2.5L Timing

Tech Question


Marcus Canon, Longview, TX, 1991 Dodge Shelby Daytona 2.2

Hi, all knowing Rick. I recently bought a real nice 1991Shelby Daytona turbo I, auto. So far I have installed a K&N airfilter,Gibson muffler, 2.50 inch tailpipe and gutted the cat. This car isreally fast, but, I want a little more power.Can I advance the timingmanually, if so, how much, or do I need the Mopar Performance computer? Iwill add a Spearco water injection system. The car does not have aintercooler. Thanks, Marcus.


Marcus, you say you have a 2.2L. But I think, if you check, you’ll find thatit’s really a 2.5L, with a Mitsu, not Garrett, turbocharger, and a one-pc.tuned intake manifold (similar to the ’88-89 T-II piece) – unless, ofcourse, a prior owner swapped in an older mill.

As long as you run at least 93 octane (or the water inj.) at all times, youcan safely advance the timing about 6 degrees (max.). Just twist the dist!Use the factory service manual procedure and underhood emissions label forguidance.

The MP SBEC (computer) will also bring up the boost a bit more quickly. Butthe stock 1991 2.5L T-1 calibration was pretty good, so you won’t gainnearly as much, unlike the older 2.2L’s which REALLY picked up with the MPcalibration.


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