IAT's at idle help
Thread Starter
Super Member
Joined: Nov 2001
Posts: 801
Likes: 2
From: South Florida
SL65
IAT's at idle help
Once my car is warmed up. If I just sit at idle. No A/C. The IAT's settle around 136 degrees. In S Florida 85 degree heat.
I have to drive the car to get IAT's to manageable levels.
My pump is a brand new OEM one. The IAT's are fine when the car is moving.
This is killing me at the track.
If the car has been off for 20 min or so when I start it the IAT's are obviously very high. They don't drop lower than 140 or so unless I drive the car.
My best times at the track have been right as I arrive. If I let the car sit I will loose 2-3 mph.
I have to drive the car to get IAT's to manageable levels.
My pump is a brand new OEM one. The IAT's are fine when the car is moving.
This is killing me at the track.
If the car has been off for 20 min or so when I start it the IAT's are obviously very high. They don't drop lower than 140 or so unless I drive the car.
My best times at the track have been right as I arrive. If I let the car sit I will loose 2-3 mph.
MBWorld Fanatic!
Joined: Aug 2005
Posts: 3,466
Likes: 10
From: Southern Cali (Ontario)
bleed your IC system..
there is a write up.. how to do it.. its very easy.
all cars IAT's goes up when idling.. there is simply not enough air to cool it down.
bubbles in the system would cause the IAT to jump higher.
there is a write up.. how to do it.. its very easy.
all cars IAT's goes up when idling.. there is simply not enough air to cool it down.
bubbles in the system would cause the IAT to jump higher.
Thread Starter
Super Member
Joined: Nov 2001
Posts: 801
Likes: 2
From: South Florida
SL65
What do your IAT's peak at while idling for a long time?
The only time it hurts me is at the track. In the real world I don't sit at idle long enough for the IAT's to get out of control.
My system is fully bled. I have done it more than few times now. Cheers
The only time it hurts me is at the track. In the real world I don't sit at idle long enough for the IAT's to get out of control.
My system is fully bled. I have done it more than few times now. Cheers
Last edited by FLSL55; Oct 28, 2009 at 11:04 PM.
MBWorld Fanatic!
Joined: Oct 2006
Posts: 4,856
Likes: 4
02 C32 AMG
i get this too in my car.
when the car is sitting in the staging lanes, no cool air (or in our case, hot air) passed across the heat exchanger. an increase in air volume across the heat exchanger is the reason why, as you pointed out, the IATs drop when you are driving back to the staging lanes (i, again, get my best results as well when slowly driving back to cool it down).
IATs go up when the car is off b/c the intercooler system isn't actively cooling and all the heat of the engine is being released without being countered by the intercooler system.
fan comes on at certain engine coolant temps along with the i/c pump. YES, you CAN run the i/c pump all the time and the fan on all the time. Hooleyboy ran the pump all the time....but as he was sitting in the staging lanes, his battery died from running it with his car off to keep the temps down. also, this will dramatically decrease the lifespan of the stock Bosch (and piece of crap) i/c pump and fan life as well.
best bet is to upgrade the heat exchanger if you havent and split the coolant system into two separate circuits.
when the car is sitting in the staging lanes, no cool air (or in our case, hot air) passed across the heat exchanger. an increase in air volume across the heat exchanger is the reason why, as you pointed out, the IATs drop when you are driving back to the staging lanes (i, again, get my best results as well when slowly driving back to cool it down).
IATs go up when the car is off b/c the intercooler system isn't actively cooling and all the heat of the engine is being released without being countered by the intercooler system.
fan comes on at certain engine coolant temps along with the i/c pump. YES, you CAN run the i/c pump all the time and the fan on all the time. Hooleyboy ran the pump all the time....but as he was sitting in the staging lanes, his battery died from running it with his car off to keep the temps down. also, this will dramatically decrease the lifespan of the stock Bosch (and piece of crap) i/c pump and fan life as well.
best bet is to upgrade the heat exchanger if you havent and split the coolant system into two separate circuits.
MBWorld Fanatic!
Joined: Aug 2005
Posts: 3,466
Likes: 10
From: Southern Cali (Ontario)
Before on a 85F degree day..it would hit 130+ after about 8 mins. This was before a proper split of the coolant lines and system not fully bled correctly. Just bigger HE and CM30 pump
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Joined: Jun 2008
Posts: 3,834
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From: Texas
2003 CL55
I was able to see a lot of IATS on cars with different mods this last weekend. So far, none of the 8-10 cars we checked IATS on could keep up with Shardul`s and my system..
Even cars with 172 pulley`s, heat exchangers were still higher. Even though we run 175 and 180mm..
Whithout going into all the different mods / cooling and other factors; to have a good system , it takes a few big things and all the samll things..
1) Aux H/E ,high flow pump (we use Mezarie pumps)
2) Pump runs when key is on ( a must for colder weather low IAT goals or track). Do not need to run all the time but just cycle on and off every 10 minutes or so.
3) Split system on E-class (mine is not split but different)
4) 160 T stat
The above simple cooling mods neted about 20 deg. lower IAT`s on average over cars with just larger H/E or added H/E.. The big catch, is that it can be 30-40 deg. cooler on the start of a run from idle!!!! That is huge for 60 ft Tq/power..
Even cars with 172 pulley`s, heat exchangers were still higher. Even though we run 175 and 180mm..
Whithout going into all the different mods / cooling and other factors; to have a good system , it takes a few big things and all the samll things..
1) Aux H/E ,high flow pump (we use Mezarie pumps)
2) Pump runs when key is on ( a must for colder weather low IAT goals or track). Do not need to run all the time but just cycle on and off every 10 minutes or so.
3) Split system on E-class (mine is not split but different)
4) 160 T stat
The above simple cooling mods neted about 20 deg. lower IAT`s on average over cars with just larger H/E or added H/E.. The big catch, is that it can be 30-40 deg. cooler on the start of a run from idle!!!! That is huge for 60 ft Tq/power..
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E63 Biturbo, UPD Cold Air induction kit, UPD performance crank pulley and UPD adjustable rear suspension with ride height adjustment.
CL55 UPD Cold Air Boost kit, UPD 3000 stall converter, UPD 77mm SC clutched pulley and beltwrap kit, Custom long tubes, UPD crank pulley , UPD suspension kit, UPD SC pulley, Aux. HE, Trunk tank w/rule 2000 pump, Mezeire pump, UPD 5pc idler set, Aluminum rotor hats.
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E63 Biturbo, UPD Cold Air induction kit, UPD performance crank pulley and UPD adjustable rear suspension with ride height adjustment.
CL55 UPD Cold Air Boost kit, UPD 3000 stall converter, UPD 77mm SC clutched pulley and beltwrap kit, Custom long tubes, UPD crank pulley , UPD suspension kit, UPD SC pulley, Aux. HE, Trunk tank w/rule 2000 pump, Mezeire pump, UPD 5pc idler set, Aluminum rotor hats.
www.ultimatepd.com
instagram @ultimate_pd
facebook.com/ultimatepd
