I am not an engineer nor have I had engineering fluid flow / thermal transfer dynamics classes. My Dad did but has long since pitched his engineering books.

What I would like to know is this...

The intercooler core underneath the Radix is of a certain/fixed I assumed a non-upgradeable size. The pump that comes with the kit flows a certain volume. The heat exchanger transfers heat (out) with a specific air flow, ambient temperature, and its inherent coolant resonance time (time coolant is in HE). Heat transfers at a specific rate given a known ambient temp air temp outside and that known air across the HE at a known speed.

My question is two fold..., not getting into sexy iced reservoirs, there is an optimized flow rate to transfer a maximum known inlet air temp to the coolant. Would a flow increase or decrease improve heat transfer on a fixed size intercooler core under the S/C if the heat exchanger and reservoir were larger?

I'm thinking at some point sizing of reservoirs and heat exchangers meets a brick wall... the size of the intercooler core underneath the S/C.

Before I go to Ron Davis and start "reinventing the wheel" on a heat exchanger and reservoir... do you have a feel for what the max size, volume wise, of each would be before you are "spinning your wheels" so to speak? ...

Thanks,

Bill

 

In CHP they talked about lowering the pump voltage to improve the heat transfer rate. The coolant was flowing through too fast to absorb all of the heat that it possibly could. BTW they got the best results with a 1ohm resistor in series with the positive side of the pump and ended up with 12 volts at the pump instead of the 14-14.5 it normally runs.

Dave

 

I would leave the pump alone.....works great in the Lightning and Cobra

As for the H/E, any time you can increase the surface area of the cooling system it will be better. To answer your question will it help, sure....will the gains be noticeable....doubt it.

I would not increase the size of the reservoir past a gallon, there comes a point when it will just be a water heater.

 

I have heard of the resistor to slow down the pump as well. I saw a 20+ degree drop at the end of the quarter mile with my hx upgrade.

 

I am sure you did, however I question over time how it will react once the coolant gets to temp. I am sure the recovery time will be better, but will it actually drop the temp.

 

My peak temp during a long pull was lower. Some due to more volume maybe but much of it due to the larger volume in the Hx and it flowing through more slowly=better heat exchange and cooler coolant. I agree the limitation with mine was still the size of the intercooler in the blower itself. Bottom line, better heat exchange = cooler water which = more temp drop. That is the way I see it anyway. I don't have a mech eng degree and can't do the math on thermal efficiencies but all I know is my IAT's dropped and allowed me to add more timing. Which later =

 

I installed the new HX I got from Brian last night inline with my original Setrab unit. My initial impression (took a long drive when I was done) is that the peak IAT's are probably gonna be close to the same, but like you said, the recovery rate is faster and it recovers further than it did before (did a WOT run and saw IAT's hit high 140's-low 150's). I need to do some in-traffic driving during the middle of the day before I throw out my "official" numbers, but I did see my IAT's drop from 150 after initial start-up down into the low 120's very quickly, where normally it will take a very long trip on the freeway out of boost to even touch upper 120's. SOTP it did feel stronger on the WOT run because it was starting from a lower IAT. I watched the EFILive log run through the Spark IAT tables and it was pulling less timing to start with, even though it did get up to the same high numbers in the end.

I had a question that I thought of last night - since the intercooler pump runs with the fuel pump, does the voltage increase and flow rate increase with the fuel pump as well? Or does the fuel pump circuit just act as a switch to turn on a relay for the intercooler pump?

I figure that the cooler you can get the coolant flowing into the internal heat exchanger the more you increase it's capacity to remove heat from the intake air. At some point though you're right, you can get to where you have enough HX surface to remove ALL of the heat from the coolant before you send it back to the Radix, so you would reach a point where adding more HX surface would be a waste. I have no idea where that point is, probably very large amount. On the other hand, the more you increase the surface area the fewer trips the coolant has to make through the HX to return it to ambient air temp, making recovery rate much faster.

 

Agreed, recovery time is important. And I also agree that driving around in traffic over the next few weeks down here in hell would surely test your setup.

Bill

 

Any idea what you're planning on doing with your H/X?

 

I will probably do a big heat exchanger up front with a fan(s)... and remove all of the stock tranny cooler/line stuff making more room... relocate that either under the front bumper or under the truck altogether. Either place it will be an oversized cooler with a fan. Goal is to get the tranny cooler loop out of the radiator... and that joke of an external cooler up front. Derale has a nice unit... but I may do a custom core on that as well. Tranny cooler mod will take place first... then I can start playing with cardboard and mocking up an heat exhanger up front. Once thats done then I'll have the guys at Ron Davis build it. I'll fit it in and it works good then I'm sure Tim at Ron Davis will assign a part number to it... and I'll try to get Xtreme Motorsports in Tempe to carry a few in stock...


With all the fans I'm planning I may need a bigger current capable alternator

Bill