355 Tuning in C.A.T.S.
05-18-2010, 05:37 PM
#1
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355 Tuning in C.A.T.S. OK, heres whats going on. I am trying to tune a friends 355 lt1. It has dart heads, LT4 hot cam, 32lb injectors, 1.6RR's, headers, is a 355, and has a TH350. Is also ODB1 in SD mode.
We set the:
cyl volume to 726.22
Injector flow rate to 32lbs
Random SES fixes
Bumped up the idle to 700 rpm
and advanced the Closed TPS Spark Advance VS RPM a few degrees throughout the rpm range
Right now the car feels great at WOT, but still has some hesitation when you accelerate from idle. Could any tuners chime in and point me in the right direction with what to adjust?
Thanks
We set the:
cyl volume to 726.22
Injector flow rate to 32lbs
Random SES fixes
Bumped up the idle to 700 rpm
and advanced the Closed TPS Spark Advance VS RPM a few degrees throughout the rpm range
Right now the car feels great at WOT, but still has some hesitation when you accelerate from idle. Could any tuners chime in and point me in the right direction with what to adjust?
Thanks
05-19-2010, 12:46 AM
#3
he is correct about the data logging, but also just from having a hotcam in my car, they dont exactly like to be idled that low. ive never idled mine below 750, and would recommend 800-900rpms. somewhere in there will help with your tip in. ran into some of the same issues when idling so low. hope this helps.
05-19-2010, 07:24 AM
#4
i had a cc306 idling at 750 with no tip in issues, you should be able to get a hotcam to idle at 500 in gear. get a wideband, you're pretty much guessing until you see the a/f. hesitation can be from going lean or rich, or from your timing being screwed up. How much timing at idle are you running? Smooth transition into the main spark tables?
05-19-2010, 04:20 PM
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Were deff data logging. I am a novice tuner so to say. Most of my experience is with tranny tuning on a bolt on engine. This is my first modified engine tuning gig. SO, we upped the Closed TPS vs RPM timing table up 4* in the 400-1200 RPM range and 3* in 1600-4800RPM. What were you meaning by a smooth transition into the Main spark tables? Those are left stock. A wide band is in the works since I do want to get into tuning as a hobby. I am using FreeScan at the moment. Is there any other program that may put the log data into a little more user/noob friendly format. Maybe bar/line graphs? Thanks alot for the help so far. Keep it coming 
