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Thread: 347 w/ Paxton Blower Settings Help!

  1. #21

    Default 347 w/ Paxton Blower Settings Help!

    Thanks, just ran out and swapped those settings. It is the Magnaflow system with x-pipe on MAC longtube headers. It sounds beastly when you get on it but no drone when cruising at 65mph. Love it!

    My wife pointed out that while I may hear the popping sound on the second video at 0:24 seconds, it actually happened before you see the MAP reading jump to 19 due to travel delay. So I am thinking the jump to 19 is probably just myself getting off the throttle after I heard the popping. If that makes any sense, haha.

    Another exhaust popping video;

  2. #22

    Default 347 w/ Paxton Blower Settings Help!

    First of all - that is a beautiful car and super clean setup! Very nice.

    The first thing that catches my eye is that you say you're under boost when the popping occurs (I can definitely hear the popping on the videos), yet I never see the MAP go above about 19" Hg. If you are truly building boost, then the MAP should be reading something above local barometric pressure (absolute local baro - not the corrected value reported by the TV stations). The easiest way to reference your local barometric pressure is to note the MAP reading with the Key On / Engine Off. Just for reference - Sea Level Barometric Pressure is 29.92 " Hg. That being said, if you are under light boost (say 2 psig), I would expect to see the MAP around 34" Hg. At 6 psig of boost, the MAP should be around 42" Hg.

    All this considered, did you make any changes to the 1/16" NPT pipe plug that is used to configure the throttle body for blow-through versus draw through operation? At this point, I am wondering if the MAP sensor is actually seeing true manifold pressure - or if it is being adversely affected by a lag or bias.

    If you are actually building boost, but the MAP sensor never sees it, then that can cause a multitude of problems - not the least of which is a very lean A/F ratio.

    Please double check the MAP sensor pipe plug location and / or make sure the MAP sensor port is not being restricted or partially blocked by the airbox base or baseplate gasket.

  3. #23

    Default 347 w/ Paxton Blower Settings Help!


    The second short video that shows the MSD Atomic dash as I was driving is actually just gradual throttle pulling away. That is where I saw as high as 19"HG, I failed to mention that it was barely boosting. I will make another video tonight to see how high it climbs when I am boosting to 5-6psi.

    This video below shows how I accelerated in correlation to that second video of the Atomic EFI dash;

    For some odd reason I just didn't think about it and was expecting the MAP reading on the Atomic dash would read similar to a mechanical vacuum:boost gauge but that is not the case. Thanks for explaining that!

    I have not made any adjustments to the Atomic 'boost reference port'. My understanding from the instructions was that it was only to be used with a draw-through supercharger system, so the atomic would be able to see what pressure is produced below the unit. With my blow-through setup the Atomic MAP sensor would see it.

    I have an Autometer Sport Comp II analog wideband air/fuel gauge installed as well. The AFR readings on the Atomic dash is pretty much spot on to what I see on the Autometer gauge. I have never seen much lean conditions, always way richer, it has become a lot better as I have been tweaking everything. I am still wondering if 52psi fuel pressure it too much, it is setup now to increase 1:1 as boost builds.

  4. #24

    Default 347 w/ Paxton Blower Settings Help!

    First things first - I am not advocating that you go out and flog it at full boost and WOT if there are indications of problems at low boost. Everything needs to be right before you start pushing it.

    In the video, it seems a though there is some other creaking / popping that occurs - especially when you are turning corners. I might be mistaking that noise for the popping out of the exhaust.

    I know it's hard, but keep an eye on the MAP reading as your roll into it and start to build boost. If you do not see the MAP respond and rise above the local barometric pressure, then something is wrong.

    In my mind, I am envisioning a non-standard baseplate gasket or that the airbox base is somehow obstructing the MAP sensor port. It responds reasonably well to vacuum (normal driving), but as boost starts to build, the gasket might be sealing off the MAP sensor port.

    The MAP sensor port is located underneath the throttle body - on the base plate. If you flip the throttle body over, you will see a threaded hole - opposite the linkage, next to the two sets of throttle blades. If you follow that passage rearward, you should see a 1/16 NPT pipe plug installed in the passenger side rear of the baseplate - on the extreme outboard edge. If this is what you see, then you should be okay - as long as there is nothing blocking the MAP sensor port.

    It sounds crazy, but it's worth checking.

    The next thing to check is the ignition timing. Have you verified the base timing with a timing light? Is timing control "Enabled" on the handheld? These are two very important (and often overlooked) factors when optimizing the system.

    For that matter - is the system wired correctly to actually allow the system to control the timing? Sometimes, when the original install was performed by another person, you think everything is configured one way - when it is actually configured in a totally different way. If you still have the installation instructions, or can download an electronic copy, it might be a good idea to look over the wiring between the distributor, the Throttle Body and the Ignition Box - just to make sure it correct. Only then can you start to completely eliminate the variables - one at a time.

  5. #25

    Default 347 w/ Paxton Blower Settings Help!

    Alright. I looked at the MAP and it was clear and unobstructed. My fastback fold down seats creak and squeek in the back of the car, you may be hearing that more than actually popping.

    I have been playing around with other stuff today. I noticed some black marks on the paxton manifold, thinking it is backfire through throttlebody and not exhaust.

    I noticed that when I put a small filter on my bypass valve the popping stops and the car feels way better at low rpms around the neighborhood.

    Checked all wiring and everything matches the instructions exactly. I just didnt feel confortable taking the distributor apart, so cant say what settings are set in there.

    I made a video ofmy timing. I've never done this before so please bare with me. I am pretty confused if I need to keep the timing light at zero or advance it to 15 to match the timing lock on the MSD unit? The video shows both at zero and 15 advanced with the timing lock on.

    With the timing light at zero the car shows what looks close to 20 and with the light set to 15 it looks like right at 10. This is with the msd atomic locked at 15

    Video; Hs

    Edit; I also noticed the car runs better with vacuum advance set to 0

  6. #26

    Default 347 w/ Paxton Blower Settings Help!

    Since you are using the adjustable timing light, the offset should be at zero (00). When you were checking it with the offset zeroed, it looked as though the timing was at 22°. That being the case, you need to pull out 7° (retard it) to get the 15° base timing that is required.

    In order to retard the timing, you will need to loosen the distributor hold down clamp and rotate the distributor in a counter-clockwise direction (the same direction as normal rotation). Once you are reading 15° on the balancer, tighten the hold down clamp.

    Looking back through all you've done up this point, I don't see the rotor phasing check mentioned. That is also very important. Since you are going back and verifying the setup the shop did, now would be a good time to check the rotor phasing.

    It should be phased 15° opposite distributor rotation. So, in your case with, if you remove the distributor cap and look down on the rotor, the offset should be in a clockwise direction. If not, then that adjustment needs to be corrected before proceeding.

  7. #27

    Default 347 w/ Paxton Blower Settings Help!

    I took two photos of the MSD phaser, they are attached to this post. It looks like it is in the correct position. The washer also looks installed correctly as per the MSD instructions. It is 15* (clockwise) in the opposite of what the distributor is moving (anti-clockwise).

    I adjusted the timing and it is now dead on at 15*. I am a little short on time this evening, hopefully I can do a quick drive around the block on Wednesday evening.

    Video of timing at 15* ;

    I am still unsure about the fuel pressure. I am back at 50 psi and I have the fuel regulators vacuum port hooked up to see only boost from the Paxton manifold. I cannot find a definitive answer if the fuel regulator should be able to see vacuum or just boost or whether I need to install a check-valve inline with it.

    PS. alfalfa426, you are awesome! I cannot thank you enough for answering all my questions. Thanks for explaining as you answer but also responding in a manner that someone less in-the-know such as myself can easily understand and respond to.

    Attached files

  8. #28

    Default 347 w/ Paxton Blower Settings Help!

    Cool thread guys, learning a lot about supercharging. I do have one question though.

    The kit normally has a 1 Bar MAP sensor for normally aspirated motors. So I believe that it can only measure up to 14.9 psi (sea level) and supply fuel appropriate up to that level.

    Since there is 5 to 6 psi boost the 1 Bar MAP sensor would be incapable of going over 14.9 psi. Under boost the pressure would be around 20psi so it wouldn't realize that and not compensate with the extra fuel needed.

    I believe that MSD sells a 2 Bar MAP sensor so should this system be using this? It would be capable of handling up to 29psi and provide appropriate fuel up to that pressure level.

    Again, I know very little about superchargers so I could be totally off here but I am trying to learn as much as possible here.

    EDIT: Also a second question, fuel pressure is 50psi and what I have read is that fuel pressure should be a least 5 psi above boost (20psi) so isn't the current fuel pressures that you are seeing adequate?

    This MAP sensor is for up to 20PSI boost.

  9. #29

    Default 347 w/ Paxton Blower Settings Help!

    You are most welcome robb86 - and thanks for having the patience to stick with it. If only more people would take the time to tinker with the system and take the time to ask questions and learn the way you have.

    I really think you're on the verge of a breakthrough here since the photos of the rotor show that it is adjusted in the wrong direction. It should be adjusted "opposite normal distributor rotation". Since your SBF distributor rotates counterclockwise (as viewed looking down on the rotor) you'll need to loosen the screw and rotate the top half of the rotor clockwise past the "zero" mark, and on to the opposite 15° mark. While you're at it, remove the rotor hold down screw and add a dab of blue Loctite before you reinstall it. Judging from the photo, the Belleville washer is installed correctly, but make sure you tighten the screw enough to fully compress (flatten) the Belleville washer.

    Correcting the rotor phasing can only help and I suspect it might just make the car run and drive like you hoped it would all along. The timing looks to be right on 15° - so good job there.

    To address your concern bojo - the Atomic TBI's internal MAP sensor is rated for 2-Bar. That's 1-Bar of naturally aspirated operation plus another 1-Bar of boost - so it's good for about 15 psig of positive manifold pressure.

    Robb86 - back to your question about the fuel pressure and regulator connection. Typically, 45-48 psig is a good base setting. The regulator vacuum / boost reference port should be connected to the intake manifold plenum or one of the non-ported locations on the throttle body base plate. It does not necessarily need to see vacuum (lots of people run the regulator reference port open to the atmosphere), but it does need to see boost. In your case, connecting it so that it sees both will be fine.

    I'm anxious to see how it runs once you correct the rotor phasing!

  10. #30
    Join Date
    Sep 2017

    Default 347 w/ Paxton Blower Settings Help!

    I think Prostreet1 described best how to set the phasing correctly. "If you grab the base of the phaseable rotor with one hand, grab the adjustable top portion with the other hand and turn it OPPOSITE your normal distributor rotation.

    Your normal "FORD" rotation is counter clockwise, so you will want to rotate the top of the rotor 15* clockwise"

    Check out this thread which also has a picture showing phasing for Ford & Chevy.

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