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Holley sniper

I have tried advancing farther, it wanted to buck the starter, It could go a little more, just backed it off far enough to quiet the ping a little, I still need octane boost, with out it, it pings on this setting.
 
How many miles do you have with the Sniper? You are aware that it needs about 500 miles, stop/go, cruise, wot, etc for it to learn. Also if ya don’t want to wait, down load the v4 version and then take it somewhere that can tune it.
 
5.7 hemi said:
How many miles do you have with the Sniper? You are aware that it needs about 500 miles, stop/go, cruise, wot, etc for it to learn. Also if ya don’t want to wait, down load the v4 version and then take it somewhere that can tune it.
Click to expand...
I have a single plane under my fast 2.0, 1200 cfm throttle body. I wouldn`t run a dual plane for anything w/ it. My throttle body is bigger than dual plane type holes, no way it would work. Also have 21 initial, (bucked when hot at 22) and 34 all in at 3400. 10.3 c.r., 91 octane pump gas, 254/260 at .050 street roller. Any one care to comment on my all in figures/ like I said 91 lawnmower gas. I figure more and sooner timing w/ better gas. " All comments welcome !! " ????
 
For some reason the tb type efi units don’t like dual plane manifolds due to the dividing wall.
 
I was just told yesterday by a friend with a contact at Holley that the 8 Injector version of the Sniper will be released at the PRI show December 6-7 I believe.
 
HYRDGOON said:
I was just told yesterday by a friend with a contact at Holley that the 8 Injector version of the Sniper will be released at the PRI show December 6-7 I believe.
Click to expand...
Ya that’s the debut, orders will still be 14-16 weeks out.
 
Wow, I have 10.5 compression and it pings bad on 91 non ox gas, without booster, in it at the timing I have which is 12 tdc. I haven't changed it since I bolted on my sniper. I have around 300 miles on my sniper and it says learning is 100 percent. I may try a little more timing and see what happens, I am also running a single plane edlebrock, it makes sense that I would need a single plane as there is only 1, o2 sensor.
 
Why would it ping? Not using aluminum heads?
 
HT413 said:
Interesting stuff about the dual vs single plane. I'm about to install a new fitech kit on my rpm intake and they say theirs works fine on either.
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A friend of mine has a FI TECH up top a RPM in a mild cam 383. He loves it.
 
rumblefish360 said:
A friend of mine has a FI TECH up top a RPM in a mild cam 383. He loves it.
Click to expand...
Mine also has 8 inj. in it. It is still learning some, it was learning a lot last Saturday when I drove it, first time in cooler weather. I think my injector location is bigger than any dual plane opening I`ve ever seen. ????
 
1967coronet440 said:
Good idea, I might pick one up next summer.
Click to expand...

Steve sells tuning videos that are apparently very informative and easy to follow for about $30. In my case since he has had an 8 Inj for some time now testing for Holley he has a video with a 505" Procharged RB block Mopar.... Couldn't get much better for me :)
 
I may have figured out my problem... to simple a solution to see right away, new throttle cable, my old one didn't have enough movement to get full throttle, it I adjusted it to get full movement it was to tight for any engine movement, took off when leaving a stop light, not good, have a new cable installed, is working much better, also added a plastic spacer. under the sniper and it removed the annoying whistle that occurred at 2 different throttle positions. Life is getting better WOO WOO
 
Russtoy said:
I may have figured out my problem... to simple a solution to see right away, new throttle cable, my old one didn't have enough movement to get full throttle, it I adjusted it to get full movement it was to tight for any engine movement, took off when leaving a stop light, not good, have a new cable installed, is working much better, also added a plastic spacer. under the sniper and it removed the annoying whistle that occurred at 2 different throttle positions. Life is getting better WOO WOO
Click to expand...

Couple years ago I had a similar issue, turned out I got a little crazy with the carpet padding, which was limiting gas pedal travel.
 
Now getting full throttle but tps not reading wide open reading 78percent. makes it ping DAMN sent 2 email messages to holley no response, and I thought their service was going to be better then fitech right
 
Let's be realistic. 10.5:1 static compression. Very mild camshaft. Factory Iron heads. Moderate timing.

Don't blame the EFI.

You're dynamic CR is around 8.90-9:1 with that specific Hughes camshaft. Should have in the neighborhood of 185psi (+/-) cranking compression. This engine, isn't going to be happy on 91. It may not be happy on 93. I have what I consider a mild camshaft for a 470ci engine, 259/267 @ .050 with a 70.5* @ .050 ABDC. With this camshaft in your 512, you're still right at borderline running pump fuel with iron heads (8:1 dynamic cr). That is why you're required to run octane additives and nowhere near the timing that is typically ideal for an iron headed engine. Your 383 would probably run nearly identical with the 512, as dramatically increasing stroke without adding additional head flow just moves the torque peak much lower in the curve; which is fine if you're also dramatically increasing cylinder head flow. I hope you get your issues worked out. It's difficult to believe that many are misled and are purchasing 10.5:1+ cr stroker assemblies for pump gas street engines with mild camshafts, typically there is a 3-4% power loss per point of cr (diminishing returns at higher CR's). With a 400hp engine, that's 12-16hp, which is normally negligible as the engine will be able to run optimal (and not reduced) ignition timing. 32-34* total is normally optimal for aluminum heads. Anywhere from 36-38* for iron.

There is an older gentleman with a beautiful Mopar (top tier build, don't want to give out specifics). Runs a 500 cube, 12.5:1 stroker on the street with a mild camshaft. Pulls off the trailer and mixes 93 and 116 so it won't self-detonate, simply idling into the show (yes, show queen). Constantly complains about how much it cost to drive it around town :rolleyes: He could have opted for 9.5:1 static and lost 30-40HP at the peak (compared to 12.5:1), running 89-93 (10% Ethanol blended) octane. Doubt he would notice as he runs radial t/a's in a 3,000# car with 4.30 gears. So his goal was street/show gloating, not actual performance. It's very easy to make less power with additional compression, if limited timing is used as a band-aid to compensate for the required octane. It's a very slippery slope, always easier to be conservative.

At this point, your options are limited. Most cost effective way to lower compression would just be to custom order thicker cylinder head gaskets which are readily available, or swap in a larger duration camshaft to lower the dynamic ratio with a much higher ABDC. I just find it hard to believe EFI is the issue, Carbs will often lower cylinder temps due to literally dumping raw (cool) fuel in the cylinder which will lower the chances of detonation occurring. In the end, thermodynamics 'voodoo' (factory iron + poor combustion chamber design vs. aluminum + modern combustion chamber design + rapid heat dissipation) is generally why aluminum headed engines offer the ability to tolerate slightly higher compression ratios. Good luck on getting everything sorted out.
 
Last edited:
Sweet5ltr said:
Let's be realistic. 10.5:1 static compression. Very mild camshaft. Factory Iron heads. Moderate timing.

Don't blame the EFI.

You're dynamic CR is around 8.90-9:1 with that specific Hughes camshaft. Should have in the neighborhood of 185psi (+/-) cranking compression. This engine, isn't going to be happy on 91. It may not be happy on 93. I have what I consider a mild camshaft for a 470ci engine, 259/267 @ .050 with a 70.5* @ .050 ABDC. With this camshaft in your 512, you're still right at borderline running pump fuel with iron heads (8:1 dynamic cr). That is why you're required to run octane additives and nowhere near the timing that is typically ideal for an iron headed engine. Your 383 would probably run nearly identical with the 512, as dramatically increasing stroke without adding additional head flow just moves the torque peak much lower in the curve; which is fine if you're also dramatically increasing cylinder head flow. I hope you get your issues worked out. It's difficult to believe that many are misled and are purchasing 10.5:1+ cr stroker assemblies for pump gas street engines with mild camshafts, typically there is a 3-4% power loss per point of cr (diminishing returns at higher CR's). With a 400hp engine, that's 12-16hp, which is normally negligible as the engine will be able to run optimal (and not reduced) ignition timing. 32-34* total is normally optimal for aluminum heads. Anywhere from 36-38* for iron.

There is an older gentleman with a beautiful Mopar (top tier build, don't want to give out specifics). Runs a 500 cube, 12.5:1 stroker on the street with a mild camshaft. Pulls off the trailer and mixes 93 and 116 so it won't self-detonate, simply idling into the show (yes, show queen). Constantly complains about how much it cost to drive it around town :rolleyes: He could have opted for 9.5:1 static and lost 30-40HP at the peak (compared to 12.5:1), running 89-93 (10% Ethanol blended) octane. Doubt he would notice as he runs radial t/a's in a 3,000# car with 4.30 gears. So his goal was street/show gloating, not actual performance. It's very easy to make less power with additional compression, if limited timing is used as a band-aid to compensate for the required octane. It's a very slippery slope, always easier to be conservative.

At this point, your options are limited. Most cost effective way to lower compression would just be to custom order thicker cylinder head gaskets which are readily available, or swap in a larger duration camshaft to lower the dynamic ratio with a much higher ABDC. I just find it hard to believe EFI is the issue, Carbs will often lower cylinder temps due to literally dumping raw (cool) fuel in the cylinder which will lower the chances of detonation occurring. In the end, thermodynamics 'voodoo' (factory iron + poor combustion chamber design vs. aluminum + modern combustion chamber design + rapid heat dissipation) is generally why aluminum headed engines offer the ability to tolerate slightly higher compression ratios. Good luck on getting everything sorted out.
Click to expand...
I have tried to make sense of your post for a few minutes now. You are throwing out a ton of good info here. Are you saying that his dynamic compression ratio is too high for his setup. Therefore he needs to lower his compression?

If static CR doesn't mean jack then how do you go about figuring out if you components work together on the dynamics CR side? I am planning out a 440 right now and haven't yet considered dynamic cr. Just static at 10.5 for pump gas.
 
I guess my problem was kind of missed here, the car runs fine, but I think it ran a little stronger with the 750 eddy that was on it at least to 5000 rpm. I know the 750 was to small, and the sniper throttle position sensor is not calibrated correctly, only show 78% at wide open, that could be a big part of my problem. Holley being reallt slow at getting back to me. email them 2 time already
 
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