adding a spacer, is jetting normally needed?

Posted By: Deepockets

adding a spacer, is jetting normally needed? - 10/17/11 11:38 PM

finally putting on the 1" spacer atop of my super victor with a 1050 dominator. 528ci wedge for drag race. i have been running 88 jets all around and never checked the jetting before or read the plugs. it ran pretty good. but just wondering if there's a general rule of thumb when adding a plenumn space as for main jets. best et of 6.03 & 114.86 mph in the 1/8th before the spacer. i'll be takeing it out this thursday for results. thanks.

Posted By: CHAPPER

Re: adding a spacer, is jetting normally needed? - 10/17/11 11:47 PM

I would think it needs more jet,,spacer or no spacer.

Posted By: MR_P_BODY

Re: adding a spacer, is jetting normally needed? - 10/17/11 11:57 PM

Quote:

finally putting on the 1" spacer atop of my super victor with a 1050 dominator. 528ci wedge for drag race. i have been running 88 jets all around and never checked the jetting before or read the plugs. it ran pretty good. but just wondering if there's a general rule of thumb when adding a plenumn space as for main jets. best et of 6.03 & 114.86 mph in the 1/8th before the spacer. i'll be takeing it out this thursday for results. thanks.

Not normally... you changed the volume not the air
flow... also I think your on the lean side... I was
running 94s squared in my 1050 on gas... 88s came
in them stock

Posted By: racerx

Re: adding a spacer, is jetting normally needed? - 10/18/11 12:55 AM

Quote:

Quote:

finally putting on the 1" spacer atop of my super victor with a 1050 dominator. 528ci wedge for drag race. i have been running 88 jets all around and never checked the jetting before or read the plugs. it ran pretty good. but just wondering if there's a general rule of thumb when adding a plenumn space as for main jets. best et of 6.03 & 114.86 mph in the 1/8th before the spacer. i'll be takeing it out this thursday for results. thanks.

Not normally... you changed the volume not the air
flow... also I think your on the lean side... I was
running 94s squared in my 1050 on gas... 88s came
in them stock

Heck i was running 97/98 w a 500 ci w/a 2"spacer

Posted By: Locomotion

Re: adding a spacer, is jetting normally needed? - 10/18/11 12:58 AM

When I make any changes like that, I try to make back-to-back comparisons at the track and let the ET/MPH tell the story. But you have to make sure that "YOU" do everything the same to make sure the jets are the only variable.

Any changes may depend on where you were to optimum jetting to begin with.

Just my theory, but I figure that the added plenum volume, especially due to an open spacer, can reduce the vacuum signal. That may require more jetting and possibly added accellerator pump volume and/or duration.