FYI If you decide to use a progresssive secondary throttle rod your vacuum advance will no longer work.
I ran with the HEI for a little while then decided to go with the hyperspark dizzy & coil. I got way better results.
CK5
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Sniper EFI
- Thread starter Holey76 - Square Nut
- Start date
FYI If you decide to use a progresssive secondary throttle rod your vacuum advance will no longer work.
I ran with the HEI for a little while then decided to go with the hyperspark dizzy & coil. I got way better results.
And last i knew zero tech help is progressive link swap on a sniper .
If your still using the HEI I wouldn’t power the cpu with the HEI bat+ directly, I would make that a trigger to a relay to prevent interference like Bent77 suggested.
I was talking to one of my customers who has a few racecars and his comment about these EFI kits was something like this:
Holley designed this kit and it works ideally when combined with its own dizzy, coil and CDI box.
Sure it works with HEI or small dizzy and coil but the entire system works best as it was designed as a complete kit.
I ran mine with an HEI for a bit but had issues. After I installed the hyperspark, coil and CDI all my issues went away.
I was talking to one of my customers who has a few racecars and his comment about these EFI kits was something like this:
Holley designed this kit and it works ideally when combined with its own dizzy, coil and CDI box.
Sure it works with HEI or small dizzy and coil but the entire system works best as it was designed as a complete kit.
I ran mine with an HEI for a bit but had issues. After I installed the hyperspark, coil and CDI all my issues went away.
In terms of ?
Aaah !! Ok. Good to know
My engine didn’t react very well with instant wide open throttle. It’s not a race truck, more of a slow rock crawler.
You can get a progressive secondary rod that opens the secondary’s later than the primary’s.
I installed the progressive rod and it did a little better but that made my vac advance not work.
Without the vac advance my timing couldn’t keep up.
In the end I decided to ditch the HEI and get the hyperspark dizzy and all those little issues went away.
More of an FYI based on my own experience.
So opening the secondaries later causes the engine not to make enough vacuum? Seems like the opposite would be true and you would have more vacuum, so maybe the vac can was set too aggressively? What does "not work" mean?
That's exactly what mine does, and it pisses me off
So the progressive rode and the hyperspark dizzy put it back to a normal take off. Ya, the launch is a bit much. I was behind a squad car today and had to wait for him to get 35-40 ft away before i launched. Wouldn't that have been embarrassing.
Thank you for the advice !
I just looked around, and didn't find either. Do you happen to know part #'s ?
Link rod is a different brand and replament carb part . Holley last i knew did not aprove of this and doesn't list a specific part # .
I think it was a quick time fuel item . I might have posted it a few years ago with my sniper story / problems .
I think it was a quick time fuel item . I might have posted it a few years ago with my sniper story / problems .
Progressive secondary info:
Holley.com progressive rod parts:
www.holley.com
There are different options so you need to decide which rod works best for you based on what percentage of TPS you want the secondary to open.
There’s also an adjustable link available on Summit
Part Number: HLY-20-122
The ported vacuum port is sourced from the seconday throttle body and is ineffective using a progressive secondary rod.
Holley.com progressive rod parts:
Search The Holley Website
There are different options so you need to decide which rod works best for you based on what percentage of TPS you want the secondary to open.
There’s also an adjustable link available on Summit
Part Number: HLY-20-122
The ported vacuum port is sourced from the seconday throttle body and is ineffective using a progressive secondary rod.
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If your throttle is too snappy, like 0-100% in an instant you can get a throttle lever extension to slow down that WOT on a green light in front of the cops feeling.
Holley approved part # 20-16
Holley Sniper EFI 20-16 Sniper EFI Throttle Lever Extension
The Sniper EFI Throttle Lever Extension provides significantly decreased pedal effort and a smoother pedal feel. This is especially noticeable at tip-in or low throttle input, such as when you are leaving a stoplight. This solution is great for those that may have noticed a stiffer throttle...
What about going into fuel mapping and reduce fuel input at just above idle to about ?1200Progressive secondary info:
Holley.com progressive rod parts:
Search The Holley Website
There are different options so you need to decide which rod works best for you based on what percentage of TPS you want the secondary to open.
There’s also an adjustable link available on Summit
Part Number: HLY-20-122
The ported vacuum port is sourced from the seconday throttle body and is ineffective using a progressive secondary rod.
Might that take some snap out of it ? It's running very rich anyway, and I'm still trying to tune it...
I don't recommend the FITech or Sniper or anything else that has the ECU in the throttle body on the engine, it allows more issues, the Sniper was mainly created just to compete with the FITech. If people want a lower cost TBI style injection to put on their current intake manifold I recommend the FAST EZ-EFI 1 or 2 or step up to the Holley Terminator X Stealth, both of these have a separate ECU you can mount under the dash or at least off of the engine. I sell all of these, but recommend the better options, because of this I haven't sold any sniper, yet I still seem to help people with it. I've sold a lot of Terminator X, ProFlo 4, and some Dominator/HP and FAST.
What do you mean it didn't react very well? It was lazy or sluggish? Or too much response and not enough control?
If you instantly apply WOT, the progressive linkage doesn't really change anything, it's all open instantly anyway.
Also, you don't want your vacuum advance hooked up to ported vacuum, unless you are just trying to pass emissions with a stock engine. You want the vacuum advance hooked up to full manifold vacuum for best performance, it also helps the engine run cooler at idle. The factory purposely wanted the combustion hotter for emissions, hence not giving it the timing it wanted, aka, ported vacuum advance. This is one thing some EFI companies don't get, and don't allow you to apply the vacuum advance during idle, which helps most performance engines. With the Holley, you can change this manually in the timing table.
With the advance hooked up to ported vacuum, it has no vacuum advance at idle, that's the only difference. The moment you give it any throttle, the blades pass the ported opening and supply vacuum. Now, if you adjust the secondary idle position to be open over the port at idle, then it will have vacuum at idle anyway, however, this will likely cause too high of idle in most situations.
So with ported vacuum, no advance at idle, then you give it a little throttle and it has advance again, then you give it WOT and no advance again of course, back and forth. With full manifold vacuum, it will have advance at idle, it will idle cleaner, and when you give it some throttle it will still have advance, smoother. If you give it WOT, advance drops away under load, which it should.
You sound like you have not enough control on part throttle tip in? Is that the only problem?
The progressive linkage will start to open the secondary throttle at about 1/3 of the primary opening, and still open it all the way by WOT. If you are slowly opening the throttle, or opening it less than ~1/3, then the progressive linkage will give you a little more finesse in that situation. If you are opening the throttle to WOT fast, it won't really matter.
If you have almost 12:1 compression I recommend you use a CDI box, you likely won't have enough spark power with just the HEI. This will also allow you to control the timing with the ECU, which will give you nearly infinite timing control.
What is your cam, and what fuel are you using?
Usually you can get the proper throttle response by hooking to the appropriate hole on the throttle linkage plate. Too close to the pivot will give you that twitchy no control feeling, too far away and you will have way more control but you may not even get WOT when the pedal is floored. You need it where you can just get WOT when your foot pedal is almost touching the floor. I have never needed the extension with a GM throttle and cable, in fact if you use the very top large hole in a Holley linkage you usually can't even get WOT with the pedal and need to lower it down one.
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