Engine bucking

[BlownMarauder]

Hello everyone.I have recently finished my supercharger project on my marauder.Dennis R and Jerry W have been helping me with the tune on it and so far its running pretty good.I do have a few issues to still sort out and it also may come to just buying the sct software and starting over myself.Anyhow,the question i have is how are people tuning out the low speed bucking that occurs at about 1500 rpm?it seems about gone at 1200 and also at 1800.but right around 1500 (cruising with o/d on) around town is getting annoying.some have said the bypass valve.others have said the plug gap.the bypass is kenne bells billit plumbed right back into the inlet.the plugs are densos gapped at around .032.any help/input that you guys can come up with would be great.i have searched many forums (corral-svtperformance) and came up empty handed.thanks so much in advance..jeff........here is a picture of the car finished

[BlownMarauder]

hrm,,dunno what happened to the picture

[jimfitzgerald]

A lot of bucking problems can be caused by the bypass valve dumping air back into the intake too close to the MAF meter. The air backwashes across the MAF. The bypass should dump the air back in as close to the blower intake as possible.

[BlownMarauder]

the bypass valve dumps back into the inlet manifold WAY upstream from the maf,i would guess about 3 feet away from it.interesting today with the temps hovering at a brisk 1 degree the bucking was almost gone.im wondering if its too rich in that range

[BigCohiba]

upstream or downstream? It makes a difference - you stated upstream (in front of). Every setup I have seen has the bypass discharge downstream of (after) the MAF.

[jimfitzgerald]

Originally posted by BigCohiba
upstream or downstream? It makes a difference - you stated upstream (in front of). Every setup I have seen has the bypass discharge downstream of (after) the MAF. I assumed he meant downstream, unless he has a blow through MAF.:dontknow:

[BlownMarauder]

sorry misunderstood,its downstream.its a kenne bell bypass for an 03 cobra which mounts right onto the manifold plate and gets plumbed up underneath the inlet side of the blower case.didnt seem to buck today in the cold(subfreezing) weather telling me its too rich and the dense air equaled it out

[Ed Clark]

Sounds like excessive EGR flow.

Ed

[roush22]

atleast you know that its cause your rich in that area, now you can work off of that

these other members have some good opinions to go off of

[Mana4Real]

I'm having the same problem with my setup. We're working on getting it fixed... Mine bucks pretty much anytime at part throttle. It's really annoying.