GNSpyder

Hijacked thread from Cadillac CTS-V:

Looking for some tech here. I have a device where I can manually set parameters in the spark vs airtemp table via the airtemp sensor. New product being beta tested. What I find is a considerable pull in timing in this table with the factory calibration, as much as 8 degrees of timing pull, and it seems typically 3-5 degrees pulled under normal operating temperatures. There is a lot of power available here with a few "tweaks".

Anyone on the list here have any experience with this? I can adjust the table to anything I want, within reason, and use the gauge device to set the timing factor. The gauge goes from -8 to +7 in 16 steps, but I think all I will need is maybe +4 or +5 degrees maximum.

Any ideas?

-John

jimmyblue

iTrader: (11)

You'd want to work into it based on observed KR at hot
conditions. You probably want to look into managing the
actual inlet air temp, more than managing the spark for
hot crappy air as-is.

GNSpyder

I am just using the air temp sensor wiring as a means to input the device to the ECU. The sensor will be taken out of the equation completely and I would be able to increase (or decrease) WOT timing with the device. The factory tables provide too much timing pull - IMO - and the engine can sure benefit from some additional timing added to equation. I'm figuring I could run 100 octane which would allow more timing, and as a result, make more power. With this gauge, I can manually choose how much timing suits the scenario, while monitoring KR with the scantool. There is definitely more power on tap with additional timing, as long as the KR is controlled. I am trying to find out if anyone has played with this table to gain some power, and if so, to what extent.

I agree, cold air is better, but here at the trackside, you get what you get...

-John

P Mack

iTrader: (6)

I would use the ECT correction table instead. The reason is, the IAT reading is very important to fueling calculations so you don't wanna mess with the IAT input just to tweak timing. ECT would affect some stuff but you could easily get around that.

patSS/00

iTrader: (6)

The spark vs. IAT vs. map table doesn't get to -3 deg. until the intake air temp is 45 C = 113 F. That's pretty high, I wouldn't call it normal - you're either sitting in traffic, or you're in Arizona in the summer. I would expect knock problems if you add the timing back at those temps.

GNSpyder

I'm thinking of using high octane to offset the detonation effect. While at the race track, those temp's get at least that hot, and typically 122 deg. would be seen. That much timing pull is obviously essential for a "normal" setup, but high octane (100) is in order. I'm trying to optimize the timing and prevent pull at those air temp's. The way I am doing it:

www.installationinstructions.com/103033.pdf

Hopefully I can find an optimal table value that can do the trick.

-John

P Mack

iTrader: (6)

You still haven't addressed the fact that IAT affects fueling. Why don't you want to use the ECT table instead?

GNSpyder

I think that using coolant temp might affect the time it takes the engine to go into closed loop - and stay there. The coolant temp plays into the equation when switching from open to closed loop, and if the device I'm using were to be set to a low number, it could force the engine into open loop based upon theoretical coolant temperature.
The airtemp sensor is more versatile, since it basically scales the timing into a negative value based on theoretical air density (hot air less dense) and it's a convenient means to get to the ECU.
Gee I wish the ECU's had extra, unused inputs. That'd make it so much simpler.

-John

slow

iTrader: (7)

what tables show how IAT's effect fueling?

Ryan

P Mack

iTrader: (6)

IAT's affect fueling through speed density calcs. But I guess as long as you're not doing a speed density tune and you're using the device mostly for wide open throttle, the IAT vs spark table would be the better choice. I just looked and there's a lot of tables that are affected by ect.