stevebez

There is one real answer here in my opinion ... and thats bigger I/C's with a suitably large H/E to serve it. The rest is a major PITA in terms of setting up and maintaining... but I applaud your efforts!!!!

SleeperX

Thanks. I thought I was on to something and the thought does still cross my mind that I can get this thing to work. Larger waterchiller which will be chilled with CO2 and a cryogenic bulbs which will chill the air in the intake. The only problem with this setup is refilling the bottle. I dont know how guys run NOS if they have to constantly refill the bottle after using it 10-15x.

NSM

I take three 10 lb bottles of nitrous to the track when I race.

This isn't on my SL65, but a '69 Mach 1...

anerbe

agreed

larger (more efficient) heat exchangers, higher pump flowrates and positioning of the heat exchangers will make the best effect on the system. once you add these auxillary systems that require additional maintenance, you take away its driveability and reliability. i wouldn't want to be driving everyday wondering if i'm getting leakage of CO2 into my intake.

ultimately, you'll also need to check how much heat these installed components reject (in terms of kW or BTU/min) for your particular configuration. Manufacture claimed temperature changes are totally dependant on both the inlet temperatures and mass flows of both mediums involved. Of course something could lower intake temps 10 degrees, but you could be slowing down the flowrate enough to reach those temps...

Although I appreciate your trial and error experimenting on these new parts, you may be able to save your time (and money) if you figure out how well the components actually reject heat and the resulting pressure drops they induce.

Larger Front Mounted Coolers typically are a given, since increasing the amount of passes can possibly decrease pressure drop (resulting in more flow from the pump) while increasing the effective heat transfer area. The air inlet mass flow (cooling medium) is high also, since it's in front of the CRFM getting the most of ram air. Look at the ports in those components you plan to install. How much flowrate are you getting? Although the inlet temps might be low, I doubt you're getting enough mass flow to make it effective.......

anerbe

looking at those cryofusion sites, you should ask what the heat rejection is thru those chillers at a given inlet temperature and flowrate. if they did the real testing, they should have some numbers.

regarding the whole "frost on the intake", curious at what conditions will you see this.....

anerbe

although your generalized idea makes sense, heating does not erase gains.

for a given heat exchanger, if the I.T.D (Inlet temperature differential) is greater, you get more heat rejection. Putting the cooler in an area of flow which temperatures are closer to ambient, you get less heat rejection (lower decrease in inlet temperature), opposed to putting the cooler post heat source where inlet temperatures are much greater.

so in effect, if you put it "pre-charger", the heat source does not erase the gains. the gains "pre-charger" are simply less than post-charger

for a given "cooler", you want to put it where the temps it's trying to cool are the greatest.

blackbenzz

I have done the larger heat exchanger and it feels like it helps when the car is moving but after you sit in traffic the inevitable heat soak arises. I am ordering a nitrous spray bar for the heat exchanger soon for these occasions (and for the track in between runs). I will let you guys know how it effects engine temps (I dont have anything that reads IATs)

pshek

Have you tried hooking up the water pump to a switched relay so that it turns on when you have the key in the ignition, but the engine not running? Might be better than a N02 spray bar. That will keep the coolant flowing to draw heat from the engine. Then you could install a couple of fans behind the heat exchanger to dissipate heat from the heat exchanger. Otherwise, you'll have coolant running but no air to transfer the heat through the heat exchanger (since your car is not moving). If you're only doing this at the track or at home, then I guess you could place a fan in front of the car. BTW, I haven't gotten around to doing this mod yet. These are just ideas from others who have done these mods.

I want to upgrade my water cooling system this way; I already have a CM90, just need to find an appropriate HE from afco.

blackbenzz

Yes, my Johnson pump turns on with the ignition (no need to turn on the car). Fitting fans back there is imposiible for my setup, there is no clearance. Like you said, having a bigger heat exchanger doesnt help if you're not cooling the fluid going through it (you'll just be cycling hot fluid). Which is why I have decided to do a nitrous spray bar.

I can help you out with the HE. I bought a AFCO pro series dual pass HE (made for modded cobras) and just had the inlet/outlet relocated to the side by cutting them off and rewelding them. The HE is MASSIVE so make sure you have clearance on your car before upgrading. Hope that helps.

pshek

Which Johnson pump are you using? I bought the CM90, but the thing is huge, which makes me a little worried. 1 1/2" fittings versus 3/4" fittings. I was looking at afco parts for the cobra, they seem to match up well to the benz.

chiromikey

the cm30 works great, is rated for the same life span, and has no problem fitting (even though it's more efficient than the oem bosch unit, it's actually smaller). imho, cm90 is not a viable replacement unless you're willing to cut the radiator bracket and even then it may not allow the coolant to stay in the heat exchanger long enough because of it's high flow rate. if that's not enough, it states in the manual to NOT reduce the diameter of the inlet line (1.5" compared to oem 5/8") as it may cause cavitation which will not only take away it's ability to pump water but may also ruin the pump itself.

blackbenzz

I dont remember the model number but it flows 90L/min. CM90 sounds right. The thing flows ALOT! I didnt have to worry about fittings, hoses, etc because my car came N/A stock so all the plumbing was there with the Kleemann kit and I just changed it a little to fit the HE. I think the nitrous will take care of the weak link

SleeperX

A nitrous spray bar will help if the nitrous is sucked in throught the air intake. If you are spraying the heat exchanger you probably wont see a drop in IAT. Now if you can spray the intercooler under the supercharger, that will definitely help.

Sean03S55

I had the NX cooler system spraying the front mount on my old Volvo C70, it worked pretty well to restore power that heat normally kills, it doesn't really add much power though.

blackbenzz

Thats all I want. Not looking to add power. Although I do need to find a way to force more air into the engine, a hint of nitrous wont hurt either

anerbe

your larger heat exchanger most likely lowered airflow through your cooling module by being a bigger restriction. The fan system was most likely not sized to accomidate for the higher restriction. Going down the road, you won't see a problem, but on idle with only the fan to cool, this is totally possible.

a possible improvement is to spray the heat exchanger with some form of water/cooling medium to increase the specific heat capacity. Water vapor transfers heat much better than dry air alone.

Lets check math -

Q = m*Cp*(T2 - T1)
where
Q = Heat Transfer (kW)
m = mass flow of cooling air medium (assume .5 kg/s)
Cp = specific heat of cooling air medium (1.01 kj/kg_C)
T2 = Temperature of Cooling air medium (assume 25C for ambient air)
T1 = Temperature of Coolant (assume 100C for coolant)

So for normal cooling conditions, you get the following:
Q = .5 * 1.01 * (25 - 100) = -37.9 kW heat rejected to air

Senario 1 - Making the cooling air 10C cooler
Q = .5 * 1.01 * (15 - 100) = -42.93 kW heat rejected to air

Scenario 2 - Making the cooling air into water vapor (via some form of water spray)
The Cp of water vapor is 1.86. Of course this is with 100% saturation of water in the air. Air droplets would increase this number, while an incomplete saturation would decrease.
Q = .5 * 1.86 * (25 - 100) = -69.75 kW heat rejected to water vapor

Increasing the Cp to 1.15 would make it comparable to lowering ambient temps 15C. I don't know the exact Cp value of adding a sprayer, and I didn't account for density changes by adding water to the air, but you get the effect.

Sorry for rambling
This is why some makers utilize water sprayers for heat exchangers... however it's added complexity adding a completely different system.

Jrocket

You lost me here.Are you meaning HE surface area?If thats the case,Im not sure how a larger surface area is going to slow down air flow?

blackbenzz

+1. Its a water to air setup. Increasing the HE has NOTHING to do with aiflow. You must be thinking of a air to air setup where you get a boost drop from a large intercooler but then I dont see how fans come into play

Jrocket

What I think he's talking about is not internal air for the motor but external cooling air,air thats traveling over the face of the HE? Or maybe not.

blackbenzz

I guess that makes sense, i'm a little slow. The math stuff is really cool though .

silence

what are dimensions of your stock heat exchanger guys?

I'm intending to try to fit upgraded '04 cobra he- but haven't really looked at how much cutting i want to do yet either

-drew

blackbenzz

The HE I am using now is an upgrade for the 04 cobra's. My stock one was tiny