Go Back   EcoModder Forum > EcoModding > General Efficiency Discussion
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 05-09-2008, 11:41 PM   #1 (permalink)
Master EcoModder
 
tasdrouille's Avatar
 
Join Date: Jan 2008
Location: Mirabel, QC
Posts: 1,672

The Guzzler - '08 Hyundai Elantra GL
90 day: 33.12 mpg (US)

Got Soul? - '11 Kia Soul 2U
Thanks: 35
Thanked 80 Times in 52 Posts
Testing the IAT mod

So I decided to give a shot at the IAT mod on the TDI. In fact for this car, it's the FAT mod (Fuel Air Temperature) as we also have a fuel temp sensor to play with.



I used switches so I could toggle the mod on and off without too much hassle.



Here's the resistor attached to the fuel pump harness. Inline on pin 7 in my case. The other 2 wires are bridging pins 2 and 3 with a 1k pot, fooling the pump's piston movement sensor so I can dump in more fuel (hardly useful for FE...)



And finally the IAT sensor which is located post intercooler.



I did a couple of tests run.

Stock timing for the TDI is supposed to be between -3 to 4 at idle and between 8 and 12 at 3000 rpm. My car, as per my SG, was at -1 or 0 at idle and 8 at 3000 rpm, a bit on the retarded side.

With the mod on, my reported timing jumped to 2 at idle and 11 at 3000 rpm.

Here's a very boring video showing what happens when I switch the mod on and off at idle. Basically you'll see the timing switch from 0 to 2 and the temp from 85 F to -15 F when I switch the mod on.



I'll report on FE as I get some data.

__________________



www.HyperKilometreur.com - Quand chaque goutte compte...

Last edited by tasdrouille; 08-21-2008 at 09:42 PM..
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 05-09-2008, 11:45 PM   #2 (permalink)
Dartmouth 2010
 
SVOboy's Avatar
 
Join Date: Nov 2007
Location: Hanover, NH
Posts: 6,427

Vegan Powa! - '91 Honda CRX DX
Team Honda
90 day: 66.52 mpg (US)
Thanks: 92
Thanked 114 Times in 82 Posts
Send a message via AIM to SVOboy Send a message via MSN to SVOboy Send a message via Yahoo to SVOboy
Looking forward to seeing your results!
  Reply With Quote
Old 08-21-2008, 09:47 PM   #3 (permalink)
Master EcoModder
 
tasdrouille's Avatar
 
Join Date: Jan 2008
Location: Mirabel, QC
Posts: 1,672

The Guzzler - '08 Hyundai Elantra GL
90 day: 33.12 mpg (US)

Got Soul? - '11 Kia Soul 2U
Thanks: 35
Thanked 80 Times in 52 Posts
I got my new toy in the mail earlier this week and decided to try to log some data to evaluate the impact of this mod on FE.

Here's a graph showing the injected quantity in mg per stroke during the course of my test (X axis in seconds). The black line is a moving average based on 60 data points (seconds).



I just did an A-B test as it took almost an hour of driving. The cruise control was set at 90 km/h the whole time and the car was never turned off. Run A1 started at a coolant temp of 85.5 Celcius and 90 Celcius was reached at the end of the run. All remainning runs were done at 90 Celcius.

During run 1, the ECU thought the intake air temp and fuel temp were -23.4 Celcius.
During run 2 the ECU saw actual intake air temp and fuel temp which were respectively averaging 45.22 and 50.4 Celcius.

The average injected quantity in mg per stroke was as following:

A1 - 11.9172
A2 - 11.2812
Var = 5.3368%

B1 - 8.4111
B2 - 7.9727
Var = 5.2121%

Let's average the variation at 5.5% to be on the safe side and account for unknown errors.

So it looks like the injected mass was actually higher with the mod. But wait, the ECU thought the temperature of the fuel was way cooler than what it really was and ajusted the volume accordingly.

Diesel volume varies approximately 0.125% per degree Celcius. The ECU thinking the fuel was 73.8 Celcius cooler than it really was, it should have adjusted the volume by approximately 9.225%, but let's use 9% just to be safe.

So, for any given mass the actual injected volume should be 9% smaller with the mod (at least during the summer), but since the injected mass was 5.5% higher the theorical net result is an increase in fuel economy just shy of 4%.
Attached Thumbnails
Click image for larger version

Name:	INJQTY.JPG
Views:	1446
Size:	75.9 KB
ID:	1499  
__________________



www.HyperKilometreur.com - Quand chaque goutte compte...

Last edited by tasdrouille; 08-21-2008 at 10:13 PM..
  Reply With Quote
Old 09-24-2009, 12:45 PM   #4 (permalink)
Master EcoModder
 
Join Date: Mar 2009
Location: Northeast Ohio
Posts: 269

The Wife's Hot Rod - '09 Pontiac G8 GT
Last 3: 23.22 mpg (US)

Big Outback - '13 Subaru Outback 2.5i

Little Outback - '02 Subaru Impreza Outback Sport
Thanks: 0
Thanked 16 Times in 16 Posts
Do you have plans to use variable resistors to be able to find the "optimal" setting?

Don
  Reply With Quote
Old 09-24-2009, 01:08 PM   #5 (permalink)
Master EcoModder
 
tasdrouille's Avatar
 
Join Date: Jan 2008
Location: Mirabel, QC
Posts: 1,672

The Guzzler - '08 Hyundai Elantra GL
90 day: 33.12 mpg (US)

Got Soul? - '11 Kia Soul 2U
Thanks: 35
Thanked 80 Times in 52 Posts
In the end the fuel temperature had absolutely no impact on ignition timing, just the IAT had an impact.

The optimal setting is as much advance a you can get as long as you're still within spec. At idle max spec advance is 5 btdc. Whatever resistance you use will not give you more than 2 additional degrees.
__________________



www.HyperKilometreur.com - Quand chaque goutte compte...
  Reply With Quote
Old 09-27-2009, 02:05 PM   #6 (permalink)
Renaissance Man
 
Formula413's Avatar
 
Join Date: Jan 2008
Location: In the Northeast dreaming of the Southwest
Posts: 595

Aegean Sea - '17 Honda Civic LX
90 day: 43.26 mpg (US)
Thanks: 19
Thanked 30 Times in 23 Posts
I tried playing with the IAT on my car. I actually found a potentiometer that could plug right into the IAT pigtail. I wasn't able to see any FE benefit or increase in timing, but the pot I found would only allow me to dial in an IAT as low as 40*F, so maybe I just needed to go lower. I can't remember if less resistance=colder IAT or warmer IAT, I would assume colder but I'm not sure.
__________________

  Reply With Quote
Old 09-27-2009, 05:09 PM   #7 (permalink)
Master EcoModder
 
tasdrouille's Avatar
 
Join Date: Jan 2008
Location: Mirabel, QC
Posts: 1,672

The Guzzler - '08 Hyundai Elantra GL
90 day: 33.12 mpg (US)

Got Soul? - '11 Kia Soul 2U
Thanks: 35
Thanked 80 Times in 52 Posts
The higher the resistance, the colder the IAT.

__________________



www.HyperKilometreur.com - Quand chaque goutte compte...
  Reply With Quote
Reply  Post New Thread


Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Potential engine mod? Otto to Atkinson conversion AndrewJ EcoModding Central 84 09-23-2014 07:13 PM
IAT sensor madness Green Machine Off-Topic Tech 10 10-10-2008 09:42 PM
an interesting point of view (wool tuft testing video) fabrio. EcoModding Central 10 04-02-2008 05:16 AM
Testing aero.mods. over time ( Lowering car ) Cd Aerodynamics 2 03-22-2008 05:32 PM



Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2019, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com