Open track rear gear selection. Help!!! T-5 5.0

Discussion in 'Road Racing' started by Man-child79, May 10, 2014.

  1. Man-child79

    Man-child79 New Member

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    Pretty much stock powered 94 Cobra. Stock T-5. I've done some calculating online and I'm thinking 3.31 rear gear. My tires are right at 26" tall and that will have me around 135 at the top of 4th gear. Open trackers and road racers let me hear your thoughts based on experience.

    One of the guys was running a 94-95 GT at CMP and was running out of gear with a 3.73 (he said 125) @ the top of forth. Redlining at stock limiter. I need to find a middle ground and I'm thinking 3.31... What do you guys think or recommend based on experience? I know for sure I'd run out of gear at CMP and Roebling.

    On a side note / FYI, I'm more concerned with running out of gear than top speed. There's nothing worse than getting half to three quarters of the way down the front or back straight and hitting the redline.
     
  2. ba#97

    ba#97 Well-Known Member

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    I'm planning on going 3:55's. right now the car has 3:73's and I run out at the end of the straights a thunderhill and big willow. 3:55's would be the ebst middle ground especially for the twisty tight corners. you still want to be able to highlight the tq that our cars make and use it when you can. so yep....i'd say 3:55's is pretty spot on.
     
  3. Man-child79

    Man-child79 New Member

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    Agreed... I did a little more digging around and found that if ran up to 6000 rpm with a 25.7" tall tire at the top of four gear it would put me right at 130 mph... I'm trying to find a middle ground were I don't kill what tq the engines put out and bring my speed up in fourth...

    Do you know were the stock rev limiter / fuel cut off is set at???

    I've read 6250, 6500 and 7000 rpm but I think a 6000 rpm shift point would be ideal... I do have upgraded internals / valve train component that should handle 6000 or 6250 with no problem.

    What speed are you limited to at the top of fourth gear???

    Thanks!
     
  4. ReplicaR

    ReplicaR Well-Known Member

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    Based on what my powerband is, and how fast I get the car up to, I've decided to pick 3.55s. I figured that 3.73s would run me into the rev limiter, so I didn't want that.
     
  5. Burninrock24

    Burninrock24 Active Member

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    Thats why you remove the rev limiter. To reach out and touch the face of God.
     
  6. ReplicaR

    ReplicaR Well-Known Member

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    I rev to 6500, and still make power there, anything beyond that is just hurting the motor.
     
  7. Man-child79

    Man-child79 New Member

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    Do you know were the stock rev limiter / fuel cut off is set at???

    I've read 6250, 6500 and 7000 rpm but I think a 6000 rpm shift point would be ideal...
     
  8. Man-child79

    Man-child79 New Member

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    Raised / modded limiter or stock limiter settings?
     
  9. ReplicaR

    ReplicaR Well-Known Member

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    Mine is tuned, so mine is 6500. When the motor was stock, I've revved it that far, just to see what happens (which is nothing really), and it went to 6500. My guess is, if you want to find out, just rev it, and see what happens. If the motor is stock, it's a non-interference motor, so you shouldn't hurt anything.
     
  10. RichV

    RichV Well-Known Member

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    Not sure on the limiter. Rev it in idle and find out. It don't make power past 5500 anyway, so here's my experience.

    ran 3:27 in the Fox race car, great gear. Better to have a useable 4 speed than a unuseable 5 speed. My SN got 3:73, I'm going back to 3:27s. I run out of gear, even holding it in 4th reving the piss out of it, just breaks lifter retainers and they end up seizing your oil pump. Shifting to 5th just feels like dropping an anchor while everyone around you inches past. You can get a road race 5th gear too. Then you can go higher rear gear.
     
  11. kb1982

    kb1982 Active Member

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    The manual cars hit the limiter at 6250. I can vouch for this with 2 tachs in my car. Stocker is accurate in my Cobra, who woulda thought?? As for auto's,Ive read 5500, but Ive never driven one so Im not sure.
     
  12. Pete@FTR

    [email protected] Active Member Preferred Vendor

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    I'll be copying you sir. Will be fun to test out at the new thunderhill :headbang:
     
  13. ba#97

    ba#97 Well-Known Member

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    I've never hit the rev limiter on my car and I am in the same boat as richv is. once I get passed 5500 its not giving me much more if I rev it to 6000. that being said I try not to shift into 5th anyways cuz it's just a waste of time knowing you'll be dropping it back down more than likely really quickly....i.e. thunderhill...by the time you hit 5th (which won't gain you any speed anyways) you're on the binders for turn one. that's why I'm planning on the 3:55's. though am I the only one here that would love to just have a 4 speed geared right? I only ever use 3rd and 4th anyways. lol.

    pox - as for the thunderhill west...I'm pretty interested in how it is cuz it is definitely a night and day difference from the original track. way more technical. I'm mostly excited about running thunderschleiffe as we call it though! both tracks put together!
     
  14. Man-child79

    Man-child79 New Member

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    Based on what you just said where do you find it beneficial to shift at?
     
  15. Man-child79

    Man-child79 New Member

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    You as well sir... Based on what you just said where do you find it beneficial to shift at?
     
  16. darinmasse

    darinmasse Member

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    Autos are 5500 at least mine is I accidently hit my limmiter frequently

    Sent from my Huawei-U8665 using Tapatalk 2
     
  17. RichV

    RichV Well-Known Member

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    I use the dynosheet for a baseline shiftpoint, but personally I shift just above 5500. 5800 max, I don't have a shiftlight so I go by sound and the occasional glance. Unless I stay in gear just before a braking zone, I may keep it rather than shifting. By the time you complete the shift, you're braking and downshifting.
     
  18. ba#97

    ba#97 Well-Known Member

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    I haven't had the chance to hit up the dyno in the car at all to see where the best shift point would be but from a seat of the pants feeling I am right where rich is. 5500 and then you can kind of feel the car fall flat on it's face. I have to feather it at thunderhill at the end of the straight cuz I don't feel like revving the crap out of it for no reason and it's pointless to shift by then. and seeing as I'm not racing or doing TT yet I'm fine with just lifting. lol. I think the fastest I've had the car at the top of 4th gear was like 120ish honestly. I've never been close to 135. lol.
     
  19. mustang3550

    mustang3550 New Member

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    After looking at gears charts with speed vs rpm im leaving 3:27 in my irs with 26.1 rear tire. I want rpm to stay under 62 6400. I want survivability.

    Coming out of turns at 3500 in a high gear and making the motor pull you were you dont have to fight torque from rear gear 3:73 or 4:10 snapping your ass end around.

    Sent from my SCH-R530X using Tapatalk
     
  20. ba#97

    ba#97 Well-Known Member

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    I don't think you'll ever be that high in rpm's even with 3:73's. actually you won't be. and that's mainly up to you when it comes to revving it out. I'd say 3:27's would be the lowest I would want to go and that's mainly because you make more of your speed up in the corners and even with my 3:73's I've never really had an issue with the power I have of snapping the back end around due to power oversteer. I wouldn't blame the gears on that at all. the only issue I have with the 3:73's is that at the one fast track we have in norcal I run out of gear at the end of the straightaway. but for the most part you aren't going to be topping your car out all the time anyways. you'll be in corners more than straightaways....remember that. so don't think top speed too much. cuz you shouldn't be as worried about that as you might think.