So i resently installed a Ported FAST 90 and NW TB on my stock internal car! (Big heads and cam are on the way so thats why i desided to get it ported) but when i took it for a ride i noticed that my car will backfire if i slam on the gas and once in a while when i turn on the car or am taking off from a stop/red light!!! and it runs slugish too!! the car doesnt have any eradic idle or surges that would indicate that i installed it wrong. I have never tuned the car and i have everything on my sig!! do you guys think this is a tunning problem? and if not what does it sound like it could be? Thanks!!!

 

What is a ported Fast 90 and NW TB? Are you referring to the FAST intake manifold and a 90mm TB? Anyway, to answer your question, yes the backfiring and sluggishness is a symptom of an overly rich A/F ratio. Tuning is recommended. In other words, raw fuel is making it into your hot exhaust and it is basically hitting it's flash point and 'popping' in your exhaust. If you reconnected everything correctly and your check engine light isn't on I wouldn't worry too much about it. Just make sure to have it tuned as soon as you get those heads and cam. The worst thing that can happen when running rich is fouled plugs, bad fuel mileage, minor carbon deposits, and possibly a disgruntled catalytic converter. If your plans for a head and cam are still quite a ways off I would consider getting it tuned now.

 

Yes i am referring to a FAST 90mm Intake and a Nicw Williams 90mm Throttle Body!!!!