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A thread for EFI newbie questions and answers

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  • #16

    Re: A thread for EFI newbie questions and answers

    Re: A thread for EFI newbie questions and answers

    For EFI you really need to have some injectors installed low - under the blower. Otherwise you will have tuning issues.
    I disagree a little here, I did a conversion from one of those "mechanical fuel injection" manufacturers' EFi systems (alpha-N based) and left the injectors where they were, up above the blower, this was on a 454" BBC and we didn't have any distribution problems. It was that shoebox that was on that TV show "wrecks to riches" or whtaever, after the show it was delivered to us with a "make this thing drivable" request, we got it to run awesome with a simple conversion to a speed density combo. I won't say that one might not run into tuning issues with injectors above the blower, but it's not always the case that it'll run badly. Same goes for TBI units and big cams. It may be a crapshoot, but careful diagnostics (and changes if necessary) will sort out the problems.
    www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!

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    • #17

      Re: A thread for EFI newbie questions and answers

      Re: A thread for EFI newbie questions and answers

      BDS has been putting efi on blowers for about 20 years. I guess they work, I could never afford one though.

      I also have entertained the idea of making an efi setup for my 55, to sit on top of the blower, and tuck everything under the hood. Didn't get much past the concept stage, though.

      My fabulous web page

      "If it don't go, chrome it!" --Stroker McGurk

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      • #18

        Re: A thread for EFI newbie questions and answers

        Re: A thread for EFI newbie questions and answers

        Matt,
        I really don't know yet, but I've got an older Jacobs CD-ignition unit with a secondary trigger on the shelf. I think this ignition won't have any trouble igniting the compressed mixture in the cylinders, but if needed I'll step it up a notch.

        Here's a link to the (Dutch) company who makes these vapor injectors...
        http://www.prinslpgnetwork.com/productprofile.html

        On the '07 SEMA-show there was a 1000HP Chevelle which had similar injectors on it's motor I think...
        http://www.autoblog.com/2007/10/31/s...le-by-mothers/
        www.BigBlockMopar.com

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        • #19

          Re: A thread for EFI newbie questions and answers

          Re: A thread for EFI newbie questions and answers

          BDS has been putting efi on blowers for about 20 years. I guess they work, I could never afford one though.
          Craig Railsback (owner of BDS) is a good guy, and Craig and I are both FAST dealers, but even he will admit to having tuning problems when the injectors are only above the blower. I'm not saying you can't get it to work, but the first few blower motors I did (all with BDS blowers BTW) had transition issues that were tough to correct. I also fought the typical idle surge problem. I got them tuned and they do run pretty good, but it takes longer to get right.

          When a FAST engineer suggested I try with 8 down low on my next motor - I did just that, and it worked very well. The FAST ECU can drive 16 injectors so I had no other problems.

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          • #20

            Re: A thread for EFI newbie questions and answers

            Re: A thread for EFI newbie questions and answers

            BDS has been putting efi on blowers for about 20 years. I guess they work, I could never afford one though.
            Craig Railsback (owner of BDS) is a good guy, and Craig and I are both FAST dealers, but even he will admit to having tuning problems when the injectors are only above the blower. I'm not saying you can't get it to work, but the first few blower motors I did (all with BDS blowers BTW) had transition issues that were tough to correct. I also fought the typical idle surge problem. I got them tuned and they do run pretty good, but it takes longer to get right.

            When a FAST engineer suggested I try with 8 down low on my next motor - I did just that, and it worked very well. The FAST ECU can drive 16 injectors so I had no other problems.
            Yikes, sounds like an expensive suggestion from FAST. What I found is, after the VE tables right off idle were tuned at constant load on a loadbearing dyno, the big trick to tip-in response was making sure an appropriate "pump shot" was tuned... it takes longer for the fuel to reach the cylidners being that far from the combustion chamber, I just made sure to tune it so the fuel delivery was consistent with the air delivery and I ended up with off idle response that was as good as any MFI setup I'd encountered. no moving of injectors required. Coincidentally, we were using Craig's threaded injectors, now THAT is a neat idea. We like Craig a lot.
            www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!

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            • #21

              Re: A thread for EFI newbie questions and answers

              Re: A thread for EFI newbie questions and answers

              Yeah - that's what I meant by "transition tuning". I did the same thing too. But I didn't like it because the A/F ratio went very rich (to my thinking at the time) during those periods. Later when I had a chance to monitor a carbureted blower motor on the dyno I was pleasantly surprised at how rich that motor ran as well. I guess at the time, I just wasn't used to seeing transition A/F ratios that low. I'm over it now. But the injectors down low still worked better.

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              • #22

                Re: A thread for EFI newbie questions and answers

                Re: A thread for EFI newbie questions and answers

                Yeah - that's what I meant by "transition tuning". I did the same thing too. But I didn't like it because the A/F ratio went very rich (to my thinking at the time) during those periods. Later when I had a chance to monitor a carbureted blower motor on the dyno I was pleasantly surprised at how rich that motor ran as well. I guess at the time, I just wasn't used to seeing transition A/F ratios that low. I'm over it now. But the injectors down low still worked better.

                awesome! because I went through the same thing. All these guys who told me "carbs run jhust as good as EFI" so I put a wideband on one; I then discovered most of that crowd are driving around at 11:1 AFRs all the time. Sure it's got great throttle response!! lol

                -scott
                www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!

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                • #23

                  Re: A thread for EFI newbie questions and answers

                  Re: A thread for EFI newbie questions and answers

                  On a related note, Jerry's been working with EGT probes on a carbed car. We'd seen a couple TBI setups where it seemed impossible to get the fuel distribution right, so we're investigating if it was ever all that good to start with. It's easy to get one cylinder way hotter than the others.

                  I've seen those injectors before. With a regular Megasquirt you can fire eight of those LPG injectors directly, but it's very unforgiving of bad grounds. I suspect the eMS-Pro would do better, or there are a few tricks you can do to a Megasquirt to beef up its noise resistance. (I'd also make sure the blower doesn't rely on gasoline for lubrication!)

                  Depending on what system you're running, I'd probably put in a Lean Burn distributor (unless you really wanted to run a billet item) and either use the Lean Burn's pick-up or a crank trigger. Jacobs did build some junky ignitions in the past (their non-CDI stuff was no hotter than many OEM modules) but I would expect their CDI to have been competative. Or you could get really fancy and ditch the distributor altogether.

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                  • #24

                    Re: A thread for EFI newbie questions and answers

                    Re: A thread for EFI newbie questions and answers

                    heh...blower carb tuning is fun, mine's only rich when the pedal is down a ways, it's pretty lean cruising.

                    My fabulous web page

                    "If it don't go, chrome it!" --Stroker McGurk

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                    • #25

                      Re: A thread for EFI newbie questions and answers

                      EFI above blower re-visited

                      heh...blower carb tuning is fun, mine's only rich when the pedal is down a ways, it's pretty lean cruising.
                      Scott et al. scanning through historical records and found this thread. Since I am fast approaching the start up of my blown v6 EFI (above blower injectors only) I am trying to absorb any lessons learned. I did install a MAP and will be using speed density. I will be using E85 and no more than 15 pounds of boost. One of the problems I had with the MFI is that I had to run it rich at idle in order to have enough fuel for the tip in. In fact in ran so rich, it fouled plugs a lot. Part throttle issues and rich conditions convinced me to go EFI. It doesnt have to be perfect, but its gotta be better than what I had. Anyway you can send me a copy of the VE tables for review? I know it will be apples to oranges but it might be helpful. Any other advice or suggestions will be warmly received.

                      thanks
                      ed

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                      • #26

                        Re: A thread for EFI newbie questions and answers

                        This needs to get pinned to the top of this forum!
                        I'm still learning

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                        • #27

                          Re: A thread for EFI newbie questions and answers

                          This needs to get pinned to the top of this forum!
                          fir what..? to reveal the other side of reality see saw? my own needed 2more psi in fuel pressure and a custom needle to gain afr into the 13 at part throttle.. Way too lean. I also left an optuon for fat, a finesse with my foot. that is where injection fails monitoring what to mix with what. Locally something in the autumn air over rules in quick sprites. Causes a lean.. it only takes seconds for some of us.
                          Previously boxer3main
                          the death rate and fairy tales cannot kill the nature left behind.

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                          • #28

                            Re: A thread for EFI newbie questions and answers

                            Holy ancient thread resurrection Batman!
                            I did not know we had Nedbal on the site, at least for a while. His latest Hemi build is a good example of what this thread is all about. Why is he no longer here?
                            BKB
                            www.FBthrottlebodies.com
                            Bruce K Bridges

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                            • #29

                              Re: A thread for EFI newbie questions and answers

                              subscribing to this one

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