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So I am about to purchase a Haltech R3 after consideration of several options like the Haltech Rebel, or keeping the stock PCM (and adding other external controllers). Before I do I want a sanity check based on what I have and want to accomplish.
Details:
- Stock LS1, with a T56 based dog box, swapped into a fully-race-prepped Miata. LS6 intake.
- Currently drive by cable (DBC).
- Currently using the GM PCM flashed with EFILive. Works great.
- Mostly road racing (closed circuit courses like CoTA) with some street. I'm not street racing.
Goals:
- Convert to DBW throttle for downshift throttle blipping.
- Going forced induction (turbo) so I want an EBC that can handle boost by RPM, throttle position, and gear, preferably all three at once.
- Traction control suitable for road racing, NOT drag racing.
- I'll add ABS as well. I know the R3 does not do this, just mentioning it. That will provide the wheel speed signals for traction control. From what I know, one sensor can do dual-duty.
- E85 fuel conversion
- Ability to tune it myself. I self-tuned a turbo car using a Megasquirt that ran well so I am comfortable with tuning. I will go to a dyno for timing tuning once it is running.
- Digital dash, starting low budget with something like an android running RealDash (app)
- I am looking at the R3 over the Rebel for more versatility and more I/O channels. I want to run more inputs than the Rebel or the stock PCM can handle.
- I already have a good swap harness in the car and want to repin it (or build an adapter harness - GM to Haltech) to plug it into the R3.
From those that have used a R3 (or an R5), or a Haltech in general, do you see any problems with the above? I have already talked to Haltech and it looks like I am good to go, but it is always a good idea to check with the user community for practical input.
My only concern with a r3 instead of an r5 is running out of io since you will have abs and 4 wheel sensors.
the rest is good to go. I just helped set up a c5 corvette with r5 for an almost identical use case and combo. Bosch abs, road racing, dbw, traction control not for drag racing, etc.
the ecu has everything you need software wise.
they just released the iPhone and android app and it might do your dash needs but I’d really suggest saving a bit longer and get a keypad and ic7 and be done with it. The quality of life those two provide are well worth the financial cost.
Adding more.
id spreadsheet out the r3 and then consider the ic7 added io if you get thin. The new firmware will be out in the next couple weeks and that adds a bunch of avis and some spis also I think.
Anything that isn’t time critical you throw on the ic7 like temperatures, some pressures, etc. the nexus can treat them as native inputs but they are over can. All your abs, map, boost you want direct to the ecu.
The keypad is ridiculously useful once you start adding multiple traction control maps or boost limits. It also eliminates the need for any other buttons or switches in the car except the main ignition on/off. Even the starter can go through the keypad. My 73 wagon is one press start like a brand new car. Kinda cool.
That all sounds like a fun build, go R3 or R5 depending on how many inputs you plan on using so definitely build a spreadsheet with your ins and outs so you know exactly what you need. But as Trendsetter said you can also use the IC7 or the newer IC10 for more I/O as well. Most aftermarket ABS systems have the ability to output a signal for each wheel to use with other devices such as the R3 with it's traction control and some do CAN comms.
Well if I have it right, following Haltech's wiring guides for the LS1, then all but two of the R3 inputs are used up to run the engine. Therefore, to get the wheel speed sensor inputs for traction control, I would either need to upgrade to the R5 or add an I/O expander box like a Haltech HT-059905. Adding the I/O expander box is much less expensive than upgrading to the R5 of course.
EDIT: OK I see what you mean about adding the IC7 for additional input. Some of the R3 input channels can be freed up with the IC7 dash inputs. I presume the inputs into the dash unit can be sent (via CAN) to the R3 so they can be logged and/or used as triggers?
For ABS I plan to adapt an OEM Bosch unit. From what I have seen the aftermarket ABS units are very expensive.
Last edited by Deude_Mann; Jul 1, 2024 at 12:09 PM.
Well if I have it right, following Haltech's wiring guides for the LS1, then all but two of the R3 inputs are used up to run the engine. Therefore, to get the wheel speed sensor inputs for traction control, I would either need to upgrade to the R5 or add an I/O expander box like a Haltech HT-059905. Adding the I/O expander box is much less expensive than upgrading to the R5 of course.
EDIT: OK I see what you mean about adding the IC7 for additional input. Some of the R3 input channels can be freed up with the IC7 dash inputs. I presume the inputs into the dash unit can be sent (via CAN) to the R3 so they can be logged and/or used as triggers?
For ABS I plan to adapt an OEM Bosch unit. From what I have seen the aftermarket ABS units are very expensive.
I have always heard that if you need high data rates like wheel speed sensors to not use a CAN expander or IC7 for that, presumably because you can overload the can bus with too much data but if that's all it's being used for then I'm not sure how it would flood a 1 Mbps bus. Maybe they are talking about multiple devices though with very high data rates. I thought the R3 had more inputs than just 2 available but if that's the case I would upgrade to the R5 or use an IC7 dash. If you are adapting an OEM bosch unit it's non-adjustable so not sure how well it would work and not sure what the output is for wheel speeds on it.
if you arent going automatic trans the r3 should have more than 2 spare IO i thought. i mapped out an r3 for a 5.3/4l80e and extra sensors and it just barely had enough.
im sure some would advise against it, but i wouldnt hesitate to put coolant temp, iat, oil pressure, etc on the ic7 or other can device to make room for at least the minimum vss inputs direct to the r3.
maybe its not a big deal, considering the 1mb bus and the size of the data, but there could be latency that adds up in the context of such a time-critical component as traction control.
i didnt mention the uc10 mostly because its like $1000 more than the ic7.
if you arent going automatic trans the r3 should have more than 2 spare IO i thought. i mapped out an r3 for a 5.3/4l80e and extra sensors and it just barely had enough.
im sure some would advise against it, but i wouldnt hesitate to put coolant temp, iat, oil pressure, etc on the ic7 or other can device to make room for at least the minimum vss inputs direct to the r3.
maybe its not a big deal, considering the 1mb bus and the size of the data, but there could be latency that adds up in the context of such a time-critical component as traction control.
i didnt mention the uc10 mostly because its like $1000 more than the ic7.
Maybe there are more than two left over; that was my first run through on the mapping. I would use the two left over for trans oil temp and engine oil temp so they could be logged. I would like one for diff oil temp as well. At any rate I would need to expand to have enough for vss.
I agree that would be the way to do it, vss direct to the R3 and slower sensors to the ic7 (or a Haltech HT-059905).
Also yes I saw the uc10 and though it is really nice it is a lot more than the ic7 like you mentioned.
FWIW this is what I came up with... I am going to update it as I go through it again.
- EDIT: If I have this right, I do not need expansion for the VSS sensors. I had assigned too many I/O channels to the DBW setup.
- Note that I have not used the Haltech power outputs to power items like the DBW, VSS, or other sensors. I presume this could be covered by a separate power source if need be, or by the Haltech if there are enough leftover power outputs of the correct type.
- AFAIK the ground references for the sensors (and cable shields) can be covered by a common ground reference at the Haltech main ground; this works well on the megasquirt ECUs for example.
- Additional inputs as needed could still be covered by a Haltech CAN add-on (dash or I/O module).
Last edited by Deude_Mann; Jul 1, 2024 at 05:54 PM.
the r3 already has dedicated 5v outputs for sensors like the dbw, map, tps, vss if its hall effect, you dont use outputs for those.
same with sensor ground. it is expected that you split the sensor ground and sensor 5v out for each sensor, there is only one of each of those pins at the ecu.
you have 6 SPI which dont include the home and trigger. those have dedicated pins at C1-4.
your 'throttle pedal out' in low side drives im not sure what that is. throttle pedal pinout is correct in the boxes to the right. there isnt anything to drive.
for the 25a ignition and injector outputs, that is 'optional' and you could power those things externally, but one of the big advantages to the nexus series ecus is the built in pdm. you should take full advantage of it and use haltechs recommendation here.
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Haltech R3 pre-purchase questions 
