Not the OP but it looks like they connect to U2 through the two diodes.

I meant where do the wires go to external to the board.

 

What do the wires on SS1 and SS2 connect to?

SS1 and SS2 go to the toggle switch

 

Maybe, just maybe...
That J260 component is a current shunt in series with the motor. The circuit detects the excess current when the motor reaches the end of travel and turns off the motor.

If this is the case then maybe (again) the new motor draws more current than the original.

Do they manufacture current shunts in set current intervals? Could I just purchase a few and trial and error my way until I find one that actuates correctly?

 

Do they manufacture current shunts in set current intervals? Could I just purchase a few and trial and error my way until I find one that actuates correctly?

That would certainly be possible. The current shunt is just a glorified resistor that has a low enough resistance as not to intervene too much with motor operation. However keep in mind that setting it too low will cause the circuit to never denergize the motor, probably overheating the motor.

 

You can try it now, short the shunt (safely) and see if the motor makes it all the way. Remove the power when it does as not to overheat the motor.

 

The suggestion of current monitoring is likely.
Is your replacement motor the same, or jerry rig?
What causes higher current is typically a higher load. If you road bumped your motor, good chance you have a mechanical bind. A 10 hp motor will move a 5hp load with the same current as a 5hp motor.

 

The suggestion of current monitoring is likely.
Is your replacement motor the same, or jerry rig?
What causes higher current is typically a higher load. If you road bumped your motor, good chance you have a mechanical bind. A 10 hp motor will move a 5hp load with the same current as a 5hp motor.

Although the motor's nominal speed at that voltage may be higher and thus a bigger power demand?

 

It seems that the control board is indeed set up to work like the automated window down system, where it cuts off when the current spikes at the end of travel. So I am guessing that the replacement motor draws a bit more current than the previous motor.
Are you able to operate the whole setup on a bench? Do you even have access to that valve assembly for debugging? Or is it already installed on a race car and no way you will ever get to even see it again?
What I would suggest, if you can do a bench test, is to see if helping the system move the valve so that the motor draws less current, makes it travel farther. One simple option is to put a small resistor in series with the motor to reduce the current, and see what that does for you. Probably 2.2 ohms and 2 or 5 watts for the resistor power rating. Another option is to contact the company that makes the control board and ask if they can provide one calibrated for a different sized motor.
How often does this valve need to operate, and how fast does it need to move?

 

It seems that the control board is indeed set up to work like the automated window down system, where it cuts off when the current spikes at the end of travel. So I am guessing that the replacement motor draws a bit more current than the previous motor.
Are you able to operate the whole setup on a bench? Do you even have access to that valve assembly for debugging? Or is it already installed on a race car and no way you will ever get to even see it again?
What I would suggest, if you can do a bench test, is to see if helping the system move the valve so that the motor draws less current, makes it travel farther. One simple option is to put a small resistor in series with the motor to reduce the current, and see what that does for you. Probably 2.2 ohms and 2 or 5 watts for the resistor power rating. Another option is to contact the company that makes the control board and ask if they can provide one calibrated for a different sized motor.
How often does this valve need to operate, and how fast does it need to move?

Its all installed on my own racecar in my garage. The reason the current doesn't match the old one is that Granatelli doesn't ship replacement parts, so the motor is a universal fit. Likely a different motor and almost certainly with a different transmission. But the resistor option is very clever. I appreciate the suggestion.

 

The suggestion of current monitoring is likely.
Is your replacement motor the same, or jerry rig?
What causes higher current is typically a higher load. If you road bumped your motor, good chance you have a mechanical bind. A 10 hp motor will move a 5hp load with the same current as a 5hp motor.

I don't think the mechanism is bound, the valve moves extremely easy by hand, i can turn the valve by pinching the stem between my middle and pointer finger, so no issues there. I think its likely that this motor doesn't have as high of gearing in the transmission as the previous one, so its having to work harder and thus draw more current

 

If the series resistor solves the problem then the challenge will be finding the best value.
This sounds like a cut-out valve, since that is the only kind that would be under that part of a "race" car. So it does not operate frequently, I am guessing. I suggest moving the motor installation to a safer location, more proyected from speed bumps.

 

Certainly the system monitors current. That part is obvious on the PCB. And of course they have removed the markings on the IC, that is very common among makers of small stuff that has no patent protection. It is most likely either a comparator or an op-amp, and with a bit of effort we should be able to reverse engineer the simple circuit and discover how to change the calibration to match the replacement motor.

 

It is most likely either a comparator or an op-amp, and with a bit of effort we should be able to reverse engineer the simple circuit and discover how to change the calibration to match the replacement motor.

It operates two relays so it would have to be a dual comparator or op-amp.
However, as those two diodes connect to pins 2 & 3 of the chip and I can see no other connections to those pins, I suspect that it is a microcontroller using weak pull-ups on those pins, The direction of the diodes would allow them to pull down the pins.

[EDIT] Also, Q1 looks like a voltage regulator which would only be needed for a microcontroller.

 

The idea that it is controlled by a micro is probably correct. Going to the Granatelli website gets this -
"Some exhaust cutout systems have an activation switch that must be held down to open and close the butterfly plates. That can lead to over torqueing the butterfly shaft, which can damage the internal gears of the drive system. The Granatelli exhaust cutout systems have a smart chip-controlled, one-touch switch to open and close the butterfly plates and prevent over torqueing. " From - https://granatellimotorsports.com/p-35854-exhaust-cutouts.html

 

I'm wondering how the chip can sense the current as I cant see a trace that connects to the chip from the supposed current sense resistor.
Maybe the OP can trace that part of the circuit to the chip? And maybe also do a resistance reading for that part?

 

I am thinking that the larger 3-terminal device is a power transistor, since the lead from the big chip resistor goes to the center pin.
With same angle pix of top and bottom on the same page we should be able to reverse engineer this board. I am not convinced that the IC is a micro.

 

I am thinking that the larger 3-terminal device is a power transistor, since the lead from the big chip resistor goes to the center pin.
With same angle pix of top and bottom on the same page we should be able to reverse engineer this board. I am not convinced that the IC is a micro.

Would make more sense, why would anyone give a voltage regulator a Q designator. I'm wondering why the 220ohm resistor is in there though. Could it be the base resistor?
P.S. if everything fails, buy this:
The design looks eerily similar and allows you to adjust the current by hand. Note: im not advocating the use of cheap aliexpress products in anything critical!