So like I promised, I compared the Pressure control of the Autotrans Inerceptor with the B&M shiftplus. The results might (or might not) surprise you. For reference, here are how the two circuits look
B&M Shiftplus is a simple set of two resistors you can select between
The ATI uses an NMOS transistor that you bias with a simple low power potentiometer (i.e. variable resistor). Essentially, its a good way to make a high power potentiometer.
... and here is the result
Long story short, if all you care about is max line pressure, go with the B&M...or wire in a cutoff switch.
Personally, I was expecting only the output voltage to decrease, and was surprised to see that the duty cycle decreases with an external load. This means that the JBody PCM must use a current feedback loop to protect the PCM's output circuitry from over-current, which is a very good, safe design. In the video, I mentioned that the computer "freaked out" a couple times. What that meant is that when I either put the ATI at full turn (counterclockwise) or the B&M to step "2", I would get the sharp current spikes like you see in the video, but then they would go away, and the computer would essentially just shut off the PCS control all together. This is almost certainly the reason you have to occasionally shut the car off whenever you switch from step "2" on the B&M in order for the PCS control to come back.
I will see if I can do the TCC side of the ATI tomorrow...no promises.
I have no signiture
this neat!
i want more!
please!
My car was made with wrenches, Not chopsticks.
Good info man!
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
i approve of this info.......good stuff
RIP JESSE GERARD.....Youll always be in my thoughts and prayers...
Interesting info for sure.
I would just skip both of these and use HPT.
From when I had a B&M on the Reaper you could feel the harder shifts in normal driving (yes you can turn it off), but you can set it up with HPT to only affect WOT, and not normal driving.
FU Tuning
I agree completely, John. Like I said in the video, these are static devices, and so you can't really do anything interesting with them.
The point is, though, some people either can't afford or simply don't care to buy HPT. So, it's good to know how and why these devices work, and whether it's worth it to them to spend more for the ATI over the ShiftPlus. Honestly, beyond the TCC control, I really don't see the allure of the ATI over the B&M, unless you absolutely must have the pressure somewhere between step 1 and step 2 of the ShiftPlus
I have no signiture
only WOT on hpt huh... i didnt know that. jesus its a nightmare to figure out though...
-Z Yaaaa- wrote:only WOT on hpt huh... i didnt know that. jesus its a nightmare to figure out though...
You can do all, but you donlt have to. You have normal and performance.
FU Tuning
Just tune the performance part, and leave the normal one alone, and while driving around normally it is drive like stock.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
I'm using HPT but have the ATI to take care of the slush box.
I'm also set on the line pressure to 75% or 3/4 control to give me the perfect shift points for daily use and track use. Having it set for full line was a bit much in the 'slam' factor of the tranny so the 75% setting has been working fine for me now for over 8 years.
Good info you got there and the trouble you went through to find this information out.
My reasoning for not using HPT for tranny settings is that once I eventually do the manual swap the settings won't make a bit of difference to me. With the ATI it's just icing on the cake.
Misnblu.com
Newbie member since 1999
Thank you Dave and JBO! 
