RCCAZ 1

iTrader: (10)

Everyone,

I've done my fair share of searching on the 99 spec radiator fan conversion threads. I've seen several that discuss the conversion, even part numbers and how toos, but I can't seem to find anyone who has strong opinions or definitive data that show that this conversion will in fact move more air or positively impact cooling as opposed to the stock FD fan setup. Anyone convert to two 4 blade fans with better success?

Let me know what you've experienced!

Thanks,

Tim

7racer

its so hard to tell. My system was working fine with the stock fans and also fine with the 99 spec fans. The drivers side one (the five blade I think) definitely moves more air. Wether its more than the stockers I really couldn't tell. I also read the threads about the balance issue... I think if you plan to replace the fans or have broken ones go ahead and get the 99 spec. If you don't mind tinkering and seeing if balance is an issue but with a possible benefit of moving more are then get two of the 4 fin stockers or two 5 fin 99 spec. (My friend runs two 4 fins without a prob). If your having cooling issues then I would track those down first and not rely on the fans.

Sled Driver

iTrader: (9)

I did the 99 spec fan swap & didn't notice any difference (other than the cool black color)

Like "7racer" posted above, if your system is operating properly (mine is) when your temps rise above 95C the fans kick on & in a couple of minutes the temps drop to 82-85C. If Im in stop & go traffic I manual turn on the fans to keep them from cycling on & off.

Had I been a little smarter I would have timed the temp drop from 95C (fans on) to 85C & compared the difference between the two. It's a bitch to pull the fan shroud so I don't thing Im going to switch back & find out, sorry.

Since Im more aware of temps & fans (because the $$$ I spent) It seams like it actually might take longer to cool down from 95C to 85C, but I have no hard evidence to support this. Again, since I spent the bucks I tend to watch it & expect a miracle.

Granted I have just the 99 spec fans, but not the motors. Could the 99 spec motors actual spin faster? My thoughts are that Mazda added more blades to quite the operation down some, not increase cooling. With the 99 spec bumper/nose the radiator opening is already larger to address airflow issues

Bottom line, is it worth the $$$ & effort to switch?????

NO

Kento

Well whaddya know....finally, an honest assessment.

The 99-spec fan motors, IIRC, drew less amperage, so they most likely spin slower. The added fan blades are to increase the efficiency of the fans, since it appears the newer motors were utilized to decrease the electrical load on the engine at idle (and possibly decrease noise, as you stated). "So if they added blades to make it more efficient, shouldn't they move more air if I spin them faster with the old motors?" Unfortunately, no. Gaining more cfm with a fan blade setup is a lot more complicated than just adding blades and spinning them faster. If it were that easy, then propeller-driven planes in WWII would've had as many blades as they could cram on the prop nose.

RCCAZ 1

iTrader: (10)

Thanks for the honest assessment guys. I'll probably pursue the dual 4 blade approach (if any). Ambient temps here in Phoenix have been BRUTAL the past week (112 to 116F) and I was just looking into possible ways to bring the car down a degree or two economically.

Thanks for the feedback!!

GUITARJUNKIE28

stock radiator?

RCCAZ 1

iTrader: (10)

GUITARJUNKIE28,

Not sure I'm understanding your question? Yes, I have an upgraded radiator (Mazdacomp) and the cooling system is optimized to the max (i.e., 70/30 water to coolant mix, new hoses, extra ducting aroud rad/condensor assy to improve airflow).

Freeway running temps on my Power FC with the AC running on 114F day were around 98 to 99C (~210F). Turn the AC off and it drops to around 95C. It would just be nice to pull it down a few more degrees with the AC running, since driving at 114F with the AC off is not a whole lot of fun

7racer

rccaz,

I might get flamed for this...but all I can tell you is my experience. When I had the stock thermostat in the car I would also run similar temps (~98) on a 100 degree texas day. I also did all of the upgrades with the ducting, radiator, pfc adjustment for fans etc.

However, the biggest difference in temp came after I changed to a lower temp (the old pettit one) thermostat. I know that once the car gets warm enough that the thermostats are all fully open regardless of the initial temp. Also I know that warm up is slow (which it is). However at cruise my temps with 70/30 was 78degress I actually switched to Evans to keep the temp up a bit. Also driving it hard would raise the temp but sustained cruising would bring it right down. Also, my PFC has the fans come on so I rarely see above 100 even with the Evans (note haven't boosted on the new engine with Evans yet).

Take the info for what its worth. Changing the thermostat was the thing that effected my temps the most dramatically.

RCCAZ 1

iTrader: (10)

7racer,

Interesting experience. My assumption based on your experience would be that the cooler temp stat actually CAN make a difference. I noticed that Chuck from RotaryExtreme has a SARD 68 degree C thermostat listed on his web site. Pretty pricey at $85, but it might make a huge difference during the summer months, especially running on the freeway. My only fear would be getting the car up to temp during the cooler time of the year. Might have to go with seasonal thermostat swaps, or just live with the slightly higher temps. We'll see, but thanks for the info!