I kinda like how the stock gears react to day to day city driving,worried about hitting the gas too hard either to pass or lane changes,don't want to either spin the tires too much or launch the car too hard in the wrong situations lol.
I wish I could comment on the auto with 4.10s. I would imagine the physics behind it are the same, but I'm not smart on shift points or when or how the auto shifts.
but I'm 100% with vapor trails. If my top speed (drag limited not rev limited) is 160mph. I will go 0-160mph faster with 4.10s than with 3.55s.
Now the problem with 4.10s comes in certain roll racing situations. Like if I did a 50 mph roll race with 4.10s I would really have to be in 3rd gear, whereas with 3.55s I could still be in 2nd gear.
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2005 Mustang GT
JLT II CAI, Kooks LTs w/ catted X, FRPP CMCV deletes, FRPP 4.10 gears, Steeda UDPs, FRPP Axle backs, BMR LCAs, BMR Rear Sway Bar, BMR Panhard Bar, Panhard Bar Brace, CHE K member brace, Xcal2, Hurst Shifter, Steeda STB.
I wish I could comment on the auto with 4.10s. I would imagine the physics behind it are the same, but I'm not smart on shift points or when or how the auto shifts.
but I'm 100% with vapor trails. If my top speed (drag limited not rev limited) is 160mph. I will go 0-160mph faster with 4.10s than with 3.55s.
Now the problem with 4.10s comes in certain roll racing situations. Like if I did a 50 mph roll race with 4.10s I would really have to be in 3rd gear, whereas with 3.55s I could still be in 2nd gear.
with a tuner from what I hear shift points can be calibrated,say at 6k.
here is a vid of another member (Baha) doing a 0-125mph run;auto,4:10s,pulleys,tune.
Not sure but I think the gears would help with roll racing because it would always be in the powerband.Being stock gears on my GT,it takes a second before power kicks in which sucks because the 5 speed guys (especially lightweight imports) would always get the take off during roll racing.
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2008 MUSTANG GT/CS 5 SPEED AUTO C&L RACER CAI BRENSPEED 90 OCT TUNE PYPES MUFFLER DELETE RACE PIPES
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RE: Thinking of going with 4.10s - 
