Radiator temp drop inlet/outlet | FerrariChat

Radiator temp drop inlet/outlet

Discussion in 'Technical Q&A' started by 60cyclehum, Jul 1, 2013.

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  1. 60cyclehum

    60cyclehum Karting

    Nov 26, 2011
    92
    #1 60cyclehum, Jul 1, 2013
    Anyone ever measured the temp drop across a Ferrari radiator from inlet to outlet? I used an IR gun on my 308 QV and got around a 20-25 degree drop. This is with a coolant gauge temp of about 205-215F. My radiator was showing around 195 inlet and 175 outlet.
     
  2. finnerty

    finnerty F1 World Champ

    May 18, 2004
    10,406
    #2 finnerty, Jul 1, 2013
    That's pretty good for a stock radiator in average, used condition.

    I get closer to a 35-40F drop from mine, but that is with a newer, modern core fitted and a baffling change in the stock frame and using the stock tanks.

    Also, as a rule, the higher the inlet temp the greater the drop in proportion with T(in)^4 - T(out)^4 for radiative heat transfer. Convective and conductive transfer rates are greater as well, but not as sensitive since governed by lower order relations.
     
  3. Cribbj

    Cribbj Formula 3

    Jan 1, 2011
    2,295
    Cooke City MT, The Coolest Small Town in America
    Full Name:
    John
    #3 Cribbj, Jul 1, 2013
    You're a very lucky owner to see a 20-25 degree drop across your radiator :) What were the conditions when you measured?

    Ambient temperature?
    Thermostat rating?
    Any A/C?
    What coolant mix?
    Fans On/Off?

    For my 550 Maranello I've seen as low as 9 degrees deltaT, as measured with contact thermocouples on the radiator inlet/outlet nozzles under these conditions:

    Ambient: 105 F
    Thermostat: 79 C / 174 F
    A/C: On
    Coolant: 50/50 premix
    Fans: On

    I've also seen about 13 degrees deltaT under the very same conditions as below, with the exception of changing the 50/50 coolant mix to pure water + a corrosion inhibitor.
     
  4. 60cyclehum

    60cyclehum Karting

    Nov 26, 2011
    92
    #4 60cyclehum, Jul 1, 2013
    Wow- 35-40, that's quite a drop. Not a 308 is it?

    Ambient was about 80F, 160F thermostat,no AC, mainly distilled w some water wetter and maybe 10% antifreeze, fans on at 170F.

    I'm using a cheap IR temp gun, so the temps may be off, but I would guess the drop is probably about right.

    I'm chasing down a "running hot" issue and trying to decide on recoring the the radiator. I had it cleaned out last year, I measured only about a 10 degree drop before I did that.

    Car is still running 195-220 in hot weather. Maybe more fan....but if I could get a recore and a 35 degree drop, that would do it.
     
  5. Ferraripilot

    Ferraripilot F1 World Champ
    Owner Project Master

    May 10, 2006
    17,182
    Atlanta
    Full Name:
    John!
    #5 Ferraripilot, Jul 1, 2013
    Last edited by a moderator: Sep 7, 2017

    I designed a crossflow aluminum radiator which several on f-chat have had excellent results using, myself included. PM me for details. I did a run a little over a month ago and will probably do another run at the end of July. Cores are difficult to get at the moment due to the season or I would start on the new run now
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  6. finnerty

    finnerty F1 World Champ

    May 18, 2004
    10,406
    #6 finnerty, Jul 1, 2013
    Last edited: Jul 1, 2013
    '81 308 2V injected. However, I should add that I have no A/C condenser blocking airflow either ;).

    The biggest improvement you can make to the stock radiator (other than a quality, high-efficiency re-core) on the 308 is to reposition the upper tank baffle ---- Ferrari (or whomever they had make them) really screwed up with the original design as it is in the worst possible location for best flow through the radiator. And, yes, removing the A/C radiator helps tremendously (A/C in the car sucks anyway, so I had no quandary about removing mine :)).
     
  7. finnerty

    finnerty F1 World Champ

    May 18, 2004
    10,406
    #7 finnerty, Jul 1, 2013
    Last edited: Jul 1, 2013
    All the newer cars generate (and retain) a lot more heat than most of the older ones ---- and with the 12's, you've got 50% more combustion events contributing to the heat per crank revolution :).
     
  8. 60cyclehum

    60cyclehum Karting

    Nov 26, 2011
    92
    #8 60cyclehum, Jul 3, 2013
    I'm about at the point where I am ready to remove the AC condenser, AC is pretty poor, but there is no point in addressing it, as there is no way I would try to use it with the car running too high a temp for my liking. I think I'm going to try and use one of John's custom radiators shown above- looks like this will do the trick, and I may even be able to use my AC!
     

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