Any ideas on how I can soften my launch so I dont keep blowing my tires away. I haven't gotten lower than a 1.54 60 launching at 2700 on a 2 step and trans brake. Anything higher and it spins or wheel hops. I was thinking maybe pulling some timing in the lower rpm.
Also any idea why my actual logged timing is a couple degrees different than commanded in the wot map?
Thanks
Airflow -> Electronic Throttle -> Max Demanded Throttle Voltage will let you limit throttle opening. Pulling timing would work too but gonna generate more heat if you pull a crazy amount. What are the details on this car?
Don't have a lot to recommend on the launch, but I would guess the reason you're seeing a difference in timing advance form commanded to actual would be due to the IAT Hot Spark table doing what it's programmed to do. Just as an example, in your log at time marker 8:35:15.224, your logged RPM is 6174, MAP is 226 kPa, and Actual Spark is 12*.Originally Posted by jabbott1
Looking at your WOT map, at that RPM and MAP breakpoint, you'd be commanding a little over 13.5*. So, you're seeing a -1.5* discrepancy.
But if you reference your IAT Hot Spark table, you'll see that at that RPM and MAP range, it's commanded to pull -3* once the Hot Spark Ref IAT value is reached, which is set to 194*F. Your Cold Spark table is all set to 0, and your Cold Spark Ref IAT value is set at 86*F.
So, between the cold and hot reference, it will simply interpolate between the 2 tables. Your IAT at the above mentioned point in your log is 160*F.
Hot 194 - Cold 86 = 108* span.
160 (your iat at that point in log) - 86 (cold ref iat) = 74* above cold ref IAT.
Divide that by the span (74 / 108 = .685). You will use this result to multiply against the Hot Spark Table to find what it should be actually commanding.
-3 * .685 = -2.055*
So, instead of receiving the full 13.5+* advance, you're getting up to a -2.055* penalty on IAT (Hot/Cold Deadband could be playing into the equation which would affect the actual penalty applied, hence why you're getting more actual advance than what would otherwise be calculated if you were getting the full -2.055* penalty).
You can raise WOT pedal threshold and use Driver Demand to limit throttle also. Can make lower N/V request more power to get more power at higher speeds.
Boostjunk, thank you for that detailed explanation.
2006 charger, 426 manley stroker, thitek heads, comp cam, Custom twin turbo kit with twin turbonetics benita 78mm. Running mt 275 pro radial
I copied the hellcat max throttle setting but not much of a difference than before.
Looking at the log seeing where it spun the tires any suggestion for a max throttle table to try?
I've always found pulling a few degrees of timing to be the easiest and most efficient way to soften the launch. Just play with it until you find what works. Much easier to adjust for track conditions as well.
Just 3-4* can make all the difference sometimes
So since the rpm never goes under 5000 after first gear should I just pull timing from 5000 rpm down and 100 map and up?
Could check log for RPM spikes from spinning and pull some in that area. I wasn't looking at tune or logs when I was talking about pulling power with throttle. Turbo car you will pull a bunch of power with timing adjustments and keep boost up so I would do that.
Ok so had some runs yesterday and got the 60 foot down to a 1.42 just by taking around 4 degrees of timing out of the launch and spool area.
The max throttle settings didn't really do much if anything for helping the traction issue.
The other thing I noticed is how sensitive it is. All the test runs were done on the transbrake with the launch set to 2800 rpm. The next pass I set it to 3000 rpm with the same timing and it started to spin and had to pedal it.
Hopefully with a little more tweaking i can get some 1.3 60 foots next time
Here is my log if anyone wants to use it for reference.
22 9-4.hpl
Any way to reduce boost in first gear. Not sure if you have any electronics for those turbos
Im using an aem truboost. No way to do gear based boost that I know of.
Don't know how much that would help anyway. It was breaking the tires loose with only a few pounds of boost on spool up. The torque would come in so hard and fast the tires couldn't take it. Looks good on a dyno graph but not so much for traction.
Here's a video of the runs. The last pass is the one where i figured out the timing to pull some power out on the launch and did a 1.42 60 foot. Think next time out I can get her into the 1.3s.
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