Holley Sniper EFI and intake manifold plenum modification.
Thread Starter
Melting Slicks
Joined: Nov 2017
Posts: 2,355
Likes: 518
Holley Sniper EFI and intake manifold plenum modification.
Greetz All,
Now that I have my Edelbrock EPS (closed plenum) intake manifold off of the car... I am thinking about modifying it.
I have read that it is a good idea, if you are running a Holley Sniper EFI, to grind down one inch by one inch slot of material in the top of the plenum. Something about the O2 sensor readings be more accurate.
Aside the valve issues I have been having... my idle seems fine. I understand that is where this mod would make most of the difference... improved idle quality.
So, to do or not to do... please opine and drop some knowledge.
MTIADC3.
Now that I have my Edelbrock EPS (closed plenum) intake manifold off of the car... I am thinking about modifying it.
I have read that it is a good idea, if you are running a Holley Sniper EFI, to grind down one inch by one inch slot of material in the top of the plenum. Something about the O2 sensor readings be more accurate.
Aside the valve issues I have been having... my idle seems fine. I understand that is where this mod would make most of the difference... improved idle quality.
So, to do or not to do... please opine and drop some knowledge.
MTIADC3.
Last edited by DorianC3; Yesterday at 11:34 AM.
Melting Slicks
Joined: Apr 2021
Posts: 2,683
Likes: 2,134
From: Minnesota
Personally I wouldn’t feel comfortable taking material off the intake while it’s installed on the engine, so if you’re removing it anyways you might as well replace it with a true single plane.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
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Cruise-In VIII Veteran
I had my EFI on a Edlebrock duel plane manifold. Everyone said, cut out the divider. It'll run better, better MAP sensor readings.
I removed my intake. Milled out the divider. Reinstalled and properly resealed my intake. Couldn't notice any difference whatsoever.
Everyone said, you need a single plane manifold for your EFI, once again pulled intake. Installed single plane manifold.
Couldn't notice any difference whatsoever!
I removed my intake. Milled out the divider. Reinstalled and properly resealed my intake. Couldn't notice any difference whatsoever.
Everyone said, you need a single plane manifold for your EFI, once again pulled intake. Installed single plane manifold.
Couldn't notice any difference whatsoever!
Thread Starter
Melting Slicks
Joined: Nov 2017
Posts: 2,355
Likes: 518
I had my EFI on a Edlebrock duel plane manifold. Everyone said, cut out the divider. It'll run better, better MAP sensor readings.
I removed my intake. Milled out the divider. Reinstalled and properly resealed my intake. Couldn't notice any difference whatsoever.
Everyone said, you need a single plane manifold for your EFI, once again pulled intake. Installed single plane manifold.
Couldn't notice any difference whatsoever!
I removed my intake. Milled out the divider. Reinstalled and properly resealed my intake. Couldn't notice any difference whatsoever.
Everyone said, you need a single plane manifold for your EFI, once again pulled intake. Installed single plane manifold.
Couldn't notice any difference whatsoever!
Race Director
Joined: Nov 2006
Posts: 13,199
Likes: 7,796
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
No, it's runs fantastic. Still does.
Safety Car
Joined: May 2001
Posts: 4,754
Likes: 1,642
From: Fairfax Virginia
I agree with doing the machining work out of the engine compartment. There are so many ways to get trash into your engine.
Have you ever looked at the information regarding the Holley Snipers at: EFIsystempro.com. Their website has a LOT of great information regarding the Sniper systems.
I am using a Edelbrock RPM Air Gap Intake manifold on my 427 and it works great despite being a bit too tall. The Air Gap has the notch already machined into the plenum. I have had no bad effects caused by using the dual plane Air gap intake, probably because of the notch in the divider inside the plenum.
Best regards,
Chris
Have you ever looked at the information regarding the Holley Snipers at: EFIsystempro.com. Their website has a LOT of great information regarding the Sniper systems.
I am using a Edelbrock RPM Air Gap Intake manifold on my 427 and it works great despite being a bit too tall. The Air Gap has the notch already machined into the plenum. I have had no bad effects caused by using the dual plane Air gap intake, probably because of the notch in the divider inside the plenum.
Best regards,
Chris
