RADIATOR & OIL COOLERS
-
Elva 11
- Posts: 47
- Joined: Sat Aug 25, 2012 7:46 am
RADIATOR & OIL COOLERS
I'm looking for advice on cooling for my new X1 build. Do you find the original Midget radiator is sufficient for fast road and occasional track use? If not, any recomendations for replacement. Do you fit an oil cooler? Engine is 1380 fast road spec.
-
xkfeng7
- Posts: 31
- Joined: Mon Aug 13, 2012 3:33 am
- Location: Boston, MA
Re: RADIATOR & OIL COOLERS
Elva,
I've only had about 1000 miles on a series 1 W11 with a Midget radiator.
The coolant temp has never gone above 185degrees F. The hottest situation was idling in a queue for about 15min with an ambient temp of about 85F. I did turn on the electric puller fan after about 7-8 minutes and the temp dropped to 170F.
If the midget radiator is in good condition, I think my car would have no problems in standing traffic up to 100deg F or more. The system does have a pressurized expansion/overflow tank so the system coolant level remains fixed (e.g. doesn't lose any coolant).
Oil temp: I have never seen it go over 190deg F. That happened when I was driving at a constant 4500rpm and the ambient temp was 85deg F. Usually the oil runs much much cooler (140deg F). If I were to install an oil cooler, I'd also install a thermostatically controlled valve because it is not good to have the oil too cold all the time.
I've only had about 1000 miles on a series 1 W11 with a Midget radiator.
The coolant temp has never gone above 185degrees F. The hottest situation was idling in a queue for about 15min with an ambient temp of about 85F. I did turn on the electric puller fan after about 7-8 minutes and the temp dropped to 170F.
If the midget radiator is in good condition, I think my car would have no problems in standing traffic up to 100deg F or more. The system does have a pressurized expansion/overflow tank so the system coolant level remains fixed (e.g. doesn't lose any coolant).
Oil temp: I have never seen it go over 190deg F. That happened when I was driving at a constant 4500rpm and the ambient temp was 85deg F. Usually the oil runs much much cooler (140deg F). If I were to install an oil cooler, I'd also install a thermostatically controlled valve because it is not good to have the oil too cold all the time.
-
Westfield 129
- Posts: 867
- Joined: Sat Jun 04, 2011 4:20 am
Re: RADIATOR & OIL COOLERS
Here in California, it's hot, and I mostly drive in the canyons, so getting stuck behind a slow moving SUV is a common occurrence. My system doesn't have an expansion tank, just a swirl pot fill point. The car has never overheated in all the time I have had it, including idling in 110F traffic. While I often see 190 to 200F, this is only in extreme circumstances, and the temps drop as soon as I can get the car rolling and free air flowing again. The engine has never overheated, ever.
The stock cross flow Midget radiator is certainly adequate, even with my 125+hp engine. However, if you install it to Westfield's specifications, it isn't. The problem is with the fan mounting, which is in front of the radiator, and covers more than 30% of the core. The trick is to mount a PULLER fan (don't use the Westfield supplied fan from the kit, as it is a pusher, and is not efficient when reversed), no shroud. If you angle the radiator back (lower edge mounted forward) you can get better air flow (through the core and out the bottom of the car), and a little alloy sheet to create a duct will ensure that all the air goes where it is needed. My old LHD car has the rad angled forward. This works, but it's not really the best way to mount the radiator. I plan to change this in the near future when I go back through the car and bring it up to date with all that I have done on the others.
With all that said about the Spridget rad, I went another way on my new RHD car, having a much smaller and lighter radiator built by Ron Davis racing radiators. These guys are suppliers to Indycar, NASCAR and all other racing series here in the US. This radiator is much shorter, and fits against the forward frame bulkhead, needing only an 8" puller fan. It is a "double pass" design, with side tanks and both inlet and outlet on the same side, reducing the amount of engine compartment plumbing. The radiator weighs in at 1 kg, about 1/4 the weight of the standard cross flow Spridget rad. What is interesting about all this is that the smaller, lighter radiator is far more efficient than the Spridget unit, doing a better job of cooling, while improving packaging at the same time. During 20 minute of fast idle when running in the cam on the new engine (ambient over 80F), the temp never reached the 170F necessary to turn on the fan. Impressive. In hot weather, we have yet to see 180F, even in 100F ambient, and the fan hardly ever cycles, even in traffic. This system has a header/fill tank, air bleed hose from the cylinder head (replacing the heater tap) to the header tank, and a bleed hose from the radiator to the header/fill tank. Lots of circulation with no chance of any air pockets. I filled the system using an "AirLift" vacuum test/fill system. This vacuum filled the entire system eliminating any air bubbles.
The alloy rad is expensive, though, at over $600 a copy. I am still developing the design for the Westfield, mainly to improve packaging and airflow. My next design will be an inch shorter, and an 1.5" wider. This should allow mounting flat against the bulkhead, much as the original Lotus 11 radiator, simplifying the ducting, mounting and air flow to the underside of the chassis. The Westfield supplied coolant tubes and hoses will still work with this setup, requiring only minor modification.
Having witnessed several racing engines overheat due to a driver neglecting to turn on the fan, I always use a thermostatically controlled fan switch. These are universal on modern cars, and are just about failure proof. I trust them to handle the cooling in all situations, even on the race cars. While drivers may forget to turn on a switch, the automatic thermostat switch never fails, ever. I get fan only when I need it. I also "hot wire" the fan so that it runs when the engine is shut down, keeping the components cool in the engine compartment until the coolant temp drops enough for it to shut off. The end result is that components last longer, and starting is quick, as there is little heat soak. With a full rad duct, this probably wont be of any value, though. Wiring through the ignition might be a better plan.
Pictures of the alloy radiator and inlet duct/mount are in my build album on either of the Westfield Yahoo sites. Westfield_Eleven has it under "The Last XI".
The stock cross flow Midget radiator is certainly adequate, even with my 125+hp engine. However, if you install it to Westfield's specifications, it isn't. The problem is with the fan mounting, which is in front of the radiator, and covers more than 30% of the core. The trick is to mount a PULLER fan (don't use the Westfield supplied fan from the kit, as it is a pusher, and is not efficient when reversed), no shroud. If you angle the radiator back (lower edge mounted forward) you can get better air flow (through the core and out the bottom of the car), and a little alloy sheet to create a duct will ensure that all the air goes where it is needed. My old LHD car has the rad angled forward. This works, but it's not really the best way to mount the radiator. I plan to change this in the near future when I go back through the car and bring it up to date with all that I have done on the others.
With all that said about the Spridget rad, I went another way on my new RHD car, having a much smaller and lighter radiator built by Ron Davis racing radiators. These guys are suppliers to Indycar, NASCAR and all other racing series here in the US. This radiator is much shorter, and fits against the forward frame bulkhead, needing only an 8" puller fan. It is a "double pass" design, with side tanks and both inlet and outlet on the same side, reducing the amount of engine compartment plumbing. The radiator weighs in at 1 kg, about 1/4 the weight of the standard cross flow Spridget rad. What is interesting about all this is that the smaller, lighter radiator is far more efficient than the Spridget unit, doing a better job of cooling, while improving packaging at the same time. During 20 minute of fast idle when running in the cam on the new engine (ambient over 80F), the temp never reached the 170F necessary to turn on the fan. Impressive. In hot weather, we have yet to see 180F, even in 100F ambient, and the fan hardly ever cycles, even in traffic. This system has a header/fill tank, air bleed hose from the cylinder head (replacing the heater tap) to the header tank, and a bleed hose from the radiator to the header/fill tank. Lots of circulation with no chance of any air pockets. I filled the system using an "AirLift" vacuum test/fill system. This vacuum filled the entire system eliminating any air bubbles.
The alloy rad is expensive, though, at over $600 a copy. I am still developing the design for the Westfield, mainly to improve packaging and airflow. My next design will be an inch shorter, and an 1.5" wider. This should allow mounting flat against the bulkhead, much as the original Lotus 11 radiator, simplifying the ducting, mounting and air flow to the underside of the chassis. The Westfield supplied coolant tubes and hoses will still work with this setup, requiring only minor modification.
Having witnessed several racing engines overheat due to a driver neglecting to turn on the fan, I always use a thermostatically controlled fan switch. These are universal on modern cars, and are just about failure proof. I trust them to handle the cooling in all situations, even on the race cars. While drivers may forget to turn on a switch, the automatic thermostat switch never fails, ever. I get fan only when I need it. I also "hot wire" the fan so that it runs when the engine is shut down, keeping the components cool in the engine compartment until the coolant temp drops enough for it to shut off. The end result is that components last longer, and starting is quick, as there is little heat soak. With a full rad duct, this probably wont be of any value, though. Wiring through the ignition might be a better plan.
Pictures of the alloy radiator and inlet duct/mount are in my build album on either of the Westfield Yahoo sites. Westfield_Eleven has it under "The Last XI".
-
Westfield 129
- Posts: 867
- Joined: Sat Jun 04, 2011 4:20 am
Re: RADIATOR & OIL COOLERS
On the subject of oil coolers, I always run one, though most A series don't need them.
I run them without any thermostat valves, as I find that they add complexity, and are not needed. The engine warms quickly, and the oil temp comes up fast enough. I don't worry about cold oil. I just watch the oil pressure and as soon as it drops to around 70psi, the engine is ready. You can speed this process up by using a 0W30 or 5W30 oil, rather than the 10w40 or20w 50 weight that I usually use. With a cooler installed, you can use the lighter oils.
When I run the car at the track, my venue is Willow Springs, which is in the desert. It's hot there. Also, in the canyons, stuck behind an SUV, the oil cooler will help keep temps low.
I have a whole lot of miles on my engine, and find that there is no wear problem running the cooler without a thermostat. In fact, of all the engines I have rebuilt, I have yet to grind a crank, even on some very clapped out 1275s that I have rebuilt.
I run them without any thermostat valves, as I find that they add complexity, and are not needed. The engine warms quickly, and the oil temp comes up fast enough. I don't worry about cold oil. I just watch the oil pressure and as soon as it drops to around 70psi, the engine is ready. You can speed this process up by using a 0W30 or 5W30 oil, rather than the 10w40 or20w 50 weight that I usually use. With a cooler installed, you can use the lighter oils.
When I run the car at the track, my venue is Willow Springs, which is in the desert. It's hot there. Also, in the canyons, stuck behind an SUV, the oil cooler will help keep temps low.
I have a whole lot of miles on my engine, and find that there is no wear problem running the cooler without a thermostat. In fact, of all the engines I have rebuilt, I have yet to grind a crank, even on some very clapped out 1275s that I have rebuilt.
-
erictharg
- Posts: 680
- Joined: Thu Jan 29, 2009 7:50 pm
Re: RADIATOR & OIL COOLERS
I changed the arrangement of the stock rad pretty early on. It can be moved to nearer vertical to improve airflow through it, and mount the fan behind the rad on something that blocks the airflow less than the factory mounting. Along with some ducting this should cope with road use if your ambient temperatures are not too high (below 25 degC say).
The factory set up is very poor, relying on the fan most of the time as there is insufficient airflow without it.
One option, which I've run now for over two years, is an early Metro radiator (from an A Series engined car). It fits out in front of the suspension and is shallow enough to clear the bonnet with only a minor tilt from vertical. It has a low restriction two pass core and means my racer runs at no more than 80 degC in 20 deg ambient. The radiators are reasonably cheap in the UK - I paid less than £40 for mine and a spare. Both new and un-used. I would guess that the later K series Metro rads would also fit, and be lighter as they are aluminium. If you are interested I can provide some installation photos.
I run an oil cooler but don't need to given the low coolant temp the engine runs, and the fact that I choose to use synthetic oil. My oil temperature scarcely gets over 100 deg C. Fine even for a good mineral oil.
So, if you have a relatively high water temp (90 deg +) I would run the oil cooler as the oil will run that much hotter given the higher temp of the engine as a whole. If you have a water radiator that gets the engine temp down don't bother with an oil cooler.
The factory set up is very poor, relying on the fan most of the time as there is insufficient airflow without it.
One option, which I've run now for over two years, is an early Metro radiator (from an A Series engined car). It fits out in front of the suspension and is shallow enough to clear the bonnet with only a minor tilt from vertical. It has a low restriction two pass core and means my racer runs at no more than 80 degC in 20 deg ambient. The radiators are reasonably cheap in the UK - I paid less than £40 for mine and a spare. Both new and un-used. I would guess that the later K series Metro rads would also fit, and be lighter as they are aluminium. If you are interested I can provide some installation photos.
I run an oil cooler but don't need to given the low coolant temp the engine runs, and the fact that I choose to use synthetic oil. My oil temperature scarcely gets over 100 deg C. Fine even for a good mineral oil.
So, if you have a relatively high water temp (90 deg +) I would run the oil cooler as the oil will run that much hotter given the higher temp of the engine as a whole. If you have a water radiator that gets the engine temp down don't bother with an oil cooler.
-
Westfield 129
- Posts: 867
- Joined: Sat Jun 04, 2011 4:20 am
Re: RADIATOR & OIL COOLERS
One thing that I have found is that the engine will run fine at higher temps. My race spec engines seem to like running at 85~95C (even 100C, without any ill effects at all), temps close to 212F just fine. Nice idle, no boil over, crisp throttle response,excellent power, no problems with detonation, and oil at around the same temp as the coolant. This is ideal, and seems to promote engine life as well, eliminating any condensation or raw fuel blowby from the oil. My temperatures track the thermostat quite accurately, as I run a 70C 160F (an 80 might be better). I get quick warmup, and steady temps, even in very hot (42C) ambient temps.
My Weber carbs are properly jetted, and I use the tubular Maniflow intakes and exhausts. It all seems to be very happy at these higher temps.
My Weber carbs are properly jetted, and I use the tubular Maniflow intakes and exhausts. It all seems to be very happy at these higher temps.
-
erictharg
- Posts: 680
- Joined: Thu Jan 29, 2009 7:50 pm
Re: RADIATOR & OIL COOLERS
That's interesting Jan. I'm working on old wisdom (Vizzard I think) claiming that the A Series makes its best power running cooler. And whilst I'd be happy to try running it hotter I prefer the headroom I currently have for the very rare Northern European day with higher ambient temps!
I don't seem to have any problems to date with wear (famous last words). I've also ditched the thermostat now the car is almost exlusively racing. It's just one more thing to go wrong. I do run a thermostat blanking ring though to give the right resistance in the circuit for the pump and flow.
I don't seem to have any problems to date with wear (famous last words). I've also ditched the thermostat now the car is almost exlusively racing. It's just one more thing to go wrong. I do run a thermostat blanking ring though to give the right resistance in the circuit for the pump and flow.