[R.martin]

Hello, I am new to speeduino and to have little personal experience with tuning engine management, (I have only modified the stock settings on my motorcycle) however I have been loitering around two local shops that work with megasquirt since 2008 and have tried to absorb whatever knowledge that I can regarding MS ECUs. Much of the vocabulary and many engine building concepts are familiar to me, as I have done the crank up mechanical assembly of my modified BMW M30b32 with direct supervision of an experienced machine shop.

When it comes to the actual electronics, I have designed trivially simple boards and had a small batch produced for an ignition system, but am unfamiliar with the more complex circuits we are dealing with here. Also I am comfortable flashing microcontroller firmware and modifying C code, although I am not sure to what degree this is needed.

Presently I have persuaded a friend to see the value in the speeduino and he has agreed to let me build one for his ITB SBC 350 which is intended for a manual swapped C4 Corvette. Prior to posting I tried to read as much as I could understand about the various boards that are available which could run a V8.

It seems that the 0.4.4c is capable if the injectors are wired in parallel? However I feel like there is some detail to this that I don't comprehend as my mental visualization has each cylinder in a pair firing as well as injecting fuel every 360deg? Which would mean that fule is injected even if the valve is closed and I doubt I am right about this.

I also found this board which seems to be built around a Teensy 3.5 which seems to be unavailable but a Teensy 4.1 is.
Does anyone run this board?
SCG-ECU-1.0

Another option seems to be an STM32 variant linked here:
STM32 version

But I do not know which of these broads has reasonable support and decent documentation as the teensy variant as well as the STM32 version didn't seem to be in the Wiki.

Also to my understanding there is a Linux native version of TunerStudio is this correct?

I am here to learn and happy to take direction.

Our ITB setup on the Vette



My BMW setup intended to be a future speeduino project.

[jonbill]

I can't speak to the availability of 8x8 boards, but I will say a 0.4 speeduino will run that engine fine.
I understand Injection is always timed to inject on closed valves. with paired injection, twice per cycle and with sequential, optionally only once. But in each case, the same amount of fuel is waiting to be ingested when the inlet valve opens.

[PSIG]

+1. Some boring stuff that is essential in finding success, as that's what we are about here. A few suggestions. First is that Speeduino is not MS, or any other system. Yes, the general EFI basics can still apply, but use care not to confuse the systems, their setup and application. I get confused a lot, moving from system to system.

Second, is to not assume anything you thought you knew is always valid. Many go down rabbit holes that are incorrect or unnecessary, and the more basic the assumption is, the more it misguides the project planning. Example - sequential injection. The urban legends and misinformation about full-sequential, its purposes, uses, tuning, etc, are substantial. I have to approach every project fresh, and question if any of my assumptions are true in this application. It can be humbling.

IMO, @jonbill is (as-usual) on-target with his statements, but the answers to many of your unasked questions will be from project planning. 1) What are the ultimate goals of the project? 2) What does the engine (and vehicle) need to do (project requirements)? 3) What specific fuel will you use? 4) What are the limitations to using any method or process to reach the goals? And we can go on from there, in order to gain a clear picture of what we want to end-up with and options to get there.

You are less likely to get where you want to go if you don't have a clear "map" of your path. That's what you build with a project plan, making decisions, compromises and choices so much easier and focused on the goals. "Because it looks cool" can be a valid goal, but you can imagine the decisions will be very different if the goals also included 2hp per pound, and why. Your plan will show you and us a clear picture of where you want to be when you get there. Post it up!

[R.martin]

Thank you guys. I do agree, I do Linux computer systems for work and I have many times experienced a customer who is fixated on some kind of solution which I know is absolutely no more effective than another solution. And as you explained the same principal applies here.

For the Corvette the goals are simple and honest, to build a system that is unique when compared to the rest of the SBC engines around here as many of them have a holly carb on them with automatic trans.

Our goals are to swap to manual (ZF 6 speed showed up today) and then do an EFI & ITB setup with domed high comp pistons. Also have the ability to run on 93 premium or e85. Shooting for 450-500hp which feels realistic.

Obviously I like the concept of sequential control, but it seems you guys are saying that there is no effective performance difference when paired to an engine like the 350 which has pairs of pistons at TDC at the same time?

For my future knowledge, are those 8x8 boards I linked some kind of fringe project that never gained traction?

Is there a scenario where sequential injection would make a difference, such as in a Porsche V8 which does not have the same crank design as the Chevy?

Is there a specific revision of the v0.4 board that I would want to use?

And we are definitely doing the ITBs as primarily a fashion statement of mechanical complexity, is it true that other than synchronization of the butterflies there is additional complexity to ITBs? There seems to be a sentiment in the local circle regarding ITBs being "untunable" and I struggle to accept this as fact.

[jonbill]

I don't think 8x8 would be called fringe - if it wasn't for the chip shortage, I think the 8x8 boards would be much more mainstream by now (mainly for faster processing, more features and IO). But I think all v8s will have paired pistons so will run well with paired on 4x4. (are there any v8s that dont?)
AIUi, ITBs dont work so well with MAP sensor for load index, so tend to use TPS for load or a mix of both which can be more complicated. but perfectly doable and can work well.

[R.martin]

Thanks Jonbill, I'm not sure if there are V8s without paired pistons. While I want to keep this thread on the Vette, I am wondering about another engine that I have.

It is a BMW M70 which is similar to two M30s with a common crank and it is sort of the endgame plan for my speeduino development. From my reading it seems that a popular idea is to run a pair of speeduinos, and configure one to do 12 ignition channels and the other to do 12 fuel channels. Do you know if the teensy 4.1 has enough timers to control a 12x12 setup?

Alternatively if my math is right the arduino 2560 has 9 available timers and can be configured with 9 outputs? Would this mean that an M70 could run with the pair cylinder fueling and wasted spark ignition?

Also where do I get a speeduino 0.4.4d kit? Or do I have to have one made from somewhere like PCBway and then source parts?

[PSIG]

… experienced a customer who is fixated on some kind of solution which I know is absolutely no more effective than another solution. …

All too often less effective, more costly and more time-consuming. You got it - focus on the ultimate goals.

… unique when compared to the rest of the SBC engines around here…swap to manual (ZF 6… EFI & ITB setup… 93 premium or e85… 450-500hp

Project goals list made. Let us know if any of it changes or re-prioritizes. Does your customer realize he could have a unique setup with 8 trumpet tubes on a shrouded carb or 4x2Vs, with nitrous to get a goal-reaching result? He's not likely to want that, but it could allow him to open his brain to alternatives and where that could lead.

Obviously I like the concept of sequential control, but it seems you guys are saying that there is no effective performance difference when paired to an engine like the 350 which has pairs of pistons at TDC at the same time?

Sequential is better. Ultimately, 1.5 to 3% better across the range with very deep tuning. So, it's not raw power. The difference is how you are using it, where the OEMs wanted to meet emissions regulations and a bit of a boost in economy. We want it to access independent cylinders for fuel and ignition control (equalize cylinders, reducing the limitation of the weakest cylinder). I really doubt your customer cares about that or spending that much to get there.

Conversely, today's OEMs are using quasi-sequantial (on full-sequential setups) in order to inject twice per cycle for even fuel distribution, quicker response (every rev), and longer (yet even) fuel dwell time for better vaporization. We can get most of that with paired 4-channel and two squirts per-cycle on each cylinder. The difference in advantage falls very low, making anything more a brass ring for the deeply committed. Reality check.

Is there a specific revision of the v0.4 board that I would want to use?

Not particularly. The original v0.4.x, UA4C, Core4, and many others have similar capabilities, each with specific advantages. Shop with your goals list and layout plan, considering how you want to handle packaging and wiring.

And we are definitely doing the ITBs as primarily a fashion statement of mechanical complexity, is it true that other than synchronization of the butterflies there is additional complexity to ITBs? There seems to be a sentiment in the local circle regarding ITBs being "untunable" and I struggle to accept this as fact.

True, and agreed there are setup and tuning challenges, but doable. ITBs are impressive because they are difficult and expensive to execute. Not because they work "better". Random alternative thinking - if you placed the throttles on tubing rails (plenum), you bypass many of the issues using the same parts for the same look. If you face a challenge, how could you overcome while still being unique? He wants to be unique, and sometimes that means being unique in concept and execution as well. Have fun!

[R.martin]

Project goals list made. Let us know if any of it changes or re-prioritizes. Does your customer realize he could have a unique setup with 8 trumpet tubes on a shrouded carb or 4x2Vs, with nitrous to get a goal-reaching result? He's not likely to want that, but it could allow him to open his brain to alternatives and where that could lead.

Thank you for your input and I do concur with your take on this. I should add one other dimension to our goals list, and that being the Swiss watch philosophy.

What I mean with this Swiss watch philosophy is that even though we are trying to keep this build financially conservative, one of our musts is that the modifications we do undertake be done in a manner that feels very genuine. That if a guy such as yourself or any other skilled machinist looks at our work it will be observed that we paid our respects to the under-recognized fashion statement of mechanical complexity. I want skilled eyes to feel like we did put in genuine effort to pay respect to the craft.

As a teenager these were always the builds that left an impression on me, the ones where there was an easier way, but the builder chose to do it a certain way to highlight the art of functional engineering. With this being one of our "musts" we needed to be very realistic about how far we planned to go with the modifications, and I said that a manual swap from a later gen Vette + unsprung 6-puck clutch/lightened flywheel, and a tastefully tuned but simple high-comp motor with authentic ITBs + Speeduino could be honestly achieved. The intent is for this to be a driving experience car rather than a competition racer.

Similar to my e28 with the twincharged setup, where guys have exceeded my power goals of (500hp) with just a turbo and stock manifold, but there is definitely an experience that is had with something uncommon. My engineering justification for the blower on that car was that the turbo lags and it will improve lower-end power, obviously this could be rectified by just putting an appropriate turbo on the car, but I feel if I do this I will forfeit the mechanical intrigue that an unorthodox setup offers if it can be justified from an engineering perspective. I think the vast majority of people will never understand all of the small parts which need to be created to get that to work, but the people who do recognize the effort will be genuinely interesting people themselves.

However learning from the long build time the BMW has I want to make sure we are only trying to get edgy in a few areas with the Vette.

I hope the "Swiss watch" comment doesn't come off as pompous, I do not own a Swiss watch or any kind of wrist watch for that matter, I just felt it was an accurate analogy to that sort of nebulous value we are trying to create.

Sequential is better. Ultimately, 1.5 to 3% better across the range with very deep tuning. So, it's not raw power. The difference is how you are using it, where the OEMs wanted to meet emissions regulations and a bit of a boost in economy. We want it to access independent cylinders for fuel and ignition control (equalize cylinders, reducing the limitation of the weakest cylinder). I really doubt your customer cares about that or spending that much to get there.

Conversely, today's OEMs are using quasi-sequantial (on full-sequential setups) in order to inject twice per cycle for even fuel distribution, quicker response (every rev), and longer (yet even) fuel dwell time for better vaporization. We can get most of that with paired 4-channel and two squirts per-cycle on each cylinder. The difference in advantage falls very low, making anything more a brass ring for the deeply committed. Reality check.

You are correct neither my friend or I see an extra 3% as being worth it especially when we already have used our "let's be unique" budget on this ITB setup. So long as the performance is acceptable with 4x4 and we can get those ITBs working correctly our goals will be met.

True, and agreed there are setup and tuning challenges, but doable. ITBs are impressive because they are difficult and expensive to execute. Not because they work "better". Random alternative thinking - if you placed the throttles on tubing rails (plenum), you bypass many of the issues using the same parts for the same look. If you face a challenge, how could you overcome while still being unique? He wants to be unique, and sometimes that means being unique in concept and execution as well. Have fun!

Sorry I was responding while reading, you have it exactly correct, we are going for that reserved gentleman's car. Trying to build the Vette with a bit of je ne sais quoi. I just want to get the mechanical details right at this stage and then later we can worry about cleaning up the cars appearance.

[R.martin]

so we took the advice both of you have offered and ordered the apre-built fishdog which just seemed really cost-effective even though I liked the idea of building it myself.

https://speedyefi.com/product/fishdog-u ... duino-ecu/

If I understand correctly we will need an IAT to do speed-density tuning. under normal circumstances where do you install the IAT sensor? My thought is that we will have to drill and tap for NPT in the actual intake manifold, but I am also wondering if it is actually meant to go closer to where a normal MAF sensor is installed just after the filter. I do recognize these two sensors are not measuring exactly the same thing and that maybe for IAT we want to take that reading as close to the injection point as possible and therefore the manifold is the right place.

[stum]

Hi, im sure others will respond as well. This has come up a number of time already. And my experiences are in line with them.

If you mount your IAT in the inlet manifold you will suffer heat soak which will lead to readings which will be artificially high at times.

When I first set my IAT up (about 2 years after I first got Speeduino running) i drilled and tapped the aluminum plenum. On a warm day (about 25'C) the IAT would read 55'C + while shut down after a run, and would take some time to cool down once started. Didn't cause me any real problems but was reading 25'C above actual air temp. i have now moved it up stream of the throttle body and it responds faster and is more in line with actual temperature.

Have fun.