3.73 or 4.10 on auto 06 gt

scupking · Oct 5, 2007

kooldawg6 said:
Nice birdie chirps scupking That is about the same RPM I turn at 80 with the 4.10s. These 5 speed autos are nice.
Here are the trans ratios for the S197 GT. The autos nearly have the same first gear, but a steeper second & third gear than the manuals
TRANSMISSION
Standard Five-speed manual (Tremec 3650)
Gear ratios
1st 3.34:1
2nd 2.00:1
3rd 1.32.1
4th 1.00:1
5th 0.68:1
Final drive 3.55:1
Optional Five-speed automatic (5R55S)
Gear ratios
1st 3.25:1
2nd 2.44:1
3rd 1.55.1
4th 1.00:1
5th 0.75:1
Final drive 3.31:1

I agree. I heard that your auto is much better then the S95. Stock my car was very clunky in the shiffts but with any auto a custom tune will make a world of difference. I also just ordered blisteins and FRPP B springs. Can't wait to see how she drives after that. Anyways 4.10s would probably be the better gear in the s197 auto.

maxima · Oct 5, 2007

when cruising at 75 80 what are your rpms at ? thanks wit 4.10s

kooldawg6 · Oct 5, 2007

maxima said:
when cruising at 75 80 what are your rpms at ? thanks wit 4.10s

With the factory 235/50-18(27.2" tall), I run about 2800 RPM @ 75 and about 3000 RPM @ 80 in OD. On a highway trip, 75 MPH will still get you low 20s for MPG.
In a few weeks I will be going to a 28.3" rear tire which will drop my revs a bit. I'm guessing 100. The tire size will grow by 4%.

Five Oh Brian · Oct 6, 2007

S197's are heavy, so I went with 4.10's for my 07 GT automatic. Also went with a big (maybe too big) stall converter so that my car launches at 3,800 rpm's at the dragstrip (peak torque is 4,200 rpm's, so I launch just short of the ideal rpm's). Only other mod is a Predator tuner set for 93 octane gas. Still have the factory exhaust & air intake, even the factory airbox with paper filter. On drag radials, it runs consistent 1.80's to the sixty foot line, 8.40's in the 1/8 mile and 13.30's in the 1/4 mile, so it pulls hard from a stand still.

With the factory 18" wheels/tires, it turns 2,800 rpm's at 80 mph. Gas mileage barely dropped with the 4.10's (down about 1 mpg city down to 14 mpg, and basically the same on the highway at 23 mpg). The stall converter has killed my fuel economy as the car is always prone to rev if I give it any throttle. Getting about 12 mpg city now, and no better than 20 mpg highway, with mixed driving around 15 mpg over an entire gas tank.

For a drag car, the 4.10's (or 4.30's) would be best. Street/strip car, I'd still get 4.10's. 3.73's just aren't enough change from the factory gearing to really feel satisfied with the difference. Generous overdrive keeps fuel economy almost the same, regardless of gearing.

Stall converter at around 3,000 to 3,200 rpm's would be ideal for guys with the automatic (check out www.fuddleracing.com), but only if you can stand the fuel economy drop. The converter alone, dropped my sixty foot times and 1/8 mile times about 2 tenths of a second.

Leftoverchinese · Oct 7, 2007

3.73's work just fine for me, although i have wondered how much better i'd do with 4.10's

Bullitt2343 · Nov 17, 2007

maxima said:
bullit 2343 did u feel it alot , off the line and driving around with the 3.73s did it pull alot harder

Yes- great for daily driving, gets the jump on the lights-

It all depends on how you plan on using your car and how much 70+ driving you do.. 2400-2600 is do-able but when running 3k rpm's for hours at a time your going to increase engine wear plus use more fuel....

3.31 to 3.73 = big differance (.42)
3.31 to 4.10's = huge differance (.79)

fobra559 · Nov 17, 2007

I'd say 4.10's and a stall converter for you car. That alone will get you low 13's and maybe very high 12's if the conditions are right. If you don't race and do a lot of highway driving, 3.73's will do fine.

ranger04 · Nov 17, 2007

You can be quick or you can be quicker, If I didn't need my car for a DD, I'ld run 4:56's. 4:10's isn't anything to be afaid of as they put them in 4 cylinder rangers, explorers, jeeps right from the factory. 4:10's are a power gear and works well behind 4 cylinders, surely your 4.6 could take them without breaking a sweat. I ran 4:56's in my 70 maverick with a boss 302 create motor and 4-speed on the street. I drove it to highschool everyday. It ran 12.90 in the 1/4 and topped out at around 112 mph. However, gas was about 58 cents a gallon in 78, not a big deal, now I couldn't afford to run 4:56's, but I will 4:10's. You just don't want to run out of steam before the end of the 1/4, with 4:10's you should be fine, even 4:30's if you wanted to push it. Needless to say, even 3:73's will be a big improvement over stock.

fobra559 · Nov 18, 2007

ranger04 said:
You can be quick or you can be quicker, If I didn't need my car for a DD, I'ld run 4:56's. 4:10's isn't anything to be afaid of as they put them in 4 cylinder rangers, explorers, jeeps right from the factory. 4:10's are a power gear and works well behind 4 cylinders, surely your 4.6 could take them without breaking a sweat. I ran 4:56's in my 70 maverick with a boss 302 create motor and 4-speed on the street. I drove it to highschool everyday. It ran 12.90 in the 1/4 and topped out at around 112 mph. However, gas was about 58 cents a gallon in 78, not a big deal, now I couldn't afford to run 4:56's, but I will 4:10's. You just don't want to run out of steam before the end of the 1/4, with 4:10's you should be fine, even 4:30's if you wanted to push it. Needless to say, even 3:73's will be a big improvement over stock.

58 cents per gallon! man I wish those prices were here right now. I have to pay 3.69 per gallon

kooldawg6 · Nov 18, 2007

ranger04 said:
...4:10's isn't anything to be afaid of...You just don't want to run out of steam before the end of the 1/4, with 4:10's you should be fine, even 4:30's if you wanted to push it.

I still have alot of steam at the end of the 1/4 mile. I was trapping 106 @ around 5200(+/-100). As far as crusing RPMs and MPGs, after stepping up the rear tire size to 28.3" from 27.2", I've reduced RPMs by nearly 300(can cruise at 85 MPH @ 3000 RPM now)and have gotten back 1-1.5 MPG(if I keep it to 70 MPH on the interstate). The car still feels just as fast by SOTP. Never took it to the track with the new wheels/tires to see and don't plan on it as I will have dedicated 17s with stickies next year.

ranger04 · Nov 18, 2007

Yeah Kooldawg6, 4:10's should work out great for a good all around gear, street and track. As you say, he should have plenty of steam left when he lights the board. It allmost seems like the newbe's are afraid of 4:10's as this question is ask alot. Actually, 4:10's are a pretty tame gear and is put behind 4 bangers from the factory. Now when you start running 4:56, 488, or 5:13's, then your getting radical.

kooldawg6 · Nov 18, 2007

(Off the record of course)I've hit 130 and it was still pulling. I didn't look at the tach as I was more concerned on what was in front of me and a quick glance at the speedometer. That is plenty fast for me for sure! I've talked to Spyder7724 who has 4.30s and says it is still easily streetable and cruising at highways speeds.

Five Oh Brian · Nov 18, 2007

I ran 4.30's in my 03 Mach 1. Totally streetable as the overdrive keeps revs in check in 5th gear. I went with "just" 4.10's in my 07 GT as the overdrive isn't as deep (.71 vs .62) and I didn't want to be over 3,000 rpm's cruising at 80 mph on the freeway (it's 2,800 rpm's with stock tires and 4.10's).

StonePony · Nov 19, 2007

The 3.73 gear is the best all-around gear for the automatic.
In fact 3.73 + automatic + twin -screw= great combination.
The important thing if you are a drag racer is what gear will you be in when going through the traps? I am running a 3.73 and trapping at 120 MPH at the top of 4th gear. If I had 4.10s it would be too much for me.
If you look at KB's web site they recommend the 3.73.
You realy should run 4.10 -4.30 gear in a higher revving motor than 6200 RPM.

Five Oh Brian · Nov 19, 2007

For those of us who aren't going to add a supercharger (or other power adder), we'll be trapping 100-110 mph in the 1/4 mile and 4.10 gears leaves enough room to do so.

On shorter 275/40/17 drag radials, I cross the finish line at 102-103 mph about 5300 rpm's with the 4.10's in 4th gear. With factory height tires, it would be lower, of course. For those with lots of bolt on's who trap at 110 mph, that's about 5600 rpm's with 4.10's and factory height tires.

Either way, that leaves a bit of a cushion for us with NA GT's.

kooldawg6 · Nov 19, 2007

I don't know what RPM Spyder crosses the line, but I believe he's running a 28" rear tire and traps in the 114-115 MPH range with the 4.30s.

steedman07 · Nov 20, 2007

I can only speak for myself, but I love my 4:10's with a centrifigal with my auto..If I had a roots, I would have gone with 3:73's of maybe even 3:55's.. It doesnt take long at all to get to 4,000 rpm's with 4:10's, where she really wakes up...On the highway, in overdrive, at 75 or so, it doesnt scream at all....its perfect

3.73 or 4.10 on auto 06 gt

scupking

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maxima

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kooldawg6

mine works really well and can take a fair amount

Five Oh Brian

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Leftoverchinese

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Bullitt2343

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fobra559

At least it's more erect and not floppy anymore.

ranger04

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fobra559

At least it's more erect and not floppy anymore.

kooldawg6

mine works really well and can take a fair amount

ranger04

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kooldawg6

mine works really well and can take a fair amount

Five Oh Brian

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StonePony

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Five Oh Brian

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kooldawg6

mine works really well and can take a fair amount

steedman07

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3.73 or 4.10 on auto 06 gt

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