dual stage engine management system
dual stage engine management system
(OP)
Hi all
I own a modified '93 Corvette ZR-1, the one with a Lotus designed V8 32 valves engine.
This engine has 16 injectors. 8 primaries for low speeds or 8 primaries + 8 secondaries for higher rpms or power output.
Injectors are all the same (bosch 200cc). Currently LT5 ECU works with a MAP sensor. Accelerator works with mechanical link + potentiometer.
Delco ECUs are not available any more for this car, the same for the ignition control unit, etc ... Engine control units are bulky, slow, etc...
I have a friend who has installed an LS1 engine in his Corvette C3 (seventies ...) controled by LS1 oem engine management with great success (OBD2).
I own the softwares to modify the ECU programm for LS1s or my LT5 ZR-1, so software accessibility is not a problem. I can do both, but the more recent systems are much more pleasant to use, softwarewise and much cheaper too (ECUs on ebay are us$ 100.00 each...).
I would like to know what do you think of this idea:
Throttle body would be replaced by 2 siamesed LS1 throttles bodies, each working with its own MAF sensor.
- the primary one works with the mechanical link and TPS from accelerator (like it is with LS1 Firebird Transams or at this time on my car)
- the secondary one works with Fly By Wire like it is in C5 Corvettes. Secondary throttle receives signal from TPS of primary throttle.
Primary LS1 ECU works by its own.
When secondary LS1 ECU is switched on (key on the dash board), secondary ports are opened (they're vacuum operated on the ZR-1). Secondary throttle body would set by itself to the same position at primary throttle body.
The primary would take care of the ignition. The secondaries would take care of the cruise control and ASR (ignition advance control problem ...).
I don't think the MAP would be needed anymore.
I would probably have to replicate informations from camshaft position sensor, temperatures, etc...
What do you think of this idea? (Motec ECUs are more expensive...).
Could there be any problem with mutual effects between the 2 ECM. I think it could.
Your opinion will be greatly appreciated!
Thank you
David
I own a modified '93 Corvette ZR-1, the one with a Lotus designed V8 32 valves engine.
This engine has 16 injectors. 8 primaries for low speeds or 8 primaries + 8 secondaries for higher rpms or power output.
Injectors are all the same (bosch 200cc). Currently LT5 ECU works with a MAP sensor. Accelerator works with mechanical link + potentiometer.
Delco ECUs are not available any more for this car, the same for the ignition control unit, etc ... Engine control units are bulky, slow, etc...
I have a friend who has installed an LS1 engine in his Corvette C3 (seventies ...) controled by LS1 oem engine management with great success (OBD2).
I own the softwares to modify the ECU programm for LS1s or my LT5 ZR-1, so software accessibility is not a problem. I can do both, but the more recent systems are much more pleasant to use, softwarewise and much cheaper too (ECUs on ebay are us$ 100.00 each...).
I would like to know what do you think of this idea:
Throttle body would be replaced by 2 siamesed LS1 throttles bodies, each working with its own MAF sensor.
- the primary one works with the mechanical link and TPS from accelerator (like it is with LS1 Firebird Transams or at this time on my car)
- the secondary one works with Fly By Wire like it is in C5 Corvettes. Secondary throttle receives signal from TPS of primary throttle.
Primary LS1 ECU works by its own.
When secondary LS1 ECU is switched on (key on the dash board), secondary ports are opened (they're vacuum operated on the ZR-1). Secondary throttle body would set by itself to the same position at primary throttle body.
The primary would take care of the ignition. The secondaries would take care of the cruise control and ASR (ignition advance control problem ...).
I don't think the MAP would be needed anymore.
I would probably have to replicate informations from camshaft position sensor, temperatures, etc...
What do you think of this idea? (Motec ECUs are more expensive...).
Could there be any problem with mutual effects between the 2 ECM. I think it could.
Your opinion will be greatly appreciated!
Thank you
David





RE: dual stage engine management system
Regarding ignition advance - if the secondary controller is using the exact digital information available to the first controller, then I think there will be no issue. If you are re-creating that information with different sensors and/or have a slow communication network with some lag there could be an issue. It sounds like you plan to replicate parameters to the second controller, and modern networks are very fast, so I think you won't have a problem here.
I'm not sure I clearly understood exactly what signals you were passing to your secondary controller, and exactly which parts you were controlling with it, so I'll correct or update as you think something isn't addressed.
RE: dual stage engine management system
RE: dual stage engine management system
RE: dual stage engine management system
A Motec controler with dual stage injector system is rather around us$ 2500.00 if I'm not mistaken. Other brands are in the same prices. That is 12 times more expensive than a pair of Delcos!
That makes quite a difference for a box, which, if one day fails, will probably be much more expensive again to repair or replace than a Delco LS1 ECU (avaibility in the long run?).
Important point to say: transiant position can not be covered by this system because when you switch on ECU2... it accelerates! You could only switch it on when throttle #1 released.
About feedback for ECU1 I was meaning that potentiometer signal was replicated and sent to both ECUs. So ECU 1 gets its TPS signal as usual and ECU2 gets its signal as it would be with a fly by wire accelerator. So I'm not sure there would be such a great lag... for this.
Anyway, I think too it wouldn't work easily for a least 1 reason:
When 2 ECUs are operating, fuel calibration won't be the same for ECU 1 as when only ECU 1 is operating because total flow is not twice the same. At least it's not a linear thing...
Now a simpler way to use LS1 ECUs could be instead to use only one device and short secondary injectors when needed.
The problem though is when in parallel, you get 7 Ohm impedance instead of 14 Ohm so I'm sure the ECU drivers wouldn't like it either. It would definitively require something else that an on off switch for ground...
Then, the trick to say to the ECU that injector time must be divided by too would be to add a signal divider between MAP sensor and ECU.
- 8 injectors: normal MAP signal
- 16 injectors: signal divided by 2
Thanks again
David
RE: dual stage engine management system
Thanks
David
RE: dual stage engine management system
RE: dual stage engine management system
From another perspective, the LS6 engine is similar displacement, has similar power output, but has cleaner emissions and still manages to make do with one injector per cylinder.
I suspect that having sixteen injectors was more marketing ploy than anything else.
RE: dual stage engine management system
In fact there is no harm in raising your idle speed to meet the minimum injector pulsewidth anyway. You dont sound like a Prius competitor!
Whilst my experience with dual ECUs has been all good, it has relied very heavily on high speed OEM CAN & treated both banks as 2 separate VR6s - no real problems but MAJOR support from the supplier.....
I personally wouldnt risk it - go single programmable ECU, big 8 big injectors & rest assured you will be OK, it will be worth it in the end.
MS
RE: dual stage engine management system
Thanks again!
David
RE: dual stage engine management system
http://hre.com/cgi-bin/discus/discus.cgi
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RE: dual stage engine management system
RE: dual stage engine management system
Autronic doesn't want the do-it-yourselfers installing their products, they will recommend a shop to do it for you to eliminate any bad word-of-mouth from the "I can tune a carb, this fuel injection thing should be a cinch"-types screwing up and blaming the product.
The SMC or SM4 is standalone (although their are some piggyback units for certain vehicles). As a standalone, you have complete control over all aspects without having to calculate what your injector pulse width, etc, should be, like MegaSquirt (not knocking MS, I haven't used it). I have installed and tuned with Autronic and wouldn't go with anything else unless cost was a major concern. Their documentation is fairly poor though, because it's assumed that an experienced shop is performing the work but their customer support is fantastic (I had to call the distributor at home on a Saturday for help once).
RE: dual stage engine management system
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Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: dual stage engine management system