2 issues with heads/cam tune, chime in please.
05-08-2007, 09:52 PM
#1
2 issues with heads/cam tune, chime in please. ok, got two minor issues. after reviewing several vid. clips of guys with similar cams (mine is 235/242 on a 112+2) or bigger, seems like I should be able to have 900rpm idle no problem. but tuner set it to 1050 (or maybe 1000,) after I had him lower it from the ridiculous 1200rpm. I couldnt stand that. I love choppy cams, so I see no reason to have it idle higher, IF I can do so w/o any driveability symptoms. so, for first problem listed,
1) whats your cam size and idle speed?
and
2)does it rev. smooth from idle up, or does it kinda hesitate on initial light throttle?
Im talking a normal, very light throttle like your rolling away from a light in front of a cop-type transition. mine is smooth, but I was lead to believe (and maybe its true?) that if we lowered the idle speed more, it might bring on that type of symptom.
now, for the second question. this one seems like a no brainer, just curious if its normal at all or not. I also installed a ported throttle body when I did th heads/cam. seems like the throttle bore isnt tight enough around the blade, cause my IAC counts go to zero after the cars warm. now, it orig. had a bad issue with the idle speed not dropping back down when I pulled to a stop light, but the tuner fixed that with something in the tune (throttle cracker? seems that what he told me). it doesnt do that at all anymore, but, I still see zero IAC counts at idle. idle hoovers around 1050 actual rpm, but desired rpm is 1000. so obviously its still not able to do its job properly, and Im wondering if thats hurting the driveability, or do alot of you guys have zero IAC counts during a hot idle?
the tune is pretty decent (at the least, Im no expert though) Im still happy with the tune, but I think maybe Im obsessing over something petty. and its really not hurting anything the way it is. your opinions please. and idle clips/reving clips if you wish. Id love to see/hear them.
1) whats your cam size and idle speed?
and
2)does it rev. smooth from idle up, or does it kinda hesitate on initial light throttle?
Im talking a normal, very light throttle like your rolling away from a light in front of a cop-type transition. mine is smooth, but I was lead to believe (and maybe its true?) that if we lowered the idle speed more, it might bring on that type of symptom.
now, for the second question. this one seems like a no brainer, just curious if its normal at all or not. I also installed a ported throttle body when I did th heads/cam. seems like the throttle bore isnt tight enough around the blade, cause my IAC counts go to zero after the cars warm. now, it orig. had a bad issue with the idle speed not dropping back down when I pulled to a stop light, but the tuner fixed that with something in the tune (throttle cracker? seems that what he told me). it doesnt do that at all anymore, but, I still see zero IAC counts at idle. idle hoovers around 1050 actual rpm, but desired rpm is 1000. so obviously its still not able to do its job properly, and Im wondering if thats hurting the driveability, or do alot of you guys have zero IAC counts during a hot idle?
the tune is pretty decent (at the least, Im no expert though) Im still happy with the tune, but I think maybe Im obsessing over something petty. and its really not hurting anything the way it is. your opinions please. and idle clips/reving clips if you wish. Id love to see/hear them.
05-09-2007, 04:47 PM
#2
Theres no reason you should need an idle that high, IMO. I have a much smaller cam, but it idles fine at 750, with no idle dips or stalling. Count your blessings if you dont have any bucking @ 1600-1800 rpm. Thats where most of the issues are apparent, not directly off idle.
Your IAC counts are bottomed out. See if you have the screw cracking the blade slightly at idle. if not, maybe you can fill the TB blade hole to get the counts up. If the IAC is bottomed out, you cant set the idle any lower.
One reason your tuner might like using a high idle is because the cam will have some reversion which will play havoc with the MAF at low rpms. It will also be hard for the O2 sensors to keep hold of. You can always go open-loop at 1200 rpm and below (via PE Enable table)
Your IAC counts are bottomed out. See if you have the screw cracking the blade slightly at idle. if not, maybe you can fill the TB blade hole to get the counts up. If the IAC is bottomed out, you cant set the idle any lower.
One reason your tuner might like using a high idle is because the cam will have some reversion which will play havoc with the MAF at low rpms. It will also be hard for the O2 sensors to keep hold of. You can always go open-loop at 1200 rpm and below (via PE Enable table)
05-09-2007, 05:56 PM
#4
well, it idled great at 800rpm before the tune. ofcourse check eng. light was on throwing maf codes......
thats why I was suprised he had issues with leaving it at 850 or 900. also, it is open loop tune for the reason of all my overlap. I think it was like 14deg.s. he thinks thats alot. too much in his opinion. but nevertheless thats part of it maybe.
and it does have some light cam surge under 2000, but I never drive there, and neither does pops. on the freeway its good to go, can cruise at 65 in 6th if you want to. but at lower speeds when i try to upshiftto a higher gear to keep revs really low it does have a bit of surge. mostly very light. but i was expecting that. I cruise at about 2000-2400 mainly anyways just cause I dont like to lug the eng.
Im suspecting whatever it was that he messed with before to allow the eng. to reach lower speeds is what will affect the driveability if he tries to lower it more. it had 0 iac counts before he lowered it to 1050rpm.
I thought of doin just what you said with the throttle body hole. easy epoxy job and see what happens. hell, I could just use clay to test it out really. then epoxy if it helps/works.
thats why I was suprised he had issues with leaving it at 850 or 900. also, it is open loop tune for the reason of all my overlap. I think it was like 14deg.s. he thinks thats alot. too much in his opinion. but nevertheless thats part of it maybe.
and it does have some light cam surge under 2000, but I never drive there, and neither does pops. on the freeway its good to go, can cruise at 65 in 6th if you want to. but at lower speeds when i try to upshiftto a higher gear to keep revs really low it does have a bit of surge. mostly very light. but i was expecting that. I cruise at about 2000-2400 mainly anyways just cause I dont like to lug the eng.
Im suspecting whatever it was that he messed with before to allow the eng. to reach lower speeds is what will affect the driveability if he tries to lower it more. it had 0 iac counts before he lowered it to 1050rpm.
I thought of doin just what you said with the throttle body hole. easy epoxy job and see what happens. hell, I could just use clay to test it out really. then epoxy if it helps/works.
05-09-2007, 06:01 PM
#6
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mine idles perfect at 900 RPM's 
its all in the tune.
http://www.youtube.com/watch?v=gWfIxvE0-0E
btw.. mine revs perfectly smooth. throttle response is crisp and instant. it surges pretty badly when its cold but once it warms up it runs/idles/drives like a stock car. only difference is a huge lope and a shaking car
its all in the tune.
http://www.youtube.com/watch?v=gWfIxvE0-0E
btw.. mine revs perfectly smooth. throttle response is crisp and instant. it surges pretty badly when its cold but once it warms up it runs/idles/drives like a stock car. only difference is a huge lope and a shaking car
05-09-2007, 08:23 PM
#7
https://ls1tech.com/forums/generation-iii-internal-engine/705196-results-my-loooong-heads-cam-build.html
here's a tread that I put some vids up before. this is from before the tune. stock tune, and idle speed. it had great throttle response. we drove it around for about 12 miles before taking it to the tuner to make sure there werent any major issues before it went WOT getting tuned. and the dyno graph on the other link shows the WOT tune it great.
here's a tread that I put some vids up before. this is from before the tune. stock tune, and idle speed. it had great throttle response. we drove it around for about 12 miles before taking it to the tuner to make sure there werent any major issues before it went WOT getting tuned. and the dyno graph on the other link shows the WOT tune it great.
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05-09-2007, 08:28 PM
#8
sweet. what kinda times you running with that?
Originally Posted by LostCauseZ06
mine idles perfect at 900 RPM's
its all in the tune.
http://www.youtube.com/watch?v=gWfIxvE0-0E
btw.. mine revs perfectly smooth. throttle response is crisp and instant. it surges pretty badly when its cold but once it warms up it runs/idles/drives like a stock car. only difference is a huge lope and a shaking car
its all in the tune.
http://www.youtube.com/watch?v=gWfIxvE0-0E
btw.. mine revs perfectly smooth. throttle response is crisp and instant. it surges pretty badly when its cold but once it warms up it runs/idles/drives like a stock car. only difference is a huge lope and a shaking car