Chip for 4+3
Thread Starter
Drifting
Joined: Dec 2003
Posts: 1,493
Likes: 94
From: Westfield MA
Thats what I do now, but at my advanced age, I forget to take it out of OD when I stop sometimes, then I get that big jump to second gear with OD when I am not expecting it. Ideally, once the car is in first, it shouldn't go into OD until I hit the switch.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
Here's a Link that shows how the different years of the OD unit works.
Once you get the coolant temp to 122 degrees, you should be able to use the button on the shifter to shut the OD completely off until you turn the ignition key to off. You can engage the OD with the switch anytime to return to the "automatic" mode and hit it again to turn the OD off; or use the throttle position to control upshifting in lower gears.
Note in the chart where the OD can be shut off by throttle position; that works great until you shift into 4th when OD will engage again.
Just remember that hitting the button the first time when temp passes 122, it only works until you have to re-start the engine, then you have to hit the button again.
Once you get the coolant temp to 122 degrees, you should be able to use the button on the shifter to shut the OD completely off until you turn the ignition key to off. You can engage the OD with the switch anytime to return to the "automatic" mode and hit it again to turn the OD off; or use the throttle position to control upshifting in lower gears.
Note in the chart where the OD can be shut off by throttle position; that works great until you shift into 4th when OD will engage again.
Just remember that hitting the button the first time when temp passes 122, it only works until you have to re-start the engine, then you have to hit the button again.
Melting Slicks
Joined: Aug 2003
Posts: 3,401
Likes: 397
From: Lakeville MI
With custom programming the 4+3 can do just about anything you want it to.
In an 86, both first gear and 4th gear are detected by the ecm by comparing the engine rpm/mph (or n/v ratio) to pre-set limit values.
This permits separate control strategies for 1st gear, 2nd and 3rd gear together, and 4th gear.
As you are aware, the O/D is intended to be off in 1st, and available in 2nd-4th gear.
I've gone through many variations of 4+3 tuning myself. Here are a few examples of how I've used my 4+3 in different ways:
Currently, I prefer to run OD off by default, also with the OD off following downshift feature (my own invention).
In this manner, the OD is only activated for upshifts via the switch. Kick-down functions and normal OD downshifts occur normally. To me this is the most natural feeling approach for the 4+3 .
The 4th gear activation after 5 second delay with very sensitive 1st gear look ahead ok setting was also very reasonable and comfortable for normal driving.
The 5 second delay feels quite natural when driving and also avoids an accidental upshift into OD while drag racing, or at least delays it until after the stripe if OD happens to be left on by mistake.
In an 86, both first gear and 4th gear are detected by the ecm by comparing the engine rpm/mph (or n/v ratio) to pre-set limit values.
This permits separate control strategies for 1st gear, 2nd and 3rd gear together, and 4th gear.
As you are aware, the O/D is intended to be off in 1st, and available in 2nd-4th gear.
I've gone through many variations of 4+3 tuning myself. Here are a few examples of how I've used my 4+3 in different ways:
- OD off by default. This is the most basic mod.
- OD activation in 4th gear after a 5 second delay with very sensitive 1st gear look ahead ok setting (15% tps) to effectively lock out 2nd and 3rd OD for most normal driving. There are other ways to do this as well.
- OD off following OD downshift or kickdown prevents re-activation and also prevents re-activation after an engine stall or rapid restart (bonus).
- 1st -> 2nd ->2nd OD forced shift with rev-limiter assistance to save having to shift into 3rd and 4th for drag racing. This is well suited to 3.07 gears in an L98 since 2nd OD is numerically equivalent to 3.54.
Currently, I prefer to run OD off by default, also with the OD off following downshift feature (my own invention).
In this manner, the OD is only activated for upshifts via the switch. Kick-down functions and normal OD downshifts occur normally. To me this is the most natural feeling approach for the 4+3 .
The 4th gear activation after 5 second delay with very sensitive 1st gear look ahead ok setting was also very reasonable and comfortable for normal driving.
The 5 second delay feels quite natural when driving and also avoids an accidental upshift into OD while drag racing, or at least delays it until after the stripe if OD happens to be left on by mistake.
Last edited by tequilaboy; Nov 27, 2007 at 11:16 AM.
Thread Starter
Drifting
Joined: Dec 2003
Posts: 1,493
Likes: 94
From: Westfield MA
With custom programming the 4+3 can do just about anything you want it to.
In an 86, both first gear and 4th gear are detected by the ecm by comparing the engine rpm/mph (or n/v ratio) to pre-set limit values.
This permits separate control strategies for 1st gear, 2nd and 3rd gear together, and 4th gear.
As you are aware, the O/D is intended to be off in 1st, and available in 2nd-4th gear.
I've gone through many variations of 4+3 tuning myself. Here are a few examples of how I've used my 4+3 in different ways:
Currently, I prefer to run OD off by default, also with the OD off following downshift feature (my own invention).
In this manner, the OD is only activated for upshifts via the switch. Kick-down functions and normal OD downshifts occur normally. To me this is the most natural feeling approach for the 4+3 .
The 4th gear activation after 5 second delay with very sensitive 1st gear look ahead ok setting was also very reasonable and comfortable for normal driving.
The 5 second delay feels quite natural when driving and also avoids an accidental upshift into OD while drag racing, or at least delays it until after the stripe if OD happens to be left on by mistake.
In an 86, both first gear and 4th gear are detected by the ecm by comparing the engine rpm/mph (or n/v ratio) to pre-set limit values.
This permits separate control strategies for 1st gear, 2nd and 3rd gear together, and 4th gear.
As you are aware, the O/D is intended to be off in 1st, and available in 2nd-4th gear.
I've gone through many variations of 4+3 tuning myself. Here are a few examples of how I've used my 4+3 in different ways:
- OD off by default. This is the most basic mod.
- OD activation in 4th gear after a 5 second delay with very sensitive 1st gear look ahead ok setting (15% tps) to effectively lock out 2nd and 3rd OD for most normal driving. There are other ways to do this as well.
- OD off following OD downshift or kickdown prevents re-activation and also prevents re-activation after an engine stall or rapid restart (bonus).
- 1st -> 2nd ->2nd OD forced shift with rev-limiter assistance to save having to shift into 3rd and 4th for drag racing. This is well suited to 3.07 gears in an L98 since 2nd OD is numerically equivalent to 3.54.
Currently, I prefer to run OD off by default, also with the OD off following downshift feature (my own invention).
In this manner, the OD is only activated for upshifts via the switch. Kick-down functions and normal OD downshifts occur normally. To me this is the most natural feeling approach for the 4+3 .
The 4th gear activation after 5 second delay with very sensitive 1st gear look ahead ok setting was also very reasonable and comfortable for normal driving.
The 5 second delay feels quite natural when driving and also avoids an accidental upshift into OD while drag racing, or at least delays it until after the stripe if OD happens to be left on by mistake.
Melting Slicks
Joined: Aug 2003
Posts: 3,401
Likes: 397
From: Lakeville MI
It is easy to get into custom programming and do it yourself.
Lots of good info is available in the scan and tune section and on other sites like TGO.
The basics:
Buy an inexpensive eprom programmer that will work with your pc, get a moates style adaptor and some flashable chips from moates.net, or get a spare memcal and and a u/v eraser.
You can read, erase and reprogram your existing memcal many times, but its always a good idea to have a spare memcal or adaptor on hand, in case the original eprom is damaged somehow or over-erased.
I use a socketed memcal and u/v eproms and simply erase, reprogram and replace the eproms into the socketed memcal as desired.
You also need an appropriate editor program like TunerPro or TunerCat and appropriate definition files to work with your ecm mask. These programs are very inexpensive or shareware.
Lots of good info is available in the scan and tune section and on other sites like TGO.
The basics:
Buy an inexpensive eprom programmer that will work with your pc, get a moates style adaptor and some flashable chips from moates.net, or get a spare memcal and and a u/v eraser.
You can read, erase and reprogram your existing memcal many times, but its always a good idea to have a spare memcal or adaptor on hand, in case the original eprom is damaged somehow or over-erased.
I use a socketed memcal and u/v eproms and simply erase, reprogram and replace the eproms into the socketed memcal as desired.
You also need an appropriate editor program like TunerPro or TunerCat and appropriate definition files to work with your ecm mask. These programs are very inexpensive or shareware.
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