My experience with idle tuning
04-21-2012, 02:23 PM
#1
My experience with idle tuning I've never had an issue with the street tune, tuning with the MAF disabled and dialing in the VE, tuning the MAF to match up, all been easy stuff following the guides here and on the HP Tuners forum.
This is my 3rd cam, first was a TR224 (VERY easy to tune for a LS1 I found)
and 2 custom comp cam's with similar profiles.
First was a 230/230 with 0.613 lift and a 114 LSA
2nd was a 230/230 with a 0.615/0.608 with a 115+2 LSA
What I found was with the TR224 and the first comp cam, I had none of the traditional "stalling" issues that the 115+2. Both passed emissions fine (with a slight idle bump) and both had near similar characteristics.
When I went to the 115+2 cam I also went to a L92 block and found the displacement increase wreaked havoc on the open loop areas. This time around I found myself following the basic guidelines and not even making a dent into my stalling issue and in fact making it worse.
I ended up referencing my LS1 + 224 cam tune and found my derived values from my SD and MAF tunes being within 5% of the guideline for the 800 and 1200 rpm sections. The 400 rpm section where it was recommended to drop the stock table by multiplying by 0.6 made recovering from a below idle drop near impossible.
What I was able to come away with was that trusting the 800 and 1200 rpm VE values you get from data logging is correct for your car. This produces a nice idle in closed loop and should translate well in open loop. End result is my idle isn't killing small animals anymore and is actually "spitting" water out the tailpipes.
The timing portion of the idle guide is bang on I found EXCEPT for the 400 and 600 rpm range for my car. I ended up leaving 400 rpm range as stock and 600 with only 1 additional degree.
I did have to enrich up my base idle tune before hitting closed loop. From stock, I put it up 5% from stock. MAF tuning had me adjust my MAF table by almost 9% from stock I think in the lower areas.
I didn't adjust my idle set screw. Praying to god my IAC motor doesn't die since its still the stock 98 one, but it has counts around 89-90 in closed loop and I can live with that. I've seen it go as high as 250 when trying to just "idle" launch the car, but I feel that since the idle launch now feels like it did when stock it should be ok. It settles to 90-100 once moving so its not like the IAC isn't doing its job.
Now to deal with the AC/Defroster on moderate start issue.
I'm now going to work on the mileage portion of my tune. Both the TR224 and comp 114 had mileage of 28-30mpg on highway and 18-20mpg in city.
This is my 3rd cam, first was a TR224 (VERY easy to tune for a LS1 I found)
and 2 custom comp cam's with similar profiles.
First was a 230/230 with 0.613 lift and a 114 LSA
2nd was a 230/230 with a 0.615/0.608 with a 115+2 LSA
What I found was with the TR224 and the first comp cam, I had none of the traditional "stalling" issues that the 115+2. Both passed emissions fine (with a slight idle bump) and both had near similar characteristics.
When I went to the 115+2 cam I also went to a L92 block and found the displacement increase wreaked havoc on the open loop areas. This time around I found myself following the basic guidelines and not even making a dent into my stalling issue and in fact making it worse.
I ended up referencing my LS1 + 224 cam tune and found my derived values from my SD and MAF tunes being within 5% of the guideline for the 800 and 1200 rpm sections. The 400 rpm section where it was recommended to drop the stock table by multiplying by 0.6 made recovering from a below idle drop near impossible.
What I was able to come away with was that trusting the 800 and 1200 rpm VE values you get from data logging is correct for your car. This produces a nice idle in closed loop and should translate well in open loop. End result is my idle isn't killing small animals anymore and is actually "spitting" water out the tailpipes.
The timing portion of the idle guide is bang on I found EXCEPT for the 400 and 600 rpm range for my car. I ended up leaving 400 rpm range as stock and 600 with only 1 additional degree.
I did have to enrich up my base idle tune before hitting closed loop. From stock, I put it up 5% from stock. MAF tuning had me adjust my MAF table by almost 9% from stock I think in the lower areas.
I didn't adjust my idle set screw. Praying to god my IAC motor doesn't die since its still the stock 98 one, but it has counts around 89-90 in closed loop and I can live with that. I've seen it go as high as 250 when trying to just "idle" launch the car, but I feel that since the idle launch now feels like it did when stock it should be ok. It settles to 90-100 once moving so its not like the IAC isn't doing its job.
Now to deal with the AC/Defroster on moderate start issue.
I'm now going to work on the mileage portion of my tune. Both the TR224 and comp 114 had mileage of 28-30mpg on highway and 18-20mpg in city.
Last edited by SladeX; 04-21-2012 at 02:43 PM.
