Go street 400 tuning tips?
You have a 400 on a 468 big block?
yes
The reason I ask. That unit barely supports 400hp. Can you tell me a little more about your issues.
The 400 unit has been dyno proven to produce well over its intended 400hp capability. It’s main limitation is the finer adjustments however it is the base model.
I have personally not used the 400 because of the lack of features. And would not be my recommendation for a Big Block. That would be pushing its capabilities. That put aside, let's figure out what is going on. We have very little to go off of....
timing was way off but it is still running really rich and i can't get my iac's down
What is your coolant temp on handheld when having problems.
I had same drama with my 400 unit going off the size of the motor I’m guessing it’s gonna want to run pretty rich. Try running 10deg initial timing and set idle afr at 14.2
1100 afr 14.1
cruise afr 14.5
accel pump all to +10.
This is how I’ve set my 350 Chevy up and it runs mint and pulls hard. Given your another 100+ cubes your engine might want more fuel. It’s a starting point for you anyway. Try that and see if it’s better or worse then report back
thanx so much for the info my coolant is barley warm when its havin issues but my timing is 12 before tdc and sounds really good but havin isssues getin my iac lowered
If coolant is not reading over, I believe, 130 degrees, the Fitech is still in open loop. IAC cannot be adjusted until engine is at operating temp. Verify your temp to handheld. May need to replace sensor. This is a common problem.
Good news, we are getting somewhere now. Should get you going soon.