Miata cooling system thread
#201
Exactly. Large farm tractors are "only" 500-600 horsepower, less than F1 cars. But, given that their average operating speeds are in the 1-4mph range, compared to 100+ for F1 cars, the fan and shrouding requirements for them is massive.
For cars on track at speed, the key requirements are that the incoming air be ducted such that it must pass through the heat exchangers rather than around them, and that the airflow then be given an exit from the engine bay. The stock undertray provides the second part. For greater heat rejection the hood can be vented. For advanced aero configurations (flat/partial flat underbody, front splitters, etc) care must be taken when venting the hood to ensure the trans and diff still receive enough airflow to be properly cooled.
For cars on track at speed, the key requirements are that the incoming air be ducted such that it must pass through the heat exchangers rather than around them, and that the airflow then be given an exit from the engine bay. The stock undertray provides the second part. For greater heat rejection the hood can be vented. For advanced aero configurations (flat/partial flat underbody, front splitters, etc) care must be taken when venting the hood to ensure the trans and diff still receive enough airflow to be properly cooled.
Power draw from engine to turn a cooling fan on a 600hp class 8 highway truck can reach as much as 90 hp!
#202
90 hp 66 diameter 85,000 cfm adjustable pitch tube-axial fan [90HP] - $8,995.00 : Cavlon Online Store
I have no personal feeling to how much 85,000 cfm is, but 40m3/s sounds "decent" (my small living room per second).
#204
I took my heater core out of the loop and tig welded a 1/8" thick plug the right dia. in the mixing maniflod outlet and installed a plug in the M-tuned housing where the heater hose was. I wanted to get rid of the pipe hanging off the exh. manifold and any heater hoses back by the turbo manifold.
#205
I took my heater core out of the loop and tig welded a 1/8" thick plug the right dia. in the mixing maniflod outlet and installed a plug in the M-tuned housing where the heater hose was. I wanted to get rid of the pipe hanging off the exh. manifold and any heater hoses back by the turbo manifold.
__________________
#206
Emillio I haven't had it out on the track on a cool day yet, but before I eliminated the pipe,[just capped it off] I did take it out for a drive on the road and with the windows out like on the track to keep my warm air from breathing getting to the windshield I had no issues with just turning the fan on with the controll on defrost. I thought with my helmet on and the shield almost closed it should be even better. Maybe I well find it doesn't work on the track, in that case I well replace the mixing manifold and reinstall the pipe with hose partially blocked.
I have run for several years with the pipe bent and hoses wrapped, just wanted to clean things up. Stay tuned, won't be able to find out until probably Jan. down at Thunderhill. Have you already tried this?
I have run for several years with the pipe bent and hoses wrapped, just wanted to clean things up. Stay tuned, won't be able to find out until probably Jan. down at Thunderhill. Have you already tried this?
#208
Yeh I wrapped them too. Like I said I just wanted to clean it up, didn't think I really needed the heater hooked up, could be wrong. As for the water needing somewhere to go the water pump is not a sealed pump like a rubber impellered pump is [positive pressure] It should just sit there and churn the water until the stat opens. I never go out until up to temp anyway.
#209
Yeh I wrapped them too. Like I said I just wanted to clean it up, didn't think I really needed the heater hooked up, could be wrong. As for the water needing somewhere to go the water pump is not a sealed pump like a rubber impellered pump is [positive pressure] It should just sit there and churn the water until the stat opens. I never go out until up to temp anyway.
#210
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Coolant needs to circulate all the time. Period. Even in vehicles which have electrically-driven water pumps as OEM, the pump is constantly in operation even when the engine is stone-cold.
#211
Of course, if you're just idling in the paddock until warm, I can't see how you'll hurt anything. But for the rest of us, not a good plan to block off that bypass.
#212
The thermostat has a air bleed hole at the top orientation, all be it small and I did enlarge it to a 1/4" so this is allowing circulation. I don't know how this compares to restricting the bypass side like was stated above, but that is also creating a potential cavatation situation. I did alot of research before doing this and the main reason for the bypass circuit on cars is so the heater well blow hot air sooner as the water isn't sent through the radiator until the thermostat opens up, other then that you could bypass the thermostat on the other side with a loop before and after in the upper rad. hose, since I don't plan on using the heater, I wasn't concerned. The main reason I did this wasn't that I couldn't protect the heater hoses as they were wrapped, but I run a 3" downpipe off of the turbo which sits on a log style manifold so everything is up high unlike a long tube manifold which I choes not to run for certain reasons and even though I have shieling and everything is ceramic coated this thing makes a bunch of heat at the whp and psi it runs at. I wanted to get rid of the heat soaking that I'm sure was taking place towards the end of sessions and make all the water go through the radiator as we don't have a system that shuts the bypass off and I didn't have the room for a bunch of valves and crap on the bypass system, nor did I want it. This is strictley a Track car and I would not suggest doing this to a DD, nor would I want to delete the heater to begin with, and I realize that not many are running this much power and heat on the track for 25 and 30 min. sessions, but for those that are with a similar setup it might help. My biggest concern is what Emillio brought up and that is if I can keep the windshield defrosted in the cool northwest spring mornings.
Last edited by jmann; 12-17-2014 at 01:42 PM.
#214
I just ordered one of these as the one that came with the M-tuned setup is 195*, fine for emissions but would like to be 180* at the stat. I like the high flow feature and the 3 bypass holes. Anybody have any experience of actually having used one?
http://www.summitracing.com/parts/emp-301/overview/
John
http://www.summitracing.com/parts/emp-301/overview/
John