The WidowMaker
04-10-2008, 10:04 PM
well ive done some searching, and ive developed a few questions that i cant find answers for.
first, the plan is to run an lsx block, l92 or ls7 heads and shoot for 454ci and 600hp+ with a decent size cam. thats about as far as i have gotten. nothing has been purchased, so im looking for a complete system (coils, rails, ecu, etc...). like i said i need everything.
before today, i didnt know anything about efi setups. everything ive run in the past has had a carb. so heres what i think i know.
the efi systems use an ecu to "pick" the correct duty cycle for the injectors along with the correct timing for the dis and coils. this is done by receiving info from the many sensors and inputing them into a table. the value that falls within the box that correlates to the sensors inputs is then transmitted to the ignition and injectors.
the aftermarket systems mostly use a closed loop system that employs an o2 sensor to make sure its doing its job correctly (does an open loop have an o2 sensor?). there are also two different types of o2 sensors; the narrow band and the wide band. the narrow tells you if your rich or lean, but it doesnt know by how much. a wide band lets you know the a/f/r, so you can tune it.
there are also two different methods to calculating the air input. the first is the maf, but this isnt used in the aftermarket. the second is the map which uses the speed density method. this is the preferred method in the aftermarket.
now for some questions. ive been looking at the fast system. from what i gather, i need their total install kit which includes the ecu, the xim, the harnesses and the sensors. but, since im starting from scratch, what is the difference btwn the ls1 and ls2 stuff? ive found about a $700 difference btwn the two. what makes the ls2 different, besides the 58x? is there something included in one that is not in the other? cant i just use the 24x crank and the ls1 coils and call it good?
besides the stuff listed above, plus the coils, fuel sys, fuel rails and injectors, what else is needed to make the swap and get it running?
also, with a sophisticated computer, why cant this thing tune itself? also, what makes one motor need a different a/f/r curve than another? now i know one engine may need more fuel, but that shouldnt change its needed a/f/r. i guess i just cant understand how if my motor was as efficent as say an ls7, both were at the same fluid temp, with the same heads, at the same rpm, at the same altitude, with the same ambient air temp, with the same humidity etc........ that they wouldnt be reeeeeeeaaaaaaaly close to needing the same afr.
one more thing, how does the tuning work? i know guys drive them with a labtop in the passenger seat, but what are you inputing? if you do a wot run and it tells you that at 6100 rpm you were at 13.2:1, do you then just change that figure to where you want it? does that value now just fulfill one category out of a possible million (meaning do you have to do the same thing at 6200rpm or even do it again at 6100 rpm when the air temp is a little cooler)?
way too many questions, but i appreciate the help.....
thanks in advance,
Tim
first, the plan is to run an lsx block, l92 or ls7 heads and shoot for 454ci and 600hp+ with a decent size cam. thats about as far as i have gotten. nothing has been purchased, so im looking for a complete system (coils, rails, ecu, etc...). like i said i need everything.
before today, i didnt know anything about efi setups. everything ive run in the past has had a carb. so heres what i think i know.
the efi systems use an ecu to "pick" the correct duty cycle for the injectors along with the correct timing for the dis and coils. this is done by receiving info from the many sensors and inputing them into a table. the value that falls within the box that correlates to the sensors inputs is then transmitted to the ignition and injectors.
the aftermarket systems mostly use a closed loop system that employs an o2 sensor to make sure its doing its job correctly (does an open loop have an o2 sensor?). there are also two different types of o2 sensors; the narrow band and the wide band. the narrow tells you if your rich or lean, but it doesnt know by how much. a wide band lets you know the a/f/r, so you can tune it.
there are also two different methods to calculating the air input. the first is the maf, but this isnt used in the aftermarket. the second is the map which uses the speed density method. this is the preferred method in the aftermarket.
now for some questions. ive been looking at the fast system. from what i gather, i need their total install kit which includes the ecu, the xim, the harnesses and the sensors. but, since im starting from scratch, what is the difference btwn the ls1 and ls2 stuff? ive found about a $700 difference btwn the two. what makes the ls2 different, besides the 58x? is there something included in one that is not in the other? cant i just use the 24x crank and the ls1 coils and call it good?
besides the stuff listed above, plus the coils, fuel sys, fuel rails and injectors, what else is needed to make the swap and get it running?
also, with a sophisticated computer, why cant this thing tune itself? also, what makes one motor need a different a/f/r curve than another? now i know one engine may need more fuel, but that shouldnt change its needed a/f/r. i guess i just cant understand how if my motor was as efficent as say an ls7, both were at the same fluid temp, with the same heads, at the same rpm, at the same altitude, with the same ambient air temp, with the same humidity etc........ that they wouldnt be reeeeeeeaaaaaaaly close to needing the same afr.
one more thing, how does the tuning work? i know guys drive them with a labtop in the passenger seat, but what are you inputing? if you do a wot run and it tells you that at 6100 rpm you were at 13.2:1, do you then just change that figure to where you want it? does that value now just fulfill one category out of a possible million (meaning do you have to do the same thing at 6200rpm or even do it again at 6100 rpm when the air temp is a little cooler)?
way too many questions, but i appreciate the help.....
thanks in advance,
Tim