Holley Sniper progressive linkage stumble?

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jcolman

jcolman

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I'm trying to see if this is just my imagination or do I have a part throttle stumble? My car was recently retuned because I added the progressive linkage. The secondaries don't open until after 2000 rpm as you can hear in the video. My issue is that the engine isn't as smooth as I would like from idle to around 2000rpm. I'm thinking I need to add a bit more gas and/or timing between idle and 2000 but I wanted to hear what you experts thought.

 
Who cares what it does in neutral? Go out and drive it and pull a log. Make changes based on the data in the log. If the engine goes lean when the secondaries open then add fuel there.
 
The above link explains acceleration enrichment pretty well. You’ve effectively cut the airflow in half up to 2000 rpm and you need to cut the acceleration enrichment (pump shot) in half up to that point as well. Just make sure to add in what you take out after 2000 rpm.
 
dano said:
Probably the best way to tell is to data log. Was the re-tune before or after the change?

Have you read this?

Tuning Sniper Progressive Link
Click to expand...
The re-tune was done after the change. I did read the link you sent and I undestand it a bit. I don't use a PC laptop so I'll take the car back to the shop that did the tune and I'll let them figure it out.
 
TT5.9mag said:
Who cares what it does in neutral? Go out and drive it and pull a log. Make changes based on the data in the log. If the engine goes lean when the secondaries open then add fuel there.
Click to expand...
I noticed the hesitation while driving after the transmission swap...hence my concern.
 
jcolman said:
The re-tune was done after the change. I did read the link you sent and I undestand it a bit. I don't use a PC laptop so I'll take the car back to the shop that did the tune and I'll let them figure it out.
Click to expand...

It’s going to get frustrating having to take your car in every time you’d like to change part of the tune. You should get a laptop and download the tuning software and learn how to adjust it. Once you start working with it, it’s pretty easy to make simple changes. Especially so if you can data log and tune from the log.
 
TT5.9mag said:
It’s going to get frustrating having to take your car in every time you’d like to change part of the tune. You should get a laptop and download the tuning software and learn how to adjust it. Once you start working with it, it’s pretty easy to make simple changes. Especially so if you can data log and tune from the log.
Click to expand...
I suppose so. I have a Mac Pro laptop but I hate using PC software on it. I guess however that my real question was "does this sound like a low throttle stumble or am I imagining it"? After getting my car back from the shop after the transmission swap and throttle linkage adjustment (among other things) I'm not 100% happy with the off throttle acceleration until after I reach 2000 rpm's. I'm just trying to figure out the issue before I talk to the shop again.
 
turbovan said:
Why the switch to progressive?
Click to expand...
Makes the drivability smoother. Instead of all four throttle blades opening at the same time, the front two open and the secondaires open at about 40% throttle. Otherwise the car is a bit "jumpy" when you give it gas, which is great if you're racing but for street driving it's a bit much, especially since I switched from an auto to manual shift.
 
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