A/C not getting cold
I've never seen IAT's on a hot engine lower than ambient in my CL. Typically at a slow/low RPM cruise like that I was looking at 40-50* above ambient. The hotter the day the worse it was as the A?C running always raised IAT's even more.
I've never seen IAT's on a hot engine lower than ambient in my CL. Typically at a slow/low RPM cruise like that I was looking at 40-50* above ambient. The hotter the day the worse it was as the A?C running always raised IAT's even more.
Last edited by Dr Matt; Jun 1, 2016 at 02:53 AM.
The Best of Mercedes & AMG
I can't imagine how better air flow, better traction, and colder IAT's hurt my times.
I can't imagine how better air flow, better traction, and colder IAT's hurt my times. 
If conditions were the same or better, then I just wonder about the top end IATs. Depending on what the actual system capacity is I still think there could be quite a large rise during that 10 seconds. I mean during a pass you're basically just heatsinking into the water and there's no active cooling taking place. Do you have IAT log data from the runs?
How was your 330 and 1/8 mile compared to before? If you're seeing improvements there but not overall then I would say you might just need to add some water mass to the system with a small reservoir somewhere. If you're not seeing improvements there either and/or you ARE watching the top end IATs then I don't know what to guess at as the cause. In any case the car is rocket anyway, lol.
I can't imagine how better air flow, better traction, and colder IAT's hurt my times. 
On a different note and a silly question, has the Killer chiller been proven to pick up alot of time on the strip with other platforms? I can see it being a great addition for normal spirited driving, almost like a self replenishing ice tank.
As far as compromised performance, I'd say a difference of 20-30 degrees can add up to quite a bit of loss. I wouldn't be shocked if it cost you 2/10ths and a little MPH. Don't forget better 60 ft times also usually lead to slightly lower MPH. Another thing, who knows if the additional rotational mass of the heavier tire/rim combo along with a little more height had any affect. It may be negligible, but it's a negative not a positive.
I was wondering about the throttle body gasket. Do you think this is done for a reason to prevent turbulence at the TB? It may be a long shot, but how could something so simple be an oversight for a performance platform from a manufacturer that already makes a larger gasket? If not time for a 90MM and a little bit of grinding, hahaha.
Last thing, I agree with almost everything you share and see pretty much eye to eye with your thinking. However, 71 degrees is NOT sweltering heat!!!! LOL I was battling 90 degrees plus this past week. That would be the true test with the Killer Chiller for recovery time and maintaining cabin temps.
On a different note and a silly question, has the Killer chiller been proven to pick up alot of time on the strip with other platforms? I can see it being a great addition for normal spirited driving, almost like a self replenishing ice tank.
I was wondering about the throttle body gasket. Do you think this is done for a reason to prevent turbulence at the TB? It may be a long shot, but how could something so simple be an oversight for a performance platform from a manufacturer that already makes a larger gasket? If not time for a 90MM and a little bit of grinding, hahaha.
DA was not great, but was not bad either. I'm pretty sure my 10.73 was at a DA of 330' or so. Most of this weekend it was between 600-1200. That could make a difference, but better exhaust and intake flow along with colder IAT's should have offset that.
Yes, the added weight of the widened wheels and tires are a detriment to ET & trap speed, especially since it is rotational weight, but again I was hoping that it would allow me to hit it harder on launch and drop my 60' enough to be a wash there. Maybe not.
I took some video of my IATs during a couple runs so once I take the SD card out of the camera and download it I'll post up the video. I saw IAT drop to 50 right after launching once, (75* ambient air) and climbed to 120 or so by the time I lifted. On a hot lap, where I ran a 10.80, it climbed to 140 something. So yes, they do climb quite a bit in 10 seconds. I'm thinking of adding temperature sending units to the hot and cold side lines to see if it is coolant temp climbing, or is there just not enough water flow with the wimpy CM-30 pump.
Next winter, the plan is to put phenolic spacers under the intercooler's, coat them with Llizard Skin, and add temp sending units. I will do some experimenting to see if I can squeeze the Meziere pump in there too. I may yet go ahead and remove the washer fluid tank and build a custom one that still holds some washer fluid and the pumps, but also holds some intercooler fluid. I think I can get about 1 gallon of extra capacity. Just not sure if I want to do that. Keeping IAT's below 100 might require it though.
To clarify, the .25 is a round number for the btu/lb it takes to cool dry air (it's actually more like .24). Divided by 6 to knock the lb/min down to lb/10sec to match up closer with your 1/4 mile run. And multiplied by the 250 degree temp differential (which would become somewhat of a calculus problem to get more accurate due to a diminishing temp differential as the run progresses, but I didn't get into that).
Obviously it's rough math but is a good ballpark and actually matches up really closely with your real-world results. It would be relatively easy to double your system capacity since it's such a small amount of water to start off with. Twice the system water mass = half the temp rise. If you could find somewhere to stick another gallon to gallon and a half of water then you'd only be seeing maybe 30-35 degrees rise.
Last edited by ZephTheChef; Jun 1, 2016 at 12:30 PM.
I know you think it's kind of a pain, but it's hard to argue with 138x the volumetric heat capacity of water (144x the mass heat capacity).
I would also say if you do add a reservoir, it might be good to leave room for ice in there. It really wouldn't take much of it to drop that heat rise to zero (under 5 lbs) and your chiller would mostly keep it from melting in the lanes.
I know you think it's kind of a pain, but it's hard to argue with 138x the volumetric heat capacity of water (144x the mass heat capacity).
Last edited by Dr Matt; Jun 1, 2016 at 02:45 PM.
It just could be a much more energy dense solution space-wise compared to adding more water capacity.
http://www.summitracing.com/parts/atm-2281
and two of these sensor kits (last one on the page)
http://www.aeroforcetech.com/products_sensors_temp.html
And I can see intercooler coolant inlet and outlet temps right on my existing Interceptor gauge in real time. A comparison of coolant vs. charge temps will tell me if I need more coolant reserve, or more coolant flow. If it is flow, I need to find a way to squeeze in my Meziere pump. If the coolant temps are the problem, I need more fluid.
In the videos I'll post later, you can see my IAT's DROP after I lift off the the throttle at the end of the 1/4. It makes me think it is a low coolant flow issue letting the IAT's climb more than a coolant temp issue.
Last edited by Dr Matt; Jun 2, 2016 at 12:39 AM.
The indicated IAT drop after getting off the throttle doesn't surprise me. When the throttle closes you get an immediate expansion of the air in the manifold. Rapid pressure drop/expansion like that results in cooling, much the opposite process of heating during turbo compression (except with near 100% efficiency). It's the same concept as the air conditioning system. When you throttle a fluid that has been compressed and then cooled, it creates a pressure differential and resulting expansion and cooling just past the restriction. Granted, it's not going to be near to the extent of a phase change operation like in your A/C system but there is still a definite cooling effect.
I find myself wondering, in light of my system flow tests I did tonight, if you might be right about flow being the issue though. The CM-30 has more or less been determined to be close to a stock equivalent replacement, correct? If I'm flowing 5 GPM through my system with one pump through the bypass, that should be similar to what you're doing. 12 seconds to flow a gallon. So you may be right, you might not even be flowing your entire sytem capacity through the intercoolers once during a pass. In which case more capacity probably wouldn't help a bit without additional flow. Unfortunately, I fear it might be a combination of both.
It also has me worried now. 7gpm isn't much better. I was initially pretty happy with that result, but the more I think about it, it's not enough. If I have say 1.5-2 gallons in the intercoolers/heat exchanger/lines, and plan to run half ice, half water in the tank then that's another 1.2 gallons. So let's call it 3 gallons system capacity (plus the ice that ends up eventually turning into water). It's going to take 30 seconds to flow the whole system capacity through the intercoolers...so my system capacity is overkill for my flow rate. Or to look at it another way, my flow rate is about 1/3 of what would be optimal. Ideally, I would like to flow the entire capacity during the 1/4 mile.
There are just so many variables when you are at the track. Density altitude, humidity, fuel, and headwind are huge factors that add up quickly. Run again to get a better baseline if you can.
From the pictures I see your airboxes are gone, what set up are you running? I can't tell from the pictures.
Thank you very much for sharing your expierences with us. I am very interested in what you think of the KC on the track, but especially on the street.




