Cheapest way to convert 4 speed 2nd gen car to T-56

Discussion in 'High Tech Retrofits' started by z2871rsbb396, Jan 24, 2010.

  1. BondoSpecial

    BondoSpecial Veteran Member Lifetime Gold Member

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    I have always wondered, if you gear your car appropriately, what good is a 6th gear? I had an 0.6x overdriven 5 speed with 3.73s and the overdrive was too much overdrive. I cruised well under 2000 rpms with a big cam and it was borderline annoying. With 4.10s it would have been perfect and I still would have had a low rpm cruise that didn't lug the cam below its powerband. Yeah the drop from 1:1 to 0.6x is big but if you are dumping it in top gear you aren't trying to accelerate

    just curious, I am running a junk 4 speed and at some point am going to be looking into a proper 5 or 6 speed
     
  2. badazz81z28

    badazz81z28 Veteran Member

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    Last I checked...Im not 100%, but the T56s 6th is darn near the same ratio as the TKOs 5th...Worth a look into

    Also Im sure I have read the gear spread is better in the TKO. Again just some things to consider during your research.
     
  3. Aceshigh

    Aceshigh Veteran Member Lifetime Gold Member

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    Gear spread varies on which T56 you get. So you can't really say they're all the same.

    Depends on what gear you want coming out of the hole.
    I wanted 3.73's or 4.10's for maximum neck snap fun. :bowtie:

    So with 3.73's I can put it in 6th gear at ~65mph @1500rpm with a 27" tire and cruise.
    I don't have a crazy cam, so that's obviously a factor to consider tho.

    I figured 4.10's would get old really quick driving around town.
     
    Last edited: Jan 25, 2010
  4. z2871rsbb396

    z2871rsbb396 Veteran Member Lifetime Gold Member

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    The gear ratio is one of those things that does have me a little miffed.
    With one of the tranny options you get a better 1-3rd ratio and the other you get a better 4-6th.. in my opinion. Someone should rebuild it and make the best of both.

    I have seen some gear/ final drive type calculators. ( I think it was on Bonzo's) build thread... anyone have a link to one. I would like to compare the two different T-56's options as well as the TKO 600... that might help end the debate in my head...

    My big block don't have a crazy cam, it sounds good but does not require high RPM's to make power... it is basically a 1500 to 6500 range.. (almost like the edelbrock, so I don't think crusing at 80 at around the 2000 RPM range would be lugging down the highway.

    Currently the car has 275 60r15's in the rear with 3:55 gears, with the 4 speed that is in it, there is no cruising (75+) on the interstate. These gears will be changed once the tranny is installed to make the best out of whatever tranny gets installed.

    I do appreaciate the input (replies) but it is really more of a debate on what is the cheapest or best bang for the buck... I would like to save some coin on this mod to have the change for other upgrades that I would like to do.. and as most know, that list always grows faster than the budget. That is one of the reasons why I want to keep the current bellhousing, clutch, flywheel etc. that I have. I wish someone lived close so I could go for a ride in a TKO600 equiped ride.

    I am really surprized to see that Bonzo and Todd both have 6 speeds and state that they would use the TKO 5 speed if they were to do it again. Why? biggest reason? no need for 6th gear, gear spread? cutting up the car? cost?

    Kirt
     
  5. Todd80Z28

    Todd80Z28 Moderator Staff Member Lifetime Gold Member

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    For me, I'd rather save the 50lbs with the TKO, because I don't do that much highway cruising anymore, so I don't need the ultimate lowest RPM on the interstate. There was a time when I did- after I put the T56 in in 1995, I daily drove the car- it was my only car- until Dec '98. My wife had an Accord, but I drove the Z to work, 45 miles round trip, mostly highway, every day for nearly 4 years. I also drove it on the occasional road trip to Fort Myers from Orlando (200 miles or so each way). So, at the time, I really desired and made use of the T56. Plus, good 5spd options were limited back then.
    These days, the car is strictly a toy. I cruise for fun, drive it back home to WV when me and my buds go to car shows, etc, but that's about it. I do drive it to work VERY occasionally, but that's 6 miles each way.

    I will say that having both 5th and 6th is nice. I can cruise in 5th around town at 45-50mph, around 1500-1700rpm. I can also get on the interstate, continue in 5th to about 60, then shift into 6th (about 1350rpm at 60mph). If your engine will not be happy at these low RPMs, then I would say you are carrying one too many gears. Get the TKO with the .64 5th, you can use a more reasonable rear ratio (say 3.31 or 3.23 if you want really low cruise RPM), or keep a higher ratio to keep a higher strung (meaning more cam) engine happy at 2000-2300rpm at 65mph. My engine is happy at 1500rpm, so I get the full use of the transmission. I know some guys that don't shift into 6th until 70-75mph- that is a waste IMO. Just gear the car right in the first place.

    On what to purchase- I think a used T56 in good shape is more than stout enough to sit behind your big block for years. The "Magnum" thing sounds nice, but if you don't see 550+hp in your future, there's no reason that a good used unit won't stand up. And you can save a lot of loot. I wouldn't concern myself for a second about putting a 450hp small block (like a stout 383) in front of my transmission. They're well built right from the factory, IMO- I think you really have to brutalize it (high RPM clutch drops, power-shifting, etc) to break it. Some people drive like that, I don't.
     
  6. marc_b

    marc_b Veteran Member

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    I have a couple of buddies go with the tko600 in there camaro's and they love it. bolts right in.
     
  7. BonzoHansen

    BonzoHansen Administrator Lifetime Gold Member

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    Todd, I can't believe a TKO is 50 lbs less than a T56. Really?
     
  8. PolarBear

    PolarBear Veteran Member Lifetime Gold Member

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    Yeah I would like to see some numbers on this too, There is no way the T56 weighs 125 lbs like it says, I can pick one up and carry around quite easily as Scott has seen me do on several occassions :) . I saw one of the TKO trans' at SEMA and it is close in size to a T56, I find it hard to believe that it weighs 50 lbs less, maybe 20

    **EDIT** I just checked on the Tremec site, the TKO is between 5 and 25 pounds less then a T56 depending on the actual models involved.
     
    Last edited: Jan 26, 2010
  9. EricsZ28

    EricsZ28 Veteran Member Lifetime Gold Member

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    I have a TKO600 that replaced my original 4-speed.

    My only comment (never having done the T56 conversion) is that I wish I had gone with the road race version of the TKO600. The only time I use 5th gear (3.73's with 29" tires) is when I'm going 65+ on the highway. Otherwise, I'm dropping below my cam's usefull rpm range (<1800 RPM's) and the car is lazy.

    Otherwise, if you opt for the offset shifter, it will bolt right into your 4 speed car. I simply clearanced my tunnel...

    +1 for CC5S (Hurst Driveline Conversions).
     
  10. Todd80Z28

    Todd80Z28 Moderator Staff Member Lifetime Gold Member

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    I had bad numbers in my head, then. I figured the TKO at 95lbs, and the T56 at 145. Looks like I was low and high.:)
     

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