We built a 1988 5.0 w/ paxton super charger it runs perfect up to 4800 RPM and then breaks up real bad it almost sounds like a rev limiter any help Thanks Kirk

 

would it happen to sound anything like pinging? as in pre-detonation

 

when did problem occur?? how are the plugs an other tune up parts??

 

I bet it isnt tuned

 

All tune up parts are new plugs look good as far as color I think it's a tuning problem too we baught the car as a basket case and built a fresh motor it did this right from the start can anyone help me with the tuning no pinging sounds just like a rev limiter breaking up Thanks Kirk

 

without driving it it's hard to guess accurately..first thing would be monitor spark via occiliscope to see if it's ignition related

 

spark blow out...what are they gapped at?

 

.054 We unhooked the intake tube (no supercharger) and it still breaks at 4800 ? Thanks to all for helping Kirk

 

for starters, with boost, you should be gapped around .040-.045 some people even go less. very very closely inspect your plugs... you have probably melted more then one.

are you running stock plugs, a colder plug, copper, platinum, iridium.....

more info plz

 

Get plugs that are 1-2 heat ranges colder. Gap them to 0.32. That should solve your problem. Also superchargers are prone to excessive heat and will run crappy in hot climates. In Texas with high humidity and no intercooler,my car will drive fine for short periods. But if I drive for more than an hour the supercharger will heat soak and won't rev to 6,000. Just a thought.