2012 SS N/A Build

[morepowerjoe]

I had to adjust my shift schedule under wot because of the new converter but got it shifting right around 6400 rpm now. And since I've been data logging I found out my current tune is running a little lean at part throttle cruising so now I'm looking to get that sorted out. My idle in gear was bucking real bad because of the amount of spark that the tuner put into it but I reduced that and it's a lot better now. Just tweaking things for better drivability.

[acammer]

Originally Posted by morepowerjoe

I had to adjust my shift schedule under wot because of the new converter but got it shifting right around 6400 rpm now. And since I've been data logging I found out my current tune is running a little lean at part throttle cruising so now I'm looking to get that sorted out. My idle in gear was bucking real bad because of the amount of spark that the tuner put into it but I reduced that and it's a lot better now. Just tweaking things for better drivability.

With peak power coming at 6300 - I would expect to shift this at 6800-7000rpm for best overall performance. Automatic cars recover a lot better than stick cars on upshifts, but they still need to go past the peak power rpm to deliver best average power over their operating range.

[morepowerjoe]

Originally Posted by acammer

With peak power coming at 6300 - I would expect to shift this at 6800-7000rpm for best overall performance. Automatic cars recover a lot better than stick cars on upshifts, but they still need to go past the peak power rpm to deliver best average power over their operating range.

Thanks for the tip as always from the pro. I was thinking of having shift later then 6400 but wasn't entirely sure about how far to go past peak power. Thanks Andrew I'll give it a try.

[acammer]

Originally Posted by morepowerjoe

Thanks for the tip as always from the pro. I was thinking of having shift later then 6400 but wasn't entirely sure about how far to go past peak power. Thanks Andrew I'll give it a try.

The best way to set those would be at the track, or with a consistent draggy test. I'd start at 6700rpm and add 100rpm until it stops getting faster. I expect with that cam it's gonna be around 6900rpm.

[LS1Formulation]

Damn, have I been shifting too early? My car peaked out at 6430 RPM at the wheels and fell off fairly quick after that, so I had my shift light set at 6400 ( figuring by the time I saw the light and reacted, it would hit around 6600 ). Too late to test the theory this year, lol.

[acammer]

Originally Posted by LS1Formulation

Damn, have I been shifting too early? My car peaked out at 6430 RPM at the wheels and fell off fairly quick after that, so I had my shift light set at 6400 ( figuring by the time I saw the light and reacted, it would hit around 6600 ). Too late to test the theory this year, lol.

It's very difficult to set any sort of hard and fast rule, because each combination is very different. Camshaft, intake manifold, valve train, torque converter (if auto), transmission gearing - all of those have a "say" in where a given combination wants to shift. But, if it peaked at 6400rpm, I'm sure it was still pretty strong to 6800-7000, and the shift point probably wants to be somewhere in there for a auto car. Probably more like 7000-7200rpm if it's stick car.

The goal of picking the shiftpoint is to maximize average power. Although power starts to fall after the peak, there is some, or even a lot of usable RPM there that can contribute to a better average power throughout the entire gear. Consider the image below - this was my old cam only setup - manual trans car. It peaked at 6500rpm. You can see I've bracketed out two operating ranges based on a manual trans third to fourth shift recovery value - that's how far the RPM is going to drop on the gear change. If we shift at peak power, we drop down to 4500rpm, and that buries the engine pretty far back on it's power curve. Conversely, if we stretch the RPM about 750rpm beyond the shift, we stay in a much better place after the upshift. It's not hard to see which one is going to be faster - the one in the green brackets makes more average power.

The best way to set shift points is as I described in the previous post - you need a timing system like a drag strip, or a draggy, so you can make repeatable passes and check your results. If it's an auto car, start with maybe 300rpm beyond the peak, and then keep push the rpm up until the gains in trap speed fall off. Stick cars usually need as much RPM as the valve-train will take, they want to be 700-1000+rpm beyond the peak - so keeping a practical, safe RPM limit in mind is key.

Knowing what the car does for a complete power curve, including AFTER the peak, is crucial information - and something I wish more dyno operators would keep in mind. It's fairly common practice to tug on the car until you see the power level off, and then quit. I'm not sure what drives this - mechanical empathy, a desire to make sure nothing gets hurt, etc. I would suggest that a dyno run should end at where-ever the practical, reasonable RPM limit of the combination is, in order to see the full results, and give a more informed decision on the starting place for shift points.

[morepowerjoe]

Just a few other things that I did in the engine when it was a part. I had this oil pan baffle from Improved Racing installed for when I get to do some auto cross or road racing

IRP-EGM-205https://www.summitracing.com/parts/irp-egm-205



Plus I tried out the mishimoto radiator hoses and they look and fit awesome.

[morepowerjoe]

Here's a current shot of the engine bay, it's not too bad right?

[morepowerjoe]

Just a quick update. I got it currently shifting at about 6700 rpm and the engine seems to like it. I'll have to wait until I get to the track to fully test it out but it's a blast to drive. I did have an annoying little problem. When I would come to a stop with each downshift the rpm's would drop real low and I thought it was an airflow issue but what it turned out to be was I have torque reduction disabled so, without all the timing pull from T/R I had to also disable the closed throttle down shifts to get it to stop dipping down in rpm. And presto it is now fixed. I think my tuning is almost complete but the next challenge will be getting traction control working correctly. lol

[acammer]

Glad to hear it's coming along. I've never messed with trying to make traction control work. It's my extremely limited understanding that although you can modify some of the values that control the thresholds sending inputs to the TCS (Traction Control System) I don't believe you can do much of anything to change the actual behavior of the TCS system. I'd really like to be able to have some authority over things like allowed slip percentage vs. mph and vs. throttle position, attack and decay settings, etc - but I've not seen any of that. It would be really nice if you could have authority over both the standard and competitive driving modes, so you could have an aggressive standard mode for say when you get caught in the rain on slicks, competitive mode is your normal "fun" street mode with some nannies if your balls overstep your talent, and then full off like we have now. You may be able to work the min and max torque parameters to get it to behave some - that would be a game of experimentation.

Mine has been disabled for years now - when I light the tires up (with TCS on) I still get the flashing light on the dash, but the ECM doesn't take any corrective action. So, instead of the factory system I use a highly sophisticated sensor in my ass cheeks wired to the TCS module between my ears.

[morepowerjoe]

I just installed some bmr trailing arms with the poly bushings. And to my surprise it did help. No more wheel hop and it doesn't change lanes anymore form a dig it just moves over slightly but it still of course blows the tires off. I also got a scoop for my CAI intake and tow hook I need to install when it gets warmer. I'll add some pictures soon.

[morepowerjoe]

Originally Posted by acammer

Glad to hear it's coming along. I've never messed with trying to make traction control work. It's my extremely limited understanding that although you can modify some of the values that control the thresholds sending inputs to the TCS (Traction Control System) I don't believe you can do much of anything to change the actual behavior of the TCS system. I'd really like to be able to have some authority over things like allowed slip percentage vs. mph and vs. throttle position, attack and decay settings, etc - but I've not seen any of that. It would be really nice if you could have authority over both the standard and competitive driving modes, so you could have an aggressive standard mode for say when you get caught in the rain on slicks, competitive mode is your normal "fun" street mode with some nannies if your balls overstep your talent, and then full off like we have now. You may be able to work the min and max torque parameters to get it to behave some - that would be a game of experimentation.

Mine has been disabled for years now - when I light the tires up (with TCS on) I still get the flashing light on the dash, but the ECM doesn't take any corrective action. So, instead of the factory system I use a highly sophisticated sensor in my ass cheeks wired to the TCS module between my ears.

Yeah I've messing around with the traction control settings a little bit and can confirm that when you lower the max torque under traction control it just blows the tires off at a longer duration so I think that you would want it to be a bit higher then your actual engine torque that seems to work best. And then I tried lowering the active dc min value from 40% to 10% and really can't tell a difference. Also I'm only using the spark method of traction control at the moment because I feel like the throttle control is too invasive. But I need to try messing with the max torque versus rpm I guess controlled by spark.

[morepowerjoe]

On the traction stuff this is what I found out but most of you probably already know. I have all torque reduction turned off in the transmission settings and everything in torque management under engine off except under TCS method I have it set to spark only. I also have the max torque set to 525 ft lbs. Now I found out that your ecm will pull timing from the engine under the min spark base table. So if your still at stock it will pull up to -25* but I data logged it and mine only pulled up to -7* at wot in 1st gear from a dig at the stock settings at which I had at previously 5*. Now if I'm right I should now be able to play around with the max torque to get it dialed in a little better now. I'll report back after I test that theory.

[morepowerjoe]

Here's the new ride height with the Bilstein B6's and Eibach ZL1 drop springs. About 15/16" lower in the front and 5/8" lower in the rear. This strut / shock / spring set up is pretty stiff but should do good at the track.