Advised by a fellow SVT Stanger to AVOID 4.10 gears! Soo confused now, help.

Discussion in 'SVT Tech Forum' started by Craig Mack, Dec 15, 2003.


  1. Craig Mack

    Craig Mack Busted Buffing the Bishop Founding Member

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    In short, he says 4.10's are horrible gears for the street, and that they are only good for the strip from a dead stop. If I get 4.10's, they will ruin all my sweet spots in the power band. For instance, downshift into 3rd @ 70mph on the highway. If I were to go 4.10's, I would be shifting out of 3rd too quickly, thus giving my competitor the advantage, becuause they would pull ahead when I shifted. Same goes for second gear. If I was racing someone from a 40mph roll, I would have to shift instantly, and would lose to a stock geared snake.

    That's basically the opposite of what I had assumed. What I want is more low end passing power. For instance, if I need to merge ahead of someone at a low speed, I want to be able to pass them easier. I thought gears would significantly improve my passing power in 2nd and 3rd gear around town, becuase the combination of shorter gearing + our high redline would match perfectly.

    Basically, not i'm just confused. I was going to get 4.10's for Christmas, but now I don't know what to do. I'm also afraid i'll run out of gear in 1st too fast. I hear my first gear will end at like 20mph at redline with the 4.10's.

    People say don't fear the gear, and DO IT! But I want a significant around town improvement in passing power. Part of me thinks that gears primarily fool you into thinking your faster, becuase of the shortness of the gear ratios. The other part of me thinks that these shorter ratios can help me tremendously at low rpm, and at high rpm becuase we have 6800rpm redlines!

    Please help me out here, Christmas is coming and if I don't order really soon it'll be too late!
    #1
  2. 1996COBRA

    1996COBRA Founding Member

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    4.10s minimum.... I would even recommend the 4.30s over 4.10s. 4Vs love gear.
    #2
  3. COBRyan

    COBRyan Founding Member

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    4.30 are the gear I always choose with the dohc
    #3
  4. Lo Pony

    Lo Pony Founding Member

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    If you're primarily around town, then go with the 4.10's. If you do lots of interstate driving, then go with 3.73's. I can tell from your post, that I think you'd be happier with 4.10s than 3.73s, but if you're talking about dropping it into 3rd on the interstate, you'd better stick with nothing lower (numerically higher) than 4.10s (i.e. no 4.56s).
    #4
  5. 99SVTAddict

    99SVTAddict New Member

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    Bull. This person has no clue. 4.10's are horrible at the track because it forces you to shift right before the traps, so you aren't in your idle power band.

    4.10's are the perfect street gear for a DOHC....think about it. Power kicks in around 4,000 RPM's. 4.10's were a blast on the street for me before and after I got the blower. I'm having a solid axle put in now, and I stepped it up to 4.30's.

    Trust me, you will get 4.10's and at first think, this is awesome...then after a week or so and you get use to it you will be thinking you should have gone with 4.30's. :D

    You will NOT be dissapointed with 4.10's.
    3.73 :shrug: Why waste your time and money.

    Have fun :nice:
    #5
  6. Snake03

    Snake03 New Member

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    You can easily calculate what your RPM will be in any gear at any speed by using the ratio of the new gear to your current gearing. For example, I'm with the stock 2003 3.55 gears in my Cobra, and cruise at 70MPH in 6th is ~2000RPM.

    3.73/3.55=1.051. 1.051*2000=~2102 RPM (70 mph, 6th gear, 3.73 rears)

    4.01/3.55=1.155. 1.155*2000=~2230 RPM (70 mph, 6th gear, 4.01 rears)

    You can also calculate the mph you would be at for any rear gear change in the same manner, by flipping the ratio. For instance, (just picking numbers to use as an example). My cobra redlines 3rd gear at just about 100 mph, so at the strip I would be doing the 3-4 shift just a tick or two before the traps. Switching to 4.01's....

    3.55/4.01=.885. 100mph*0.885=~89mph. IOW, my 3/4 shift which now happens at redline at 100mph will now be at redline at 89mph

    To calculate your redline speed in first (or any other gear), determine what your current redline speed is and use the ratio for whatever gearing you have and the one that you're thinking of.

    Make sense?
    #6
  7. Craig Mack

    Craig Mack Busted Buffing the Bishop Founding Member

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    So, will 4.10's improve 1/4th ET's over my stock gears at all, despite the shift near the end of the track?

    The one thing I like about the stock gears is flooring it from 3000rpm in first gear. It hauls some pretty nice @ss, and the gear is long so you travel a far distance. It gives that sensation that your going somewhere. Shorter gears will give you a "thrown back" feeling, but you wont feel the catipult of gaining lots of speed. Does that make any sense? Maybe i'm being too dramatic, becuase I don't know what mph each 4.10 gear redlines at in comparison to the 3.27's, but I don't want to be thrown back in my seat without actually going anywhere.

    Which brings me to my next point. Snake03, thanks for the explanation. Yes, it makes sense. One question though, since when did they start making 4.01 gears? :shrug: :p

    Does anyone know the redlines of the gears on the stock 96-98 Cobra? I'll try to see if I can find some numbers...
    #7
  8. WhiteDevil

    WhiteDevil New Member

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    Man your thinkin too much into this. Here is the plain and simple truth. A cobra with stock 3.27 gears versus a cobra with 4.10s, the stock gears cobra is going to get raped. Ok from any roll from any mph, the 4.10 cobra is gonna work the 3.27 cobra. Your car makes power past 3,500 and gears will get you there faster. Yeah you will probably be almost at the top of 2nd when the stock gears cobra is at the top of 1st but what does that matter when your pulling it like its standing still. With the stock gears if you like to drop it into 3rd at 70mph like u were saying before just wait till you get 4.10s and you rpms fly up to 5 grand insteat of like 3,500. Just get the gears, man.
    #8
  9. 99SVTAddict

    99SVTAddict New Member

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    Yes, you will improve your 1/4 mile.

    First gear with 4.10's will be shorter...if you punch it at 3K RPM's, you will get more wheel spin than with 3.27 stock gears. As for being thrown back in your seat, you will be thrown back harder with the 4.10's, and even though you shift earlier than with the stock gears, when you do shift you will be more in your ideal power band (RPM) so you will continue to feel pinned back.

    Add a blower on there and it gets damn scary quick :nice:
    #9
  10. missouri_guy197

    missouri_guy197 New Member

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    I love my 4.10's on the street...they are perfect if you don't go to the track much since they do make you shift right before the traps...I have a set of 4.30's waiting to go in this spring because I do go to the track a lot...4.10's from a 40 punch on the highway are great in 3rd gear, that'll take you all the way up to about 95mph...rather quickly too may I add...
    #10
  11. Craig Mack

    Craig Mack Busted Buffing the Bishop Founding Member

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    Based on Cobra03's formula, first gear with 4.10's will redline at approx 36.987mph vs. 45mph for stockers.

    Now, i'm confused on how to do the other gears. I tried to do third gear and came up with like 35mph. Here is a chart of the stock gear ratios/mph.

    Gear Ratio Speed
    1st 3.37 45 mph
    2nd 1.99 77 mph
    3rd 1.33 115 mph
    4th 1.00 152 mph
    5th 0.67
    Reverse 3.22
    Final drive 3.27
    #11
  12. Craig Mack

    Craig Mack Busted Buffing the Bishop Founding Member

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    Do you recall how much mph you gained/ET you lost in the quarter with the addition of the 4.10's?
    #12
  13. Mr.DOHCtor

    Mr.DOHCtor New Member

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    I second him. Hes right... 4.10's are optimal for the street and horrible for the track. 4.30's are better for track usage. However, I have 4.10s right now and they work like a charm. Seeing as how you only really have to shift three times total when cruising, 1st,3rd,5th, all at 3000 rpms, it makes driving a lot easier when cruising but when under wot, they speak for themselves.
    Go with at LEAST 4.10's!
    #13
  14. Craig Mack

    Craig Mack Busted Buffing the Bishop Founding Member

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    You say 4.10's are horrible for the track, but would you still say that they are a significant improvement over the stock gears for the 1/4th?

    In "passing power" acceleration, like 45-65, and 20-50, etc. is where i'm really looking for a big boost in acceleration.

    I know it sounds like I'm beating a dead horse...I just don't want to do something as drastic as gears, and end up hating the short ratios. :bang:
    #14
  15. RAYS99COBRA

    RAYS99COBRA New Member

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    You will be happy with 4.10s. I just got them installed about 4 days ago and I am already wishing I went 4.30s. Your 4V will love 4.10s. Anything less and you probably won't feel much of a difference. Sounds like you got bad advice. Just look in the sigs and you'll see most of us are running 4.10s minimum. Don't fear the gear.
    #15
  16. mike keirstead

    mike keirstead New Member

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    My friend had 4.30s and his car just tears. It eats stock geared cobras to pieces. 4v love to rev. dont worry about the highway, youve got overdrive. Get the 4.30s for the track and the street. My cousin has 4.88s in his solid axle 03. It also has a Kenne Belle so you cant really compare. But they are a fun gear also.
    #16
  17. missouri_guy197

    missouri_guy197 New Member

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    Forget about the formula...this webpage has a calculator that makes things much easier...it doesn't have the T3650 that's in the 01 Cobra's but their gear ratios are close to the T45's

    http://www.corral.net/tech/gearcalc.html
    #17
  18. missouri_guy197

    missouri_guy197 New Member

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    My car was bought with 4.10's so I don't know what 3.27's even feel like...I test drove a 98 Cobra with stock gears but it was so long ago I forget what it was like...The real way to run 4.10's at the track is either to short shift the 3-4 shift so you get a little more out of 4th, or wind every gear out to 7k so at least you are shifting in the middle of the traps instead of before them...
    #18
  19. Snake03

    Snake03 New Member

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    Typo....meant 4.10's. :doh:
    #19
  20. Snake03

    Snake03 New Member

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    The guy is trying to understand how gearing changes will affect rpm/mph etc.

    If he understands that the changes in both mph and rpm in any gear are directly proportional to the ratio between the two rear gear sets in question then he's going to have a better understanding of the way his car works/reacts. AND, you don't have to worry about what transmission you have, what your tire size is, etc; and perhaps pick a wrong setup from the calculator........or use an approximation.

    Figure the ratio and it's inverse and you can apply that number to any speed/rpm combination you can get from your transmission.
    :banana:
    #20

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