# Lower IAT temps



## KyleGT05usmc (Feb 28, 2009)

Can someone who's done it give me a play by play of what ill need and how-to install a switch to manually turn the fans on please?

thanks
05 m6


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## Rukee (Feb 8, 2007)

Turning on the fans sooner will not lower the AIT. A CAI will, and a retune to lower the temp the fans turn on along with a 160 thermostat will yield a couple HP, but not much.


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## KyleGT05usmc (Feb 28, 2009)

more so talking about for instance sitting in the lanes @ the strip, to manually turn the fans on while i push that fat ass down staging lanes so i dont have all that unwanted heat just sitting around.


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## svede1212 (Nov 1, 2005)

turning the fans on is of dubious benefit for IATs. "C"AIs are of dubious benefit for a couple of reasons also. first you have to look at where the air is coming from that feeds the the intake. take a good look. the stock box isolates the inlet from the engine bay fairly well. the air mostly comes from the little vent in the decorative radiator cover, the small gaps around the headlight and from a couple of holes in the part of the fender below the box. 

it's not perfect but then look at where the supposed "C"AIs get theirs from... pretty much the same places and sometimes worse from all of the gaps. i've seen people go to extremes to insulate the "C"AI box such as on the Volant. well enough but that box empties out in a nano-second so where does that replacement air come from? the insulation does squat. the only answer to cooler intake air is to go outside the engine bay. 

to my knowledge, and i've tested quite a few, the only ones that get the best temps are the so called "Hardcore" which goes down thru the fender and draws air from under the car. the other is the Over The Radiator Cold Air Intake (OTRCAI) which draws from in front of the radiator. 

both of those suffer a little as the Hardcore draws in that hot air that rolls out from out from under the car when stopped. the OTRCAI can draw air that goes forward thru the radiator when the fans are off when stopped so none are perfect.

actual "heat soak" is the heat that "soaks" into an object and then when subjected to cooling takes a while to cool off based on mass and material. the "heat soak" that we talk about is the heat that soaks into the IAT sensor and the relatively long time it takes to cool off based on the temperature of the air coming in and the location and mass of the sensor.

on the LS2 the IAT is located in a large metal MAF sensor. that's a material that soaks up the heat in the engine bay and its large mass means it doesn't read the actual air temp quickly. the LS1 sensor is a smaller mass but it still takes too long to cool down and it's located right next to the radiator where it keeps soaking up heat.

the answer for those forms of heat soak outside of pulling in cooler air are to relocate the sensor out of the MAF sensor or away from the radiator. the other part is to use a smaller mass sensor which then cools off faster and thus reacts quicker. there's the HSRK (heat soak reduction kit) which gives you a smaller sensor mass with a $15 sensor and a wiring harness that lets you hook it up without splicing wires. at $100 IMHO it's a pretty steep price for that but it works. the other cheaper option is to get the Omega (omega.com) 44005 probe and splice it into your wiring. for the LS1 it's the only option. locating a quicker sensor to a better location away from external heat and with a source for cool air is the answer to heat soak.


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## Rukee (Feb 8, 2007)

KyleGT05usmc said:


> more so talking about for instance sitting in the lanes @ the strip, to manually turn the fans on while i push that fat ass down staging lanes so i dont have all that unwanted heat just sitting around.


Open your hood while your pushing it. :cheers


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## KyleGT05usmc (Feb 28, 2009)

hmmm. pretty good tips guys. 
like i said in other posts havent gotten to do much studying of this car yet, just dont want the performance to suck because im sitting in a staging lane and my engine feels like its drowning. i want to try and accomplish that 'cranked up and just starting to register on temp gauge' performance, i live in a pretty warm climate. in the days easily 90+ in afternoons, couldnt imagine the actual temp of air going into the engine. 

but ive seen the switch im talking about for sale for my old maro on slp, never really looked into it, however, i want to see how it works for the gto. just a plain jane manual 'on' switch for the fans


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## svede1212 (Nov 1, 2005)

KyleGT05usmc said:


> hmmm. pretty good tips guys.
> like i said in other posts havent gotten to do much studying of this car yet, just dont want the performance to suck because im sitting in a staging lane and my engine feels like its drowning. i want to try and accomplish that 'cranked up and just starting to register on temp gauge' performance, i live in a pretty warm climate. in the days easily 90+ in afternoons, couldnt imagine the actual temp of air going into the engine.
> 
> but ive seen the switch im talking about for sale for my old maro on slp, never really looked into it, however, i want to see how it works for the gto. just a plain jane manual 'on' switch for the fans


depending on type of intake turning on the fans might make things worse. you're taking heat out of the engine and blowing it into the engine bay heating up the sensor and intake. not really a net loss of heat. get your IAT sensor replaced and figure a way of getting air from outside the bay. i've logged having fairly cool intake temps and within 3 seconds of launch within 5* of ambient.


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## KyleGT05usmc (Feb 28, 2009)

guess ill stick to popping the hood then...


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## GM4life (Mar 18, 2007)

Rukee said:


> Open your hood while your pushing it. :cheers


:agree

If dragracing your thing, go with a 160deg thermostat and coated headers. I have Ti ceramic coated headers on my car and it cools down alot quicker than with the stock iron headers. The thermostat will keep the car cooler while running keeping engine/bay temp down. The fans can only be adjusted by a good dyno tune. I haven't looked at the fan wiring for the 05 GTO's yet but if they're like the old GM's you'll just need to wire up a ground switch to turn on the fans. IAT's measure temp accuratly while air is moving across it, there is very little you can do to lower it just sitting in the staging lane. The best you can do is to get cool air across it as quick as you can when moving.


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## bluhaven (Jan 24, 2005)

I run a switch to the fan relay #1. Standing on the passenger side pull fan relay #1, where the relay would plug in attach a jumper wire with spade ends and plug in at the 12:00 position and 3:00 position, now you've got low speed fans. What I did was use a pair of wire cutters and sliced the spade ends up the middle and attached them to the appropriate prongs on the relay and put a toggle switch in between. I've used this for 3 years with no problems, it also won't set a check engine light if you start the car with fans on. Just remember you can run the battery down doing this. Hope that helps. This is on our 05, don't know if it works on the 04 or 06.

Kevin


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## KyleGT05usmc (Feb 28, 2009)

thats what i was looking for. i'll give that a try then, see how it works out. 

now the way you setup seems to still let the fans operate normally just you can opt to turn them on when you want correct?


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## bluhaven (Jan 24, 2005)

KyleGT05usmc said:


> thats what i was looking for. i'll give that a try then, see how it works out.
> 
> now the way you setup seems to still let the fans operate normally just you can opt to turn them on when you want correct?


Yep, we drag race a lot so we use this to help cool off in the pits. I mounted a switch in the engine compartment I've seen others put them on the inside of the car. You don't need the key on either. Hope that helps you out.

Kevin


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## GM4life (Mar 18, 2007)

bluhaven said:


> I run a switch to the fan relay #1. Standing on the passenger side pull fan relay #1, where the relay would plug in attach a jumper wire with spade ends and plug in at the 12:00 position and 3:00 position, now you've got low speed fans. What I did was use a pair of wire cutters and sliced the spade ends up the middle and attached them to the appropriate prongs on the relay and put a toggle switch in between. I've used this for 3 years with no problems, it also won't set a check engine light if you start the car with fans on. Just remember you can run the battery down doing this. Hope that helps. This is on our 05, don't know if it works on the 04 or 06.
> 
> Kevin





bluhaven said:


> Yep, we drag race a lot so we use this to help cool off in the pits. I mounted a switch in the engine compartment I've seen others put them on the inside of the car. You don't need the key on either. Hope that helps you out.
> 
> Kevin


Good call Kevin.


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## xtranaut (Jul 23, 2009)

*New dyno..really bad gas mileage ???*

Noting the dates on these posts I hope that some of you are still around and can help me out with this. I just got my 04 A4 GTO dyno tuned. I thought I was getting crap gas mileage 15-16 city before i took it in but now I get 12 and 13! Holy s***! Everytime i spend some money to make the car perform better, it takes two steps back.

I put a K&N CAI and Air Raid TB spacer on the car about a month ago and it seemed to run a little smoother..not really that much faster and I saw no improvement in gas mileage. I couldn't even begin to tell you if it ran cooler because the gauges are worthless in this car. They could have done hi-po enthusiasts a favor and dumped the cute digital overspeed crap for a VDO, Oil pressure gauge and an actual temp gauge. Anybody know what each mark is supposed to represent?

So after dyno they tell me it was running way to lean at 10 and it dynoed at 12.5 which should give me a few more MPG and some kick, if I don't start feeling too good about the extra umph and keep my foot out of it.

One thing the dyno did that wasn't happening before is rset the fan. Once the thermostat opens up, the fan comes o and stays on. That annoys the crap out of me and i see no difference on the gauge from stand still to when the car is in motion so what am I actually doing..blowing hot air around under the hood? I called the shop and they said, "well if you had a good set of pipes, you wouldn't have to hear it" LOL But acted like it was all for the better.

If I pop a 160 thermo in, will it reset that fan? I have never had a problem with overheating. Not even in summer and I live in Houston. I don't even remember the fan coming on to tell ya the truth. Now it sounds like a Piper Commanche!

Anybody with experiences like getting really bad gas mileage after a tune UP?? Don't seem right.


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## svede1212 (Nov 1, 2005)

xtranaut said:


> Noting the dates on these posts I hope that some of you are still around and can help me out with this. I just got my 04 A4 GTO dyno tuned. I thought I was getting crap gas mileage 15-16 city before i took it in but now I get 12 and 13! Holy s***! Everytime i spend some money to make the car perform better, it takes two steps back.
> 
> I put a K&N CAI and Air Raid TB spacer on the car about a month ago and it seemed to run a little smoother..not really that much faster and I saw no improvement in gas mileage. I couldn't even begin to tell you if it ran cooler because the gauges are worthless in this car. They could have done hi-po enthusiasts a favor and dumped the cute digital overspeed crap for a VDO, Oil pressure gauge and an actual temp gauge. Anybody know what each mark is supposed to represent?
> 
> ...


your covering a lot of ground there. first the temp gauge is engine coolant temp and the temp needs to change 15-20* to even see it. it's more an indication than a real reading. you can see what it's doing by doing the start up method of pushing the mode and set button at the same time while starting the car. that will get you into a menu of which actual engine coolant temp is one.

engine coolant temps (ECT) and intake air temps (IAT) are two different things and lowering your ECT doesn't make much difference in your IAT. for that you need a real intake like a Hardcore style or an Over The Radiator CAI (OTRCAI) to pull air from outside the hot engine bay. in fact if you're blowing a lot of hot air thru the radiator it's going to make you IATs worse from a stand still. that's why i have mixed feelings about the fans running. one of the things it's doing is pumping the heat in the engine right back into the engine bay where your "C"AI is sucking it back in. i also haven't seen to my satisfaction that 160* stats do much for performance at all.

as far as tuning i have a really strong opinion on that. unless you are as sure of your tuner as your mother i wouldn't trust them to tune my car. it's even rare for the good ones to do a really thorough job as it's a business and it takes a full day or more to do a 100% tune. the best thing that you can do for yourself is spend the bucks to get a tuning suite and a wide band O2 controller and take the little bit of time to learn to do it yourself. you can then also monitor every parameter on the car and easily adjust things like fans and such yourself. unless it's really ridiculously hot down there right now your fans shouldn't be running all the time. they have them set for an unrealistically low setting that they can not achieve and no, popping the stat in there could very well not do what you want.

as far as mileage they could have smurfed up your tune, you're driving differently because of it (the faster my car gets the faster i want to drive it), winter blend gas which gets poorer mileage or a combination of things. a wideband would tell you if your air fuel ratio is right.


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## jpalamar (Jul 22, 2008)

xtranaut said:


> Noting the dates on these posts I hope that some of you are still around and can help me out with this. I just got my 04 A4 GTO dyno tuned. I thought I was getting crap gas mileage 15-16 city before i took it in but now I get 12 and 13! Holy s***! Everytime i spend some money to make the car perform better, it takes two steps back.
> 
> *That is a problem, with a tune, your car should run more effeciate and probally do slightly better then before*
> 
> ...


See my opinions in bold.


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## LOWET (Oct 21, 2007)

svede1212 said:


> /QUOTE]
> 
> 
> 
> ...


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## LOWET (Oct 21, 2007)

xtranaut said:


> I put a K&N CAI and Air Raid TB spacer on the car about a month ago and it seemed to run a little smoother..not really that much faster and I saw no improvement in gas mileage.



Remove that TB spacer. I don't think anyone on here uses one and I don't know anyone who does have one. They are a waist of money.

As far as gauges. The factory ones are OK but they don't tell you the whole story. Get something like a DASH HAWK. Takes all of 10 seconds to plug it in and turn it on. You can keep a close eye on tons of stuff with this gauge and even clear or search for codes .


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