Single Plane vs. Dual Plane with Sniper

[daddio4048]

Just wanted to see if anybody that is running the Holley Sniper EFI has seen any difference running a single plane over a dual plane when it comes to tuning the EFI.

 

[PatrickM]

Run a 1/2 inch spacer on the dual plane or mill down the divider unless you actually need a single plane.

 

[daddio4048]

I have done both & my AFR does not want to level off. O2 sensor changed with no affect .

 

[PatrickM]

Sounds like you have an exhaust leak. Where is the sensor located in the exhaust? What’s your idea of “level off”? It’s not going to read a constant number.

 

[daddio4048]

No exhaust leak. O2 is on passenger side about 20 inches down from where head pipe attaches to manifold. AFR bounces from 12.95 to 14.5

 

[PatrickM]

What are your settings?

 

[daddio4048]

Which ones are you looking for?

 

[PatrickM]

Ignition timing and air fuel ratio at idle, cruise, and wide open throttle.

 

[daddio4048]

15 degrees at idle. 36 degrees at cruise, 36 degrees at WOT AFR at idle set for 13.5

 

[PatrickM]

Settings aren’t bad. Try setting the afr to 14.5 at idle and see what it does. 12.9 isn’t far off from 13.5. It will never read a constant afr. Does it run well?

 

[daddio4048]

Runs pretty good. I have a Edelbrock Air Gap on it right now; but I also have a Torker I could try. You hear a bunch of opions on this & makes me wonder if there is any validity to it.

 

[PatrickM]

I wouldn’t worry about it if it runs well

 

[Bewy]

With EFI, I would run a single plane. More consistent runner shape/length/number of bends.

 

[MrCab]

Just wanted to see if anybody that is running the Holley Sniper EFI has seen any difference running a single plane over a dual plane when it comes to tuning the EFI.

Don't the instruction from Holley say to run a single plane intake with that throttle body injection system?
I bought and installed and then did engine dyno tuning on it for a customer several years back probably 12+ yrs ago so that information may not apply to the units their selling today.
I told the customer to do the final tuning in his car due to the exhaust system and the engine dyno being wide open headers during that break in and initial tuning. I told him to run it in the open loop initially and once it ran like he wanted it to switch it to close loop to lock that tuneup in.

 

[nm9stheham]

No exhaust leak. O2 is on passenger side about 20 inches down from where head pipe attaches to manifold. AFR bounces from 12.95 to 14.5

Is this bouncing around some steady state condition or across a wide range of operating conditions?