Page 1 of 2 12 LastLast
Results 1 to 15 of 30

Thread: Thermostat

  1. #1
    Newbie
    Join Date
    Sep 2018
    Location
    Dayboro
    Posts
    2

    Default Thermostat

    What's the advantage of a High Flow thermostat against a normal flow ?
    To fast and the coolant doesn't have time to remove heat . Isn't that true ??
    Cheers

  2. #2
    Part of the furniture
    Join Date
    Jan 2017
    Location
    Nth Qld
    Posts
    935

    Default

    HI
    Theory behind heat exchangers is
    Must have a min flow rate
    The faster u flow oil/water the bigger the cooler needed . The opposite is also true.
    I cannot remember if thin oil cools better or worse than water . Thick oil is harder to cool.

    In a vehicle
    additional flow can do both increases//decreases cooling pending many things
    water pump capable of pumping more yes/no without cavitation
    engine capable of flowing more

    The theory behind a larger holed thermostats is for an engine that spins faster RPM than stock and generates more heat . The thermostat needs to beable to flow the water to the larger than stock radiator . The heat exchanger needs tobe therefore larger .

    Don't forget air bleed holes most often need drilling . Some systems have constant bypass built in the heater piping acting as the bleed .

    The formula for heat exchanging is complex and u need to put in ALL the correct numbers . Many retailers advertise with false numbers. [ ""adjust the formula""' ]

  3. #3
    Newbie
    Join Date
    Sep 2018
    Location
    Dayboro
    Posts
    2

    Default

    You’re a champion Swampy.
    Well explained..
    In my case I don’t think It would be of any advantage. Could actually make it worse.
    Cheers

  4. #4
    Part of the furniture
    Join Date
    Jan 2017
    Location
    Nth Qld
    Posts
    935

    Default

    Hi
    A thermostat is for warm up only . It then/can regulate water flow . Its the radiator that should do the cooling not the thermostat. Ideally u want correct flow to give u a temp of 180-190f or 80--90cel . The response of an engine is far better at 90cel than at 70cel . Try it on a cold morning .

  5. #5
    Do you ever leave? paulzig's Avatar
    Join Date
    Oct 2008
    Location
    Gold Coast
    Posts
    15,566

    Default

    You make more power at lower temps, like 150-160F ... So you tune the engine for 150-160 instead of 180-190 and there is the same response...

  6. #6
    Part of the furniture
    Join Date
    Jan 2017
    Location
    Nth Qld
    Posts
    935

    Default

    HI
    An engine makes more power at 160f . I would question that.
    Cold intake for dense mixture
    Upto temp bottom end to help oil and clearances

    As I understand more hp and lower emissions are at higher operating temps .
    Tuning rich or lean at a cold engine temp makes only moderate difference eg putting choke on a winters morning . Once the engine temp is up the mixture canbe more appropriate to application .

    Lowering operating temp lowers detonation risk so operating temps become a fine line to walk depending application .
    Last edited by swampy; 31-03-2019 at 11:07 PM.

  7. #7
    casual poster
    Join Date
    Sep 2010
    Location
    North Brisbane
    Posts
    88

    Default

    Modern engines run hotter for emissions and fuel economy. There are gains in HP at lower temps maybe not under 170f but every engine is different.

  8. #8
    Do you ever leave? paulzig's Avatar
    Join Date
    Oct 2008
    Location
    Gold Coast
    Posts
    15,566

    Default

    Quote Originally Posted by swampy View Post
    HI
    An engine makes more power at 160f . I would question that.
    Cold intake for dense mixture
    Upto temp bottom end to help oil and clearances

    As I understand more hp and lower emissions are at higher operating temps .
    Tuning rich or lean at a cold engine temp makes only moderate difference eg putting choke on a winters morning . Once the engine temp is up the mixture canbe more appropriate to application .

    Lowering operating temp lowers detonation risk so operating temps become a fine line to walk depending application .
    The topic is thermostat, so I am referring to water temperature... Oil temp is different, and if you are running molasses for oil then you need some heat in it, a modern synthetic you can forego a thorough warmup procedure...

    Better emissions are at higher temps, better power is not... How the hell does lowering operating temp increase the risk of detonation, an engine that has more heat in the piston, rings chamber, cylinder wall etc is more likely to detonate than one that is cold...

  9. #9
    Part of the furniture
    Join Date
    Aug 2010
    Location
    geelong
    Posts
    1,146

    Default

    Quote Originally Posted by paulzig View Post
    The topic is thermostat, so I am referring to water temperature... Oil temp is different, and if you are running molasses for oil then you need some heat in it, a modern synthetic you can forego a thorough warmup procedure...

    Better emissions are at higher temps, better power is not... How the hell does lowering operating temp increase the risk of detonation, an engine that has more heat in the piston, rings chamber, cylinder wall etc is more likely to detonate than one that is cold...
    Don’t argue with stupid Paul , you will never win !
    The way it works is ask a question , , you respond with a answer and then you get a 12 page response to why the response you made that he asked about was wrong ! Make sense ? Yep ofvourse!

  10. #10
    casual poster
    Join Date
    Nov 2018
    Location
    Sydney
    Posts
    165

    Default

    I have seen one test where coolant temps were kept constant. Three temps were used, cannot remember what they were now, but the lower temps made more HP.

    Slowing the coolant speed down to 'pull more heat out' is an old wives tale. If the coolant stays in the engine longer, it picks up more heat...which means more heat that the radiator has now got to get rid of.....

    More on cooling & cooling tips: www.stewartcomponents.com

    Do not drill the stat! They all have some type of burp hole or jiggle valve to get rid of air in the system. A few warm up/cool down cycles will get rid of the air.

    The drilled stats were introduced by Howard Stewart, who made the Stewart racing water pumps. These did NOT have an internal bypass, which was why the drilled stats were used with these pumps, not production type pumps & cooling systems that still retain bypass. Using a drilled stat in this case will cause the engine longer to warm up & the stat no longer fully regulates coolant temp, both not good for the engine.

  11. #11
    Part of the furniture
    Join Date
    Jan 2017
    Location
    Nth Qld
    Posts
    935

    Default

    HI Paul

    less likely detonation at colder . I think u misread this .
    Heat dissipation is very close oil and water just different figures in the formula .

    Synthetic oils are not created equally and depends on specs like pumpability /viscosity at ""W" spec . A 10weight oil can be 7w thru 12 w . A v8 that has not been started for a while in cold weather 0-5c flows oil slowly when cold . A POA Ester oil is best for quick flow .

    In the online drag magazine write ups it seems popular to cool the intake agreed . BUT not the bottom end which u need some heat . So it depends on how much heat u need and how your engine clearances are setup . For a 100% street car for me 85deg cel is fine .. I don't mind a little warmth in my inlet manifold without excessively rich mixtures which only help running at colder temps or when close to detonation .


    A drilled t/stat will help to bleed air out the top hose out rad cap. Many OEM caps are done this way .""Jiggle Valve ""

    A water pump bypass either needs bigger holes in t/stat or bypass hose [pump to t stat] or internal water bypass

    Some moderns use hose to pressurised resivour

    Mini Moke Some vehicles use a very small radiator [probably to small] Remove thermostat and overheating happens =water flow to fast . The opposite to this XF falcon remove thermostat and runs way way cold bottom of scale .
    Last edited by swampy; 02-04-2019 at 01:28 AM.

  12. #12
    Do you ever leave? paulzig's Avatar
    Join Date
    Oct 2008
    Location
    Gold Coast
    Posts
    15,566

    Default

    Quote Originally Posted by GtoGeoff View Post
    I have seen one test where coolant temps were kept constant. Three temps were used, cannot remember what they were now, but the lower temps made more HP.
    Did you just agree with me Geoff??

  13. #13
    Do you ever leave? paulzig's Avatar
    Join Date
    Oct 2008
    Location
    Gold Coast
    Posts
    15,566

    Default

    Quote Originally Posted by swampy View Post
    HI Paul

    less likely detonation at colder . I think u misread this .
    Heat dissipation is very close oil and water just different figures in the formula .

    Synthetic oils are not created equally and depends on specs like pumpability /viscosity at ""W" spec . A 10weight oil can be 7w thru 12 w . A v8 that has not been started for a while in cold weather 0-5c flows oil slowly when cold . A POA Ester oil is best for quick flow .

    In the online drag magazine write ups it seems popular to cool the intake agreed . BUT not the bottom end which u need some heat . So it depends on how much heat u need and how your engine clearances are setup . For a 100% street car for me 85deg cel is fine .. I don't mind a little warmth in my inlet manifold without excessively rich mixtures which only help running at colder temps or when close to detonation .


    A drilled t/stat will help to bleed air out the top hose out rad cap. Many OEM caps are done this way .""Jiggle Valve ""

    A water pump bypass either needs bigger holes in t/stat or bypass hose [pump to t stat] or internal water bypass

    Some moderns use hose to pressurised resivour

    Mini Moke Some vehicles use a very small radiator [probably to small] Remove thermostat and overheating happens =water flow to fast . The opposite to this XF falcon remove thermostat and runs way way cold bottom of scale .
    You want the oil up to temp sure, but water/ coolant as low as you can get it on a petrol based engine, not alcohol that likes hotter... It may run at 85C here in QLD and I wouldnt really care, nor would I care if it ran at 75C on the street, if also would have no hesitation in burying my foot to the wood on an engine with 65C in it given I wasnt running diff oil in the engine like most do... 5w30 or 10w40 yeah..

  14. #14
    Part of the furniture
    Join Date
    Jan 2017
    Location
    Nth Qld
    Posts
    935

    Default

    HI
    agreed an engine that's set up /built for cold running no problem .Although engine clearances can only be so tight . A colder engine does like richer mixtures to regain some of the response lost . A warmer engine will have better throttle response because its warmer and not run pig rich mixtures which are sluggish by comparison . Excessivelyrich mixtures can flood an oil pan .

  15. #15
    Do you ever leave? TRIKHQ's Avatar
    Join Date
    Apr 2008
    Location
    Taylors Lakes VIC
    Posts
    4,260

    Default

    I ran a Hi Flow 160 thermostat and it was useless, from a running around 175 ave temp , ended up with 200 ave temp, water just runs to fast through radiator to early. I put std 180 deg thermostat back in with 4 x 4mm bleed holes drilled around the outside , it works the best. 406 SBC with 650HP and can sit in bumper to bumper traffic all day in 35 deg heat. Rest of system is alloy radiator and AU fans which come on around 173 deg.

Page 1 of 2 12 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. what thermostat should i have for my vn v8
    By wildvk in forum Holden V8's
    Replies: 24
    Last Post: 16-10-2011, 02:00 PM
  2. What thermostat ?
    By 3VClevo in forum Ford V8's
    Replies: 16
    Last Post: 28-01-2011, 09:00 PM
  3. Help - Best thermostat for 308?
    By Hemity in forum Holden V8's
    Replies: 1
    Last Post: 24-09-2010, 11:35 AM
  4. No Thermostat??
    By 1TUFWB in forum Holden V8's
    Replies: 30
    Last Post: 18-03-2010, 09:17 AM
  5. Thermostat help
    By mattyv in forum Holden V8's
    Replies: 3
    Last Post: 11-03-2010, 10:58 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •