PCM Diagnostics & Tuning HP Tuners | Holley | Diablo

Spark VS Airtemp table modifications

Thread Tools
 
Search this Thread
 
Old Jun 16, 2005 | 09:38 AM
  #1  
GNSpyder's Avatar
Thread Starter
Teching In
 
Joined: Apr 2005
Posts: 33
Likes: 0
From: Chicago Illilnois
Default Spark VS Airtemp table modifications

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
Reply
Old Jun 16, 2005 | 11:05 AM
  #2  
jimmyblue's Avatar
Moderator
iTrader: (11)
 
Joined: Mar 2002
Posts: 12,604
Likes: 7
From: East Central Florida
Default

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.
Reply
Old Jun 16, 2005 | 11:28 AM
  #3  
GNSpyder's Avatar
Thread Starter
Teching In
 
Joined: Apr 2005
Posts: 33
Likes: 0
From: Chicago Illilnois
Default

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
Reply
Old Jun 16, 2005 | 10:44 PM
  #4  
P Mack's Avatar
TECH Addict
iTrader: (6)
 
Joined: Jan 2003
Posts: 2,382
Likes: 2
From: Phoenix
Default

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.
Reply
Old Jun 17, 2005 | 01:26 AM
  #5  
patSS/00's Avatar
TECH Fanatic
20 Year Member
Photogenic
Photoriffic
Liked
iTrader: (6)
 
Joined: Nov 2001
Posts: 1,010
Likes: 17
From: AZ
Default

Originally Posted by 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".
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.
Reply
Old Jun 20, 2005 | 06:23 PM
  #6  
GNSpyder's Avatar
Thread Starter
Teching In
 
Joined: Apr 2005
Posts: 33
Likes: 0
From: Chicago Illilnois
Default

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
Reply
Old Jun 20, 2005 | 06:28 PM
  #7  
P Mack's Avatar
TECH Addict
iTrader: (6)
 
Joined: Jan 2003
Posts: 2,382
Likes: 2
From: Phoenix
Default

You still haven't addressed the fact that IAT affects fueling. Why don't you want to use the ECT table instead?
Reply
Old Jun 20, 2005 | 10:18 PM
  #8  
GNSpyder's Avatar
Thread Starter
Teching In
 
Joined: Apr 2005
Posts: 33
Likes: 0
From: Chicago Illilnois
Default

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
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-1

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-2

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-3

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-4

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-5

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
story-6

Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

 Verdad Gallardo
story-7

Awesome K5 Blazer Restomod Comes With C7 Corvette Power

 Verdad Gallardo
story-8

10 Camaros You Should Never Buy

 
story-9

10 LS Engine Myths That Refuse to Die

 Verdad Gallardo
Old Jun 20, 2005 | 10:47 PM
  #9  
slow's Avatar
TECH Senior Member
20 Year Member
iTrader: (7)
 
Joined: Dec 2001
Posts: 6,150
Likes: 7
From: Orlando
Default

what tables show how IAT's effect fueling?

Ryan
Reply
Old Jun 20, 2005 | 11:52 PM
  #10  
P Mack's Avatar
TECH Addict
iTrader: (6)
 
Joined: Jan 2003
Posts: 2,382
Likes: 2
From: Phoenix
Default

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.
Reply




All times are GMT -5. The time now is 11:04 PM.

story-0
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-1
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-2
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-3
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-4
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-5
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE
story-6
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes

Slideshow: A one-off sports car that looks like a vintage Italian exotic-but hides a C6 Corvette underneath-just sold for the price of a new mid-engine Corvette.

By Verdad Gallardo | 2026-03-23 18:53:41


VIEW MORE
story-7
Awesome K5 Blazer Restomod Comes With C7 Corvette Power

Slideshow: A heavily reworked 1972 K5 Blazer swaps its off-road roots for a low-slung street-focused build with modern V8 power.

By Verdad Gallardo | 2026-03-09 18:08:45


VIEW MORE
story-8
10 Camaros You Should Never Buy

Slideshow: There are thousands of used Camaros on the market but we think you should avoid these 10

By | 2026-02-17 17:09:30


VIEW MORE
story-9
10 LS Engine Myths That Refuse to Die

Slideshows: Which one of these myths do you believe?

By Verdad Gallardo | 2026-01-28 18:10:11


VIEW MORE