Would there be a benefit to converting to a thermostatically-controlled electric fan system? I'm sure removal of the stock fan assembly would free up some engine power, but I'm wondering what electric system would be appropriate - and reasons not to?
Perhaps the dual 10" or the single 15"?
Keep in mind: 1995 Q45t, 86K, B&M trans cooler, in Phoenix heat, lots of stop & go...
Cooling fans
The 78-93 Sabb 900's had a set-up like this.Dual fans,One might come up first and the second when lotsa cooling was needed.
They were both all electrical and thermostatically controlled.
During hiway drving neither would be on.So this is poetntially daoble if a major manufacturer has found this satisfactory for a long production run.
Fred...
They were both all electrical and thermostatically controlled.
During hiway drving neither would be on.So this is poetntially daoble if a major manufacturer has found this satisfactory for a long production run.
Fred...
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Q45tech
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1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
Don't you think Nissan would have saved the money if they could have gotten rid of the thermo belt driven fan.........these parts cost more than any electric driven fan plus the newer ones have two electric plus the engine driven fan.
The alternator is only 70% efficient at best and a 20 amp fan can generate 20x13= 260 watts or 260/746 x 0.7= 0.244 HP! Pretty inefficient to suck 3/4 of a HP extra to drive an alternator to translate that to electricity then convert it back to a fan..... duh!http://www.narsa.org/acj/archi...g.pdfh ... hi...t.pdf
The alternator is only 70% efficient at best and a 20 amp fan can generate 20x13= 260 watts or 260/746 x 0.7= 0.244 HP! Pretty inefficient to suck 3/4 of a HP extra to drive an alternator to translate that to electricity then convert it back to a fan..... duh!http://www.narsa.org/acj/archi...g.pdfh ... hi...t.pdf
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AZhitman
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Don't hold back, Dennis - Tell me how you really feel!
Just kidding. I just know when I replaced my Suburban's mechanical fan with twin electrics, I felt a seat-of-the-pants increase in acceleration... Just thought the Q might be a similar situation.
I have access to a 15" electric cooling unit (free)...
Just kidding. I just know when I replaced my Suburban's mechanical fan with twin electrics, I felt a seat-of-the-pants increase in acceleration... Just thought the Q might be a similar situation.
I have access to a 15" electric cooling unit (free)...
AZhitman wrote:No offense guys, but TONS of cars have thermostatically controlled electric fans... Very few modern cars do not.
I'm just wondering if the HP benefit to the Q would be worthwhile...
Actually, I believe that changeing to electric fans was one of the first thing car makers did to increase mileage after the oil crisis CAFE standards were introduced. Apparently however, ignition indepent fan activation is something only a few manufacturers featured. Too bad.
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Q45tech
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1995 G20t 5 speed 334,000 miles 16" 2002 wheels - 205/50/16 Sr20ve vvl
When the fan is just slipping along [when the air blown past the thermosensor is cool enough] you can stop the fan with some difficulty with your hand [don't try this incase your viscous has failed!!!!!!!!!]. As the air gets above 100F this gets harder!
Based on the feel of it I doubt 1-2 HP is being used to drive the fan......now there is some friction added by belts and pullies. The HP requirements increase at the cube of the fan rotation speed but the viscous allows the fan to slip and it appears that the fan never exceeds 2500 rpm:http://www.hortonsachs.de/sach....html
The problem is high rpm [when the engine is creating 10-15 times more power than at idle or low speed] the electrics can't keep up with the need to spin 5,000 rpm yet the mechanical isn't efficient enough at 650 rpm idle but ok at 1500-2000 cruise.
'A study of converting all accesories to electric showed that a 300 HP V8 would need 1200 wats for all electric cooling {PEAK} and 400 watts average power consumption'............the alternator only produces 1440 watts at 60 mph and maybe 500 watts at idle.What would the other items like injectors or AC fan run from?
This is why we will be going to 42 volt alternators to triple the available power then everything can be run electrically: brakes, steering, cooling, AC.
In theory the mechanical will last forever except for belts, electric's life is proportional to use.
Guess you could experiment by removing the fan belt or fan [make sure the auxillary electric compressor/overheat fan works] in winter then get it warmed up and measure acceleration 0-80 mph on an on ramp. Normal time is around 10-11-12 seconds.. log a least 3 tries each and average
"An M130 pusher fan measures 15 x 13.5 inches and is only 2.25 inches deep. With a 12-inch-diameter fan turning 2,000 rpm, Flex-a-lite rates the M130 for cooling up to a 125hp engine (100 with air conditioning). That cooling capacity is in addition to stock when used as an auxiliary pusher. " ..............so you need 3 such fans?????
Electrics work quite well on 100-150-even 200 HP engines just not on 300HP engines with smallish radiators.
Coolant capacity is an excellant guide to how well things are designed....our 10.5 quarts pales in comparison to MB/BMW/Audi 14-15 quarts for the same power ratings.
Just like rotors over design is good!
Based on the feel of it I doubt 1-2 HP is being used to drive the fan......now there is some friction added by belts and pullies. The HP requirements increase at the cube of the fan rotation speed but the viscous allows the fan to slip and it appears that the fan never exceeds 2500 rpm:http://www.hortonsachs.de/sach....html
The problem is high rpm [when the engine is creating 10-15 times more power than at idle or low speed] the electrics can't keep up with the need to spin 5,000 rpm yet the mechanical isn't efficient enough at 650 rpm idle but ok at 1500-2000 cruise.
'A study of converting all accesories to electric showed that a 300 HP V8 would need 1200 wats for all electric cooling {PEAK} and 400 watts average power consumption'............the alternator only produces 1440 watts at 60 mph and maybe 500 watts at idle.What would the other items like injectors or AC fan run from?
This is why we will be going to 42 volt alternators to triple the available power then everything can be run electrically: brakes, steering, cooling, AC.
In theory the mechanical will last forever except for belts, electric's life is proportional to use.
Guess you could experiment by removing the fan belt or fan [make sure the auxillary electric compressor/overheat fan works] in winter then get it warmed up and measure acceleration 0-80 mph on an on ramp. Normal time is around 10-11-12 seconds.. log a least 3 tries each and average
"An M130 pusher fan measures 15 x 13.5 inches and is only 2.25 inches deep. With a 12-inch-diameter fan turning 2,000 rpm, Flex-a-lite rates the M130 for cooling up to a 125hp engine (100 with air conditioning). That cooling capacity is in addition to stock when used as an auxiliary pusher. " ..............so you need 3 such fans?????
Electrics work quite well on 100-150-even 200 HP engines just not on 300HP engines with smallish radiators.
Coolant capacity is an excellant guide to how well things are designed....our 10.5 quarts pales in comparison to MB/BMW/Audi 14-15 quarts for the same power ratings.
Just like rotors over design is good!
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maxnix
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1995 Infiniti Q45t
2000 Infiniti Q45
Dumb remark follows
It does seem to me that I remember spying twin electronically controlled radiator fans on a Second Generation Q45 (41). I think it was a 1999. Might start looking there.
However, Q45tech's remarks are most germaine. Your only loss is at idle, not cruise. And at 112°F, you are already way down due to thermal retardation of the timing. Wait for winter when it's 72°F.
Then you can extoll on WOT while everyone N of the Mason-Dixon line or not on the Left Coast is just trying to keep it on the road.
It's 50°F in Seattle today and the Q is at full power.
However, Q45tech's remarks are most germaine. Your only loss is at idle, not cruise. And at 112°F, you are already way down due to thermal retardation of the timing. Wait for winter when it's 72°F.
Then you can extoll on WOT while everyone N of the Mason-Dixon line or not on the Left Coast is just trying to keep it on the road.It's 50°F in Seattle today and the Q is at full power.
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Mayhem_J30
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AZhitman
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Dennis - Thanks for the clarification. I'll give your experiment a shot as soon as it cools down a little more here, but I'll do it at the track and see what effect fan removal has on 60' times.
Sorry Fred - Didn't mean to jam anyone but since most modern cars have a non-transverse-mounted engine, it stands to reason they'd all run electrics. Maybe that fits in with Dennis's hp <200 theory... Hmmmm.
What's the 2002 Q got? Mechanical or electrics? Perhaps we can get Jason to post some pics of his?
My biggest concern is sitting still in traffic in the heat. Quella and I are enjoying the cooler ambient temps AND being able to run without a/c... I had forgotten how nice she runs without retarded timing.
Sorry Fred - Didn't mean to jam anyone but since most modern cars have a non-transverse-mounted engine, it stands to reason they'd all run electrics. Maybe that fits in with Dennis's hp <200 theory... Hmmmm.
What's the 2002 Q got? Mechanical or electrics? Perhaps we can get Jason to post some pics of his?
My biggest concern is sitting still in traffic in the heat. Quella and I are enjoying the cooler ambient temps AND being able to run without a/c... I had forgotten how nice she runs without retarded timing.
Just curious if anyone has ever tried an aluminum flex fan? I know that a while back I suddenly broke the alternator belt when I romped on it and my Q felt like it suddenly got a shot 50 extra ponies. It seemed far more responsive and peppy...only for a few mins since it was only running off of the battery... Could there be that much power loss from driving the belts?