One of the factors I see being consistently IGNORED or at least overlooked is that its almost a total impossibility to consistently get good results from tuning and engine if you can,t maintain consistent temperatures, now thats not easily done because both the ignition timing advance changes and the number of power strokes changes with the engines rpm levels even if you can maintain exactly the same fuel/air ratios in the cylinders.
one of the secrets of making consistently good hp is keeping the coolant and oil temps in there ideal ranges, and for oil thats in the 190F-215F range, for coolant thats in the 170F-190F range in most carburetor equipped performance muscle cars, and in some applications coolant temps just a bit higher for EFI equipped cars.
If both your coolant and oil temperatures rise noticeably when you start driving aggressively you should look into improving the cooling and lubrication system efficiency,
a multi level approach here may help!
one factor you may be having, if your engines running a bit warmer than you would like it too be, is that some coolants don,t contact the inner engines micro surfaces without a wetting agent added to the coolant ,and, I know you are sure you did a good job tunning the cars engine, but something may have changed,
Id start by verifying the fuel pressure, ignition timing, coolant levels , I'd look for vacuum leaks,and check the oil level, inspect the oil filter internally, and you may want to consider retarding the cam timing an additional 3-4 degrees and checking the piston to valve clearance, as this effectively reduces the dynamic compression, and moves your whole torque curve about 200 rpm higher and IF , anyone is reading this thread, and having a similar issue and if your car, does not have an oil cooler, transmission cooler,7-8 quart baffled oil pan, radiator fan shroud, and an adequately sized radiator,and oil temp gauge's that keep you aware of the fluid temps. you might want to install those, as those parts are all effective in reducing the thermal loads on the engine, keep in mind reducing the operational temps reduce the potential for detonation. you might want to recheck the ignition timing curve advance, has not changed, and a 160F t-stat with several air bleed holes added might help as a test, but as youve already proven , increased octane levels will potentially help avoid the issue, and filling the fuel tank with the highest level of octane fuel at the gas station ,may seem like its increasing the cost of vehicle operation, but its dirt cheap insurance spread over a life of the car, vs the cost of replacing a detonation damaged engine if you select lower octane fuel in a false effort to save cash flow.
the links and sub links will be helpful
http://garage.grumpysperformance.com/index.php?threads/water-wetter.2140/#post-11172
http://garage.grumpysperformance.co...steam-holes-posted-by-dennyw.2991/#post-57455
http://garage.grumpysperformance.com/index.php?threads/unwanted-engine-bay-heat.12186/#post-59072
http://garage.grumpysperformance.com/index.php?threads/how-radiator-caps-work.7718/#post-26294
http://garage.grumpysperformance.com/index.php?threads/octane-boosters.613/#post-46230
http://garage.grumpysperformance.co...ow-to-reduce-its-likely-hood.9816/#post-49741
http://garage.grumpysperformance.co...octane-for-compression-ratio.2718/#post-35581
http://garage.grumpysperformance.co...n-you-plan-for-quench.11298/page-2#post-51599
http://garage.grumpysperformance.co...et-it-to-last-cam-install-info.90/#post-57942
Ive been asked how long it takes for an engine to reach operational temps,obviously outside air temps play a factor here and in Florida its generally in the high 70f-low 90F range,and keep in mind my engines got an 11 quart oil pan and oil cooler capacity so it may take a bit longer than average, but Ive timed my corvette a few times and sitting at idle it takes 6-7 minutes to have the coolant temp stabilize, at the operational 190F temp its set at if I just let it idle, If I drive it slowly, and keep the rpms below 3000rpm to allow the oil to warm up and the internal engine temps to stabilize, the times reduced to about 5 minutes.
keep in mind the corvette has sensor controlled electric fans that won,t kick in until the coolant temp is well above the t-stats 190f
Keep in mind the coolant flow thru the block and heads is not at a consistent rate in all areas due to the irregular shape and size off the coolant passages and slightly different pressure levels so an additive the breaks down surface tension in the anti-freeze helps the coolant contact a higher surface area., and a high volume water pump with a more effective impeller design tends to increase the coolant flow rates, which tends to increase the heat absorbency.
a high efficiency aluminum radiator of adequate size with the proper duct work and fan design can have a huge effect on lower the coolant temp of antifreeze entering the engine, just a few degrees cooler temps can easily prevent detonation.
as most experienced guys know the fuel air ratios in about the 12.5:1-12.8:1 range generally produce the best torque and ratios of about 14.7:1-15:1 produce the best mileage , so in most cases experienced tuners try to match the fuel air ratio to the most likely use, ie, below about 3500rpm your generally going to want to maintain decent mileage and avoid fouling plugs so the engine tends to be tuned to run a bit leaner for use in daily driving in the 14:1-15:1 range and as rpms build past the 3500rpm levels most experienced tuners tend to try to let the fuel air ratio slowly but predictably shift to a richer 12.5:1-13:1 range to slow the advent of detonation and increase torque because your generally trying to increase power output significantly when your rpms start to climb over that 3500rpm level
If your having cooling issues while the cars stationary but not when the cars moving theres an excellent chance that the problem is lack of low speed air flow rates, a larger more effective fan or a more efficient fans or adding a pusher fan or more efficient fan shroud would help. clear pictures of the car,s engine compartment, radiator fans, fan shroud etc would help here a great deal.
keep in mind oil does a good deal of the heat transfer, in an engine, so an oil pan with a larger than stock capacity and an oil cooler with a built in electrical fan can do a good deal to lower engine temps.
keep in mind automatic transmissions tend to add a significant amount of heat to radiators that use the lower section to cool the transmission, adding a large efficient trans fluid cooler to the car can also significantly reduce the heat loads on the radiator
BTW one frequently overlooked factor, in cooling your engine or adding an additional oil cooler, is your alternator size,in amps and wiring the alternator correctly, if your running a 70amp-100 amp stock alternator and using electric fans to cool the engine,its not going to provide the power required to spin the fans nearly fast enough to cool the engine like a better 200 amp alternator can, Ive seen several corvettes cure cooling issues by swapping to 200 amp alternators, that simply allowed the electrical cooling fans to spin significantly faster
bit of info from BDS SUPERCHARGERS
"The cooling system for a SUPERCHARGED motor should be in a good general operating condition. Inadequate air flow across the entire radiator at low speeds is one of the most common causes for overheating. Mechanical fans and shrouds are highly recommended. In a recent study of electric fans, especially anything from 18 to 20 amps with a 3000-4500 CFM capability, these fans seem to work efficiently on blower engines, but it may still require some experimenting with location to find the best operating position. A 180 degree thermostat is recommended. Water flow restrictors may also be used, however, you will have to experiment to find the size that works best with your system. Stock factory water pumps are recommended and required in most applications. After market "High Performance" water pumps work best in the mid to upper RPM ranges and therefore may not have adequate water flow at lower RPM's to keep a blower motor cool. Three core radiators or larger are recommended for most applications. Higher performance engines will require better cooling systems because of the additional heat generated by these types of engines."
Gerald
read links
viewtopic.php?f=55&t=109&p=136#p136
the t-stat controls COOLANT temps,
which are generally 15F-25F lower than peak oil temps,
obviously the coolant temps vary as the t-stat opens allowing flow ,
and closes as temps drop off.
your oil temp may read only 10F hotter than the coolant temps,
but its a fact that oil temps vary a great deal during the trip from sump,
oil pump, valve train,and bearings and back to the oil pan sump.
get out a high quality infrared temp gun, and scan the valve springs after 10 minutes of engine run time,
youll notice the oil temp on the rockers is significantly cooler than that flowing over the valve springs
this is the most consistently accurate I.R temp gun I've used for testing
http://www.testequipmentdepot.com/e...1100200223789&utm_content=All Extech Products
INFRARED TEMP GUN
Wide temperature range from -58 to 1832°F (-50 to 1000°C)
any time that your dealing with a potential temperature issue or a trouble issue where
, knowing the exact temperature vs what a gauge might say,
\it helps to have a handy and accurate infrared temp gun handy,
to locate and confirm heat, levels.
http://www.professionalequipment.com/ex ... ermometer/
having a good cross check tool like a quality IR temp gun, and a decent multi meter, sure helps find the truth as far as a defective gauge or sensor
viewtopic.php?f=44&t=773
think you may have a blown head gasket or cracked heads ETC??
have you tested for a cracked head or block with the reactive dye in the coolant that shows exhaust gasses contamination?
watch this link
OBVIOUSLY THERE'S SEVERAL FACTORS BEING BALANCED
http://www.xcceleration.com/cr-boost 101.htm
http://www.superchargersonline.com/inde ... page&id=46
not verifying the ignition advance curve, verifying TDC and using a marked and indexed timing tape or balancer is a VERY common mistake ,Id bet fully 50% of the cars I work on have not verified TDC nor do they have a correctly marked timing tape or indexed balancer
you can,t make intelligent changes until you know exactly what your currently dealing with
viewtopic.php?f=70&t=4683
viewtopic.php?f=70&t=1015
viewtopic.php?f=57&t=5607&p=17121#p17121
viewtopic.php?f=57&t=4701
viewtopic.php?f=57&t=6888&p=22453&hilit=radiator+fin+count#p22453
viewtopic.php?f=57&t=2756&p=14146&hilit=duct+shroud#p14146
A principle problem in using a liquid to cool internal combustion engines is the fact that coolant temperatures vary within the cooling system components used, factors like but not limited too, outside air temperatures,air flow rates, coolant volume, radiator surface area, and coolant flow rates. This is generally the result of differences in the locations of heated areas in the engine that contribute to unequal temperatures. For example, metal surfaces nearest the combustion space and exhaust passages tend to be higher than elsewhere in an engine's cooling system. While reverse flow systems address certain aspects of temperature extremes and levels, localized "hot spots" can still contribute to detonation, lost power, and potential parts damage. this factor alone means that a great deal more consistency can be obtained with a very efficient cooling system that will maintain a stable and consistent engine temperature,if your cooling system has both the high coolant flow rate and rapid heat transfer ability to dissipate, changes in engine temperatures and the ability to prevent hot spots by simply overcoming the potential with high heat absorption rates, youll have much more consistent cylinder temperatures, this requires an accurate fast acting thermostat and a coolant system with the extra cooling capacity to absorb and rapidly dissipate rapid increases in engine cylinder temperatures, thru very efficient heat transfer and an understanding that the lubrication system , and additional oil coolers and high capacity oil pans also play a significant roll in engine temperature stabilization. You can,t have hot spots or rapid temperature changes and expect the engine tune to stay spot-on, or consistent, and you can,t have some cylinders running significantly cooler than others or detonation is the likely result when your pushing for the best possible power levels
so to maintain a consistent engine temperature range the cooling and lubrication systems must BOTH have the capacity to regulate their temperatures, even while the input temperatures vary rapidly
related threads
viewtopic.php?f=57&t=176
viewtopic.php?f=57&t=4230
viewtopic.php?f=57&t=2756
viewtopic.php?f=57&t=1540
viewtopic.php?f=57&t=832
viewtopic.php?f=57&t=6099&p=18844#p18844
http://www.circletrack.com/enginetech/c ... index.html
http://www.royalpurple.com/radiator-additive.html
viewtopic.php?f=44&t=10961&p=48185#p48185
viewtopic.php?f=54&t=8966&p=31978#p31978
viewtopic.php?f=57&t=348
http://www.circletrack.com/enginetech/c ... index.html
one of the secrets of making consistently good hp is keeping the coolant and oil temps in there ideal ranges, and for oil thats in the 190F-215F range, for coolant thats in the 170F-190F range in most carburetor equipped performance muscle cars, and in some applications coolant temps just a bit higher for EFI equipped cars.
If both your coolant and oil temperatures rise noticeably when you start driving aggressively you should look into improving the cooling and lubrication system efficiency,
a multi level approach here may help!
one factor you may be having, if your engines running a bit warmer than you would like it too be, is that some coolants don,t contact the inner engines micro surfaces without a wetting agent added to the coolant ,and, I know you are sure you did a good job tunning the cars engine, but something may have changed,
Id start by verifying the fuel pressure, ignition timing, coolant levels , I'd look for vacuum leaks,and check the oil level, inspect the oil filter internally, and you may want to consider retarding the cam timing an additional 3-4 degrees and checking the piston to valve clearance, as this effectively reduces the dynamic compression, and moves your whole torque curve about 200 rpm higher and IF , anyone is reading this thread, and having a similar issue and if your car, does not have an oil cooler, transmission cooler,7-8 quart baffled oil pan, radiator fan shroud, and an adequately sized radiator,and oil temp gauge's that keep you aware of the fluid temps. you might want to install those, as those parts are all effective in reducing the thermal loads on the engine, keep in mind reducing the operational temps reduce the potential for detonation. you might want to recheck the ignition timing curve advance, has not changed, and a 160F t-stat with several air bleed holes added might help as a test, but as youve already proven , increased octane levels will potentially help avoid the issue, and filling the fuel tank with the highest level of octane fuel at the gas station ,may seem like its increasing the cost of vehicle operation, but its dirt cheap insurance spread over a life of the car, vs the cost of replacing a detonation damaged engine if you select lower octane fuel in a false effort to save cash flow.
the links and sub links will be helpful
http://garage.grumpysperformance.com/index.php?threads/water-wetter.2140/#post-11172
http://garage.grumpysperformance.co...steam-holes-posted-by-dennyw.2991/#post-57455
http://garage.grumpysperformance.com/index.php?threads/unwanted-engine-bay-heat.12186/#post-59072
http://garage.grumpysperformance.com/index.php?threads/how-radiator-caps-work.7718/#post-26294
http://garage.grumpysperformance.com/index.php?threads/octane-boosters.613/#post-46230
http://garage.grumpysperformance.co...ow-to-reduce-its-likely-hood.9816/#post-49741
http://garage.grumpysperformance.co...octane-for-compression-ratio.2718/#post-35581
http://garage.grumpysperformance.co...n-you-plan-for-quench.11298/page-2#post-51599
http://garage.grumpysperformance.co...et-it-to-last-cam-install-info.90/#post-57942
Ive been asked how long it takes for an engine to reach operational temps,obviously outside air temps play a factor here and in Florida its generally in the high 70f-low 90F range,and keep in mind my engines got an 11 quart oil pan and oil cooler capacity so it may take a bit longer than average, but Ive timed my corvette a few times and sitting at idle it takes 6-7 minutes to have the coolant temp stabilize, at the operational 190F temp its set at if I just let it idle, If I drive it slowly, and keep the rpms below 3000rpm to allow the oil to warm up and the internal engine temps to stabilize, the times reduced to about 5 minutes.
keep in mind the corvette has sensor controlled electric fans that won,t kick in until the coolant temp is well above the t-stats 190f
Keep in mind the coolant flow thru the block and heads is not at a consistent rate in all areas due to the irregular shape and size off the coolant passages and slightly different pressure levels so an additive the breaks down surface tension in the anti-freeze helps the coolant contact a higher surface area., and a high volume water pump with a more effective impeller design tends to increase the coolant flow rates, which tends to increase the heat absorbency.
a high efficiency aluminum radiator of adequate size with the proper duct work and fan design can have a huge effect on lower the coolant temp of antifreeze entering the engine, just a few degrees cooler temps can easily prevent detonation.
as most experienced guys know the fuel air ratios in about the 12.5:1-12.8:1 range generally produce the best torque and ratios of about 14.7:1-15:1 produce the best mileage , so in most cases experienced tuners try to match the fuel air ratio to the most likely use, ie, below about 3500rpm your generally going to want to maintain decent mileage and avoid fouling plugs so the engine tends to be tuned to run a bit leaner for use in daily driving in the 14:1-15:1 range and as rpms build past the 3500rpm levels most experienced tuners tend to try to let the fuel air ratio slowly but predictably shift to a richer 12.5:1-13:1 range to slow the advent of detonation and increase torque because your generally trying to increase power output significantly when your rpms start to climb over that 3500rpm level
If your having cooling issues while the cars stationary but not when the cars moving theres an excellent chance that the problem is lack of low speed air flow rates, a larger more effective fan or a more efficient fans or adding a pusher fan or more efficient fan shroud would help. clear pictures of the car,s engine compartment, radiator fans, fan shroud etc would help here a great deal.
keep in mind oil does a good deal of the heat transfer, in an engine, so an oil pan with a larger than stock capacity and an oil cooler with a built in electrical fan can do a good deal to lower engine temps.
keep in mind automatic transmissions tend to add a significant amount of heat to radiators that use the lower section to cool the transmission, adding a large efficient trans fluid cooler to the car can also significantly reduce the heat loads on the radiator
BTW one frequently overlooked factor, in cooling your engine or adding an additional oil cooler, is your alternator size,in amps and wiring the alternator correctly, if your running a 70amp-100 amp stock alternator and using electric fans to cool the engine,its not going to provide the power required to spin the fans nearly fast enough to cool the engine like a better 200 amp alternator can, Ive seen several corvettes cure cooling issues by swapping to 200 amp alternators, that simply allowed the electrical cooling fans to spin significantly faster
bit of info from BDS SUPERCHARGERS
"The cooling system for a SUPERCHARGED motor should be in a good general operating condition. Inadequate air flow across the entire radiator at low speeds is one of the most common causes for overheating. Mechanical fans and shrouds are highly recommended. In a recent study of electric fans, especially anything from 18 to 20 amps with a 3000-4500 CFM capability, these fans seem to work efficiently on blower engines, but it may still require some experimenting with location to find the best operating position. A 180 degree thermostat is recommended. Water flow restrictors may also be used, however, you will have to experiment to find the size that works best with your system. Stock factory water pumps are recommended and required in most applications. After market "High Performance" water pumps work best in the mid to upper RPM ranges and therefore may not have adequate water flow at lower RPM's to keep a blower motor cool. Three core radiators or larger are recommended for most applications. Higher performance engines will require better cooling systems because of the additional heat generated by these types of engines."
Gerald
read links
viewtopic.php?f=55&t=109&p=136#p136
the t-stat controls COOLANT temps,
which are generally 15F-25F lower than peak oil temps,
obviously the coolant temps vary as the t-stat opens allowing flow ,
and closes as temps drop off.
your oil temp may read only 10F hotter than the coolant temps,
but its a fact that oil temps vary a great deal during the trip from sump,
oil pump, valve train,and bearings and back to the oil pan sump.
get out a high quality infrared temp gun, and scan the valve springs after 10 minutes of engine run time,
youll notice the oil temp on the rockers is significantly cooler than that flowing over the valve springs
this is the most consistently accurate I.R temp gun I've used for testing
http://www.testequipmentdepot.com/e...1100200223789&utm_content=All Extech Products
INFRARED TEMP GUN
Wide temperature range from -58 to 1832°F (-50 to 1000°C)
any time that your dealing with a potential temperature issue or a trouble issue where
, knowing the exact temperature vs what a gauge might say,
\it helps to have a handy and accurate infrared temp gun handy,
to locate and confirm heat, levels.
http://www.professionalequipment.com/ex ... ermometer/
having a good cross check tool like a quality IR temp gun, and a decent multi meter, sure helps find the truth as far as a defective gauge or sensor
viewtopic.php?f=44&t=773
think you may have a blown head gasket or cracked heads ETC??
have you tested for a cracked head or block with the reactive dye in the coolant that shows exhaust gasses contamination?
watch this link
http://www.xcceleration.com/cr-boost 101.htm
http://www.superchargersonline.com/inde ... page&id=46
not verifying the ignition advance curve, verifying TDC and using a marked and indexed timing tape or balancer is a VERY common mistake ,Id bet fully 50% of the cars I work on have not verified TDC nor do they have a correctly marked timing tape or indexed balancer
you can,t make intelligent changes until you know exactly what your currently dealing with
viewtopic.php?f=70&t=4683
viewtopic.php?f=70&t=1015
viewtopic.php?f=57&t=5607&p=17121#p17121
viewtopic.php?f=57&t=4701
viewtopic.php?f=57&t=6888&p=22453&hilit=radiator+fin+count#p22453
viewtopic.php?f=57&t=2756&p=14146&hilit=duct+shroud#p14146
A principle problem in using a liquid to cool internal combustion engines is the fact that coolant temperatures vary within the cooling system components used, factors like but not limited too, outside air temperatures,air flow rates, coolant volume, radiator surface area, and coolant flow rates. This is generally the result of differences in the locations of heated areas in the engine that contribute to unequal temperatures. For example, metal surfaces nearest the combustion space and exhaust passages tend to be higher than elsewhere in an engine's cooling system. While reverse flow systems address certain aspects of temperature extremes and levels, localized "hot spots" can still contribute to detonation, lost power, and potential parts damage. this factor alone means that a great deal more consistency can be obtained with a very efficient cooling system that will maintain a stable and consistent engine temperature,if your cooling system has both the high coolant flow rate and rapid heat transfer ability to dissipate, changes in engine temperatures and the ability to prevent hot spots by simply overcoming the potential with high heat absorption rates, youll have much more consistent cylinder temperatures, this requires an accurate fast acting thermostat and a coolant system with the extra cooling capacity to absorb and rapidly dissipate rapid increases in engine cylinder temperatures, thru very efficient heat transfer and an understanding that the lubrication system , and additional oil coolers and high capacity oil pans also play a significant roll in engine temperature stabilization. You can,t have hot spots or rapid temperature changes and expect the engine tune to stay spot-on, or consistent, and you can,t have some cylinders running significantly cooler than others or detonation is the likely result when your pushing for the best possible power levels
so to maintain a consistent engine temperature range the cooling and lubrication systems must BOTH have the capacity to regulate their temperatures, even while the input temperatures vary rapidly
related threads
viewtopic.php?f=57&t=176
viewtopic.php?f=57&t=4230
viewtopic.php?f=57&t=2756
viewtopic.php?f=57&t=1540
viewtopic.php?f=57&t=832
viewtopic.php?f=57&t=6099&p=18844#p18844
http://www.circletrack.com/enginetech/c ... index.html
http://www.royalpurple.com/radiator-additive.html
viewtopic.php?f=44&t=10961&p=48185#p48185
viewtopic.php?f=54&t=8966&p=31978#p31978
viewtopic.php?f=57&t=348
http://www.circletrack.com/enginetech/c ... index.html
Last edited by a moderator: