Radiator issue, advice please?

Baz116 · May 03, 2010, 02:31:39 PM

Hi,

My fd3 is running 350bhp at the fly. It has a FMIC and im finding that the water temp is a bit warm, 88 - 90 driving sensibly, 93+ when i put my foot down, its still on stock radiator so im going to uprate to a bigger aftermarket rad and move the air con rad behind the new rad if this is possible?
Also which rad should i get and where is best to get one from, any suggestions?
Should i get 2 core? 3 core? N flow? any others?
Is there anything else i can do to help keep the coolant at the correct temp?
Whatever the correct temp is?

Thanks

clive · May 03, 2010, 04:37:44 PM

If your undertray is missing this will cause your temps to rise like this

Hope this helps

Rex_FTW · May 03, 2010, 06:06:38 PM

Quote from: clive;691273If your undertray is missing this will cause your temps to rise like this

Hope this helps

Really? That\'s quite interesting. Didn\'t know it would have such a big influence.

*goes to find undertray*

Aubec · May 03, 2010, 07:15:02 PM

Temps sound fine to me mate, FD\'s run hot. Coolants good up to around 110 degrees.

pdtaylor18 · May 03, 2010, 09:26:03 PM

Undertrays plays an important part in keeping the temps down, they are not just there to stop crap splashing up but helps stop the flow of air coming into the front from \'spilling\' everywhere. It also provides a way out as air is sucked out due to the air passing underneath the tray.
I would have thought those temps were fine, what were you getting before? and whats make you think they are high if you dont know what the temps should be in the first place?

The thermostat does not start to open until 80-83 deg and is fully open by 95 deg

High water temps are not just caused by poor rads and flow but by engine modifications as well. Poor timing, poor air flow to air filter, No turbo shields etc etc all play a part.

m1tch · May 03, 2010, 09:30:06 PM

Quote from: Rex_FTW;691299Really? That\'s quite interesting. Didn\'t know it would have such a big influence.

*goes to find undertray*

Yes, like Clive and Pete say, the undertray is very important, air flows from high to low pressure, high pressure being in front of the car, if there is no undertray the engine bay doesn\'t have such a low pressure that it would usually do, so the airflow isn\'t as good as it would be with an undertray.

I would also suggest an uprated rad anyway, I know my FC3S radiator had plastic end caps! Theses can get brittle and crack with age, its not like RX7s are new! I would suggest in upgrading the support auxiliaries such as radiator and intercooler to get a better safety margin. Just think, If I spend say a few hundred on radiators and intercoolers it might protect my engine from overheating/detonation meaning my engine won\'t need a rebuild

Plus they are shiny :rollin

Baz116 · May 04, 2010, 09:54:22 PM

Quote from: clive;691273If your undertray is missing this will cause your temps to rise like this

Hope this helps

undertray is on thanks, although its cracked, duct tape soon fixed that! ha ha

Quote from: Aubec;691316Temps sound fine to me mate, FD\'s run hot. Coolants good up to around 110 degrees.

i was told above 92 is bad and can go bang 110+ ? I can quit easily get it to 110 if i put my foot down for several minutes. The problem is want to do some track days this summer.

Quote from: pdtaylor18;691346Undertrays plays an important part in keeping the temps down, they are not just there to stop crap splashing up but helps stop the flow of air coming into the front from \'spilling\' everywhere. It also provides a way out as air is sucked out due to the air passing underneath the tray.
I would have thought those temps were fine, what were you getting before? and whats make you think they are high if you dont know what the temps should be in the first place?

The thermostat does not start to open until 80-83 deg and is fully open by 95 deg

High water temps are not just caused by poor rads and flow but by engine modifications as well. Poor timing, poor air flow to air filter, No turbo shields etc etc all play a part.

i dont know what the water temps where previously as ive only noticed since apexi power fc was fitted and i could monitor water temp with commander.
i was told above 92 is bad and can go bang 110+ ?

Quote from: m1tch;691349I would also suggest an uprated rad anyway

any suggestions on makes/ type?

thanks guys

Aubec · May 04, 2010, 10:54:11 PM

There is a big coolant thread from RX7club on one of the stickies which explains the relationship between pressure and the temp the coolant can run up to.
As far as I am aware, as long as your coolant is still liquid your engine should not go pop. That\'s not an argument for deliberatly running as hot as you can, but I\'ve seen 120 degrees coming up the home straight at the \'Ring last September and the car is still quite happy.

That said, I definitely wanted lower temps so I bought a Koyo N-flow to replace the stock rad. The difference is night and day, the best I managed at the last trackday was 94 degrees, only 6 degrees above idle temp.

Bit of a git to fit, dremel and patience required...

Baz116 · May 05, 2010, 10:51:02 PM

Quote from: Aubec;691597There is a big coolant thread from RX7club on one of the stickies which explains the relationship between pressure and the temp the coolant can run up to.
As far as I am aware, as long as your coolant is still liquid your engine should not go pop. That\'s not an argument for deliberatly running as hot as you can, but I\'ve seen 120 degrees coming up the home straight at the \'Ring last September and the car is still quite happy.

That said, I definitely wanted lower temps so I bought a Koyo N-flow to replace the stock rad. The difference is night and day, the best I managed at the last trackday was 94 degrees, only 6 degrees above idle temp.

Bit of a git to fit, dremel and patience required...

Thanks!
Where did you get your koyo N-flow from? and if you dont mind me asking how much are they?
I have a dremel, hummm... patience... i`ll have a go! ha ha!
do u think i`ll be able to fit the air con rad behind a koyo N-flow rather than infront of it? or do they not fit at all?

Aubec · May 06, 2010, 08:14:25 PM

Couldn\'t tell you I\'m afraid- I ditched aircon to save weight and improve air flow

m1tch · May 06, 2010, 08:40:37 PM

Koyo have the best rads I feel, but as long as it has a thick core, good welds and metal end caps it will be better than OEM!

turbotoaster · May 06, 2010, 10:11:54 PM

depends how much you want to spend mate, alot of us are running the 52mm ebay rad as it seems to drop temps and is cheap, i know a racecar and a track car that runs them and they dont have problems with over heating, personally i think buying an expensive one is only worth it if you have money to burn, yes it may end up being 1c lower than an ebay one, but in the scheme of things i dont think it matters

Baz116 · May 06, 2010, 10:17:11 PM

Quote from: Aubec;691597There is a big coolant thread from RX7club on one of the stickies which explains the relationship between pressure and the temp the coolant can run up to.

any chance of a link?
cheers

Baz116 · May 06, 2010, 10:24:27 PM

Quote from: turbotoaster;692195depends how much you want to spend mate, alot of us are running the 52mm ebay rad as it seems to drop temps and is cheap, i know a racecar and a track car that runs them and they dont have problems with over heating, personally i think buying an expensive one is only worth it if you have money to burn, yes it may end up being 1c lower than an ebay one, but in the scheme of things i dont think it matters

do you mean the chinese copies? didnt think they`d be that good? Which particular rad on ebay do you use as ive seen a few slightly different makes?

thanks

m1tch · May 06, 2010, 10:37:21 PM

Quote from: Baz116;692201do you mean the chinese copies? didnt think they`d be that good? Which particular rad on ebay do you use as ive seen a few slightly different makes?

thanks

I know prof has an ASI rad on his FC, its faily massive, but the welds aren\'t the best and it started to leak a bit, he has sorted this by using some sealing stuff where the core goes onto the end caps, they are good rads as they give you a lot of \'bang for your buck\' but quality control means that its hard to tell how well its built.