So how does that work with the GV. Do you have a button on the shifter or is there some sort of programmable computer that comes with it? Seems like if you use a button that it would take a fair amount of practice to get used to getting the GV to do what you want. How much tunnel mods do you have to do to get the GV in and at the same time getting the correct driveshaft angle?
Yes the GV comes with a stand-alone module that has two functions, and an on/off switch.
1) when you select od by the switch, the ecu modulates the apply-signal, to gently engage the overdrive clutch. and
2) it prevents od from being engaged in reverse, which just about instantly breaks the unit.
To use the GV as a splitter, I had to bypass the ECU.
As soon as I did that, I discovered that the thing shifts like lightning. However, there is an annoying time-delay, between when exactly I punch the button and when the shift occurs.
I assume this is caused by the pump coming up to pressure.
The pump is driven by the driveshaft.
The pump is powered by the spinning driveshaft.
The unit does not seem to be able to store pressure, or at least not enough to stay engaged during a stoplight. The unit seems to have an internal leak, probably by design, I don't know.
It is IMO, that it is these things together, conspire to create the time delay.
Once overdrive is selected, it never disengages unless you come to a stop, and stay stopped for some period of time, and I'm guessing about 30 seconds.
The faster the driveshaft spins, up to a point, the quicker it is ready to shift.
With 3.55s the delay is noticeable.
With 4.88s it was hardly noticeable.
Once the unit decides to shift, it is pretty much instant, and at WOT will bark the tires at 80mph. At 50/55 it will initiate tirespin at WOT.
The delay, changes with roadspeed.
The delay I'm guessing is never more than a half a second at low driveshaft rpm, and diminishes to almost nothing at say 80 mph. But it's never instant. So then, if you were trying to have a consistent shift at the racetrack, a data-logger could measure the delay.
Speaking of backshifting
When you outshift the GV, the power needs to be interrupted, so as not to break it. I have a clutch, so when I am outshifting, at the track, I have to co-ordinate the time delay to the clutch. That is to say; I hit disengage, wait a tiny bit of time, stab the clutch, and Pow! she outshifts. This, to me is natural. I used to treat it as a normal shift. But as time went on, I figured out that I could cheat quite a bit. So I sped it up into fast-motion, and also figured out over time, that the clutch did not have to be completely disengaged.
To help me with the Reverse issue, (cuz I forgot one time which cost me $1500 plus shipping to get fixed), I installed a red LED on my tach, to indicate when the unit is on; and then trained myself to diligently look at the tach before every shift.
Now, when
selecting od at cruising speed, because the unit now shifts so hard, I treat it as another shift, and just stab the clutch.
and so, yes,
it takes a bit of practice, but, in the description above, I think I may have exaggerated the pitfalls somewhat because, as a streeter, running street gears, and the standard Not-Commando-A833 , there is no point in splitting any gears, because there is only at best, a 7% difference, which at 5500 is like 385rpm.
If you do have a Commando or an A833od, wekk then, you are only gonna split the 1>2 shift, cuz second with 3.55s tops out around 65mph which is why I'm running those 3.55s in the first place, lol.
And so, I suggest to the Newbe, to run a Second switch to return the ECU into circuit, for most driving, cuz it will automatically soften the engagement into od at cruising speed.
As to driveshaft angle, With factory springs, you'll never get it exactly right.
The driveshaft is so short, that the Angle Change from WOT at 430hp, to cruising at 50hp, is like more than 7 degrees. and hitting the middle is the best that you can hope for.
I almost got it right the first time, but with my car lowered, she needed another 2-degrees, by shims, to make it as good as it gets. I can still occasionally feel it, but I gotta concentrate.
For me, I knew all this going in, so working out the bugs was just wrenching.
As to installation;
Honestly, fitting the unit into my car was almost a breeze.
I did this job on a 4-post hoist with traveling jacks.
So the first thing to do was to fit the B/E adapter they sent. Which required one of the Front shifter bosses to be ground/cut right off and another to be trimmed(IIRC).
After that, I bolted the unit on, and
with the traveler-jack, I lifted under it, hard enough to imprint the tunnel where the interference occurred. Then I dropped the unit, and massaged the tunnel in those places. Then remounted the unit, and repeated , and so on until no more massaging was required. I think this took three installs. So next was fitting the Cross-member. With the unit jammed into the tunnel,I could see that the early style one was gonna be a PITA, so I went to my shed and got a spool mount.
This allowed dropping the spool, be elongating the mounting slots. And so the unit was almost ready to mount. The unit was jammed into the tunnel, so to get some clearance, I slotted out the X-member mounting bolts roughly a quarter inch. Then I installed the bolts, and dropped the unit down, then installed the nuts. It was in.
Next was the Speed-O. The factory drive in the A833 is not used, You now take driveshaft rpm off the GV. The unit comes with all the parts to hook it to your cable. But, if you change the rear gears, you will need Chevy gears. And when the Chevy gears run out cuz you just installed 4.88s, well you'll need a cable doubler to get back into a normal operating range, and then, another Chevy gear..... I now have, a box full of Chevy gears lol.
Ok so, there you go
Btw,
I never liked the forward-mounted stock shifter location. I understand that with a bench seat, you are sorta married to it. But I have buckets.
So taking a lesson from the Dodge Viper, I moved my Short Stick shifter way back between the buckets, and right next to my hip, and raised it high enough so that the top shifter mounting bolt goes in from inside the cabin.
Then fabricated some large-tube shift rods, and loc-tited the shift levers to the studs. Since 2005, I can't remember ever miss-shifting again.
I mounted the Radio-shack mini-switch OD button in the shift-ball at the top, where my thumb never hits it. The Line-loc is on the handle, just below it.
I installed the late-style shift-cover, cuz the scissor-style detents require a commitment to shift, and they never accidently jump out of gear, with my hand resting on the ball.
