Just wondering what the total affects of outside air temp has on the tune of TBI??? For example if my tune is withing +/- 2blm during 8to10 degrees C outside during winter will I have to lean out the entire curve during a 30Degree day out in summer. Its still has the old 7747ecm without a IAT. Also if I uprgrade to the 7427 or EBl with an Iat will there be a better temp correction factor?? Thanks for any info or links

 

great question, cause im getting ready to tune and i may use a IAT/MAT in the intake runner.

 

90C350

Since I live in SoCal I do not experience tremendous temperature extremes - my range is from 5 to 35C. IAT lends itself handy with non heated intake manifold - example Eldebrock Air Gap. Steady state cruising is not a big issue for ECM - fueling will be compensated while operating in close loop. AE and PE modes were IAT becomes invaluable with colder inlet air. With that in mind I converted 16136965 ECM as oppose to 7747 to EBL which has IAT input. There are couple of threads in PROM tuning forum addressing this issue.


//RF

 

Thanks for the reply!! So basically as long as my Ve table is close The ecm should have enough range to compensate for Air temp and fueling?? Im at the point that im ready to put the cover back on, until I get my LC-1 hooked up. That will help alot with the fine tuning and Ae tuning im sure. THanks again.

 

90C350

You welcome. BTW, I was reading a long thread (as well as several others) by 91checyz71:
https://www.thirdgen.org/forums/diy-...ce-issues.html

(plus others older posts) in DIY EPROM forum. In a nutshell, steady state operation is easily compensated by ECM in close loop. Transient throttle response seems to be a problem for wet manifold systems when operating over wide temperature range. It is worth while read.

//RF