2 potentiometers, one circuit

So the same amount of voltage across a 10K load will draw the same current as it does across a 5K load?  If both pots are connected, minus the wiper, it will be a 5K load vs. the original 10K.  Chances are he will not hurt anything with this device, just trying to give all the information he might need to make an informed decision.

Too many assumptions.... It's (probably) NOT across the 10K pot. And if it were, chances are it would be more than a 10k pot (eg, 20k-50k). Like I said, think about it. Rarely in circuit like this would the pot be effecting an output (in a stress sense). But also as I said, the pot is connected to the tacho chip (2 pins; I can't tell where the 3rd pot wire goes; yet) so it doesn't seem to be effecting the RPM cutout level...

Here's what I was thinking.... Not that the direction of the original pot is arbitrary - the relay and new pot can be from the wiper to either end depending in the circuit....

That is even worse.  Place the wiper of the original pot at top of the stroke, now place the wiper of the added pot at the right end of the stroke.  Now engage the parking brake.  What kind of load is shown to the controller?

Original poster:  Hold up a minute, do not attempt the last diagram shown until we get this sorted out.

Alright I'll let you electrical masters decide because quite frankly I don't understand the issues with either methods. For tommorow I guess I will just use it as a launch control with no lower high rpm limit. Thanks for the help looking forward to a solution

Nah - go with Idiot's suggestion. Maybe I'm misinterpreting the whole thing (I thought you wanted a second rev limit given a certain trigger) including the "break before make" problems.... And I haven't deciphered the circuit past the 1k trimpot being between pins 9 & 11 of the CS289 (Vreg & SQout?) and ??? .... (Not to be confused with the added pot as I confusingly replied earlier...)

If you can find 20K pots, I would really reccomend doing it that way.  If you can not, you will more than likely be OK with the 2 10K pots. 

Notice terminal 30 of the relay is at the top of the picture.  I did not draw the diode, but I think you need to use one.  Instructions for diode are in the picture.

Alright I'll get on to assembling that later in the day. What is the issue with running 10k pots vs 20k ones ?

If you are using only one relay, the pots will be connected to the device.  If you parallel a second 10K pot across the device, this will yield a 5K load on your device.  Chances are you will be fine with the device having to provide the power into a load that is twice as demanding as originally intended.  I just not want to give you any information that may cause a failure for your device.  If it were me, I would use 3 relays, one per wire.  You can then use the 10K pots.  If you want to use the 3 relays, I left instructions a few posts ago.

If I can find 2 20K pots it would be fine to the device as if using a single 10k? I know a single TPDT would be the best option but I cannot find one locally just yet and I have space constraints in the plastic box that i want to encase the whole thing in and 3 SPDT relays won't fit.