Drive thru at Burger King---- ambient=61.0*, underhood=155.8*, +94.8*!
Cruising Freeway 55mph----- ambient=58.6*, underhood= 88.3*, +29.7*
WOW!! Look at those numbers. No wonder the Cherokee runs HOT when wheeling.
Some more testing results.
Idling 10 mins .... ambient=76.3, underhood=150.3 difference +74.0* engine MAT=188.6*
cruise 55 freeway ambient=75.2, underhood=112.1 difference +36.9* engine MAT=121.2*
With 1/2" hood spacers raising the rear of the hood 1/2" (barely noticeable, needs more)
idling 10 minutes ambient=71.2 underhood=143.8 difference +72.5* engine MAT=174.2*
cruise 55 freeway ambient=70.7 underhood=109.2 difference +39.0* engine MAT=109*
What does this show?
Today's test were with 15-16* (75.2-76.3*F) warmer ambient
Hoodlift needs to be more than 1/2", 1" is better.
With the rear hood seal, there was barely a 1/4" gap even though I used a 1/2" spacer.
The underhood temp was lower with 1/2" lift but the ambient was lower by nearly the same amount.
But the MAT was lower by a greater amount with the hoodlift.
Idling 10 mins .... ambient=76.3, underhood=150.3 difference +74.0* engine MAT=188.6*
cruise 55 freeway ambient=75.2, underhood=112.1 difference +36.9* engine MAT=121.2*
With 1/2" hood spacers raising the rear of the hood 1/2" (barely noticeable, needs more)
idling 10 minutes ambient=71.2 underhood=143.8 difference +72.5* engine MAT=174.2*
cruise 55 freeway ambient=70.7 underhood=109.2 difference +39.0* engine MAT=109*
What does this show?
Today's test were with 15-16* (75.2-76.3*F) warmer ambient
Hoodlift needs to be more than 1/2", 1" is better.
With the rear hood seal, there was barely a 1/4" gap even though I used a 1/2" spacer.
The underhood temp was lower with 1/2" lift but the ambient was lower by nearly the same amount.
But the MAT was lower by a greater amount with the hoodlift.
1/2" hood lift- too low, was barely off the weatherstripping, no gap.
1" hood lift- good gap, aesthetically looks too high, ? need to lower to 3/4"
With the 1" Spacer, The Results-
10 min idle at BK ambient=73.6* underhood=127.9* DIFFERENCE=+54.3* fuel rail=151*
Freeway 55mph-- ambient=62.6* underhood= 86* DIFFERENCE=+23.4* fuel rail=99.5*
1" hood lift- good gap, aesthetically looks too high, ? need to lower to 3/4"
With the 1" Spacer, The Results-
10 min idle at BK ambient=73.6* underhood=127.9* DIFFERENCE=+54.3* fuel rail=151*
Freeway 55mph-- ambient=62.6* underhood= 86* DIFFERENCE=+23.4* fuel rail=99.5*
Stock the underhood temps were 74* over ambient
1" lift was 54* over ambient or 20* cooler than stock
1" lift was 54* over ambient or 20* cooler than stock
The underhood sensor was taped to the underside of the hood right in
the middle about directly above the oil fill cap. The ambient was taped
to the windshield along with the 2 digital readouts.
It was the difference that was so impressive. On that 100* day one might see over 220* under the hood.
SUMMARY
Stock hood location Sitting idling 10 mins- ambient=61.5* underhood=184.1*, MAT=?
With 0.5" hood lift Sitting idling 10 mins- ambient=71.2* underhood=143.8*, MAT=174.2*
It was the difference that was so impressive. On that 100* day one might see over 220* under the hood.
SUMMARY
Stock hood location Sitting idling 10 mins- ambient=61.5* underhood=184.1*, MAT=?
With 0.5" hood lift Sitting idling 10 mins- ambient=71.2* underhood=143.8*, MAT=174.2*
With 1" hood lift Sitting idling 10 mins- ambient=73.6* underhood=127.9*, MAT=?, fuel rail= 151*
stock hood location cruise 55 freeway- ambient=75.2* underhood=112.1*, MAT=121.2*
with 0.5" hood lift cruise 55 freeway- ambient=70.7* underhood=109.2*, MAT=109*
with 1.0" hood lift cruise 55 freeway- ambient=62.6* underhood=86*, MAT=?, fuel rail=99.5*
Having a 'cooler' underhood temp probably won't help make any more HP but it would help with the cooling problem that the cherokee has when traveling at low speed/rock crawling. And cooler underhood temps will help with the longevity of many of the parts underhood.
IAT Sensor Relocation
MAT and IAT are really the same sensor just moved/located in different positions.
When I relocated the MAT (temp sensor in intake Manifold- stock location) into the IAT position(temp sensor in the Intake tube before TB, I have Volant CAI or air filter box area), I had to splice and lengthen the wires, I saw IAT readings 3-5* above ambient temp.
Now is that a good thing to do? Some say yes, it sends the ECU a 'colder' MAT/IAT temp reading. ?Will that richen the mixture? Will that leave it in 'cold start' mode? Will it advance the timing? Will the ECU be confused when the Coolant temp is 210* and the IAT is 90*? I don't know how the ECU is programmed. I do know that on some cars this trick works and there is a slight HP increase. I have not seen any data/testing that this is the case with the jeep.
I do NOT recommend this IAT sensor relocation. It is giving the ECU wrong temp readings and risk detonation.
with 0.5" hood lift cruise 55 freeway- ambient=70.7* underhood=109.2*, MAT=109*
with 1.0" hood lift cruise 55 freeway- ambient=62.6* underhood=86*, MAT=?, fuel rail=99.5*
Having a 'cooler' underhood temp probably won't help make any more HP but it would help with the cooling problem that the cherokee has when traveling at low speed/rock crawling. And cooler underhood temps will help with the longevity of many of the parts underhood.
IAT Sensor Relocation
MAT and IAT are really the same sensor just moved/located in different positions.
When I relocated the MAT (temp sensor in intake Manifold- stock location) into the IAT position(temp sensor in the Intake tube before TB, I have Volant CAI or air filter box area), I had to splice and lengthen the wires, I saw IAT readings 3-5* above ambient temp.
Now is that a good thing to do? Some say yes, it sends the ECU a 'colder' MAT/IAT temp reading. ?Will that richen the mixture? Will that leave it in 'cold start' mode? Will it advance the timing? Will the ECU be confused when the Coolant temp is 210* and the IAT is 90*? I don't know how the ECU is programmed. I do know that on some cars this trick works and there is a slight HP increase. I have not seen any data/testing that this is the case with the jeep.
I do NOT recommend this IAT sensor relocation. It is giving the ECU wrong temp readings and risk detonation.
