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Thread: Sniper EFI & Single-Plane

  1. #1

    Default Sniper EFI & Single-Plane

    Hello guys. I have a 437 SBC topped by Sniper EFI and a phenolic 4 hole 1 inch spacer. I recently swapped to a single-plane intake from a dual-plane and wanted to go over how the engine responded and the tuning I had to do to compensate. So I went from a Holley Street Dominator to a Motown single-plane. Right away I noticed how much smoother the idle was. I did also have to enrich up the idle mix to get AFR to get in the range I've chosen. It's set to 13.5, but was hanging up at 14-15 before fattening the Base Fuel Table. With the dual-plane I had a very harsh tip-in, which a lot of people remedy with a progressive linkage, it was like on/off switch. At one point I had tuned it out but never totally got rid of it. Now with the single-plane, tip-in is so smooth. Main reason for change was due to the Street Dominator range maxed out at 5200 RPM and I like to run it up to 6500-6800. I was also disappointed with the dual-plane on the dyno my car made 357 HP 380 TQ at tire, which I'm told is respectable for a street car, but my goal is at a minimum of 400 to the tire or 500 at the crank. I'm a bit greedy. My heads are AFR 195 race port heads and they like to flow. I'm surprised because a lot of research shows a single-plane bogging off the line or below the RPM range, which I have not experienced at all. If you're considering the swap, I'd highly recommend it. The cam and idle chop are back and more pronounced as it was with the carb, but it's still smooth vs with dual-plane, it felt like it was at the edge of stalling. So as far as I can tell the Sniper really likes the direct flow of the single-plane.

  2. #2
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    It's your engine that likes the single-plane intake manifold better, not the Sniper EFI. (Chris805, please use Spell Check before posting.)
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  3. #3

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    I've switched back and forth between a Performer RPM and a Trick Flow single-plane on my engine and I don't really notice much difference. The Performer RPM might have a little more low end torque, but it's hard to feel the difference in my car. I think the Sniper runs just fine with either type of intake manifold, but your results could be different for some reason.

  4. #4
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    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  5. #5

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    Sorry for the spelling errors Danny. I'm typing on a smart phone so the auto correct fights me sometimes. I do have one question regarding the self Learn. My car is automatic and typically driving on the streets I just leave it in drive. The car shifts around 4500 WOT, which is where my peak was on the dyno. When I manually shift, I do it above 6500 RPM. I'm thinking the Sniper is Learning all the time to 4500 and leveling off after that because I rarely have the road to run it all the way out to 6500. Is this possible? Also, how many pulls to the limiter should I need to have it Learn what my engine needs? I figure I can probably run to the limiter in first a few times a week to help it shape the top of the base map. Thanks for all the information from everybody. I'm very happy to be a part of this community. I'm just looking to get the most out of my little monster small block.

  6. #6
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    When the Learn Table values stop making significant changes, the ECU is finished self-tuning. You can then Transfer Learning To Base,
    which then allows you to blend the Fuel Graph so it's smooth.
    http://forums.holley.com/showthread....7370#post47370 (Learn Table - Read this thread, especially posts #2, #6 & #11.)
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  7. #7

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    I'm going from a huge single-plane to a dual plane. I did the progressive linkage on the single plane because it was so tip-in happy. I hope it's not worse now.

  8. #8

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    I originally had my Sniper on my Edelbrock Air-Gap and it ran good. I said what the heck, let’s try it on the single-plane. Not one difference in driveability at all. It Learned a lot slower and made bigger corrections. I ran it with the old tune and a new relearn. I lost a considerable amount of power lower in the RPM too, so now the Air-Gap is back on.

  9. #9
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    Quote Originally Posted by JF74CHEVELLE View Post
    ...let’s try it on the single-plane. Not one difference in driveability at all.
    I lost a considerable amount of power lower in the RPM too, so now the Air-Gap is back on.
    Good post, JF74CHEVELLE. Although some may think there's a slight contradiction with those two statements.
    May God's grace bless you in the Lord Jesus Christ.

    '78 BRONCO: 508" stroker, TFS heads, 11:1 comp ratio, Dominator MPFI & DIS, cold air induction, Spal dual 12" fans/aluminum radiator, dual 3" exhaust/Magnaflow mufflers, Moroso vacuum pump, Accusump, engine oil & trans fluid coolers, 100HP progressive dry direct-port NOS, A/C, LenTech Strip Terminator wide-ratio AOD/2500 RPM converter, 3:1 Atlas II, modified Dana 44/60-lockers-4.10s, hydroboost/4-disc brakes, ram-assist/heim joint steering, Cage long radius arms, traction bars, 4" Skyjacker lift, 35" mud tires

  10. #10

    Default

    I meant to say it in a “daily driver” type driveability. Meaning MPG, idle quality, etc. Power-wise it did exactly what a single-plane is designed to do, pulls like a train to high RPM which is fun, so I keep it in the garage just in case I want to switch back.

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