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Thread: E38 Flex Fuel: On the fly timing and fueling - anyone interested?

  1. #61
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    Quote Originally Posted by GMPX View Post
    Sam, I wish I had more time to experiment with an E85 specific tune for my car. It's the 3.0L LFW V6, direct injection with 11.7:1 compression, factory flex fuel. Unfortunately there is no specific adjustment to the cam timing on these engines based on the ethanol content (or we haven't found the table), this is an area I've played around with on normal gasoline but it's too prone to knock once you start playing around with the dynamic compression by altering the cam timing.
    Any mileage measurements on E85 Ross?

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    Quote Originally Posted by GMPX View Post
    Sam, I wish I had more time to experiment with an E85 specific tune for my car. It's the 3.0L LFW V6, direct injection with 11.7:1 compression, factory flex fuel. Unfortunately there is no specific adjustment to the cam timing on these engines based on the ethanol content (or we haven't found the table), this is an area I've played around with on normal gasoline but it's too prone to knock once you start playing around with the dynamic compression by altering the cam timing.
    Wow......to think all this time I thought you were just a programmer....
    ...oh wait that's paul. Ha ha

    -Justin

  3. #63
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    Quote Originally Posted by gmh308 View Post
    Any mileage measurements on E85 Ross?
    91 Octane about 12.4L/100 city, on E85 15.8L/100. Feels lazy on E85 too. This was only reading 65% ethanol too as the tank was not empty when I put E85 in, so I expect it to be a little worse on full E85.

    Quote Originally Posted by L31Sleeper View Post
    Wow......to think all this time I thought you were just a programmer....
    ...oh wait that's paul. Ha ha
    I don't know, i just copied from something Google found
    I no longer monitor the forum, please either post your question or create a support ticket.

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    Quote Originally Posted by GMPX View Post
    91 Octane about 12.4L/100 city, on E85 15.8L/100. Feels lazy on E85 too. This was only reading 65% ethanol too as the tank was not empty when I put E85 in, so I expect it to be a little worse on full E85.
    Oki doki thx. Your mention of the VVT raises a good point, as the combination of VVT and ethanol makes it difficult to see what the timing needs to be without VVT.

    Anyone have a 2011 VE Commodore V8 tune they could post? Being a VVT free engine...

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    I will be developing a more accurate tune for several ECOTEC engines. We will also be developing a more sophisticated algorithm for valve timing.

    With such a compression ratio, you should be able to surpass both power and efficiency dramatically with and optimized E-85 tune. It should easily surpass what is possible with gasoline.

    Did your engine come with 11.7:1 compression stock?

    Quote Originally Posted by GMPX View Post
    Sam, I wish I had more time to experiment with an E85 specific tune for my car. It's the 3.0L LFW V6, direct injection with 11.7:1 compression, factory flex fuel. Unfortunately there is no specific adjustment to the cam timing on these engines based on the ethanol content (or we haven't found the table), this is an area I've played around with on normal gasoline but it's too prone to knock once you start playing around with the dynamic compression by altering the cam timing.

  6. #66
    Lifetime Member GMPX's Avatar
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    Yes, according to GM's press release the LF1 / LFW are 11.7:1 comp.
    I no longer monitor the forum, please either post your question or create a support ticket.

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    I'm working with a 3900 V6 LZG engine (VVT, DOD, & Flex Fuel ). So far it looks like it uses the E38. Any idea if the Flex fuel sense option will work on this version of the OS?

    It'd be a great thing to have when I drop a VGT turbo on it (Assuming I don't need an E67).

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    I have yet to find anyone that has confirmed that the flex parameters actually enable flex fuel operation. So far I have confirmed that people can shut it off, but I know of no one that has turned it on when it was off by default. This was certainly true of HP Tuners. Their flex fuel stuff didn't work for turning the function on. EFILive appears to have discovered more of the parameters, however. I am very interested in the answer and might just go ahead and burn up another license to find out.

    I am in the process of installing our dyno at work. I expect it to be up and running next week. I expect to be able to derive some really good tables for both E-85, E-100 and M-100. I will make them available when I finish. Unfortunately, all of these engines are 4 cylinder for now. I will move to a v8 next (L92). Probably a v6 after that.

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    Boy, no kidding. I am 50. The 555 was old when I was a kid! I wouldn't use a 555 for anything anymore.

    I completely agree about the AVRs. They are awesome. I just wish that documentation from ATMEL was a bit better. I've currently developing with a UC3C0512c. Amazing part. 32 bit, 66 MHz, 100 MHz DSP, 16 A/D ports, 2 DACs, I2C, SPI, USB, Flash, external memory support, great RISC instruction set and an industrial rating! It blazes! All for less than $20 in low quantities! Now that ATMEL has switched their IDE to microsoft, even the development environment has taken a giant leap forward.

    Quote Originally Posted by GMPX View Post
    Guys, forget the 555 timer, too old, will drift with temp. What this really needs is a nice little 8 pin AVR or PIC micro to generate the signal, it would cost about $2.50 for all the parts (if that).

    Early on when I was playing around with 'fooling' the ECM in to using the ethanol tables for an LPG application I had suggested to the shop that we were testing with that we make a board that simulates the ethanol signal.
    For this LPG application it was decided that on the fly variable ethanol % was not needed, I mean, you are on LPG or you are not! And adding in to the custom OS the option to force the ethanol percentage was much easier.

    As a project this could go two ways, a simple dial in the car with some markers on a label to show the percentage of ethanol (cheap), or, something with a 7 segment display showing the percentage selected (expensive).

    Lets all be thankful that GM left that legacy code to use a real ethanol sensor even though they have never released a car using the E38 and a flex fuel sensor.

    Cheers,
    Ross

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    Quote Originally Posted by samgm2 View Post
    I have yet to find anyone that has confirmed that the flex parameters actually enable flex fuel operation. So far I have confirmed that people can shut it off, but I know of no one that has turned it on when it was off by default.
    Unfortunately lurking in the ECM is many untapped calibrations that may stop Flex Fuel working even though you tell the ECM it's a FF engine. For example, all the Northstar V8 tunes have no base E85 calibrations set up at all, like GM knew this engine would never go to FlexFuel, so why bother. As a 'loose' rule, if the ECM has some ethanol tables populated (eg, the Stoich table not all one value) then you might get lucky in that all the underlying calibrations that make E85 work maybe populated with functional base values.

    Quote Originally Posted by samgm2 View Post
    Boy, no kidding. I am 50. The 555 was old when I was a kid! I wouldn't use a 555 for anything anymore.

    I completely agree about the AVRs. They are awesome. I just wish that documentation from ATMEL was a bit better. I've currently developing with a UC3C0512c.
    A few years back I messed around a bit with the Freescale MCF51 series, a great 32bit processor with everything you need and cheap as, like $3 ea. Problem was the dev environment was horrid (for me) as it was focused around C only programming.
    Our first hardware (V1) used an AVR Mega8, unfortunately at the time the AVR CAN series was 'pending', we decided to go ahead and design V1 with no CAN ability (this was back in 2004 or so). This was a good decision rather than wait for the new chip as it took Atmel about 4 years to get that AVR CAN chip to market, even then it had bugs. I found AVR studio not too bad to work with as it's not 'C' or 'asm' orientated.

    Ira (Fish Tuning) and I often have discussions on AVR's (riveting conversation for anyone listening in).

    I wish Freescale would make a small 32 pin Micro with a PowerPC core
    I no longer monitor the forum, please either post your question or create a support ticket.

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