Intake Temp Sensor - Jeep Garage - Jeep Forum

Go Back   Jeep Garage - Jeep Forum > Jeep Platform Discussion > Grand Cherokee SRT - WK2

Join Jeep Garage Today
Reply
 
Thread Tools Display Modes
 
  #1  
Old 01-12-2015, 11:49 AM
Member
 
Join Date: Oct 2013
Posts: 50
Thanks: 0
Thanked 4 Times in 2 Posts
Rep Power: 202200
RedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond reputeRedRockSRT8 has a reputation beyond repute
Intake Temp Sensor

I have posted this question some time ago without a clear answer. Does the temp sensor in the intake directly affect the timing? Or is it just for informational purposes?

Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 01-12-2015, 12:15 PM
Daniel454's Avatar
Member
 
Join Date: Mar 2013
Posts: 213
Thanks: 33
Thanked 59 Times in 39 Posts
Rep Power: 72319
Daniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond repute
Re: Intake Temp Sensor

Yes it does.... New cars use either a mass airflow sensor (MAF) or a Manifold Absolute Pressure sensor (MAP). (Well some use both but it's rare).

Ours uses a MAP sensor and calculates the proper timing & air/fuel ration based on a Speed Density calculation...

Speed density systems calculate the density of the air first by measuring the temperature of the inlet air and manifold pressure.

With the density of air known the engine controller then looks up how much air it expects to be moving at a specific engine speed and manifold pressure.

This is done in the Volumetric Efficiency table or VE table. Traditionally the VE table is 3D and has two axes Engine Speed (RPM) and Manifold Pressure or % Load.

This is why a larger Air intake (and/or better flowing filter) does little for performance. The IAT doesn't change so the timing is still based on the EXPECTED amount of air flow coming in based on that table.

A TRUE CAI would help, but most "CAI" still pull in hot air from the engine bay.

Do a 1/4 on a cold day with a well ventilated engine bay vs a hot day complete with a heavy heat soaked engine. The difference will be obvious.
Reply With Quote
The Following User Says Thank You to Daniel454 For This Useful Post:
  #3  
Old 01-14-2015, 07:06 AM
DarkHue's Avatar
Member
My Jeep: 2014 6.4L SRT8 WK2
 
Join Date: Feb 2014
Location: Dubai
Posts: 528
Thanks: 19
Thanked 31 Times in 24 Posts
Rep Power: 2152
DarkHue has a reputation beyond reputeDarkHue has a reputation beyond reputeDarkHue has a reputation beyond reputeDarkHue has a reputation beyond reputeDarkHue has a reputation beyond reputeDarkHue has a reputation beyond reputeDarkHue has a reputation beyond reputeDarkHue has a reputation beyond reputeDarkHue has a reputation beyond reputeDarkHue has a reputation beyond reputeDarkHue has a reputation beyond repute
Re: Intake Temp Sensor

Quote:
Originally Posted by Daniel454 View Post

This is why a larger Air intake (and/or better flowing filter) does little for performance.


A TRUE CAI would help, but most "CAI" still pull in hot air from the engine bay.
So a CAI is pointless unless it's a true CAI ?
Reply With Quote
  #4  
Old 01-14-2015, 09:57 AM
Daniel454's Avatar
Member
 
Join Date: Mar 2013
Posts: 213
Thanks: 33
Thanked 59 Times in 39 Posts
Rep Power: 72319
Daniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond reputeDaniel454 has a reputation beyond repute
Re: Intake Temp Sensor

Quote:
Originally Posted by DarkHue View Post
So a CAI is pointless unless it's a true CAI ?
Correct. Though do take note there are a LOT of different versions out there....

The ones that are JUST a large filter hanging in the engine bay (especially those with METAL tubes) are almost definitely going to do nothing other than make a MUCH better sound. Nothing for performance. (and they COULD even hurt performance).

Some of the "CAI" are larger filters behind a heat shield... I am not an engineer so I cant say for sure if those will help but I would say if they do, it would be very little. The SRT may field better here since it has the heat extractor right above that area....

Other "CAI" are a large filter in a box with larger than OEM inlet ducts going to the wheel wells and/or behind the grille. Again, no engineer but I would think those would work a bit better. The air isn't any hotter than OEM and with MORE air (at higher velocity) from the wheel well I would think it might read a bit cooler.

Still though, a true CAI with the filter completely out of the engine bay is likely the only one that will show a true improvement on a dyno....

Now with all of that said, this is assuming you get no tune. And I am not talking about the "canned" tunes that come on the programmer. MORE air in, coupled with a custom tune that can take advantage of it (effectively changing the VE tables to align with the larger air volume) will then give you the improvements you would want.

This is a simple downside of a Speed Density system. Its not that we cant benefit from more air, its just that the computer doesn't change timing for MORE air, it only does it for COLDER air. Get MORE Air, Colder air AND get a tune. Now you are cookin.
Reply With Quote
The Following 2 Users Say Thank You to Daniel454 For This Useful Post:
  #5  
Old 01-16-2015, 12:00 PM
Senior Member
 
Join Date: Jan 2010
Location: Mass.
Posts: 1,607
Thanks: 128
Thanked 273 Times in 158 Posts
Rep Power: 293570
Black Ops Auto Works has disabled reputation
Re: Intake Temp Sensor

Quote:
Originally Posted by Daniel454 View Post
The ones that are JUST a large filter hanging in the engine bay (especially those with METAL tubes) are almost definitely going to do nothing other than make a MUCH better sound. Nothing for performance. (and they COULD even hurt performance).
Glad someone else finally pointed this out been preaching this forever seems a lot like the looks more than the performance

Guys ^ is a fact!!!!
Reply With Quote
  #6  
Old 01-16-2015, 01:42 PM
CLStech's Avatar
Premium Member
My Jeep: 2014 6.4L WK2
 
Join Date: Nov 2011
Location: RTP, NC
Posts: 2,109
Thanks: 1,266
Thanked 560 Times in 384 Posts
Rep Power: 1548386
CLStech has a reputation beyond reputeCLStech has a reputation beyond reputeCLStech has a reputation beyond reputeCLStech has a reputation beyond reputeCLStech has a reputation beyond reputeCLStech has a reputation beyond reputeCLStech has a reputation beyond reputeCLStech has a reputation beyond reputeCLStech has a reputation beyond reputeCLStech has a reputation beyond reputeCLStech has a reputation beyond repute
Garage
Re: Intake Temp Sensor

Quote:
Originally Posted by Black Ops Auto Works View Post
Glad someone else finally pointed this out been preaching this forever seems a lot like the looks more than the performance

Guys ^ is a fact!!!!
Hey man!! Get back to work making us one. I need to spend some money!
__________________
The Albino: 2014 SRT Grand Cherokee
Bright White - Black/Sepia - Black Chrome - Tow Package - High Performance Audio - Pano Roof
*Debadged | Black Vinyl Wrapped Roof | Reflective Caliper Wrap | Billet Technology Catch Can & Accesories | Injen Intake | LED Interior Swap | LED Puddle/Entry Lighting | Lower Grill Badge | Tint | 6000K Headlights | 3000K Foglights | Road Magnet Mid Springs | Headlight DRL Mod | RAX Jailbreak | Rear Fog Lights | Electronic Cutouts | BlackOps End Links | Borla S-type | Velgen VMB5 22x10.5*
Instagram: CLStech
Twitter: CLStech
Reply With Quote
The Following User Says Thank You to CLStech For This Useful Post:
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Location of Intake Air Temp Sensor 3/ new dtc code Michaelg 2014+ Jeep Grand Cherokee Ecodiesel 3.0 4 10-17-2014 05:38 AM
Coolant Temp Sensor Fault Ozz1967 Grand Cherokee - ZJ 18 08-21-2012 06:27 PM
intake air temp sensor artrob1 Engine Performance/Intake/Exhaust 3 01-15-2012 01:09 PM
Intake Air Temp Sensor Location tommc4 Troubleshooting/Problems 6 09-09-2011 06:43 AM

Powered by vBadvanced CMPS v3.2.3

All times are GMT -5. The time now is 05:50 AM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community

JeepGarage.org is in no way associated with or endorsed by FCA US LLC. Chrysler, Dodge, Jeep, Ram, Mopar and SRT are registered trademarks of FCA US LLC.