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Discussion Starter #41
They certainly get more difficult every year.

Fundamentally, you need to keep the body electronics stock and functioning,
I would prefer that too. But it seems to be too difficult. It's looking like a full strip of the chassi, despite being a lot of work will end up being less time consuming,

while tricking them into thinking that any missing components are indeed there and functioning correctly either via basic circuits that will provide the steady-state "on-line" signal they are looking for, some sort of artificial variable signal that you create yourself (arduino boards are popular for this,) or bastardizing the donor car circuits. All of this is very tricky and time consuming
Exactly. It's looking like that.

because it's pretty much a crap shoot as to figuring out what needs to see who when, and it'll be different for every chassis, even different year to year between similar cars. And just because something works in the garage doesn't mean it will continue to work with a car in motion.
One more reason to go the full chassis strip way, I would say?

The TBW example I referenced earlier for example, may work fine until the car detects slip, at which point it tries to command a different throttle position, is unable to do so, and goes into limp mode.

Once you get that done, the rest is relatively easy, and includes:

Implement and calibrate/tune a stand alone ECU for the engine, attempting to use as many OE sensors as possible.
But a stand alone ECU will not be need if I carry over the engine donor ECU, right? Which is what I would do if doing the full chassis strip.

Use some sort of aftermarket configurable dashboard or generic gauges, piggy backing the ECU input/outputs for things like temperatures and engine speed, and harvesting others such as vehicle speed from a source you come up with.
Again not need if I fully strip the chassis and use the engine donor gauges on the dashboard?

Re-wire the rest of the car so that you can have things like a radio, power windows, power locks, dome lights, trunk releases, HVAC, etc via something like a Painless kit.
Ok. Although I might ditch things like power windows, power locks (it's a door car anyway) power mirrors (if it has) etc for shaving weight. I want to try to make the car lighter.
 

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Discussion Starter #42
You don't want a race car, you said that you want a fully-(or mostly-) functional street car.
Exactly. I used race car just as an example to explain what I meant about full chassis strip. Because I would think that's what they do if building a kappa race car. But yes, I want a functional road car.

Yes, it really is that hard. Phil summarizes it pretty well above.

Any chassis that you use is going to have the same basic problems, unless you get something that pre-dates OBD2 in the mid-90s. At that point you won't have the features that are giving you problems adapting to anyway.
Maybe not TC. But ABS and airbags surely started before OBD2?

The best thing you can do, since you say you have a fully-functional exotic donor car, is to strip the Kappa chassis down to basically nothing,
Yes. This is what I meant when I said approach it as a race car build. ;)

and use all of the components from the donor. Re-machine the uprights for the donor hubs with their wheel speed sensors and for the donor brake calipers. Use the ABS servo system from the donor, along with the fuel system and instruments. You can probably keep the drive axle, but it may be easier to mount the donor's than to adapt the propeller and axle shafts. Engine, transmission, ECU, etc of course from the donor. The HVAC and power windows can probably stay as they are stand-alone,
Yes. This was my idea. So you think it would work? That's great to hear.

but you will have to re-wire the trunk latch, hopefully with some safety circuit to prevent actuation when the car is moving.
To be honest, I don't think I would need need it. I would be fine with an old fashion lock too, if possible.

Use the airbags from the donor, since adapting them physically to the Kappa is probably easier - and safer - that trying to get the Kappa controller to play well with the donor electronics.
Ok. Good. Because that watermellow video doesn't look good. :(

Lighting control should probably be from the donor, although clearly you can splice the Kappa lights into the donor harness.
Ok fine. :)
 

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Discussion Starter #43
Pontiac, because of their low production numbers, were guinea pigs for testing new technology, IE. the Fiero was introduced to develop glue on plastic fenders for the future Saturn line. The Solstice used version x? CAN-BUS in 2006-7 and version y? CAN-BUS in 2008-9. The 6-7 ECU can be modified for LS swaps, the 8-9 ECU only supports 4 cylinders. If you can find someone that can make the CPU talk to the BCU, pay them the money, or go stand-alone, and live w/o cruise control, traction control, and all the fancy dash display. If you look at the wiring diagram for the 09, (mine is an 09 coupe), it has pins for both Can-Busses. I suspect that you could swap ECU, BCU, dash and wiring harness from an LS3 Camaro into a Solstice. Might as well take the transmission as well. Someone has some of the required wiring diagrams on the forum.
I very much doubt I would find anybody to make the CPU talk to the BCU. If it was a simple LS swap I would maybe have a chance.

I can definitely live without cruise control. Traction control would be nice but I won't get into a depression if I don't have it. ;)

ABS and airbags is what I'm mostly worried about.

But so, in an unrelated point, based on what you said the Solstice Coupes can't be LS swap then. Since I guess they are 8-9. Interesting to know. Although I'm not going LS for this project.
 

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Discussion Starter #44
GM is pretty good at sharing parts between models. A wheel speed sensor is a wheel speed sensor and will work on most models of the same vintage until GM changes/improves it. Just figure out the wiring. The bigger problem is making the computers play together. Take traction control. Is the control code in the ECU where the throttle software is or in the BCU, where the wheel sensors connect????? Does the BCU just pass the data to the ECU or tell the ECU to reduce throttle???? This is all controlled by the software loaded into each computer. That is why there are dozens of part numbers for each model ECU. The software can be unique for every combination of features for a model. Put a computer that expects wheel speed sensors in a vehicle that doesn't have them and you will get an error code and possibly limp home mode. Put a computer in a car with wheel speed sensors that doesn't expect them, and your traction control and ABS do nothing. Let's not even talk about the transmission computers. Get a donor Camaro and take everything. I put Corvette wheel hubs on my Solstice to be able to use 18x9.5 Corvette magnesium wheels. Guess what, the traction control and ABS still work.
OK. So this is yet one more reason to go the full chassis strip way. I'm not even using a GM engine or parts. :)
 

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Discussion Starter #45
I think you can go a lot faster with the four cylinder engine. Get the compact sport book from GM and see how you can make 700HP to 1200 HP without that low rpm torque of a V8 that breaks your drive train. Hair dryer motors make 500HP per liter. Go to the bank and see if you can afford it before you start. Launch control becomes a real problem.
I think I mentioned before that going faster or power is not the goal of this project. :)

Corvettes are cheap enough and way easier to get. I know a LS in a car like the kappas, with the short wheelbase etc is a totally different dynamic as a Corvette. But given the trouble I would probably just buy a C6 or something.

About launch control, honestly not worried about it. I doubt I will ever take this to a drag strip or do street racing in it. ;)
 
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