180 tstat and intake manifold temp - Cherokee SRT8 Forum
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post #1 of 69 (permalink) Old 04-16-2007, 06:32 PM Thread Starter
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180 tstat and intake manifold temp

I just got finished driving my beast for about an hour or so - mostly on the highway. The 180 Motorad/valucraft tstat works great on the freeway - consistant coolant temps never seem to exceed 190, and the oil temp, likewise, stays cooler than it did previously.

After parking the Jeep I popped the hood to check the reserve coolant levels to see if it needed any extra antifreeze since installing the stat. Out of curiosity, I also touched the intake manifold to see how hot it was. At first I just quickly brushed my hand over it since I thought it was gonna be pretty damn hot. To my surprise, it wasn't even hot at all. I was able to keep my hand on it as long as I wanted to without any discomfort at all. WTF, I'd say it was maybe about 70 degrees or so, which was amazing since I've read that it is supposed to get extrememly hot.

Anyways, it looks like I wont need to install my phenolic intake spacers from GSM. Has anyone else noticed this after installing their tstat?

Last edited by timster; 04-16-2007 at 06:36 PM.
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post #2 of 69 (permalink) Old 04-17-2007, 10:08 PM Thread Starter
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Re: 180 tstat and intake manifold temp

so it's been 3 times now that I have checked the intake manifold after extensive driving. Seems like it doesn't heat up at all.. WTH?? Not sure if it is the 180 degree tstat causing this, or if it's the cool weather, or a combination of both, but this is weird..

I guess I'll have to wait till it gets hot up here in the NorthEast to see if the intake manifold temp is due to the weather.
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post #3 of 69 (permalink) Old 04-18-2007, 12:56 AM
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Re: 180 tstat and intake manifold temp

I keep forgetting to check the temp after driving, but I just got my spacers in the mail today.


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post #4 of 69 (permalink) Old 04-18-2007, 01:23 AM
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Re: 180 tstat and intake manifold temp

For those fan and stat mod followers. I had a thought on the way to work this morning. Obviously the Jeep engineers selected the components to (thermostats and relays) to achieve the best possible HP given specific conditions. As in refrigeration, we size our systems based on the worst case senarios. I have heard a few of you mention that you feel a little better response when the weather is cooler. I may not know much, but lowering your engine temp via jumpering the thermostats or putting a 180 degree stat doesn't seem to correlate with more HP. I am confused. HP comes from a dense fuel to air ratio along with compression, timing and a whole lot of other things. However, if you take an SRT8, designed to preform on the worst case senario, how does lowering the engine temp do anything for HP? When in fact it's the cooler more dense air combined with fuel which makes more HP? Not sure I follow the logic on these mods.

I have a 1996 Jeep Cherokee with a stage II Jet chip and it recommends a 180 degree thermostat because it changes timing, fuel to air ratios and a number of other things to make the engine run hotter. That's the only reason why a person would want to change the stat. I also put in a larger radiator because even with the cooler stat, the stock radiator could not disipate the additional heat generated by the upgrade. I really don't see this need in the SRT8's. Just my two cents. I could see making the change if you made drastic tuning changes like adding a turbo or super which by nature would make the engine work harder.

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post #5 of 69 (permalink) Old 04-18-2007, 05:50 AM
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Re: 180 tstat and intake manifold temp

While driving the intake manifold should be warm or cool to the touch as all the air that is going thru the manifold is picking up the heat that the manifold has picked up.

When standing still for about 5 minutes is when you realize how bad the heat soak is on these, the manifold gets heat soaked and you can fry an egg on it. That 2-5 minutes when your waiting to stage at the track is when this is killing us, this is where the GSM or whatever spacers you want to use are going to help BIG TIME!

Dont be fooled the Tstat helps the engine run cooler and stronger while moving but once you stop that heat soak is killer. My spacers go on this week.

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post #6 of 69 (permalink) Old 04-18-2007, 09:05 AM
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Re: 180 tstat and intake manifold temp

Cooler thermostat = cooler motor = cooler intake = cooler intake charge = more hp

Quote:
Originally Posted by Derwood98sNewSRT8
I have a 1996 Jeep Cherokee with a stage II Jet chip and it recommends a 180 degree thermostat because it changes timing, fuel to air ratios and a number of other things to make the engine run hotter.
Why would you want to make your motor run hotter?

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post #7 of 69 (permalink) Old 04-18-2007, 09:25 AM
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Re: 180 tstat and intake manifold temp

...according to some previous posts....the SRTs pull out timing in correlation
to vehicle temps to avoid detonation.

When it is 85*-95* outside this summer, I am sure I will be glad I have the 170 stat in.

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post #8 of 69 (permalink) Old 04-18-2007, 10:11 AM
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Re: 180 tstat and intake manifold temp

Last summer it 100 degrees 3 weeks straight in my hood. My commute to work is very unpredictable due to traffic. Los Angeles sucks for that reason. The tstat and the spacers should definitely help out.
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post #9 of 69 (permalink) Old 04-18-2007, 11:40 AM
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Re: 180 tstat and intake manifold temp

Quote:
Originally Posted by Derwood98sNewSRT8
For those fan and stat mod followers. I had a thought on the way to work this morning. Obviously the Jeep engineers selected the components to (thermostats and relays) to achieve the best possible HP given specific conditions. As in refrigeration, we size our systems based on the worst case senarios. I have heard a few of you mention that you feel a little better response when the weather is cooler. I may not know much, but lowering your engine temp via jumpering the thermostats or putting a 180 degree stat doesn't seem to correlate with more HP. I am confused. HP comes from a dense fuel to air ratio along with compression, timing and a whole lot of other things. However, if you take an SRT8, designed to preform on the worst case senario, how does lowering the engine temp do anything for HP? When in fact it's the cooler more dense air combined with fuel which makes more HP? Not sure I follow the logic on these mods.

I have a 1996 Jeep Cherokee with a stage II Jet chip and it recommends a 180 degree thermostat because it changes timing, fuel to air ratios and a number of other things to make the engine run hotter. That's the only reason why a person would want to change the stat. I also put in a larger radiator because even with the cooler stat, the stock radiator could not disipate the additional heat generated by the upgrade. I really don't see this need in the SRT8's. Just my two cents. I could see making the change if you made drastic tuning changes like adding a turbo or super which by nature would make the engine work harder.

When the PCM senses increased coolant/IAT temps, it pulls timing to avoid detonation.
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post #10 of 69 (permalink) Old 04-18-2007, 12:57 PM
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Re: 180 tstat and intake manifold temp

Gentlemen......we did these tests last year!!! The cooler T-Stat is a PROVEN dyno tested mod performed and posted on the OC site and members on the LX site. Your overthinking this......it works.

Also, just for information....... since then, the dyno tests I did last summer, the average baseline horsepower on a Dyno Jet dyno both at GSM and Harmanmotive, for my truck were 333hp-340 depending on the configuration such as no filter, 180 degree temps, ice the manifold, first run vs 3rd run for heat soak, etc,etc. By the second or third run hp/tq starts to diminish. I had higher numbers at the XS Engineering 4 wheel DTS9000 dyno (during stock exhaust vs Mopar) but wanted to keep it apples to apples for this test so I went back to Harmans DynoJet.

Yesterday late afternoon I returned to Harmanmotives shop and wanted to test it since I had never run it with the headers/catback/ ported manifold/phenolic spacers and stock modifed cold air box as a combination......three back to back runs at 193 degrees....376hp/375tq each and every run!! Previous run at factory temps around 211-215 with stock airbox/stock exhaust was 332hp/339tq. That is a huge improvement for this combo over stock and no tune yet.

I will post those sheets tonight, all previous dyno runs are shown on the OC site under sgtstanko dyno runs. I'll run it at Irwindale Thursday to see if any improvements in times are seen.

Where is my B&G box?????

Last edited by generalconfusion; 04-18-2007 at 01:06 PM.
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