SL55/63/65/R230 AMG: SL65 intercooler system
09-11-2009, 12:38 PM
#1
MBWorld Fanatic!
Thread Starter
SL65 intercooler system
Alright guys, how does the intercooler system on the SL65 actually work?
If you've read my other thread I've complained about high IATs. I've had the system bled twice, I just had a new CM30 pump installed and rebled a 3rd time. I also had the pump wired to run continuously with the engine and not by the ECU, at least I think. No change at all. I was hoping by getting the pump running all the time that I could keep my IATs lower while in the staging lanes etc for a race vs it running up into the 170s and starting a race crippled and finishing it crippled while it tries to fight off the heat that built up while sitting. No luck, no change over stock. The IAT will only begin to drop under sufficient load, moving or not. I datalogged another SL65 at the dragstrip last weekend and it behaves exactly the same.
I know vadim mentioned that IATs will be high while sitting or low throttle because the throttle plate is closed so there's no airflow. However if I open the throttle in neutral the IATs do not drop at all. If I put it in gear and keep the car stationary while applying throttle it will drop. I can drive around with my datalogger and have it to where with the very slighest additional application of throttle I can have the IATs go up and down by significant amounts. No increase in speed and a barely noticable increase in RPM. This indicates that the the ECU is controlling...something. If my pump is running all the time then there must be something else it's doing to keep the coolant from going through the intercoolers. What is it? The longer I can keep everything flowing the lower my IATs will get over time. If I let the car do it's own thing the IATs will run in the 160s and when I want it to go try to drop into the 130s. As soon as I let off the gas enough it skyrockets back up. Now that I know how to modulate the throttle using the datalogger to keep everything running I can cruise around and the IATs will creep down into the 120s eventually on the highway and have it drop even more when I get on it. That's great when you have lots of open road, can't be done at the dragstrip or a dyno. Otherwise something is preventing the IC system from working and it gets superheated and only tries to fight it off when you want it to go, too little too late though. Frankly I'd rather have it flowing and cool all the time.
So what is it and how do I get rid of it?
If you've read my other thread I've complained about high IATs. I've had the system bled twice, I just had a new CM30 pump installed and rebled a 3rd time. I also had the pump wired to run continuously with the engine and not by the ECU, at least I think. No change at all. I was hoping by getting the pump running all the time that I could keep my IATs lower while in the staging lanes etc for a race vs it running up into the 170s and starting a race crippled and finishing it crippled while it tries to fight off the heat that built up while sitting. No luck, no change over stock. The IAT will only begin to drop under sufficient load, moving or not. I datalogged another SL65 at the dragstrip last weekend and it behaves exactly the same.
I know vadim mentioned that IATs will be high while sitting or low throttle because the throttle plate is closed so there's no airflow. However if I open the throttle in neutral the IATs do not drop at all. If I put it in gear and keep the car stationary while applying throttle it will drop. I can drive around with my datalogger and have it to where with the very slighest additional application of throttle I can have the IATs go up and down by significant amounts. No increase in speed and a barely noticable increase in RPM. This indicates that the the ECU is controlling...something. If my pump is running all the time then there must be something else it's doing to keep the coolant from going through the intercoolers. What is it? The longer I can keep everything flowing the lower my IATs will get over time. If I let the car do it's own thing the IATs will run in the 160s and when I want it to go try to drop into the 130s. As soon as I let off the gas enough it skyrockets back up. Now that I know how to modulate the throttle using the datalogger to keep everything running I can cruise around and the IATs will creep down into the 120s eventually on the highway and have it drop even more when I get on it. That's great when you have lots of open road, can't be done at the dragstrip or a dyno. Otherwise something is preventing the IC system from working and it gets superheated and only tries to fight it off when you want it to go, too little too late though. Frankly I'd rather have it flowing and cool all the time.
So what is it and how do I get rid of it?
Last edited by bfnnrgn; 09-11-2009 at 12:40 PM.
09-11-2009, 03:09 PM
#2
MBWorld Fanatic!
Thread Starter
Ok, here's the data log from yesterday to show what I mean. It's about an hour long. Stuck in some stop and go traffic for a while. I'm playing around with the throttle the whole time.
At 4:49:31 I have the car in N and on the gas to the 3k limiter, no real change in temp. However at 4:59:58 I had the car in 1st and on the gas with the brake on, 0 mph, got it to jump down 10 degrees.
I eventually get away from traffic at 5:13 and started playing with the throttle. Not much success at first, but at around 5:17 I start to get the hang of it and you see some 130s, but it still jumps around a lot. A few minutes later I've found the sweet spot where you can maintain speed with the right amount amount of throttle pressure to keep the temp down consistently, let off just a little and it jumps back up dramatically, which you can see. Now you start to see some 120s until I ran back into traffic and back in the 150-160 range.
It's a .csv file so open with excel
Data log Sept 10
At 4:49:31 I have the car in N and on the gas to the 3k limiter, no real change in temp. However at 4:59:58 I had the car in 1st and on the gas with the brake on, 0 mph, got it to jump down 10 degrees.
I eventually get away from traffic at 5:13 and started playing with the throttle. Not much success at first, but at around 5:17 I start to get the hang of it and you see some 130s, but it still jumps around a lot. A few minutes later I've found the sweet spot where you can maintain speed with the right amount amount of throttle pressure to keep the temp down consistently, let off just a little and it jumps back up dramatically, which you can see. Now you start to see some 120s until I ran back into traffic and back in the 150-160 range.
It's a .csv file so open with excel
Data log Sept 10
09-11-2009, 04:32 PM
#5
MBWorld Fanatic!
Bffnrgn...I had the additional HE from CPT put in my car (same as Marcus Frost). The datalogging prior to install, we saw operating temps of 140-160 degrees with steady temps @ 155 degrees (ambient temp was 85 degrees).
https://mbworld.org/forums/3563556-post34.html
After install, the operating temps dropped to levels between 135-150 degrees at approximately the same ambient temps. A couple of things we are looking into now for track purposes:
1. Unlike you my CM30 pump isn't running all the time and at next shop time we will wire it to run continuously.
2. C2Design is going to work on a CO2 spray (onto the CPT HE) system and see how that works.
3. We are going to work on our on reservoir tank for the rear.
4. Since I have the Revozport SL63 rear diffuser, my wrench had an idea of putting ANOTHER albeit smaller heat exchanger/radiator behind the rear vents of the diffuser to see how that effects operating temps. The issue there is fitment of the radiator...if it is possible and if so...how big of a heat exchanger.
Hopefully the combination of the additional heat exchangers, continuous IC pump, CO2 spray, and reservoir tank will have the cumulative effect we are looking for...nothing ventured nothing gained...
https://mbworld.org/forums/3563556-post34.html
After install, the operating temps dropped to levels between 135-150 degrees at approximately the same ambient temps. A couple of things we are looking into now for track purposes:
1. Unlike you my CM30 pump isn't running all the time and at next shop time we will wire it to run continuously.
2. C2Design is going to work on a CO2 spray (onto the CPT HE) system and see how that works.
3. We are going to work on our on reservoir tank for the rear.
4. Since I have the Revozport SL63 rear diffuser, my wrench had an idea of putting ANOTHER albeit smaller heat exchanger/radiator behind the rear vents of the diffuser to see how that effects operating temps. The issue there is fitment of the radiator...if it is possible and if so...how big of a heat exchanger.
Hopefully the combination of the additional heat exchangers, continuous IC pump, CO2 spray, and reservoir tank will have the cumulative effect we are looking for...nothing ventured nothing gained...
09-11-2009, 05:07 PM
#6
MBWorld Fanatic!
Thread Starter
Bffnrgn...I had the additional HE from CPT put in my car (same as Marcus Frost). The datalogging prior to install, we saw operating temps of 140-160 degrees with steady temps @ 155 degrees (ambient temp was 85 degrees).
https://mbworld.org/forums/3563556-post34.html
After install, the operating temps dropped to levels between 135-150 degrees at approximately the same ambient temps. A couple of things we are looking into now for track purposes:
1. Unlike you my CM30 pump isn't running all the time and at next shop time we will wire it to run continuously.
2. C2Design is going to work on a CO2 spray (onto the CPT HE) system and see how that works.
3. We are going to work on our on reservoir tank for the rear.
4. Since I have the Revozport SL63 rear diffuser, my wrench had an idea of putting ANOTHER albeit smaller heat exchanger/radiator behind the rear vents of the diffuser to see how that effects operating temps. The issue there is fitment of the radiator...if it is possible and if so...how big of a heat exchanger.
Hopefully the combination of the additional heat exchangers, continuous IC pump, CO2 spray, and reservoir tank will have the cumulative effect we are looking for...nothing ventured nothing gained...
https://mbworld.org/forums/3563556-post34.html
After install, the operating temps dropped to levels between 135-150 degrees at approximately the same ambient temps. A couple of things we are looking into now for track purposes:
1. Unlike you my CM30 pump isn't running all the time and at next shop time we will wire it to run continuously.
2. C2Design is going to work on a CO2 spray (onto the CPT HE) system and see how that works.
3. We are going to work on our on reservoir tank for the rear.
4. Since I have the Revozport SL63 rear diffuser, my wrench had an idea of putting ANOTHER albeit smaller heat exchanger/radiator behind the rear vents of the diffuser to see how that effects operating temps. The issue there is fitment of the radiator...if it is possible and if so...how big of a heat exchanger.
Hopefully the combination of the additional heat exchangers, continuous IC pump, CO2 spray, and reservoir tank will have the cumulative effect we are looking for...nothing ventured nothing gained...
09-16-2009, 02:46 AM
#7
Since the IAT temp sensor is on top of intake manifold basically in the center of manifold, cool air heats up inside manifold b4 it gets to sensor, now under load, tb opens and you get a rush of cool air that has no chance to be heated and therefore sensor reads much cooler, make sense? You need to remount sensor in a cooler place or keep on it, tb open to keep IAT lower.
