Author Topic: Tuning on a dyno - first step - lock out secondaries?  (Read 1814 times)

Offline 70GS455

  • Garage guy
  • **
  • Posts: 24
Tuning on a dyno - first step - lock out secondaries?
« on: September 20, 2017, 01:44:05 PM »
So if you were planning on tuning on an engine dyno, as a first step would you do a pull with the scondaries locked out to verify primaries were spot on? How about part throttle, cruise tuning, best left for the street?

Offline Cliff Ruggles

  • Administrator
  • Qjet Hero
  • *****
  • Posts: 5347
Re: Tuning on a dyno - first step - lock out secondaries?
« Reply #1 on: September 21, 2017, 04:39:12 AM »
Pretty much a waste of time and funds.  The primary side is set up for best performance and efficiency in the "normal" driving range.

A dyno is NOT set up for this, and it is a "static" test, not dynamic.

All of the accessories need to be hooked up, weight load and motion of the vehicle applied, engine fully heat soaked, pulling air from the stock air cleaner set-up, etc, and the car driven in a wide variety of scenarios to tune for best power and efficiency in all areas.

I can cut right to the chase if provided the carb number, and all of the engine/drivetrain/vehicle specs.  My experience and learning curve with these carburetors is extensive enough to know where to start and in most cases it will be right where it needs to be or at least close enough only very minor adjustments will be needed.

The dyno is a great place to nail down "basic" timing and secondary metering rods to be used, but even then it's still only a "base-line" and that tuning should be backed up with street and even better track testing to make further improvements.......Cliff