LS ECU options

[gator68428]

There are plusses and minusses to both systems.

The benefits of an aftermarket system are greater simplicity for the important tuning parameters of interest and the inclusion of a wideband and ease of tuning. For example the FAST XFI 2.0 system (and from what I hear, the Holley system as well) I have experience with is designed for exactly what ppl typically need: the ability to make tuning changes after modifying engine hardware etc (a factory computer system was not designed to be modified). For example in the fueling VE table after you've taken a data log, as you scroll through your data log, there is a bubble that tracks your position in the VE table, so you know exactly where to make changes. I think HP Tuners does something similar though... But not my Ford EEC (from a 90s Mustang) in my Firebird (long story...).

The benefits of the GM LSx ECU is the usage of MAP and MAF sensors together, which permits perfect driveability under all conditions (with hours of tuning to attain perfection) with the tradeoff of greater complexity: 1) from it being a hybrid system and 2) because its a factory platform in general there are many more parameters of less interest to get bogged down in for novices. And have to consider whether or not a factory system comes with a wideband and how to interface with it for tuning... (not a trivial expense).

My experience involves the MAF based system on my Firebird (Ford A9L EEC, from Mass-FLO EFI circa 2006, now Pro-M racing). Long story short the system (then) was not plug and play for my Pontiac 428. But I'm better for it because now I know how to modify and tune EFI systems.

I've heard many tuners for GM ECUs will disable the MAP and only use the MAF signal for airmass/fueling. It is simpler with a MAF, just a single function (airmass vs sensor voltage) versus a 2 dimensional table (volumetric efficiency as a function of MAP and RPM). But there are auto tuning functions on the FAST and Holley systems... I haven't really tried the FAST auto tuning feature... but wasn't as easy to control as i first thought (maybe Holley is easier?).



My short answer would be HP Tuners if you already had an LSx car with ECU. And stand alone like Holley or Fast if you don't already have an ECU--if you have Holley already then bingo. I have experience with FAST (my father purchased the XFI 2.0 system for his car because Jim Butler sold a kit for Pontiacs) and the system works as advertised and was straightforward; costumer service usually a 30min wait for the callback with differing levels of helpfulness depending on who you talk to; very good user manual however.

MAP systems are more configurable for carb style throttle bodies as well.