Modifying a Contemporary Car for Motorsports - ECU and Other Issues

Hello all.  My first topic post here on GRM Forums.  Likely not my last. Hopefully this is the right place for this. 

A street-car based track toy is in my near-ish future. I raced SCCA Improved Touring a couple decades ago so I have a sense for the kinds of things I want to do but I've never modified a contemporary car with a CANBUS wiring system where many things are controlled or monitored by the ECU.  The 2023 Civic Type R and the 2022 GR86 are at the top of my list.  This car will be street legal but only enough to get it to the track and back so I don't have to trailer it regularly. It will not be a wheel-to-wheel race car. The first things I plan to do will be suspension, tires and brake pads followed quickly (as needed) by cooling.  Getting as much weight out of the car as possible is a priority, too.  I will eventually get to bumping up horsepower. Goal is 400hp ish at the crank. 

I have questions,  especially related to ECU:

1. What can be modified without any issues to the ECU and engine tuning? Are there things that effect the ECU but can be silenced with a OBD2 device?  General and specific advice is welcomed.

2. Removing airbags - Will this invoke screaming and yelling from the ECU? Or just pop the fuses and yank them out?

3. Removing the air conditioning hardware.  Again, does this effect the ECU at all?  

4. Other advice and recommendations specific to a modern, ECU-controlled car?

5. At what point is tossing the factory ECU and running a standalone system a good idea? What are the tradeoffs?  Can I keep power windows and things like that without the factory ECU? 

Any advice would be much appreciated. Feel free to recommend one car or the other (Or offer alternatives) and why.

 

If you can get a power adder with an EO, there's a much better chance your supplier will be in business in the future. Those who sell devices that don't have an EO will either get a big fine from the EPA or they'll stop selling those devices. This can easily spiral into a political discussion, but no matter what it's the reality of our world at the moment - and will remain so on any car that has a license plate. Doesn't matter if you only drive it once a year, if it's ever used as a street car it's a street car.

Engine tuning will be required if you want 400 hp. The ECU will have to be reflashed (best option for emissions compliance) or replaced. It's easy to make power on a dyno with a standalone ECU, but it's very hard to get good idle and cold start and voltage compensation and all the stuff that powertrain engineers spend thousands of hours on. Most people driving less nice cars just ignore it. Note that you will not ever find a standalone that will pass an OBD emissions test, so it's a non-starter if you have regular inspections or want to sell the car to a state that does.

Generally speaking, non-powertrain related things are controlled by an independent Body Control Module. It might communicate with the Powertrain Control Module (aka ECU) but is probably not reliant on it. It's unlikely power windows will stop working if the PCM goes away. It's unlikely the airbag system is tied into the PCM either, and removing AC would probably just result in an error about non-functional AC and not affect how the car runs. Pulling the PCM will 100% result in a loss of dynamic stability control and hopefully will not affect ABS. It might also take out your gauge cluster - scratch that, it probably will unless you can get a standalone that will output the correct manufacturer-specific CAN messages. You'd be surprised how some of this stuff interacts, the fuel gauge on a modern Miata depends on a signal from the PCM for example.

The easiest option is to get a car that already has good power and concentrate on the driver and the suspension. Picking a random number like "400 ish" says you're just reading forums and specs and you like the sound of it. Keep in mind that nearly doubling engine output can have effects on a bunch of other things like differentials and transmissions that are optimized for efficiency, so going down that road can snowball. 

I'm not saying don't do it. I'm writing this from my shop where there's a 500 hp Miata on the lift and a turbo Miata parked outside and I've been living in the automotive horsepower aftermarket for over 20 years. Just go in with your eyes open.

As for which car, it would seem that FWD vs RWD dynamics would be the biggest differentiator. I like RWD.

I have a 2013 BRZ with a tuned ECU, no airbags, and no ABS or TCS.  It's not the same generation as you're looking at but should be similar.  Answers bolded below:

1. What can be modified without any issues to the ECU and engine tuning? Are there things that effect the ECU but can be silenced with a OBD2 device?  General and specific advice is welcomed. My car has an EcuTek tune on it which allows the tuner to alter pretty much any parameter you can think of.  Specifically, since mine is a rally car, many of the things which could put the car into limp mode and slow it down are disabled.

2. Removing airbags - Will this invoke screaming and yelling from the ECU? Or just pop the fuses and yank them out? I removed the fuse and airbag computer along with all the bags with no issues.

3. Removing the air conditioning hardware.  Again, does this effect the ECU at all?  Totally separate system, at least on my car.

4. Other advice and recommendations specific to a modern, ECU-controlled car? Watch what you unplug and how you unplug it- for example, there are two ABS fuses on my BRZ; one simply disables the entire system, the other gets you limp mode and loses the speedometer and a bunch of other things.

5. At what point is tossing the factory ECU and running a standalone system a good idea? What are the tradeoffs?  Can I keep power windows and things like that without the factory ECU?  Unsure, I have a healthy fear of standalones and avoid them when possible.

Keith Tanner said:

As for which car, it would seem that FWD vs RWD dynamics would be the biggest differentiator. I like RWD.

you're weird. FWD is where it's at! 

bobzilla said:

Keith Tanner said:

As for which car, it would seem that FWD vs RWD dynamics would be the biggest differentiator. I like RWD.

you're weird. FWD is where it's at! 

If you're driving in reverse, sure! ;)

In reply to msterbeau :

edit: covered

Keith Tanner said:

If you can get a power adder with an EO, there's a much better chance your supplier will be in business in the future. Those who sell devices that don't have an EO will either get a big fine from the EPA or they'll stop selling those devices. This can easily spiral into a political discussion, but no matter what it's the reality of our world at the moment - and will remain so on any car that has a license plate. Doesn't matter if you only drive it once a year, if it's ever used as a street car it's a street car.

Engine tuning will be required if you want 400 hp. The ECU will have to be reflashed (best option for emissions compliance) or replaced. It's easy to make power on a dyno with a standalone ECU, but it's very hard to get good idle and cold start and voltage compensation and all the stuff that powertrain engineers spend thousands of hours on. Most people driving less nice cars just ignore it. Note that you will not ever find a standalone that will pass an OBD emissions test, so it's a non-starter if you have regular inspections or want to sell the car to a state that does.

Generally speaking, non-powertrain related things are controlled by an independent Body Control Module. It might communicate with the Powertrain Control Module (aka ECU) but is probably not reliant on it. It's unlikely power windows will stop working if the PCM goes away. It's unlikely the airbag system is tied into the PCM either, and removing AC would probably just result in an error about non-functional AC and not affect how the car runs. Pulling the PCM will 100% result in a loss of dynamic stability control and hopefully will not affect ABS. It might also take out your gauge cluster - scratch that, it probably will unless you can get a standalone that will output the correct manufacturer-specific CAN messages. You'd be surprised how some of this stuff interacts, the fuel gauge on a modern Miata depends on a signal from the PCM for example.

The easiest option is to get a car that already has good power and concentrate on the driver and the suspension. Picking a random number like "400 ish" says you're just reading forums and specs and you like the sound of it. Keep in mind that nearly doubling engine output can have effects on a bunch of other things like differentials and transmissions that are optimized for efficiency, so going down that road can snowball. 

I'm not saying don't do it. I'm writing this from my shop where there's a 500 hp Miata on the lift and a turbo Miata parked outside and I've been living in the automotive horsepower aftermarket for over 20 years. Just go in with your eyes open.

Thanks for your response Keith.

I'm in Michigan.  No emissions stuff to deal with at the moment.  Though I don't expect that to be forever.  

Absolutely expect to do do both mechanical and ecu tuning to get to HP goals.  The more likely car is the Type R.  400hp is a +125% increase.  The GR86 is more like +170%  The Honda should be straightforward with a few bolt ons and ECU tuning.  The GR86 is more challenging and more $$$ but not difficult according to all the research I've done so far.  Reliability will be more of a factor though.  400HP ish is not a random number.  It's one based on where I've been, performance-wise, where I'd like to be and what is reasonably attainable and reliable.  Neither is it an absolute necessity.  Just a nice round number to aim towards. 

I've worked in the car industry for three decades.  All the stuff you mentioned about PCM and BCM jives with what I've heard over the years. This post is intended to get me as much input as possible before I start spending money.  I'd much rather expect certain issues than be blindsided by them.  Stability control, traction control and all those dynamic enhancements are things I would prefer to not have on the car. The only digital assistance I'm OK with is ABS. So if the former is disable with certain modifications I'm OK with that.  If the ABS goes too it becomes and issue. The CANBUS stuff definitely worries me, but at the same time I see that people/companies seem to be figuring out how to decode/interpret the signals or make devices that bypass it altogether. On the other hand, manufacturers seem to be locking things down a lot more to deter hacking by thieves. (Hello new Mustang!) There will obviously be more specific research as I get closer to deciding what car to start with.  And then more research as I get into it.  And then more research after that.  :-)

So here's a question.. it may be one you or others can't answer:  What does HPD and others that develop turn-key cars like the ones for TC/TCA class of SRO World Challenge do with their ECU's?  I assume they have a bit of custom tuning and silence any alarms from disabling certain parts of the car?  Are these special parts available and/or the knowledge on how to deal with these issues generally available to people like us? Just to racers?  No one except those who buy the whole car?  

Eyes open is the whole point of this post.  Thanks again for the input.

 

Keith Tanner said:

As for which car, it would seem that FWD vs RWD dynamics would be the biggest differentiator. I like RWD.

I've driven FWD cars all my life.  Trying to decide if I want to learn something new or stick with what I know.

¯\_(ツ)_/¯ said:

I have a 2013 BRZ with a tuned ECU, no airbags, and no ABS or TCS.  It's not the same generation as you're looking at but should be similar.  Answers bolded below:

1. What can be modified without any issues to the ECU and engine tuning? Are there things that effect the ECU but can be silenced with a OBD2 device?  General and specific advice is welcomed. My car has an EcuTek tune on it which allows the tuner to alter pretty much any parameter you can think of.  Specifically, since mine is a rally car, many of the things which could put the car into limp mode and slow it down are disabled.

2. Removing airbags - Will this invoke screaming and yelling from the ECU? Or just pop the fuses and yank them out? I removed the fuse and airbag computer along with all the bags with no issues.

3. Removing the air conditioning hardware.  Again, does this effect the ECU at all?  Totally separate system, at least on my car.

4. Other advice and recommendations specific to a modern, ECU-controlled car? Watch what you unplug and how you unplug it- for example, there are two ABS fuses on my BRZ; one simply disables the entire system, the other gets you limp mode and loses the speedometer and a bunch of other things.

5. At what point is tossing the factory ECU and running a standalone system a good idea? What are the tradeoffs?  Can I keep power windows and things like that without the factory ECU?  Unsure, I have a healthy fear of standalones and avoid them when possible.

Thanks for your input!

There's an "airbag computer"?  :-O  I would have thought that sort of thing would be dealt with by the BCM or similar?

So which ABS fuse did you pull?  

I'm not scared of eventually moving to a standalone ECU. But there needs to be a solid reason to go that way.  The main reason is not necessarily more horsepower.  I see it as a way to ease tuning while removing a bunch of headaches bypassing issues with the factury ECU that crop up when I modify or get rid of things from the stock car to reduce weight and complexity.  

CAN is just a way for the modules to talk to each other. It's like TCP/IP for the internet. There's nothing mysterious or scary about it, these things were talking before with voltages or proprietary things like BMW's IBUS. The only interesting thing about it is what they're saying :)

Airbag systems tend to be standalone in my experience and not integrated into something more generic. That's because they're a very mission-critical thing. They'll often have their own battery backup. They might send messages to other parts of the system or maybe use input from the DSC to do things like fire off pre-tensioners, but since they are meant to operate when the car is literally being destroyed they're pretty independent.

Mazda uses an aftermarket standalone ECU for the Global Cup Cars - Gem, Bosch, I'm not sure. Selling those ECUs separately would likely get them in hot water with the EPA very quickly, so they're only sold as part of a turn-key car that has a flagged VIN and is permanently a race car. I suspect Honda does the same. Be aware that most aftermarket ECUs are far less sophisticated than those in a modern production car, so tweaking the stock ECU with something like Ecutek is a good choice assuming the tuning software company has reverse-engineered the ECU well.

400 hp without a weight goal comes across as random - we get people calling us all the time with a horsepower target that was taken by reading what everyone says is easy and then adding 50 because they want more, and it's pretty easy to get tunnel vision and frustrated if the magic number can't be reached. You say your goal is based on how attainable it is but then you point out that it's a significantly higher jump for one of your cars than the other. Every car has a power level that it can reach before everything else starts to run out of headroom, I'd base my power goals on the vehicle. Or base the vehicle on my desired power/weight ratio. Or even better, look at area under the curve and weight. I will admit that I am always skeptical of the "few bolt ons and a tune" claims, because I find they often don't match what our dyno says. We once spent a large amount of time trying to get a "200 hp" package from a British shop to get past about 165, including taking the car down to sea level and testing it on a different dyno.

If I was doing this, I'd start by choosing my platform, and then get into the factory documentation on errors and see what happens when I break something specific.

I guess I'm just getting old, but modern performance cars have gotten really really good. The project you're describing sounds like a lot of money and effort and time. I'd much sooner just spend realistically probably about the same amount of money on a car that leaves the factory in the configuration you're looking for. Maybe not as cool of a story, but none of the stress, effort, or time of reengineering a whole vehicle, and it'll all just work and maybe even have a warranty.

That all said, I think I just saw today that ecutek is getting ready to release the beta version of their tuning software for the GR86. So pretty soon we'll know exactly how much you're able to do with the stock ECU.

FWD/RWD aside, I like the civic type r, but I like it as a "do everything" car, meaning it's a very compromised design. What you're looking for is a basically no-compromise track car, doesn't seem like a good matchup. For that matter there's definitely some big compromises to the GR86 as well, though much less so. Which is why I probably wouldn't start with either one like I said.

msterbeau said:

I'm not scared of eventually moving to a standalone ECU. But there needs to be a solid reason to go that way.  The main reason is not necessarily more horsepower.  I see it as a way to ease tuning while removing a bunch of headaches bypassing issues with the factury ECU that crop up when I modify or get rid of things from the stock car to reduce weight and complexity.  

So you know, both of the cars you have chosen are both direct injection.  While you may be able to find a standalone ECU that can run DI- they are far from common.  Then trying to actually calibrate that will be a real headache- hours are spent getting the injection timing correct so that the engine can run the best spark.

For a decent engine map, it takes like 6 months in a full time dyno to get enough data just to get it to run.  This isn't like it was even 15 years ago when almost all engines were PFI and had a simple(ish) air estimation system- normally MAF based.   I know you will just focus on WOT, but that's also where you need to get it the most right if you really want 400hp.  It's not hard to get it a little wrong and the exhaust will be hot enough to cause some serious problems- let alone if you manage to accidentally get into mega-knock (which happens a lot in DI engines) which will destroy the motor pretty quickly.

And finding a company who will supply code that you can retune the original ECU has gotten a lot harder, given it's been illegal to tamper for 50 years or so, and thanks to the bad actors, the EPA has really taken a dim view of plug in tuner companies.

You may end up better off buying an actual race car from Honda or Toyota- assuming they sell them.  Since they are pretty common racers, I expect they do sell them.  That way all the software to tune it to death will be readily available- since they are not really covered by the clean air act.  But you would never be able to register it.

In reply to msterbeau :

You want to pull the big green fuse for the ABS pump motor- the smaller fuse runs a module that the speed signals have to go through to get to everything else  

In reply to alfadriver :

All good points. I hadn't read that direct injection was such a hurdle to deal with from an ECU tuning standpoint.

 I've actually considered going the factory racer route.  Honda in particular is making Word Challenge level turnkey racers available.  The only problem is money.  The Civic Si is not out of my price range but the Type R is.  It's nearly $90K.  I'm really looking for that level of performance.  And that's the last generation car which I doubt they're making anymore.  Also, It's ugly.  :-)

In reply to msterbeau :

Can you get a used race car?

dps214 said:

I guess I'm just getting old, but modern performance cars have gotten really really good. The project you're describing sounds like a lot of money and effort and time. I'd much sooner just spend realistically probably about the same amount of money on a car that leaves the factory in the configuration you're looking for. Maybe not as cool of a story, but none of the stress, effort, or time of reengineering a whole vehicle, and it'll all just work and maybe even have a warranty.

That all said, I think I just saw today that ecutek is getting ready to release the beta version of their tuning software for the GR86. So pretty soon we'll know exactly how much you're able to do with the stock ECU.

FWD/RWD aside, I like the civic type r, but I like it as a "do everything" car, meaning it's a very compromised design. What you're looking for is a basically no-compromise track car, doesn't seem like a good matchup. For that matter there's definitely some big compromises to the GR86 as well, though much less so. Which is why I probably wouldn't start with either one like I said.

I'm not going to completely redo the car. I'm mainly concerned about what happens when I start pulling things like the A/C and airbags that it doesn't screw up stuff the basic driveability of the car.  It may be that down the road I will put a cage in it and get a little more track oriented, but I don't see doing that for a while.  One of the big problems I see with modern cars is weight.  I come from an era where heavy cars were 2400lbs.  Most modern compact sedans now weigh over 3000lbs.  The new BMW M2 weighs 3800lbs!!!  That's insane. A lot of what I will be doing is just getting weight out of the car and making it handle and brake better on the track. I could start with an older platform but then I have to deal with all the used car stuff: Wear and tear, rust, etc...  Starting with a new car increases the initial capital costs but the benefit is that it's clean and easy to work on. No rust!  (Can you tell I don't want to deal with rust?  :-) )

In reply to alfadriver :

Can I?  Of course.  But then I have to figure out everything the other person did if they haven't documented things fully.  Also, I want it to be streetable.  Have they gone too far it that makes that difficult?  It seems easier to come from the other direction.  If I didn't mind towing the track car I would probably get a Sports 2000 chassis and drop a more modern engine in it.  I'm fairly certain that would be a ball, but then I'd have to invest money in a tow vehicle and trailer.  I REALLY don't want to deal with that.

In reply to msterbeau :

DI is a pretty complex system, so yes if you want to do standalone.

Getting the stock one tuned to make that much more power will be pretty troublesome in terms of finding a vendor to sell it to you.

So the only real option is to find a vendor that has a 400hp package that has an EO that goes with it.

In reply to Keith Tanner :

Thanks again Keith. 

Your comments on airbags and the ECU situation on turnkey race cars sounds right.  I've never heard of Ecutek.  It seems like a lot of pro-level production based cars use Motec stuff.  I know they're pricy compared to something like Haltech or Hondata but I assume they use it for a good reason.  

The GR86 weighs a little north of 2800lbs.  2500lbs feels like a reachable goal.  The Type R is a few hundred pounds heavier but it's a sedan with more stuff to shed so 2600-2700lbs lbs seem like a decent target weight.  I'd be more worried with weight balance on the Honda since a lot of the weight would come out of the back. I know a FWD car wants to maintain a front bias but not too much.  In my improved touring CRX I deliberatly left the spare tire in place to get a little more weight towards the back. it was underweight so no big deal from that standpoint. 

Speaking of factory documentation, do factory manuals still exist?  I assume you can get digital versions - but from where?  

I'm skeptical of everything on the internet until proven in real life.  I hear what you're saying.  Whatever car I eventually go with - I will take it to the track stock, play with it a bit and then start doing stuff and see what happens with lap times. (And feel!! - It's got to be fun to drive or what's the point?).  

The reason I named Ecutek is because ¯\_(ツ)_/¯ mentioned it being used in a GT86. There are a bunch of tuning companies, read it as a generic "reflashed stock ECU". I suspect the reason you see Motec so much in high end race cars is because it has capability that lesser ECUs don't. I'll bet it can run a DI engine. And in case you hadn't figured it, alfadriver knows what he's talking about with regards to modern DI engines :)

You can still get factory manuals, but the online tools are better. I have access to the Mazda factory stuff and it's really good - you can get a "flat" wiring diagram but the online ones allow you to highlight individual circuits, etc. The dealers do need access to quality diagnostic info, so it's out there. I don't know how accessible various ones are to generic people, but once you've got your platform chosen I might be able to help with some contacts.

I know of a 2600 lb RWD modern car with 500 crank hp that's a track-ready dual purpose car. In fact, it's going up on BaT shortly. Might not be as cheap as a stock Type R, but might be less than making the Type R compete...

I thought they offered a Civic Si race car too.   
 

msterbeau said:

dps214 said:

I guess I'm just getting old, but modern performance cars have gotten really really good. The project you're describing sounds like a lot of money and effort and time. I'd much sooner just spend realistically probably about the same amount of money on a car that leaves the factory in the configuration you're looking for. Maybe not as cool of a story, but none of the stress, effort, or time of reengineering a whole vehicle, and it'll all just work and maybe even have a warranty.

That all said, I think I just saw today that ecutek is getting ready to release the beta version of their tuning software for the GR86. So pretty soon we'll know exactly how much you're able to do with the stock ECU.

FWD/RWD aside, I like the civic type r, but I like it as a "do everything" car, meaning it's a very compromised design. What you're looking for is a basically no-compromise track car, doesn't seem like a good matchup. For that matter there's definitely some big compromises to the GR86 as well, though much less so. Which is why I probably wouldn't start with either one like I said.

I'm not going to completely redo the car. I'm mainly concerned about what happens when I start pulling things like the A/C and airbags that it doesn't screw up stuff the basic driveability of the car.  It may be that down the road I will put a cage in it and get a little more track oriented, but I don't see doing that for a while.  One of the big problems I see with modern cars is weight.  I come from an era where heavy cars were 2400lbs.  Most modern compact sedans now weigh over 3000lbs.  The new BMW M2 weighs 3800lbs!!!  That's insane. A lot of what I will be doing is just getting weight out of the car and making it handle and brake better on the track. I could start with an older platform but then I have to deal with all the used car stuff: Wear and tear, rust, etc...  Starting with a new car increases the initial capital costs but the benefit is that it's clean and easy to work on. No rust!  (Can you tell I don't want to deal with rust?  :-) )

You said wheels and tires, suspension, and cooling. More power is going to need more brakes, and at ~2x stock power it'll probably eventually need some drivetrain upgrades or at least a gearing change. Forced induction will require a big cooling system upgrade. That's pretty much every vehicle system being reworked.

I definitely understand the desire for a newer vehicle, which is why I'd just buy one that already does what you want. Building really only makes sense if you can start with an older chassis that can be obtained super cheap.

People new to the sport ignore the importance of weight. I remember being lectured by "Honda kids" (my term) about how "lame" it was that I was planning on only 400 hp in my K24-based car project. What they ignored was that my car weighed less than half as much as their OEM cars. Point being, weight is really important, even more so than power, because it affects everything, acceleration, cornering, and stopping. I know the OP want to keep it streetable, but maybe back up a bit more and tell us what your intended end use is. Modifying a car is a very slippery slope, and many of us have built cars to the point that they're no longer easy to live with on the street, and they become track-only cars.

In reply to Datsun310Guy :

Yup.  Exactly that one.  And as I said the $90K price is over my budget.  And I would want the new generation one, which they haven't released and which will probably be even more expensive.