LS-3 Powered Velocity

Discussion in 'Chevy' started by rv6ejguy, Mar 27, 2019.

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  1. Jul 1, 2019 #101

    tspear

    tspear

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    First you say the factory ECU is fine and shops can reprogram it. I called a couple, they do not reprogram it. They alter the tables and tweak the settings.
    Now you state a programmable ECU are available for $400 bucks. Those same shops said, no, they will not take an empty ECU and develop the program.

    Last point, I have developed real time building control systems; with some of the work in assembly some in higher level languages. The cost is not cheap, and this is a low volume business.

    Tim
     
  2. Jul 1, 2019 #102

    rv6ejguy

    rv6ejguy

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    I got an email from the builder today and he's waiting on avionics and a prop so it will be some time before test flights will occur. He's working on augmentor tubes now and cleaning up many little details. It's an airboat PSRU as far as I know.
     
    wsimpso1 likes this.
  3. Jul 1, 2019 #103

    Voidhawk9

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    Looks to be a lightened Ballistic PSRU. Same the P85 (but lightened).
     
  4. Jul 2, 2019 #104

    Winginitt

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    I think there are a few terms being confused here. First thing to consider is that when we talk in all encompassing terms, there are always exceptions to the general statements. GM sells ECUs that are not designed for use in production vehicles but are preprogrammed for certain crate engines. These ECUs lack the programming for many of the functions that complicate use of ECUs from production vehicles. That said.the common terminology for changing tables, and eliminating certain functions in any ECU is "programming" or "reprogramming" or "tuning". The tools that are used to modify ECU tables are commonly referred to as"tuners" or "proggramers". I think that maybe the way the question was asked may have resulted in some confusion about the answer of "not reprogramming" or "tuning". Besides changing the existing tables, they can also totally eliminate some of the features contained in the ECU when those features are not needed or desired by the customer. Things like VATS (Vehicle Anti-Theft), A/C , Purge Valve, Transmission control, can all be eliminated from consideration by the ECU when it is making decisions.
    Beyond that there are the "self-learning" ECUs available thru the aftermarket which are not burdened by the complexity of factory ECUs which co-ordinate everything in the known universe of production vehicles. These units are relatively inexpensive when you consider what they are capable of. Set a few simple parameters in the supplied control unit and start the engine. It will monitor what the sensors input and start adjusting the engine operating parameters to suit the best condition. Within a few minutes you have a "drivable" vehicle that is operating at a high level of efficiency. From that point you can adjust certain tables to suit what you think is appropriate for your needs or leave it as is. It will continuously adjust to suit needs and efficiency.




     
    Last edited: Jul 2, 2019
  5. Jul 2, 2019 #105

    rv6ejguy

    rv6ejguy

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    Self learning ECUs rely on WB O2 sensors- not a very good idea when burning 100LL.
     
  6. Jul 3, 2019 #106

    Winginitt

    Winginitt

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    Is your friend going to run 100 LL in his Chevy ? I had assumed he would run the cheaper Mogas that the engine was originally designed to use. Your systems are compatible with both fuels, aren't they ? Something I hadn't considered previously was how the lead in fuel might affect the synthetic oil used in todays auto engines. Have you heard anything about compatibility of LL and synthetic oils ?
     
  7. Jul 3, 2019 #107

    rv6ejguy

    rv6ejguy

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    If he wants to do cross country flights, he'll have to use 100LL sometimes until there is more UL avgas available. You can use synthetic oil with 100LL if the change interval is 20-25 hours. Long term, it doesn't hold lead in suspension well and isn't recommended.

    Our EFI is compatible with mogas or 100LL.
     
  8. Feb 2, 2020 #108

    skydawg

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    Aircraft ECM’s are always a point of contention, and I have experience with most and may help someone avoid some mistakes. First off, my experience is as a former FAA DER and involved with development for a FAA certification of a V8 conversion for Cessnas. our objective was to use as many automotive components as possible to reduce cost but (and here’s the difficult part) have it meet FAR 23 standards. The ECM was the biggest point of contention in this regards. We tried several ECM’s, as well as mechanical fuel injection (FARs require a engine driven fuel pump or you have to make an argument called an equivalent level of safety finding). In the proof of concept process, we experienced several failures, ruined engines, and realization that automotive ECMS’s just don’t make safe aircraft ECM’s.

    As a few members mentioned above,ECMs have a lot of programming code. This code is proprietary and difficult to reverse engineer by design to prevent folks from messing with emissions and anti theft functions, and work arounds that shut the engine down or restrict rpm for certain faults. The production ECMs from the big car makers are excellent hardware, but are flashed with intrinsic automotive mission firmware that causes the problems, regardless of what so many “tuners” will proclaim....most tuners merely maybe took an online course or more likely learned from some guy racing his 1980 Toyota on Sunday’s using basic software that manipulates factory settings to decrease AFR, advance timing, or simply checks a box disabling the limp mode on aftermarket software. Here’s the issue with this approach, these ECMs are sophisticated microprocessors programed to work many functions simultaneously, and manipulating one parameter effects other parameters, and so on, and so on. they were never designed to be manipulated and in fact, designed to prevent it from happening.

    There have been engine failures just because the ECM became confused, sofrware functions hung up/timed out/looped and the internal watch dog timers were never programed to deal with it (a watchdog timer automatically resets certain software functions when they hang up or fail to operate properly, most ECMs use such features to increase reliability). That’s why FAA requires what’s called a DO178 certification which examines every line of code for potential faults....a very expensive process for modern ECMs. The aftermarket software typically used by tuners simply changes parameters, but it does not check how it may effect other functions. There are may stories online of good automotive engines failing due to unknown ECM issues.

    We did look at aftermarket ECMs but found they did not have the engineering basis needed to meet the wide range of requirements and a few failed during testing on on Cessna test aircraft. We also found that using dual car ECMs increase failure rates for a number of reasons, especially if standard automotive calibrations were used. The best aircraft solution we found is to use ECM From the big car manufacturers for proven hardware stability and internal backup functions, BUT, not one that is already programmed for automotive applications .....which is the only way you can get them except for OEMs. To erase the embedded code you would need sophisticated software and maybe a specific freq UV light source, which would then require you to develop a calibration file.

    However, most automakers do supply non-flashed ECMs to companies that use them for their own production line, such as boat engine manufacturers as Mercury marine. These OEM’s develop and flash their own calibration file. A calibration file is not a tune, it is extremely complex and tells the engine how/when to do everything from firing a plug to when to illuminate the check engine light. These calibrations can cost $200k + to develop and require specific OEM tier software and Dyno. The firm that did the calibration for the aircraft file had advance degrees in computer science engineering and actually did development for the automotive manufacturer on that specific ECM model we used. The final product was a dual ecm system that was able to restart a failed engine due to a Ecm failure within a second with a windmilling prop. So, for the individual to get a hold of a blank ECM and develop a calibration file specific for aircraft use is not likely to happen.

    There were also several changes made to wiring harness and sensors needed. For example, car fuel injectors normally share a common circuit protection, so a ground fault in a single coil can shut all injectors Down, so each component needs its own circuit for true redundancy. Lightning protection is another concern that aircraft need to consider. I have seen several ECMs fried this way.....such effective protection can cost a lot of money to develop and test so for an individual to do it right is not likely. There have been multiple inflight failures of the 2 existing piston aircraft certified ECMs, which had millions invested in development and certification including DO178 testing, demonstrating just how complex the system can be.

    So, be careful using car or aftermarket ECMs. I would suggest contacting someone with real engineering knowledge specific to the ECM you want to use and come up with a test plan matrix to test all possible faults on the ground while installed on your actual aircraft. Do not take the word of a tuner unless he has formal ECM engineering background and understands and cares you may be flying your family around in the plane with his tune.

    Hope this was helpful.
     
    tspear, raymondbird, delta and 2 others like this.
  9. Feb 3, 2020 #109

    TXFlyGuy

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    I contacted several syn-oil companies. Each one stated that leaded fuel did not pose a problem in an auto engine with their brand of synthetic oil. Except Mobil, that is.
     
    Last edited: Feb 3, 2020
  10. Feb 3, 2020 #110

    dtnelson

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    Skydawg, thanks for a very thorough explanation... you clearly have the experience to provide real insight into the challenges. As a retired EE and a long time airplane builder, I've often thought about and been in (beer fueled) discussions over the "auto engines in airplanes", and ECM type controllers for Lycoming/Continentals debate, which have been going on for years.

    You hit the nail on the head regarding the complexity of the engineering behind ECM applications in an aircraft setting.

    When I first started thinking about building an airplane in the early '80s, and thinking about what to build, an experienced friend at Oshkosh one year told me to look around and see what kinds of homebuilt designs actually showed up in any reasonable numbers... the point being that, while you see many "one of's", and while each year seemed to have a great new design that took the show by storm, the simple fact that there weren't many of them there at the big show ought to tell you that there's something wrong... some hidden complexity, some lack of performance, ... something ... (anyone remember the Wheeler Express?). It's the same with auto engines and also with ECMs as applied to aircraft engines.

    ECMs as applied to aircraft engines (or as a part of auto engines in an aircraft) are conceptually great; but the actual, real world challenges are immense, and that's why you don't see them. Which is not to say that the problems and challenges cannot be met or have no solution - I'm sure they do - but at the end of the day, for the average guy, the question most often becomes, "do I want to continue to beat my head and spend all my money solving this engineering challenge, or do I want to fly?".

    Finally, to TXFlyGuy; Would it be fair to say that oil contamination issues of burning 100LL in an auto engine isn't the only problem? How about early failure of the Lambda sensors?

    Thanks - great discussion

    Dave
     
  11. Feb 3, 2020 #111

    TXFlyGuy

    TXFlyGuy

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    That is why we will run with 93UL 80% of the time. We will not use O2 sensors, other than in the initial flight testing / ECU (Motec) tuning.
    We accept the fact that when burning the dreaded-leaded, the mixture by default will be slightly more rich, causing a decrease in economy.

    However, we may have Hutter install a dual program. One for 93 Octane, one for 100LL.
     
    Last edited: Feb 3, 2020
  12. Feb 5, 2020 #112

    rbarnes

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  13. Feb 9, 2020 #113

    skydawg

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    Dtnelson-
    you are spot on with weighing what's involved in engineering all the details out and time & expense required, and just wanting to fly the thing. To work through the details takes resources and a myriad of skill sets and qualifications , and most "amateurs" either don't have the time or funding to make a production ready conversion that essentially meets the certified standards. The NTSB noted that one of the biggest safety issues with experimental aircraft is lack of quality documentation and testing. This is likely why the "experimental" line of Lycoming and Continental keep their monopoly. These Mega companies have no intent or reason to introduce any new technologies, they already own over 90% of global market share.

    There is a company developing a complete aluminum V8 engine firewall forward kit for some Cessnas & Pipers, and have gotten a FAA G1 issue paper for moving forward with certification. But, I understand they can't get any product liability insurance for the US and have been advised not to sell the certified version in the US. So, the FAA cert will likely only be used to meet other country CAA requirements to sell outside the US. It does have the redundancies to meet the normal cert standards and a lot of development behind it. I would expect an experimental crate engine version will be available in the US eventually. This would be ideal for home builders that don't want to spend time figuring out how to build an engine as well as the air frame. I was saw one of their C172 test aircraft filling up directly from a SUV car last year, and the pilot says the C172 cost less than $18/hr to operate (mine cost $60). The engine was computer controlled and started right up when he pressed the start button even though the engine was hot. It had no mixture control or carb heat which is basically leap years in aircraft technologies even though all modern engines stopped needing it and lead gas for 40 years. There's a lot of old proven technology that works great for aircraft, but few want to jump thru the hoops to adapt it.
     
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