FD Engine Heat Soak Remedy
10-26-23, 12:56 AM
#1
Junior Member
Thread Starter
FD Engine Heat Soak Remedy
I am soaking in all the knowledge and information I can about the RX-7. So, it would seem logical to learn from those who know their craft. Pettit Racing is one of the organizations and I am pumped to share this cool coolant system tip.
10-26-23, 09:13 AM
#2
Race cars are not street cars. Not all the techniques and "secrets" transfer over. Doing this technique puts you at risk of flooding the engine. Those short starts and shut downs are not good. There are A LOT of threads on people's cars not starting due to flooding from them say..... moving it a parking space or just out of the garage then turning it off.
Not sure what state you live you in but any standalone ecu such as the power fc, allows you to trigger the fans at whatever temperature you want making the fc thermoswich mod pointless. The logic makes sense with what you're doing and why you're doing but keep in mind, everything in that engine bay is ALREADY old and cooked. You're not saving anything by doing this.
Also, the heat issue isn't all because of the coolant temperature. Its everything in the engine bay thats physically hot radiating heat in a cramped space with no where to go. The gallon or so of coolant in the radiator isnt going to have an appreciable effect on rapidly cooling everything down using this technique. If you had a coolant gauge you could actually watch what the temperature does and confirm this yourself.
Not saying cams technique doesn't work but race cars are not street cars. The benefits that he saw on a race car configuration are not the benefits you will see in stock street car configuration. So long as the radiator fan exhaust is pointing to the engine bay and so long as the hood has no vents, it WILL be hot. Theres no way around it besides using e85 or meth Injection.
The first time you flood the motor in a parking lot somewhere, it will absolutely ruin your day. Its not a good feeling to be stuck with an FD that isn't starting and not having what you need on hand to do anything about it. Sometimes it's even worse to have what you need on hand because now you have to work on your car in a parking lot and deal with strangers asking if you need help or if everything is OK. You may even get a drive by joke or two. Its a crap situation overall.
The best you can do to combat the heat in factory configuration post drive is just leave the hood up and let it breathe. Without some kind of aux Injection, switching fuel, going v mount or getting a vented hood, it's just going to be hot and thats the nature of the beast.
Not sure what state you live you in but any standalone ecu such as the power fc, allows you to trigger the fans at whatever temperature you want making the fc thermoswich mod pointless. The logic makes sense with what you're doing and why you're doing but keep in mind, everything in that engine bay is ALREADY old and cooked. You're not saving anything by doing this.
Also, the heat issue isn't all because of the coolant temperature. Its everything in the engine bay thats physically hot radiating heat in a cramped space with no where to go. The gallon or so of coolant in the radiator isnt going to have an appreciable effect on rapidly cooling everything down using this technique. If you had a coolant gauge you could actually watch what the temperature does and confirm this yourself.
Not saying cams technique doesn't work but race cars are not street cars. The benefits that he saw on a race car configuration are not the benefits you will see in stock street car configuration. So long as the radiator fan exhaust is pointing to the engine bay and so long as the hood has no vents, it WILL be hot. Theres no way around it besides using e85 or meth Injection.
The first time you flood the motor in a parking lot somewhere, it will absolutely ruin your day. Its not a good feeling to be stuck with an FD that isn't starting and not having what you need on hand to do anything about it. Sometimes it's even worse to have what you need on hand because now you have to work on your car in a parking lot and deal with strangers asking if you need help or if everything is OK. You may even get a drive by joke or two. Its a crap situation overall.
The best you can do to combat the heat in factory configuration post drive is just leave the hood up and let it breathe. Without some kind of aux Injection, switching fuel, going v mount or getting a vented hood, it's just going to be hot and thats the nature of the beast.
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10-26-23, 09:32 AM
#3
Junior Member
Thread Starter
Hi, how are you flooding the engine if you turn it on? I have been doing this for a few weeks now and not a single time has it had trouble starting or anything with flooding. I turn the car off, the fans are on, and then I turn it back on of 10-20 seconds and then turn it off. Where is the flooding happening? Flooding happens when you turn the injectors on, or they prime and you never start the car. That is not happening here. Unless the fans are not kicking off when you first turn off the car, then you might have trouble doing what I am saying.
10-26-23, 09:50 AM
#4
I bought a turbo timer back in the day when i was autoxing, but ended up not really using it but rather would drive it slowly back to the paddock area after a run then park and pop the hood and let it idle while i gave it a walk-around. Some guys would do the same and use one of those sprayers you put liquid fertilizer or bug spray in to hose down the oil coolers. Lots of jokes about termites in the car...
If you are just street driving it, drive off-boost for the last couple minutes before you park and you should be good to shut it down. Pop the hood if you are parking at home / in a secure area like a friend's driveway and can keep an eye on it.
If you are just street driving it, drive off-boost for the last couple minutes before you park and you should be good to shut it down. Pop the hood if you are parking at home / in a secure area like a friend's driveway and can keep an eye on it.
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j9fd3s (10-28-23)
10-26-23, 11:25 PM
#7
Eats, Sleeps, Dreams Rotary
I think if you just turn AC on, the fans will come on at high at whatever temperature the coolant is at?
My car doesn't have AC, but I leave the AC switch on because I get paranoid letting it idle after track runs with the fans off (I've never seen the fans actually turn on without the A/C switch on).
Idling without the fans on just makes the oil and coolant temps creep higher and higher, so a turbo timer may or may not be useful (unless you lower the fan temps).
My car doesn't have AC, but I leave the AC switch on because I get paranoid letting it idle after track runs with the fans off (I've never seen the fans actually turn on without the A/C switch on).
Idling without the fans on just makes the oil and coolant temps creep higher and higher, so a turbo timer may or may not be useful (unless you lower the fan temps).
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DaveW (10-27-23)
10-27-23, 07:39 AM
#9
Rotary Enthusiast
While it makes logical sense, its not practical for and is not needed for a street car as others have mentioned. For a lot of races builds these days, people have been going with electric water pumps that would cycle the water through the radiator and engine for as long as you would like after shutting down which is even more effective than just rotating the hot water with the batch of cooled with the method you mentioned. But for street cars, if your cooling system is in good working condition and your temps aren't excessive, your parked temps won't be enough to be damaging anything by not rotating the coolant like this.
10-27-23, 07:50 AM
#10
I think because of the larger combustion chamber surface area, starting and shutting down a COLD engine will often result in flooding or at least alot of black smoke and initially lumpy idle. But I don’t recall ever having that issue with a hot engine. And I agree the majority of underhood heat is radiated from the turbos, manifold and downpipe. That said, starting and stopping for a few seconds is going to do little or nothing for that.
In race car applications they’re coming in to the pit after several minutes of WOT and nearly continuous max boost. Hence the glowing manifolds and DP’s. If that’s how you drive on the street then by all means, follow his advice.
Otherwise, I’m with MilesBeFree, if you’re heading home or otherwise getting ready to park just stay out of boost for the last couple of minutes going thru the neighborhood or parking lot…then turn the car off, maybe pop the hood if your home and go get a beer.
IMO, turbo life-span is much more affected by oil type, change intervals, max boost llevel and driving style.
In race car applications they’re coming in to the pit after several minutes of WOT and nearly continuous max boost. Hence the glowing manifolds and DP’s. If that’s how you drive on the street then by all means, follow his advice.
Otherwise, I’m with MilesBeFree, if you’re heading home or otherwise getting ready to park just stay out of boost for the last couple of minutes going thru the neighborhood or parking lot…then turn the car off, maybe pop the hood if your home and go get a beer.
IMO, turbo life-span is much more affected by oil type, change intervals, max boost llevel and driving style.
Last edited by Sgtblue; 10-27-23 at 08:01 AM.
10-27-23, 08:22 AM
#11
I agree with the others, the recommendations in this video have no relevance for a street driven car and will only serve to waste gas and only increase the wear & tear on the car for zero benefit - the starter, charging system and all engine/turbo bearing surfaces will see extra wear if you follow this video. Remember that 90+% of all engine/turbo bearing wear happens during cranking and the next few seconds upon startup, when full oil pressure isn't quite there yet.
For a street car, just drive it nice & easy towards the end of your trip, staying out of boost, and just shut it down normally. If parked in a secure location, feel free to pop the hood open to let the heat dissipate a little faster.
For a street car, just drive it nice & easy towards the end of your trip, staying out of boost, and just shut it down normally. If parked in a secure location, feel free to pop the hood open to let the heat dissipate a little faster.
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Sgtblue (10-27-23)
10-27-23, 09:23 AM
#13
^ Nostalgiia.
I did that mod when I was still on the stock ECU back in the day. Never did much for underhood heat in my experience. Ten minutes wasn’t near enough time. But as I walked away from the car there always seemed to be some smarmy guy yelling out that my fans were running. It was kinda fun to just say “yeah, I know” as I kept walking.
I did that mod when I was still on the stock ECU back in the day. Never did much for underhood heat in my experience. Ten minutes wasn’t near enough time. But as I walked away from the car there always seemed to be some smarmy guy yelling out that my fans were running. It was kinda fun to just say “yeah, I know” as I kept walking.
Last edited by Sgtblue; 10-27-23 at 09:26 AM.
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10-27-23, 08:13 PM
#14
Junior Member
I do this on and effectively stock car, but only when I'm home. I'll pop the hood and put the key to on with AC to get as high of a fan speed as possible then let it sit for 5 min. Start the car, run it for a minute, then cut it off. I usually only do it once just to bleed excess heat out.
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FD3S2005 (11-07-23)
11-07-23, 01:48 PM
#15
I do this on and effectively stock car, but only when I'm home. I'll pop the hood and put the key to on with AC to get as high of a fan speed as possible then let it sit for 5 min. Start the car, run it for a minute, then cut it off. I usually only do it once just to bleed excess heat out.
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Driver's Therapy (11-07-23)
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