32 replies to this topic

[Chris1992]

Hi Guys, 

 

So lately I've been struggling to keep my 1380 twin-cam cool in traffic. I currently have one of the cheap fletcher 40mm twin core aluminum rads fitted, paired with the biggest Revotec electric fan I can fit to it which is set to kick in at 75 degrees. I also still have the standard plastic fan fitted (the correct way round). The car is cool as a cucumber until I end up in standstill traffic, at which point the temp gauge will begin to climb even with the heater on (something I'm sure many of us are familiar with!).

 

I've not actually overheated yet, but I'd like to prevent it. So my first question is who makes the absolute best radiator for a Mini, money no object? I'd also really appreciate any other advice people have; like should I remove the standard fan? Coolant choice? thermostat? Rad cap choice? I'd like to stick with the side rad, as I've already butchered my inner wing to fit the electric fan. 

 

Engine spec: 1380cc A-series, ported BMW K1200RS 16v cylinder head conversion, LT cams, lightened flywheel, x-drilled/knife edged crank, ARP bolts, custom Omega pistons, BMW ITBs, Full straight cut gearbox, X-pin diff, etc.

 

Cheers

Guys

[nicklouse]

Any copper/brass one. As it shifts heat way better than aluminium. Also make sure your coolant mix is not more than 50/50 as any stronger and the ability to disparate heat gets much worse. Pure distilled water with rust inhibitors added and maybe a water wetter would be the best. But if it is likely to get cold you will need some anti freeze in it.

[KTS]

if you can fit it, inner wing cowling may help to direct heat out of the engine bay

[Chris1992]

Any copper/brass one. As it shifts heat way better than aluminium. Also make sure your coolant mix is not more than 50/50 as any stronger and the ability to disparate heat gets much worse. Pure distilled water with rust inhibitors added and maybe a water wetter would be the best. But if it is likely to get cold you will need some anti freeze in it.

 

Cheers! Am I right in thinking the standard radiators are made of copper?  

[GraemeC]

There's probably a few things that aren't helping:

Unless your revotec fan is running, then it could be blocking the airflow of the mechanical fan

With the car as low as it is and the wheels filling the arches, there is nowhere for the hot air to go once through the rad - you'll be filling the underwing area with hot air that can't escape easily and just builds up.

 

Ultimately though, do you actually have a problem?  The temp may climb and the engine running a little hotter, but as long as it is still managed it may never get to overheating.  My car regularly hits well over 100 on the gauge but doesn't have an issue.

(I'd have thought the 75 degree setting of your fan was very low)

[Northernpower]

I had the same problem with my 7 port. I solved it by fitting the Minispares https://www.minispar.../C-ARA5000.aspx I initially used a 20lb cap for a much higher boiling point but was concerned about bursting a hose so reduced it to 16lb. I also fitted an electric fan in the inner wing (along with the standard one). I also fitted a manual override switch and switched it on as soon as I hit traffic; its easier to keep it from overheating than trying to cool it when it's got too hot. I also fitted the Minispares evo waterpump. I know there's a concensus saying copper dissipates heat better than aluminium and I agree, but this setup sorted my overheating. As Nick says, don't overdo coolant percentage and mix it with distilled water.

[Chris1992]

There's probably a few things that aren't helping:

Unless your revotec fan is running, then it could be blocking the airflow of the mechanical fan

With the car as low as it is and the wheels filling the arches, there is nowhere for the hot air to go once through the rad - you'll be filling the underwing area with hot air that can't escape easily and just builds up.

 

Ultimately though, do you actually have a problem?  The temp may climb and the engine running a little hotter, but as long as it is still managed it may never get to overheating.  My car regularly hits well over 100 on the gauge but doesn't have an issue.

(I'd have thought the 75 degree setting of your fan was very low)

 

I had wondered about airflow, and you're probably right. Although I had the same ride height/wheel setup with my old spicy 1275 and that could sit in traffic for hours no problem. I know a 1380 is a different kettle of fish though. My dad runs an electric fan on his frogeye without the standard fan and has no issues, so I may try removing the standard fan completely. 

 

I should really fit a temp gauge that has numbers on it! I still have the old 'C --- N --- H' style gauge. As an estimate though, I recon it probably hits 95-100 in traffic. Just paranoia I guess! I used to have the fan set to 85 but I found that it struggled to bring the temp back down from that point, so I essentially give it a head start. 

 

 

I had the same problem with my 7 port. I solved it by fitting the Minispares https://www.minispar.../C-ARA5000.aspx I initially used a 20lb cap for a much higher boiling point but was concerned about bursting a hose so reduced it to 16lb. I also fitted an electric fan in the inner wing (along with the standard one). I also fitted a manual override switch and switched it on as soon as I hit traffic; its easier to keep it from overheating than trying to cool it when it's got too hot. I also fitted the Minispares evo waterpump. I know there's a concensus saying copper dissipates heat better than aluminium and I agree, but this setup sorted my overheating. As Nick says, don't overdo coolant percentage and mix it with distilled water.

 

I had looked at the rad, gutted it's out of stock. I may try a standard brass rad like Nick mentioned above and see how I get on. Something I haven't checked is my cap pressure so I'm curious what it was supplied with from Fletcher. I maaaaaay have slightly more coolant than necessary now that I think about it, so I'll sort that too. 

 

Cheers for the help so far guys!

Edited by Chris1992, 21 July 2022 - 10:36 AM.

[Spider]

If you find yourself in stop start traffic often, then much as I detest them, you may need an electric fan, but don't loose the mechanical fan !

[cooperd70]

For coolant mix and water wetter (as per nicklouse).

If it is actually a cooling issue (as per GraemeG) and you want better rad then MiniSpares do a modern copper 2 core performance rad - part no. C-ARA4442 - this page also has some good info on it and for bigger/tuned engines (which mine is not) they recommend a 4core...can't comment on that one though.
Note: warning this 2core has a drain plug which is made of plastic and is just downright nasty and cross-threads easy...so I also bought the screw-in sensor for the later cars as it's metal and used it instead, without the need to actually use the sensor.

I also have a revotec fan kit fitted as well as the original mechanical fan...no issue with the revo fan blocking the air flow from the mech fan whilst the revo isn't running. But then I do have plenty of space in the wheel arch as running at regular height and std 12" wheels with 165/60's for the air to escape.

Revo kicking in at 75deg seems low to me...mine kicks in around 90deg. If you remove the mech fan your revo will practically be running full-time. The revo instructions tell you to remove the mech fan which I did when I initially installed my kit, but after running it a while with it kicking in, out, in, out, all the time and speaking to others I put the mech back on and set the revo to only kick in when the temp is getting high...so mine works as a backup to the mech fan and will only kick in when sat in stationary traffic for long periods and the temp climbs.

Also make sure you have the correct pressure rad cap and thermostat for your setup.

Hope you resolve any issues you have.

[Lplus]

Try Minis R us;  their ebay page "minisuperstore"  still has the non brand alloy version at £75 plus postage and the Fletcher alloy version at £93 plus postage.

[IronmanG]

if you can fit it, inner wing cowling may help to direct heat out of the engine bay

What Pat said

My gauge was past the H in traffic so I fitted the cowl first and that made a big big difference. I put a wired by wilson fan on as well just in case, and even in the weather we are having in the last week I have used it for such a short percentage of time

Edited by IronmanG, 21 July 2022 - 11:32 AM.

[Chris1992]

If you find yourself in stop start traffic often, then much as I detest them, you may need an electric fan, but don't loose the mechanical fan !

 

Already got one fitted mate! It definitely helps but things are still getting toasty.

 

For coolant mix and water wetter (as per nicklouse).

If it is actually a cooling issue (as per GraemeG) and you want better rad then MiniSpares do a modern copper 2 core performance rad - part no. C-ARA4442 - this page also has some good info on it and for bigger/tuned engines (which mine is not) they recommend a 4core...can't comment on that one though.
Note: warning this 2core has a drain plug which is made of plastic and is just downright nasty and cross-threads easy...so I also bought the screw-in sensor for the later cars as it's metal and used it instead, without the need to actually use the sensor.

I also have a revotec fan kit fitted as well as the original mechanical fan...no issue with the revo fan blocking the air flow from the mech fan whilst the revo isn't running. But then I do have plenty of space in the wheel arch as running at regular height and std 12" wheels with 165/60's for the air to escape.

Revo kicking in at 75deg seems low to me...mine kicks in around 90deg. If you remove the mech fan your revo will practically be running full-time. The revo instructions tell you to remove the mech fan which I did when I initially installed my kit, but after running it a while with it kicking in, out, in, out, all the time and speaking to others I put the mech back on and set the revo to only kick in when the temp is getting high...so mine works as a backup to the mech fan and will only kick in when sat in stationary traffic for long periods and the temp climbs.

Also make sure you have the correct pressure rad cap and thermostat for your setup.

Hope you resolve any issues you have.

 

I'd be very interested to hear the benefits of a 4-core vs a 2-core from anyone whos tried both. In the mean time I may try raising my fan activation temp and fitting one of the 2-core brass rads.

 

 

if you can fit it, inner wing cowling may help to direct heat out of the engine bay

What Pat said

My gauge was past the H in traffic so I fitted the cowl first and that made a big big difference. I put a wired by wilson fan on as well just in case, and even in the weather we are having in the last week I have used it for such a short percentage of time

 

 

It's a tight squeeze, but I could probably fit the cowling in with a few modifications. Seems to be a very effective mod from what I'm reading! Did you bother with rubber to seal the gap between the rad and the cowl? 

[GraemeC]

MiniSpares do a modern copper 2 core performance rad - part no. C-ARA4442 - this page also has some good info on it and for bigger/tuned engines (which mine is not) they recommend a 4core...can't comment on that one though.
Note: warning this 2core has a drain plug which is made of plastic and is just downright nasty and cross-threads easy...so I also bought the screw-in sensor for the later cars as it's metal and used it instead, without the need to actually use the sensor.
 

 

This is the rad I use on my tuned 1460.

(I swapped the plastic plug for a metal version - I think it may be a BMW part)

[IronmanG]

If you find yourself in stop start traffic often, then much as I detest them, you may need an electric fan, but don't loose the mechanical fan !

Already got one fitted mate! It definitely helps but things are still getting toasty.

For coolant mix and water wetter (as per nicklouse).

If it is actually a cooling issue (as per GraemeG) and you want better rad then MiniSpares do a modern copper 2 core performance rad - part no. C-ARA4442 - this page also has some good info on it and for bigger/tuned engines (which mine is not) they recommend a 4core...can't comment on that one though.
Note: warning this 2core has a drain plug which is made of plastic and is just downright nasty and cross-threads easy...so I also bought the screw-in sensor for the later cars as it's metal and used it instead, without the need to actually use the sensor.

I also have a revotec fan kit fitted as well as the original mechanical fan...no issue with the revo fan blocking the air flow from the mech fan whilst the revo isn't running. But then I do have plenty of space in the wheel arch as running at regular height and std 12" wheels with 165/60's for the air to escape.

Revo kicking in at 75deg seems low to me...mine kicks in around 90deg. If you remove the mech fan your revo will practically be running full-time. The revo instructions tell you to remove the mech fan which I did when I initially installed my kit, but after running it a while with it kicking in, out, in, out, all the time and speaking to others I put the mech back on and set the revo to only kick in when the temp is getting high...so mine works as a backup to the mech fan and will only kick in when sat in stationary traffic for long periods and the temp climbs.

Also make sure you have the correct pressure rad cap and thermostat for your setup.

Hope you resolve any issues you have.

I'd be very interested to hear the benefits of a 4-core vs a 2-core from anyone whos tried both. In the mean time I may try raising my fan activation temp and fitting one of the 2-core brass rads.

if you can fit it, inner wing cowling may help to direct heat out of the engine bay

What Pat said

My gauge was past the H in traffic so I fitted the cowl first and that made a big big difference. I put a wired by wilson fan on as well just in case, and even in the weather we are having in the last week I have used it for such a short percentage of time

It's a tight squeeze, but I could probably fit the cowling in with a few modifications. Seems to be a very effective mod from what I'm reading! Did you bother with rubber to seal the gap between the rad and the cowl?

Yes I used the rubber

Its quite awkward but the amount of heat coming out from under the wing is measurable

[Steve220]

Hi Chris,

 

I think it's alreadly been summised, but the issue you're facing isn't necessarily needing the best radiator, it's making your current one as efficient as possible, ESPECIALLY whilst stationary, when most mini's tend to die a slow, heat infused, death.

 

What fan make have you got installed on yours? Ducting is definitey the best way to make the most of it all, and get an override switch on the fan! Out of curiosity, have you currently got the D400 controlling your fan?