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727tf for autox, valve body questions #2191799
11/07/16 10:24 PM
11/07/16 10:24 PM
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omahell, ne
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buconine Offline OP
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omahell, ne
Those that are running automatics for autox/road racing what are you running for a valve body? I was discussing this with the other lone mopar at nats and wondered if anyone was running a manual valve body.
I have a tci rev man vb from my old drag car laying around but i was concerned about hitting neutral if i needed to go back to first. It also has no gear braking in first which we thought would be good but i wondered how hard it would be on the trans when you got back on the throttle and everything re-engaged at speed.

I'd appreciate any thoughts. Trying to come up with a game plan while the car is all apart. Thanks!

Re: 727tf for autox, valve body questions [Re: buconine] #2191809
11/07/16 10:38 PM
11/07/16 10:38 PM
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Nebraska
72Swinger Offline
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72Swinger  Offline
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The guy that always says T/Anks runs an auto. Pretty sure its just a Transgo kitted stocker.


Mopar to the bone!!!
Re: 727tf for autox, valve body questions [Re: buconine] #2191895
11/08/16 12:00 AM
11/08/16 12:00 AM
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omahell, ne
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buconine Offline OP
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I guess i'm just thinking of the concerns of the tf from my drag days. Everyone was always preaching to not shock 1st gear so that you didn't lay the sprag over. Just curious if the same concerns apply to autox. With a 323 rear gear i'm going to be running first most of the local courses.

The biggest thing we were talking about is the advantage of no gear braking in first. Being able to slow/rotate the car with the brakes instead of the engine seemed to be a positive benefit of a mvb. I just don't know if this is hard on the sprag or not. I'm probably overthinking the whole thing but better safe than having a bomb next to my feet.

Re: 727tf for autox, valve body questions [Re: buconine] #2192215
11/08/16 03:34 PM
11/08/16 03:34 PM
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NW Chicago suburban area
Mopar Mitch Offline
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T/Anks ahead!

I've had and run my 727 forever... bullet proof... basic full automatic, standard shift pattern, ~TransGo shift kit. Regardless if what rear gear (mostly 323, also tried 355, 391, 430), I use the trans in 1st - 2nd alot back-forth.... and utilize trans with brake pedal to slow down... hard... as however needed.

323 you'll use 1st mostly for typical parking lot events, occassional 2nd then back to 1st.... also, consider a 2.9 gear... as you'll always be in 1st, but 2nd for higher speed tracks if/when you encounter them.... I have a 2.9 gear which I'm going to eventually try.

355 mostly 2nd and 1st just to get to get started.

391 and up... 2nd most of the time, maybe occasional 3rd for higher speed courses but quickly back into 2nd.

You want mid-range to upper rpms most of the time... ~3500 lowest- 4500-5500-6000-6500 common (low rpms barely have enough torque with a SB).

As far as I know, reverse manual automatics are not preferred as they simply take away the needed assistance for engine rpm braking. Also, the fatal chance of missing a shift (down-shifting back into 1st).

My sprag has been a-ok... stock best that I know of... probably better available for options... if its not broken why fix it?

Last edited by Mopar Mitch; 11/08/16 03:36 PM.

Mopar Mitch "Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers! Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
Re: 727tf for autox, valve body questions [Re: buconine] #2192257
11/08/16 04:54 PM
11/08/16 04:54 PM
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omahell, ne
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buconine Offline OP
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Thanks for the input, i figured i was overthinking things. The engine is a 500+hp 440, so i will have gobs of torque to play with. Guess we will bolt it together this winter and tweak whats needed once it's done.

Thanks!

Re: 727tf for autox, valve body questions [Re: buconine] #2192605
11/09/16 01:34 AM
11/09/16 01:34 AM
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Mountain View, CA
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68rrunner Offline
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I used a Cheetah Reverse Manual Valve Body for a few years with great success combined with a ratchet shifter. No missed shifts and easy bumps up and down between all three gears.

Re: 727tf for autox, valve body questions [Re: buconine] #2195036
11/12/16 01:47 AM
11/12/16 01:47 AM
Joined: May 2015
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Sacramento
norcal-fjo Offline
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I run a 727 and 3.23 SG in mine. I can run 1st gear in almost all courses, but have to shift once in a while. With 26" tall tires, I think 2.94 would be better, and i am in the process of building a Sure grip 2.94 right now. I like the engine braking, and wouldn't want to run without. Have fun!

Re: 727tf for autox, valve body questions [Re: buconine] #2196109
11/14/16 12:06 PM
11/14/16 12:06 PM
Joined: Feb 2010
Posts: 1,645
Phila. Pa.
Mattax Offline
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Mopar Perfomance's Turbo Action shift kit. It will not force a downshift to first. That's the main difference I'm aware of between TurboAction and Transgo kits. Also the TA kits are specific to the year(s) of the valve body. With selector in 2nd, it still downshifts, upshifts to 1st as needed. The TA kit has engine braking in all gears.

I've run it both with and w/o the accumulator spring and currently am favoring the softer shift. It's a matter of whether you feel the shift might unexpectedly break the rear loose on a turn (autocross).

I generally run with selector in 2nd except for very small and tight courses. It's easier to be smooth in second. Choice depends on personal driving style, fastest sections of the course, and whether the course leans toward slaloms (momentum) or turns and straights (braking and acceleration).

My choice of gearing also relates to the fact that I'm running a much shorter tire than most of you guys.

Re: 727tf for autox, valve body questions [Re: buconine] #2199816
11/21/16 05:16 AM
11/21/16 05:16 AM
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Aurora, Colorado
451Mopar Offline
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If you are manually shifting to low, then the low/reverse band should be applying. Taking off in drive, low is held by the sprag without the band apply. I think a stock VB with TF-2 kit would work.
The question is the option to shift into first at any speed?
For a street car, I don't recommend the option because sifting into first at 50+ MPH will float the valves (yep, I bent a few valves this way), but in auto-X with a good shifter and attention to speed/RPM it might be something you would want?

Re: 727tf for autox, valve body questions [Re: 451Mopar] #2203922
11/28/16 05:07 PM
11/28/16 05:07 PM
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Posts: 1,440
NW Chicago suburban area
Mopar Mitch Offline
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Mopar Mitch  Offline
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451Mopar --- yesss... for AX, to be able to shift into 1st at any speed is desirable... learn the skill and it'll provide good race time results!


Mopar Mitch "Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers! Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
Re: 727tf for autox, valve body questions [Re: Mopar Mitch] #2205331
11/30/16 05:04 PM
11/30/16 05:04 PM
Joined: Feb 2010
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Phila. Pa.
Mattax Offline
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I try not shift, same as when autocrossing a manual transmission. Each shift cost measureable time so unless the engine is really dogging, and even then its better to look for a way to carry more speed so as to not lose the rpm.
Again, it depends on courses, gearing and driving style.







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