Hey guys,

I have an LTX8 controlling a JC cosmo 13b street port, with a TA-45 turbo, 550cc pri's and 1700cc sec's. I got excited a while ago and ported the standard throttle body and lower intake manifold and think i might of stuffed it up as since i did the mod it now has an anoying stumble/flatspot if i give it a sharp press on the throttle from idle, or between gear changes (cruising), it also gives a small pop out the exhaust when it experiences the flatspot. I have added a couple of pics below of the mods i did to the throttlebody and the manifold, does it look like i have cut the center of the throttle body out to much which could be causing the flatspot? My current pump 1 and pump 2 settings are as follows

Pump1
amt = 5%
pulse = 1%
trig = 12
stop = 0hg's

Pump2
start = 2500rpm
amt = 30%
time = 10
trig = 16
stop = 0hg's

I have tried a few other combinations but i can't seem to get rid of the flatspot, I have a wideband meter so any input in the way you guys setup the pump settings with a wideband etc would be greatly appreciated

http://img16.exs.cx/img16/507/lowermanifold7.jpg

http://img16.exs.cx/img16/7632/throttlebody7s.jpg

thanks in advance

cheers

Lance

 

Does it occur at 2500RPM's....if not, your pump settings are probably OK. What does the WB read when the stumble occurs?