Tried the truck coil swap for free
11-26-2009, 05:38 PM
#1
Tried the truck coil swap for free Cliff notes:
I got free truck coils with heat sinks.
Replaced my 250k mile square truck coils with the heat sink ones.
Car seemed to pull better in upper rpm.
Car seems to struggle less under load at low rpm.
EFI logging of fuel trims went up positive 6-8%
MAF peak readings went from 36lbs/min from 5800+ to 39.6lbs/min at redline (would likely continue to climb)
FULL:
I work for my uncle crushing cars and the other day a chevy truck came up with a 5.3 but it had the good truck coils with the heat sinks so I pulled them before it was crushed.
So I got them for free...I have nothing invested just wanted to check the hype for myself. I was going to wait until the car was strapped to a dyno to try them but I was bored earlier waiting on family to gather so I took 5 minutes to bolt them on and go for a drive.
I wish I had driven it right before the swap today though cause we have really cool dry weather here today. But I must say the car felt great and my butt dyno says the upper rpm pull was noticeably stronger (likely partially due to the air).
Most noticeable though was the way the car feels under load in the low-mid range in that area where you really should give it enough throttle to kick down. It seemed to struggle a little less pulling my 3800lb car stock stalled car around at low rpm.
A romp from 50-55mph that gets a 2nd gear kickdown feels brutal.
So I plugged up EFI live for the first time since summer when my laptop crashed. So take the log with a grain of salt...I don't know how much weather was playing with my readings here.
My fuel trims were pretty much leveled with this latest version of my mail order tune, they stayed around 0-3%. On first start up with the coils they were 10-13% at idle then after some cruising went to 6-8% fluctuating.
MAF readings were nearly always 34-36lbs/min before, even on dryer days when the car felt stronger. Today they were hitting 39-40 lbs/min on every WOT pull.
So I must say as a skeptic who thought spark was spark, my interest is peaked. Tomorrow while I'm waiting on the shop to warm up so I can pull my transmission for a rebuild/stall I'm going to try some back to back logs and see if it follows the coils or maybe just started running better by coincidence.
I say this because my car has always had moods and every once in a blue moon would run like a raped ape at random, but never while I was logging or scanning.
Perhaps the issue has been hiding somewhere in my coils the whole time, I do know I had a bad problem with 1 side right after the swap, I couldn't start the car due to random misfiring and backfiring which went away after I swapped for a different rail of coils on the passenger bank. Maybe the drivers side coils had issues as well just not bad enough to cause a misfire...but that still goes against the "coils work or they don't" theory.
I will update tomorrow with more info and data. I am trying to be objective and was actually planning on selling these coils instead of using them after I proved to myself on the dyno it was a bunch of crap. I will have to bend my fuel line a little more to get 1 side to line up enough to get more than 1 bolt in, and I think they look ugly compared to the square truck coils...so believe me I am not looking for an excuse to keep the ugly suckers.
I got free truck coils with heat sinks.
Replaced my 250k mile square truck coils with the heat sink ones.
Car seemed to pull better in upper rpm.
Car seems to struggle less under load at low rpm.
EFI logging of fuel trims went up positive 6-8%
MAF peak readings went from 36lbs/min from 5800+ to 39.6lbs/min at redline (would likely continue to climb)
FULL:
I work for my uncle crushing cars and the other day a chevy truck came up with a 5.3 but it had the good truck coils with the heat sinks so I pulled them before it was crushed.
So I got them for free...I have nothing invested just wanted to check the hype for myself. I was going to wait until the car was strapped to a dyno to try them but I was bored earlier waiting on family to gather so I took 5 minutes to bolt them on and go for a drive.
I wish I had driven it right before the swap today though cause we have really cool dry weather here today. But I must say the car felt great and my butt dyno says the upper rpm pull was noticeably stronger (likely partially due to the air).
Most noticeable though was the way the car feels under load in the low-mid range in that area where you really should give it enough throttle to kick down. It seemed to struggle a little less pulling my 3800lb car stock stalled car around at low rpm.
A romp from 50-55mph that gets a 2nd gear kickdown feels brutal.
So I plugged up EFI live for the first time since summer when my laptop crashed. So take the log with a grain of salt...I don't know how much weather was playing with my readings here.
My fuel trims were pretty much leveled with this latest version of my mail order tune, they stayed around 0-3%. On first start up with the coils they were 10-13% at idle then after some cruising went to 6-8% fluctuating.
MAF readings were nearly always 34-36lbs/min before, even on dryer days when the car felt stronger. Today they were hitting 39-40 lbs/min on every WOT pull.
So I must say as a skeptic who thought spark was spark, my interest is peaked. Tomorrow while I'm waiting on the shop to warm up so I can pull my transmission for a rebuild/stall I'm going to try some back to back logs and see if it follows the coils or maybe just started running better by coincidence.
I say this because my car has always had moods and every once in a blue moon would run like a raped ape at random, but never while I was logging or scanning.
Perhaps the issue has been hiding somewhere in my coils the whole time, I do know I had a bad problem with 1 side right after the swap, I couldn't start the car due to random misfiring and backfiring which went away after I swapped for a different rail of coils on the passenger bank. Maybe the drivers side coils had issues as well just not bad enough to cause a misfire...but that still goes against the "coils work or they don't" theory.
I will update tomorrow with more info and data. I am trying to be objective and was actually planning on selling these coils instead of using them after I proved to myself on the dyno it was a bunch of crap. I will have to bend my fuel line a little more to get 1 side to line up enough to get more than 1 bolt in, and I think they look ugly compared to the square truck coils...so believe me I am not looking for an excuse to keep the ugly suckers.
11-27-2009, 12:49 PM
#4
Follow up:
My conclusion is that the cool dry air has been responsible for the car picking up. I did a log with truck coils, then back to the old ones. Readings are nearly identical. IAT were up a bit on the second log due to it warming up outside and some heat soak underhood.
If I still have them when I get dyno tuned I'll try them there.
My conclusion is that the cool dry air has been responsible for the car picking up. I did a log with truck coils, then back to the old ones. Readings are nearly identical. IAT were up a bit on the second log due to it warming up outside and some heat soak underhood.
If I still have them when I get dyno tuned I'll try them there.
