More wiring questions, G4+ Fury in Series 6 RX7

[Pete_89t2]

After the great responses I got last time, I did some digging into the FD wiring diagrams, and did some refining of my Link Installer I/O table. I'd appreciate some feedback on the revised installer I/O table (attached), to confirm I'm on the right track and to answer the new cruise control related questions below.

To reiterate on my specifics, I have a modified '93 US market RX7 FD that is managed by a Link G4+ Fury. It runs a single turbo (BW) and has a GM drive-by-wire throttle body adapted to it. I'm putting the factory Oil Metering Pump back on, and I'd like to use the factory cruise control switch gear and the G4+ to implement a cruise control functionality with my DBW throttle. On to the questions:

1. Reference how I intend to use Analog Voltage Input #6, for cruise control "cancel" "set/coast" and "resume/accel" functions, will this work given that the factory cruise switch gear uses momentary contacts? Since it's a 2 terminal device, I assume I'll need to use an external pull-up to the +5VDC supply; what value pull up resistor should I use with this?

2. Since I'm out of analog inputs, but still had plenty of DI's, instead of using a 12 position trim pot for a DBW/Boost control mode select switch, I was thinking I could do the same with the free DI's. Two DI's would get me up to 4 discrete DBW/boost control modes programmed by just using 2 SPST switches (e.g., binary 00, 01, 10, 11 = 4 possible modes which is enough for me). Sound like a plan?

3. I should be able to use the CAN bus port to drive a CAN bus gauges/display devices (e.g., BTI, GaugeArt, etc) in lieu of using DI9 & DI10 as I previously though, assuming I terminate the bus properly, correct?

Thanks in advance!

 

Link G4+ Fury IO Installer Table (Rev B).pdf

[Adamw]

8 hours ago, Pete_89t2 said:

1. Reference how I intend to use Analog Voltage Input #6, for cruise control "cancel" "set/coast" and "resume/accel" functions, will this work given that the factory cruise switch gear uses momentary contacts? Since it's a 2 terminal device, I assume I'll need to use an external pull-up to the +5VDC supply; what value pull up resistor should I use with this?

Yes you will need a 5V pull-up.  Normally 1Kohm does it fine.  If you can measure the highest resistance between the two wires when you push each button I will confirm what you need.  Yes momentary is fine for these switches.

 

8 hours ago, Pete_89t2 said:

2. Since I'm out of analog inputs, but still had plenty of DI's, instead of using a 12 position trim pot for a DBW/Boost control mode select switch, I was thinking I could do the same with the free DI's. Two DI's would get me up to 4 discrete DBW/boost control modes programmed by just using 2 SPST switches (e.g., binary 00, 01, 10, 11 = 4 possible modes which is enough for me). Sound like a plan?

Hmmm.  I would have to play around a bit to confirm what we could do there.  Can you give an example of what you would want in each position - i.e would it need to swap between only 2 boost tables/settings or 4?

 

8 hours ago, Pete_89t2 said:

3. I should be able to use the CAN bus port to drive a CAN bus gauges/display devices (e.g., BTI, GaugeArt, etc) in lieu of using DI9 & DI10 as I previously though, assuming I terminate the bus properly, correct?

Yep, there is no difference in functionality between CAN port 1 and CAN 2.  Just the CAN 1 plug is a bit more fiddly to wire.

 

[Pete_89t2]

2 hours ago, Adamw said:

Yes you will need a 5V pull-up.  Normally 1Kohm does it fine.  If you can measure the highest resistance between the two wires when you push each button I will confirm what you need.  Yes momentary is fine for these switches.

 

Hmmm.  I would have to play around a bit to confirm what we could do there.  Can you give an example of what you would want in each position - i.e would it need to swap between only 2 boost tables/settings or 4?

 

Yep, there is no difference in functionality between CAN port 1 and CAN 2.  Just the CAN 1 plug is a bit more fiddly to wire.

 

Thanks Adam.

Per the FD wiring diagrams I have, the highest resistance across those cruise mode switch terminals is 910 ohms for the "resume/accel" function. It's 240 ohms for the "set/coast" and a 0 ohms/short circuit for the "cancel" function. I'll verify those with an ohmmeter when I have a chance.

For the mode control, I'm thinking I'll want at least 2 boost tables - 1 for full boost, and 1 that is a lower boost profile. Both of these would use the same direct linear proportional DBW table, i.e., 0% accel pedal = 0% throttle position & 100% accel pedal = 100% throttle position. Then I'd like to add in a 3rd driving mode, which would be a "valet/wife/kids" mode, that would be drive-able but would feel a lot like a normally aspirated 13B FD might - Thought there is to set up a 2nd non-proportional DBW table (e.g. 100% accel pedal = perhaps 50% throttle position), and pair that with the lower of the two boost tables. Does this make sense?

[Adamw]

The 1K pull-up will do fine in that case.

Yes your boost/DBW table switches should be no drama.