Announcement

Collapse
No announcement yet.

Injector placement ?

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Injector placement ?

    Some of you guys were chatting about injector placement a while back and I got a little confused. The comment that got me was intentionally putting the injectors higher on the runner instead of at the port and I'm wondering why? Other than cooling the air charge maybe, I'm unclear on the theory.

    care to share?
    Flying south, with a flock of bird dogs.

  • #2

    Re: Injector placement ?

    Our experience has been that it provided an increase in torque across the board. However the port entrance placement proved more controllable.

    But our engine is a rather specialized piece meant for a very narrow performance band.
    I'm still learning

    Comment


    • #3

      Re: Injector placement ?

      Theory should still be the same but from an induction standpoint there are alot of variables to where they may work better at a different position. Better to say depends on the application......
      Nick Smithberg
      www.smithbergracing.com

      Comment


      • #4

        Re: Injector placement ?

        I vote to aim them at the valve on a streetable engine, keeping them "down low." By running them high you can get in a situation where drivability and idle are badly compromised. It's almost not worth the few percent gain you *might* see, plus if you put them up high I think you'd need to be able to tune individual AFRs on an engine dyno, which is pricey - for a few percent power gain.
        www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!

        Comment


        • #5

          Re: Injector placement ?

          Sometimes 'conventional wisdom' is based in fact and practice. The OEM's are getting great power and mileage out their hi-po engines these days and they have uniformly stuck to injectors that are at the cylinder head end of the intake manifold. F1 cars on he other hand have the injectors well above the intake throat. Horses for courses.

          The EFI fueled mountain motors have the injectors slightly higher than midway up the runners under each 1800 CFM throttle bore. For a street strip car keep the injectors as da 'Geek described.
          Drag Week 2006 & 2012 - Winner Street Race Big Block Naturally Aspirated - R/U 2007 Broke DW '05 and Drag Weekend '15 Coincidence?

          Comment


          • #6

            Re: Injector placement ?

            those run on pulse.

            for a screamer like f1, back them away..timing is useless in ecm games of nerdy theories.
            you big blocks should be benefitting right at the head.

            I still can't find any combo for a 2.65 inch stroke, sharing one runner....I just let it draft.
            Previously boxer3main
            the death rate and fairy tales cannot kill the nature left behind.

            Comment


            • #7

              Re: Injector placement ?

              those run on pulse.

              for a screamer like f1, back them away..timing is useless in ecm games of nerdy theories.
              you big blocks should be benefitting right at the head.

              I still can't find any combo for a 2.65 inch stroke, sharing one runner....I just let it draft.
              4 x 24# at 40 psi will cover 150hp... one per side? They put them in 460's... megasquirt, any modern 4 cylinder TB will be plenty but an old Mustang V8 throttle body can be found with TPS for 20 bucks with plenum, would give you something to "adapt" with?



              Part of the reason I was asking this question is thinking about turbo or nitrous setup where you might put a secondary driver and place supplemental injectores higher up stream? Seems like more of a pain to tune. Just thinking out of my butt random question. Thanks for the responses guys!
              Flying south, with a flock of bird dogs.

              Comment


              • #8

                Re: Injector placement ?

                4 x 24# at 40 psi will cover 150hp... one per side? They put them in 460's... megasquirt, any modern 4 cylinder TB will be plenty but an old Mustang V8 throttle body can be found with TPS for 20 bucks with plenum, would give you something to "adapt" with?

                Part of the reason I was asking this question is thinking about turbo or nitrous setup where you might put a secondary driver and place supplemental injectores higher up stream? Seems like more of a pain to tune. Just thinking out of my butt random question. Thanks for the responses guys!
                Placing upstream supplemental injectors works great. It's the primaries that do most of the work at part throttle that you want to have positioned properly. Once the air is really flowing, say in a turbo app where you stage a second set of injectors with boost - you can put them almost anywhere.
                www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!

                Comment


                • #9

                  Re: Injector placement ?

                  I was just looking at a cutaway of a new small displacement turbo engine. First set of injectors were DI, second set were up the intake runners quite a bit.
                  I'm still learning

                  Comment


                  • #10

                    Re: Injector placement ?

                    Mount them low for normal driving, I raised mine and have a reversion hole at 2500 to 2800 or so. Mount the secondary ones higher to cool the intake charge better. Heck I would make a E-85 tank to run them off stand alone
                    2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
                    First to run in the .90s .80s and .70's in SBN/A
                    2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
                    2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

                    Comment


                    • #11

                      Re: Injector placement ?

                      I hadn't thought about that - I was thinking the old Oldsmobile Rocket Fuel setup meth injection / hobbes switch, but e85 under boost is a helluva thought. I had thought about that for DW ( high compression and running e85 all the time) but realized since I don't have a clue on the route, I won't know where any stations are.

                      slight derail, but I'll toss it out here anyway. Assuming the built-in ECM worked adequately with the engine NA, can you drive just the secondary set of injectors with a Mega Squirt using the same sensors or would it make the signal from them get screwed up? I figure you could use the MS for the whole thing, except the application I'm thinking about controls the trans (e40d)
                      Flying south, with a flock of bird dogs.

                      Comment


                      • #12

                        Re: Injector placement ?

                        I hadn't thought about that - I was thinking the old Oldsmobile Rocket Fuel setup meth injection / hobbes switch, but e85 under boost is a helluva thought. I had thought about that for DW ( high compression and running e85 all the time) but realized since I don't have a clue on the route, I won't know where any stations are.

                        slight derail, but I'll toss it out here anyway. Assuming the built-in ECM worked adequately with the engine NA, can you drive just the secondary set of injectors with a Mega Squirt using the same sensors or would it make the signal from them get screwed up? I figure you could use the MS for the whole thing, except the application I'm thinking about controls the trans (e40d)
                        Sure, you can use the megasquirt to run a set of secondary injectors. But you won't want to share the two temp sensors (coolant, air temp) as it will throw off the readings in the factory computer. It's too easy just to run a second CLT and IAT anyhow, since they're cheap. You CAN share the TPS signal, and the MAP is just a vacuum line you run into the MS's onboard MAP sensor.
                        www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!

                        Comment


                        • #13

                          Re: Injector placement ?

                          good news on the TPS - thanks! Should really simplify things... much to think about.
                          Flying south, with a flock of bird dogs.

                          Comment


                          • #14

                            Re: Injector placement ?

                            You can if using enough injectors run the All E-85 at the track and switch back to gas for the road. We did it on Docs last year and I will this year just bring a jug of E-85 with you
                            2007 SBN/A Drag Week Winner & First only SBN/A Car in the 9's Till 2012
                            First to run in the .90s .80s and .70's in SBN/A
                            2012 SSBN/A Drag Week Winner First in the 9.60's/ 9.67 @ 139 1.42 60'
                            2013 SSBN/A Drag Week, Lets quit sand bagging, and let it rip!

                            Comment

                            Working...
                            X