cooling when you stop after a journey ..i know i asked this before but i wasnt happy with the answer .....are you supposed to just give enough time to cool the turbos doen then switch off and walk away or do as i do and sit with the fans on (via the a/c switch ) till the apexi says less than 90 degrees??
I dont want to cook my engine by just leaving it ...but i dont want to be say for ages even after a slow drive !!! help!!
Don\'t know the correct answer mate... I tend to sit in the car and leave it running for 20-30 seconds if I have only driven the car for a short journey and haven\'t booted it at all. A minute or a bit longer if I\'ve been booting it. I like to see the temp get below 90 degrees before I switch off. After the engine is off I use my turbo timer to keep the fans running whilst I\'ve locked the car and walked away - I sometimes leave the internal fans on with the dial set to full heat to aid in getting heat out of the engine bay.
What\'s this business of using the air-con switch mate? Does that turn the fans under the bonnet on or something?
Cheers
Jon
yeah it allows the fan to come on before it usually kicks in at 93-94 and when it has kicked in gives a higher fan speed !
so you basically do the same as me but with your timer
Yeah, pretty much the same routine as you mate.
I\'ll try the air-con switch trick tomorrow. ;)
Eventually when I\'ve got the money I\'ll invest in a carbon bonnet with some large vents in it - should help shift some heat out of the engine bay.
i was told that i should open my bonnet when the fans are on to help cool it ....but this actuallly INCREASES the temp for some reason !!
Got a question if you don\'t mind Chris... Ok, so I parked up outside the office this morning, the engine is still running, I pushed the air-con button and nothing seems to happen. Am I suppose to switch the fan speed switch on to 1, or another number, or turn the dial to hot or cold or something?
Cheers
Jon
air con wont come on unless fan is running
Right - so if the air-con is switched on the fans under the bonnet automatically come on, and at a higher speed. Is that right? Should I turn the temp dial to hot or cold to aid the cooling of the engine bay?
Cheers
Jon
Turbo timer on for 2mins, Air con on, fan speed on max and cold.
Vents in my hood also help the cooling.
Quotei was told that i should open my bonnet when the fans are on to help cool it ....but this actuallly INCREASES the temp for some reason !!
Didnt know that.....
How come??
yes mate you need to have the air con on 1 or above........
QuoteQuote:
i was told that i should open my bonnet when the fans are on to help cool it ....but this actuallly INCREASES the temp for some reason !!
Didnt know that.....
How come??
i have no idea...maybe as the fans are pushing cold air over the engine with the bonnet shut....but with it open the cool air just goes strait up and away :xconfused
I set the fans to setting "1" with the air-con on and sure enough fans cranked it up a gear ;)
i only found it a few weeks ago :)
Quote from: J.j.Didnt know that.....
How come??
Yes, I would like to know the theory behind this??? ( maybe its a statement form the FIA!)
Is it not to cool the air con condensor
Scott
i normaly let the engine run for about 2/3 minutes (enough to smoke a fag) and then turn it off ! ...
if i go for a blast ... drive for a few miles normaly ... and then do the same as above ..
i want to get a turbo timer fitted to i can have it running while i run inthe shop .. .
thing is though mate in those few minutes you are lettin the turbos cool ...your coolant is getting warmer ...very quickly!! and once the pump and engine have stopped what happens........ :confused:
ummm good point ... but temp never seems to rise when it is stationary .
which gauge you have though ...the standard factor one ?? if so get an apexi &commander and you will be unpleasantly surprised !!
I open my bonnet after a drive, just to let some heat out.
Don;t see how that could make it hotter.
I normally drive sensibly for the last few miles (below 3k) so the turbos aren\'t oiled up then turn off the engine, after that i\'ll turn the key to position II and wait until the cooling fans switch off. The car always runs at 89C and the PFC is set to let the fans come on at 84C I believe. Trouble is cooling the big old turbo! Thats damn hot when I park up!! Maybe I should spray a mist of water onto it and the FMIC??
can you adjust when the fans come on via the pfc ?? cos mine kicks in/ out however you look at it at 94 degrees !
you can adjust on the commander indeed.
ahh this sounds a lot better ...pity there wasnt a hard wired fan switch already in place whihc 90%of cars have :xconfused
With having a Power Fc and handset, i found that the temp goes up more when the engine is off. So what i do if i have been on a good run i tend to drive it slowly (off boost etc) for the last 2-3 miles. Then when i get in idle for 10 seconds turn it off for ten seconds (with Aircon fans on) then start it again for 10 seconds and then turn it off and get a brew.
I found this soaks up the heat into the staitionary water then starting it again drops the temp by pulling the cooler water through from the Rad.
Anyone with a PFC try it and have a look at you temps.
If i do the 30 second idle thing i found it still gets realy hot when you keep an eye on the PFC with the engine off and the Ing still on.
The Bonnet up thing is a Mith i think as it makes very little diffrence too engine core temps.
Chris
Quote from: GrizzlyWith having a Power Fc and handset, i found that the temp goes up more when the engine is off. So what i do if i have been on a good run i tend to drive it slowly (off boost etc) for the last 2-3 miles. Then when i get in idle for 10 seconds turn it off for ten seconds (with Aircon fans on) then start it again for 10 seconds and then turn it off and get a brew.
I found this soaks up the heat into the staitionary water then starting it again drops the temp by pulling the cooler water through from the Rad.
Anyone with a PFC try it and have a look at you temps.
If i do the 30 second idle thing i found it still gets realy hot when you keep an eye on the PFC with the engine off and the Ing still on.
The Bonnet up thing is a Mith i think as it makes very little diffrence too engine core temps.
Chris
I gotta disagree with you there. If you have a stock bonnet, all that heat from the turbos and block is being released into the bay and just sitting there. Heating the bay up If the heat has nowhere to escape to then its gonna take a hell of a lot longer for the whole thing to cool down. For the water and air temps to go down then the ambient temp of the engine bay has to go down too, the more of the heat vented to the atmosphere the less is being stored in your engine bay.
does anyone have an english rx7 manual with any info on this ??
have you checked //www.iluvmyrx7.xom
they have most manuals
Quote from: Oedipus RexI gotta disagree with you there. If you have a stock bonnet, all that heat from the turbos and block is being released into the bay and just sitting there. Heating the bay up If the heat has nowhere to escape to then its gonna take a hell of a lot longer for the whole thing to cool down. For the water and air temps to go down then the ambient temp of the engine bay has to go down too, the more of the heat vented to the atmosphere the less is being stored in your engine bay.
The Idea is not to have your Turb\'s as hot. If you hammered it for 100miles then got in then i understand your point it would be VERY hot. Or if for example you car is running a Hot set up. but i have noticed if the Turbo\'s are not being Used (off boost) the heat is considerably less.
Do you have a POWER FC fitted? If so then do diffrent things untill you find it tells you the Engine stops at the coolest temp possable.
You can\'t substute cooling your car down properly but i\'ll always try to have it moving so i get lots of through air then run it at Idle for as least time as poss. as that will cause heat soke.
I do understand that Opening the bonnet will help get rid of Heat soke over say 20 mins but you must live in a better area than me. I dont leave anything open with out my presence.
Chris
Absolutely, I stay off boost for a while before the end of my journey but its still kicking out a lot of heat by the time I get home. Until I get my Scoot bonnet fitted I find the best way to cool things down at a good pace is to pop the bonnet wide open and smoke a ciggarettte for 5 - 10 mins before closing it and putting it away.
Fair play if you don;t agree but having carefully watched both air and water temps after leaving my bonnet I\'ve come to the conclusion that it makes a good few degrees difference.
QuoteI find the best way to cool things down at a good pace is to pop the bonnet wide open and smoke a ciggarettte for 5 - 10 mins before closing it and putting it away.
:yes
That\'s exactly what I do.
When allowed, I\'d even leave the bonnet just clicked, not shut for like 2, 3 hours. Found this really helped.
No i see where your coming from. Lots of air flow is always a good thing. I just do it slightly diffrently, but thats just how i am Diffrent :)
Just out of interest though do you have a Pfc? it is realy scary how hot the engine gets in the 30 seconds after turn off.
Chris
For the last couple of miles i drive off boost open the windows then turn the
heater and fan on full blast then cook myself lol.
What use this is ive no idea as i dont have a commander yet but it surely
must reduce the coolent temp.Maybe someone on here with the commander could give it a go and see if theres any difference.
Cheers Danny
LOL.
I supose if you put the Air con on with the Heater on full blast it would take heat out of the Engines coolant and would not cook you quite as much? but then i don\'t know if the Air con will add load to the engine causing a Visous circle.
I\'ll have a Play next time its out for a run.
Chris
Quote from: GrizzlyNo i see where your coming from. Lots of air flow is always a good thing. I just do it slightly diffrently, but thats just how i am Diffrent :)
Just out of interest though do you have a Pfc? it is realy scary how hot the engine gets in the 30 seconds after turn off.
Chris
I do mate. The water temps just rocket. To be honest its the air temps rather than the water temps that benefit from leaving the bonnet open, water temps I find the best thing is turning the engine off straight away but leaving the electrics on, waiting till it reaches 100, firing it back up till it gets to 84 (where my fans are set), turning it off, waiting till it getes to 100, firing it up, waiting till it gets to 84 and then leaving it. Only takes a couple of minutes and has a hufe effect. You can even do it while having a smoke.
Just been reading this thread, surely if you drive sedately for the last 5mins of your journey the engine/turbo\'s/oil will have cooled sufficiently to prevent any damage?
Obviously you will get heat spike when you stop moving due to no air flow, and again when you switch off the engine, but that spike only lasts a relatively short amount of time. If your car is still suffering after those steps then surely there is something fundamentally wrong anyway?
Best thing to do is get a form of metering Divice (power FC hand set etc) and see it for your self. I have seen water temps as high as 120 on a hot day when i have left for 20 seconds to cool down. Some of the Temps are quite scary and i think Oedipus rex is Spot on with what he does to cool down.
I think 5 minutes of slow driving when you\'ve been hamering your car may not be close to enough to stop the Temps rising dramaticly on Turn off.
Chris
sorry i must have missed something ... but why does the car temp raise so much when it is switched off .. a normal turbo run down should be ok, shouldnt it .
As you guys are getting me worried !! lol
How it basicly works is the engine uses the water system to keep the temps down to a safe level. Becouse water absorbes heat very well it is run round the core of the engine picking up as much heat as poss then in turn this heat is removed from the water by the Radiator.
What you have to understand if there was no means of regulating the heat the engine would effectivly over heat, So what you are doing when you turn the engine off is stopping the water getting to the radiator and thus causing the Water to heat up to the same temp as the engine/Turbo.
So what you will see if you watch say a Power FC is the Temp start to creep up from the 80\'s to well into the 100\'s before starting to fall. What we are saying if you Turn off as soon as you stop and let the Air con fans stay on, leave it for 10 seconds then start it again for 20-30 seconds (do that two or three times) it will never see over 100deg.
If you Run a Turbo car for 5 minutes on idle what you are doing is causing it too heat up, same Theory as the Turn off but now you have water going round the System but you don\'t have enough cold air being pushed through the rad to cool the water efficantly so the temp will start to rise, Plus you will also start to see somthing called Heat soke where the Core of the Engine will heat up alll the Inlet,IC etc.
Chris
This is all very interesting reading, out of interest how do you change the setting for the fan to come on with the pfc. Don\'t think I\'m the only one who\'s not sure about this.
Also does leaving the fans on while the car is idling create enough air flow through the rad to reduce the water temps at all? Or does the temp still rise with the engine still running?
I was thinking of getting an exhaust wrap around the manifold and front section of exhaust to help try and channel some of the heat out of the engine bay. Has anyone done this and did it help. I suppose it won\'t do any harm. Will it?
Barry
sounds like your damed if you leave it on damed if you turn it off ! lol
So get the fans going on the aircon to cool it down while off and then start it again for 20 seconds and that should be ok .
but wont turning her on and off a few seconds apart cause flooding ??
not when its hot
ahhh thats nice to know :)
And as barmar asked ..how exactly do yo change the fan cutting in temp ?? cos i sat for ages with mine a few days ago and couldnt find the menu:confused:
Quotesounds like your damed if you leave it on damed if you turn it off ! lol
Maybe we should just leave her sat there and push her round wherever we want to go :rollin
If the car is standing still you\'re right, damned if you leave it switched on and damned if you switch it off...
...so don\'t have the car standing still, just drive the last five minutes off boost and temperatures of bits in the engine bay should all even out and everything will cool together - therefore no heat soak. Some argue that forced cooling (eg popping bonnet or getting fans to come on when they wouldn\'t normally) is exactly what causes heat stresses.
Remember it\'s not just your turbo - your brake/clutch circuits and the brakes themselves also have a lot of heat to shed after a good tatering, and if the car isn\'t moving there\'s NOTHING to cool those down evenly = warped discs or broken hub bearings or boiled DOT5.
Mine\'s REALLY unhappy if you come off a motorway and then sit in a queue, so now I cruise in 6th the last mile before a junction as well (and I don\'t even have a turbo to upset things.)
Most people know where there journey is going to end, so other than maybe getting caught in a surprise traffic jam, theres no reason for not allowing time/distance in your journey for everything to drop back to low temperatures :)
Interesting stuff.
Just for the record my American \'95 manual simply says (under Protecting Your Mazda/Turbocharger Information) :
"After driving at freeway speeds or up a long hill, idle the engine at least 30 seconds to cool the turbo. Don\'t abruptly stop the engine after a hard or long drive."
As for the aircon fan thing, I assume this only works because the fans go on harder than needed to compensate for the extra heat generated by the aircon load on the engine? After all the stock computer will actually cut out the aircon automatically if the engine temp gets too high.
Z
Quote from: BrettMost people know where there journey is going to end, so other than maybe getting caught in a surprise traffic jam, theres no reason for not allowing time/distance in your journey for everything to drop back to low temperatures :)
Actually that\'s exactly what finished off the gasket in one of my many VG30DETT engines - came off the M65 onto roundabout which I was expecting to boot round in bottom of 3rd as per usual and then get onto the moors...
...and found traffic on it and on the exit I was using... sure enough, two or three clutch-shuffles later PSSSSSSSSSSSSSSSSSSSSSSSSSHHHHHT :rolleyes: