sledhead_dan
Extreme
Having trouble with 04 mpi stg 1 Rx1 mtn, engine surging bad at 4500 to 7000 rpm even when holding throttle steady.In boost sled pulls awsome. Just installed a vortech bypass to replace smaller hks, this problem showed up last year ,thought the vortech would be the cure . Now I think this could be electrical related. Tors bypassed,tried changing carb springs, needle & fuel screw settings, fuel press. and fuel reg sensing line location, even unhooked the vortech. Afr are not way out.( lost o2 sensor to race gas yest ) Checked plugs Cr9 iridium, look ok, could charging system voltage or the tps cause this ??
sledhead_dan
Extreme
Have more info, might have to rule out electrical problem. Ran sled today, surging begins just after engagement (3200rpm) in vac and gets worse up to 6500 when @ 0 boost, after boost starts surging stops. This will not be trail friendly or when loading sled. Could the vortech be that sensitive to vac to boost changes ??? Still no O2 sensor, but changed plugs and old were good. am in the process of moving vortech to charge tube.
You should have boost instantly. At 4500 rpms you should have at least 1 to 2 lbs of boost. Sounds like one of your sc belts is missing some cogs or you have a pulley slipping.
sledhead_dan
Extreme
Belts are good also pulleys, 26 btm/24 top. If I hit throttle no surge, but if I back out slowly and hold anywhere from 3200 to 6500 surging starts. Could bypass opening and closing cause slides to fluctuate causing surging ?? Bypass is on left carb side of intercooler.
