Yeah that's true. There's plenty meth related failures too and theories behind those. Ultimately a lot of this game comes down to minimizing risk and keeping the car in good shape and logging in proportion to the build. I've seen some scary logs of these situations but in practice only one or two failures possibly from it. I guess the thing is if it's not discussed it'll never get fixed.
Port Injection causing engine failure
- Thread starter dyezak
- Start date
Yeah that's true. There's plenty meth related failures too and theories behind those. Ultimately a lot of this game comes down to minimizing risk and keeping the car in good shape and logging in proportion to the build. I've seen some scary logs of these situations but in practice only one or two failures possibly from it. I guess the thing is if it's not discussed it'll never get fixed.
We are talking about controlling the second VCV? I had wondered if you could leave the first one with its existing closed loop control and run the second one open loop, but it sounds like that doesn't work. Why not? I can see why the PID gains would be wrong if you run two pumps on the same output.
It is getting relatively trivial to add high level code to these ECUs (after several months of building the backbone to do it), input variables to feed the code are easy, outputs are more tricky.
It is getting relatively trivial to add high level code to these ECUs (after several months of building the backbone to do it), input variables to feed the code are easy, outputs are more tricky.
I think it works just fine, 850whp was made DI only using an SS AIC to control the second VCV in open loop. Just need to remove that extra box from the equation.
edit: That said, I do see a benefit to proper PI control as well... valve cleaning, much cheaper and more reliable injectors, no additional hpfp to worry about, etc. Having both options available would be great
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Well I wouldn't say it's cheaper. Time you load up the cart with everything needed, you are over 2k and that's if you only order it with one hpfp. I think it really comes down to whether or not you feel safe with PI. Both of them can do the job for big power.
I think it works just fine, 850whp was made DI only using an SS AIC to control the second VCV in open loop. Just need to remove that extra box from the equation.
edit: That said, I do see a benefit to proper PI control as well... valve cleaning, much cheaper and more reliable injectors, no additional hpfp to worry about, etc. Having both options available would be great
Yes, please. ffs, I'd rather pay for this addon then buy an expensive and bulky controller with no other purpose than the control a pump. My 0.02c
That's an interesting question. Assuming PI is picking up increased demand from the e85 over e60 complicates it further. There's a dissertation in here somewhere determining the limits to fuel ignition vs misfire, which in this case is useful misfire.
Edit- anybody have any relevant mechE papers dealing with limits of combustion, specifically with alcohol fuels? It's gotta exist...
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Not quite on topic but interesting:
http://bmwmotorcycletech.info/ionization-current-sensing-ignition-susbystem.pdf
http://bmwmotorcycletech.info/ionization-current-sensing-ignition-susbystem.pdf
DB is $1700 shipped with everything you need except an extra HPFP, $200 of that is a core charge for the rail, so its really $1500 once you send that back in. Its more expensive than PI, but its also safer, and more efficient.
@Tony@VargasTurboTech , have you tried letting the DME read the overspun HPFP and run the stock location pump off the AIC?
@Erichale77 that's the current operation of the double barrell kit.
That would be based off you already having a spare hpfp sitting around correct since it's set up to run two hpfp?
It is on his site. But yeah it is $1700 assuming you have another HPFP laying around. But you get 200 of it back because of core charge on the fuel rail so without a 2nd pump it would be $1500.
And not sure if the AIC controller they use is any different from the one used for port injection. If not you can find them sometimes for as low as $100 on the BMW sites which could also save a couple hundred. I think they should do a group buy to get the shotgun kit some reviews
Justin,
Prof Fred Dryer at Princeton is one of the gurus in academia on this subject. I met Fred in his office several years ago on a different topic. Check out some of his cited publications on fuels combustion on his webpage.
http://mae.princeton.edu/people/faculty/dryer
This paper may be of particular interest.
- T.M. Foong, K.J. Morganti, M.J. Brear, G. da Silva, Y. Yang, F.L. Dryer, “The Octane Numbers of Ethanol Blended with Gasoline and its Surrogates”, Fuel, 115 727-739, 2014. http://dx.doi.org/10.1016/j.fuel.2013.07.105
(I bet you didn't know there is an academic technical journal titled, "Fuel".)
Fortunately, I do actually have a spare HPFP laying around. I think I'd make sure the older one was in a easier to access location, if it let go...If there is such a location.
The lower explosive limit on fuel is really low. In all cases of supplying a relevant amount of fuel, that amount could theoretically ignite with DI shut in. Probably more important is whether or not the amount of energy released is enough to cause damage.
