While I never did this with either of my Gen-1 NSX’s, I certainly will with my Gen-2. Kinda makes sense? Am I late to the party and everyone knows about this? (I also had a fabulous 1980 RX-7 and was clueless even back then).
Interesting [Cooling] Tip?
- Thread starter RickyJay52
- Start date
I've owned my '96 for 15 yrs and have done this since week 1. As you said, it just made sense to let things cool down and preserve the rubber components. I also leave the up-front hatch open because I installed a battery tender near the spare & I don't excess heat to damage it. Usually leave both hatches up for about 20-30 minutes with the garage door halfway open after driving. Great video!
I've been doing this from the time I got my car, but I've only had it for 13 years.
Did the same thing with the S2000, and it is now 25 years young! Pretty much do it with anything I drive now in hot conditions.
Did the same thing with the S2000, and it is now 25 years young! Pretty much do it with anything I drive now in hot conditions.
It definitely won't hurt. However, one of the appealing features of NSX ownership is that you can use it like a real car to go and get groceries and do other stuff. If all you do with your NSX is the occasional road blast and then park it, popping the hatch to speed up the cool down process might be practical. If I was a track rat this might be a perfectly reasonable procedure after coming into the pit area after doing laps. Doing this is going to impinge on the 'just get in and go' feature of the NSX, so not happening for me.
If you are really concerned about under hatch temperatures you definitely need to ditch the engine hatch cover to reduce temperatures while you are driving and perhaps install the fan that was used on the auto equipped cars to generate more air flow through the engine compartment in an after run mode.
If you are really concerned about under hatch temperatures you definitely need to ditch the engine hatch cover to reduce temperatures while you are driving and perhaps install the fan that was used on the auto equipped cars to generate more air flow through the engine compartment in an after run mode.
Many people open the engine cover after a hot lap session at the track (I do it), but it's not really necessary with the NSX unless your cooling system is not working well or you are running a modified engine that puts more heat into the engine compartment (i.e., turbo). The system is well designed and will convect hot air even sitting still. The engine cowl vent serves two purposes: first, it provides an air inlet to introduce cool air into the engine compartment at high speed. It is not a "scoop." Instead, it is an "inlet." The way it works is that the fast air rushing under the engine compartment creates a low pressure zone under the engine. The low pressure under the engine sucks in air from the cowl and draws it over the engine block, exiting under and behind the car. This effect begins to work at about 90 mph, since below that speed the engine isn't running hot enough to need air cooling. You can hear a hiss behind your head as the air is being drawn into the cowl.
Second, the cowl works as a convection vent when the car is sitting still. Hot air from the engine compartment will rise and exit the vent, drawing cool air from the bottom of the car into the engine compartment. Next time you drive the NSX and get it good and warmed up, place your hand over the cowl after you park the car. You will feel the hot air coming out. The design is so effective that Honda ditched the engine bay fan, since it never came on.
Your NSX is well designed from the factory and can manage engine bay heat quite well. There is no need to open the hatch after driving. It is impossible to get the engine hot enough to need it with street driving. At the track, I do it to accelerate the convection cooling of the engine to get ready for another hot lap session, since the engine is running at 8,000 rpm for almost 20 minutes.
Second, the cowl works as a convection vent when the car is sitting still. Hot air from the engine compartment will rise and exit the vent, drawing cool air from the bottom of the car into the engine compartment. Next time you drive the NSX and get it good and warmed up, place your hand over the cowl after you park the car. You will feel the hot air coming out. The design is so effective that Honda ditched the engine bay fan, since it never came on.
Your NSX is well designed from the factory and can manage engine bay heat quite well. There is no need to open the hatch after driving. It is impossible to get the engine hot enough to need it with street driving. At the track, I do it to accelerate the convection cooling of the engine to get ready for another hot lap session, since the engine is running at 8,000 rpm for almost 20 minutes.
Anyone want to join me in overthinking this? No? Too bad.
Personally, at a track my habit is to take the cool-down lap (or part of a lap) seriously so I'm pitting in with the coolant and oil temps levelled out at "highway" use levels, then park it to cool, lid closed. Before the next session I'll pop the hatch to visually inspect and check oil level (not every session, but a few times/day). For any road driving I rarely bother other than morning "pre-flights" on long cross-country runs.
- Is cooling a motor faster even preferable? More rapid heat cycles aren't always the best, having paid attention in material science class.
- At a casual track day, do you actually want to cool the motor all the way to ambient between sessions as that's a deeper thermal cycle on the components and fluids vs. retaining some heat such that the next start is more of a warm start than a cold start?
- What if you're parked outside and it's sunny (uncovered in a paddock, e.g.)? Does the radiant heat from the sun offset the extra space for heat to rise out of the engine bay (vs it being covered and convecting out of the rear vent?
- Leaving the engine cover open outside on an NAx NSX will expose the expansion tank and hoses to UV. Does that impact longevity more or less than being baked in the dark?
- On an NC1 does it help avoid thermal damage to the finished/painted engine/trunk lid?
- Is there a motivation to do this on a turbo car vs. NA?
Personally, at a track my habit is to take the cool-down lap (or part of a lap) seriously so I'm pitting in with the coolant and oil temps levelled out at "highway" use levels, then park it to cool, lid closed. Before the next session I'll pop the hatch to visually inspect and check oil level (not every session, but a few times/day). For any road driving I rarely bother other than morning "pre-flights" on long cross-country runs.
If there is an issue, it might be that the engine temperature as measured by coolant temperature may actually spike as the car is slowing down and comes to a stop. I don't have direct evidence for the NSX; but, I have a very vintage front engine Volvo with digital EFI retrofit and I have logged coolant temperatures. On a really hot day if I come off the highway and hit that first set of traffic lights I can watch the engine temperature rise even after the rad fan switches on. At high engine loads the iron in the block is hotter and has a lot of stored energy in it which manifests itself as that temperature spike when cooling capacity is reduced as engine speed and airflow drops. At highway speeds airflow through the rad and engine compartment associated with forward motion makes the fan pretty much irrelevant (can't speak to track speeds). The fan is there to manage cooling during idling / low speed operation. If the traffic light is long enough rad fan operation will bring my Volvo's temperatures down to normal or if the light is short driving forward and increasing airflow and coolant flow will quickly drop the coolant temperatures.
If you are a track rat, I think @R13 's advice
is probably the best advice. Drive at a speed high enough to maintain air flow through the rad and with an engine speed high enough for the all important coolant flow. Give it some time for temperatures to stabilize and you are probably golden. Even after a fast highway drive, the worst thing you could do is to pull over and shut the engine off immediately (no coolant flow).
A long time a go as a kid I remember being on a mountain pass which I think was in Yellowstone. It was a really hot day. People would pull over at the end of the climb and park for the view and as I walked through the parking lot you could see all these big'ol American V8s puking coolant in the parking lot.
Open your engine hatch if you want to reduce temperatures and preserve rubber; however, don't use it as an excuse to not do the maintenance on your cooling hoses.
If you are a track rat, I think @R13 's advice
is probably the best advice. Drive at a speed high enough to maintain air flow through the rad and with an engine speed high enough for the all important coolant flow. Give it some time for temperatures to stabilize and you are probably golden. Even after a fast highway drive, the worst thing you could do is to pull over and shut the engine off immediately (no coolant flow).
A long time a go as a kid I remember being on a mountain pass which I think was in Yellowstone. It was a really hot day. People would pull over at the end of the climb and park for the view and as I walked through the parking lot you could see all these big'ol American V8s puking coolant in the parking lot.
Open your engine hatch if you want to reduce temperatures and preserve rubber; however, don't use it as an excuse to not do the maintenance on your cooling hoses.
