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Impala tune

1300 Views 2 Replies 2 Participants Last post by  Poda
I have a 1994 Fleetwood.. LT1, 4l60e.. aka, an Impala SS in tux.
Car has no mods, and on this motor I'm looking for the most optimized bone stock LT1 possible
If I remember correctly (and I don't always do, so feel free to correct me) the Imps were tuned slightly differently than it's Caprice/Roady/Fleet LT1 counterparts
In my ongoing research to tune the car, I saw somewhere that someone was thinking of putting a 94 Impala Tune, with the Caddy V4P (Towing Package good for 7000lbs) pressure table section, into a 94 Roadmaster. I understand that the V4P is a great tune to have tranny wise for longevity and optimal shifting if you're going to be enthusiastic with your right foot in a 4500lb car..
So the burning question is: what's the difference between an Impala SS tune and a basic Fleetwood/Caprice/Roady tune? Specifically in the engine management.. obviously tranny tables can vary, as well as rear end, etc. But that's easily changed over
I can attach the .bins for each if need be..
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TunerCat and TunerPro have .bin compare functions. I took a quick glance comparing the Impala SS to a stock caddy and a Caddy VP4. Just engine management settings (not transmission). The spark, VE tables were basically the same. O2 rich/lean was set a little leaner for the SS and caddy has speed limiter MPH & RPM lower than the SS. The SS tune I looked at had PE fueling differences over the caddy tunes. Looks like all the drive-ability (and V4P towing) differences were in the transmission, TCC lockup tuning, plus each has hardware, suspension and mechanical differences. I think the VP4 has some different transmission internals, but don't really have time to research that out. Bottom line looks like putting a caddy tune in a SS will richen it about 1-2% and it will drive like a family sedan. Early softer shifts, more TC engagement,w/RPM limiter around 48-4900 and and speed limiter set at 108. Caddy tune may have a less fuel in PE mode, not sure if that's seat of pants noticeable. As far as the engine it will run without any noticeable differences.
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Thanks Bobdec.. So if I put an Impala tune on my Caddy, I'll lean it out 1-2%, harder shifts, higher speed limiter, less TC engagement.. That could actually be an improvement ;)
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