Looking to do a custom tune based off the topgun..

jongrappin · April 13, 2011, 09:58:57 PM

I want to start with the topgun bin and then change two setting...
Increase boost a few lbs
change the shift point for overdrive....reason being. there are alot of 40mph roads around here and i noticed i have to accelerate to 47mph to get into overdrive then i can back down to as low as 43-44mph and maintain overdrive. I would love to shift into overdrive at approx. 40mph or at least less than 47mph....

any help with changing the overdrive?

whats a recommended boost level? i am running yellow top injectors, no cat, walbro 255 fuel pump, k&n

other thoughts.. this trans had a fresh rebuild 5,000 miles ago and also new torque convertor(if any of this matters or is relevant)

one other tweak.. I want the car to be able to shift from 3rd to overdrive at wide open throttle :icon_eek: :icon_rolleyes: i heard this was standard in 89 but the removed the abilty to shift to overdrive at wide open throttle in 1990. I think my car either doesnt shift to overdrive when wide open in third or i was to nervious to let the Rs go super high as i dont wanna drop my tranny but would like the overdrive dialed into getaway car status considering most new vehicles and police cars limit at 100 or 135.....

flybynite · April 16, 2011, 02:02:03 PM

The only thing computer controlled in the 4T60 is the torque converter. The only way to adjust shift points is with the vac modulator and the detent cable..

jongrappin · April 17, 2011, 03:15:53 PM

Quote from: flybynite on April 16, 2011, 02:02:03 PM
The only thing computer controlled in the 4T60 is the torque converter. The only way to adjust shift points is with the vac modulator and the detent cable..

I assume you are talking about the regualor this is on the vac line going to the transmission. the regulator has a valve that exits to the atmosphere? yes to verify i understand the part your talking about. Next question what regulator, size or part number and where to buy? again its a new torque convertor if this matters.

RobertISaar · April 17, 2011, 05:01:07 PM

yes, that's the vacuum modulator. you can get adjustable ones at lots of parts stores, you may need to specify something other than a 4T60 though. but vacuum modulators only control shift firmness, not shift points, that's the job of the TV cable.

jongrappin · April 17, 2011, 05:22:42 PM

Quote from: RobertISaar on April 17, 2011, 05:01:07 PM
yes, that's the vacuum modulator. you can get adjustable ones at lots of parts stores, you may need to specify something other than a 4T60 though. but vacuum modulators only control shift firmness, not shift points, that's the job of the TV cable.

From what you are telling me i do not need the modulator then. can i get alternate TV cables? I just want the transmission to shift early into overdrive. or is there a way i could rig a switch or something to trick it to switch into overdrive manually?

RobertISaar · April 17, 2011, 05:28:08 PM

from what i understand, it was an internal change to the transmission that locked out 4th gear with high throttle. maybe a valvebody mod can allow it.

the only way you could "trick it" would be to let off the throttle far enough to allow a shift, then get back into it, but not so much as to kick back down again.

jongrappin · April 17, 2011, 06:42:37 PM

Quote from: RobertISaar on April 17, 2011, 05:28:08 PM
from what i understand, it was an internal change to the transmission that locked out 4th gear with high throttle. maybe a valvebody mod can allow it.

the only way you could "trick it" would be to let off the throttle far enough to allow a shift, then get back into it, but not so much as to kick back down again.

it seems i have tired this.... i need to go at least 47 for it to shift. once it shifts i can let the car slow to 43mph without it downshifting, then i set the cruise at 43. i just dont want to have to go upto 47 then back down to 43 in a 40mph zone...... :icon_confused:

back to the second part of the tuning...

1. Should i increase/control the boost via a chip tune or should i get a gauge and manual controller....(i can already burn chips but dont have a gauge/controller and would rather put the $100 somewhere else if it is not needed)

2. I should adjust the variance in the idle to perfect idle.

3. should i increase fuel/air ratio seeing i have the yellow tops, walbro fuel pump, no cat, k&n.... if so how can i do this ?

jongrappin · April 17, 2011, 06:45:58 PM

other thoughts: logging

I have a spare laptop sitting around.... I am willing to use it to log...

1. What cable do i need to order to log data? what exact part and where to order from?

2. What software should I use to log data? where to download it from? and is there any configuration setting i would need to know?