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-   -   Faster Blower Motor Speeds? (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/faster-blower-motor-speeds-926039/)

SpinningDorito 04-15-18 12:24 AM


Originally Posted by DaleClark (Post 12268053)
Awesome! Thanks so much for putting in the work!

I think you may have hit upon a winning combo.

FYI, trick for putting a fan with too large of a hole on a smaller shaft - wrap the shaft in Teflon tape to widen the shaft enough. Sounds weird, but my 99 spec fans have been on 93 motors on my radiator for years now with this method with zero problems, and those fans run harder and faster.

I wonder if there are other sources for motors and fan blades that may be even better, like other Mazda models or even another Japanese car brand. But for now we have a good solution.

Any recommendation on where to get that RX-8 fan motor?

Dale

That's a good idea for getting the fan back on a stock shaft after expanding it. I'll keep that in mind if it comes up later.

I would guess that this is correct. Generally the OEMs source out to designated suppliers by model year groups, so it's pretty likely that some (probably most/all) early 90's Mazdas have a very similar blower. The only difference might just be how that vent is routed for the motor.

For the RX8 aftermarket units, I used Four Seasons. Their blowers are labeled as using unimotor motors, made in Canada. For the price, the quality seems good. I bought them on Ebay, but there might be other sources. 76903 should be the model number for the RX8 replacement. They also sell 35011 that is labeled for the RX7, but isn't available with blades. From the pictures they appear to be similar units, but 35011 may actually have the vent nipple for our blower assemblies which might save you some trouble.

speedjunkie 04-15-18 05:03 AM

That's great! Thanks so much for doing those tests. I might try an aftermarket RX-7 motor to see if there's a difference, and maybe some from other cars too if I can find some similar enough. But it'll be a few months still since I'm overseas again.

Is the difference pretty noticable? Do you think you'll be happy with it? I assume you measured the speed where it exits the vents, correct?

SpinningDorito 04-15-18 09:18 PM


Originally Posted by speedjunkie (Post 12268086)
That's great! Thanks so much for doing those tests. I might try an aftermarket RX-7 motor to see if there's a difference, and maybe some from other cars too if I can find some similar enough. But it'll be a few months still since I'm overseas again.

Is the difference pretty noticable? Do you think you'll be happy with it? I assume you measured the speed where it exits the vents, correct?

I did the tests using only the blower assembly and 12v directly to the blower motor, measuring the airflow from the single exit vent of the blower assembly (I have my interior pretty much stripped for renovations right now)

I expect the net result of changes I have made to my system to be quite noticeable, but changing out the blower motor was only one change out of many repairs that were needed. As I mentioned in a few earlier posts, all of my foam seals on the hvac couplings and the foam seals on the flappers were pretty much just dust, if they were still there at all.

I'll definitely report back once everything is installed and running, but it will be a little while. I still have to finish installing dynamat in the cabin and firewall, refurbish my firewall liner, install new carpet, address all the minor problems you find when you dig into your interior, etc etc before I can put the hvac and the dash back in. Its going to be a long road.

speedjunkie 07-18-18 02:19 AM

An FD owner on facebook was asking how to get his wipers to move faster and someone said he used these power converters to bump up the voltage on his windows to 18v and said they move as fast as on a new car. So that got me thinking, and I'm gonna try one of these on the blower motor and do the windows also.

https://www.ebay.com/itm/132699411232

SpinningDorito 07-18-18 09:59 AM


Originally Posted by speedjunkie (Post 12288871)
An FD owner on facebook was asking how to get his wipers to move faster and someone said he used these power converters to bump up the voltage on his windows to 18v and said they move as fast as on a new car. So that got me thinking, and I'm gonna try one of these on the blower motor and do the windows also.

https://www.ebay.com/itm/132699411232

A quick note if you haven't already ordered these, is that the maximum amps it can put out are 2.5. That probably won't be enough to drive your blower motor at any speed. 2 amps from my small test bench didn't get any reaction from it. You'd probably want to find one that can output something closer to what the blower fuse is rated for (but obviously a little bit below the fuse rating) ie, if the fuse is 25, I'd go with something that puts out 20 amps max.

The general rule of thumb is you can generally run a dc motor 50% over its rated voltage without overheating it and causing damage, so that would be 18v. However, that rule of thumb probably wasn't with 25 year old motors in mind. Just something to think about.

I had a friend that would put a couple of rare earth magnets on the DC motors for his RC planes to get more power out of them without causing additional burnout. Not sure that's easy to do on the window motors, but might be worth trying on the blower motor.

mikejokich 07-18-18 11:56 AM

Speedjunkie,
Use a DC-DC step up buck converter to try it. There are waterproof ones sold for golf carts, etc. These are rated at different amperages and different input and output voltages. I use a 12v to 24v one for my special 700cfm intake fan. Here is one on ebay.

https://www.ebay.com/itm/STEP-UP-Tra...itleDesc=0%7C0

Mike

speedjunkie 07-18-18 07:33 PM

Good call, thanks guys! I noticed the amperage was only 2.5 on the one I posted, but I didn't think about the motor needing more than that. The other guy used the one I posted on his windows on his FC, he said it worked great. I had already bought six of these haha, but luckily they didn't cost that much. It's good to have spares anyway.

Maybe I'll get a new blower motor just in case, along with the step up converter you posted and try some rare earth magnets first.

Thanks guys!

Additionally, the first three speeds of the blower would remain the same no matter if voltage is increased, but at least the fourth setting would be pushing more. If we could figure out how to wire in different resistors for the first three, we'd really be in business. I think this would be a pretty good interim fix though. Might even be enough of a difference.

rxsexen 12-28-20 12:14 AM

Thread resurrection....did anyone figure out how to make the blower push out more air

speedjunkie 12-28-20 01:58 PM

I bought one of those converters off eBay but haven't installed it yet. I got AC working last year but I guess all the refrigerant leaked out or something over the winter and this past summer I couldn't get AC working again. When it was working last summer I had really cold air from the vents so I didn't feel the need to step up the blower motor, it worked pretty well already.

rxsexen 12-30-20 07:45 PM

do you have a link to the converter your purchased

speedjunkie 12-30-20 10:11 PM

I got the same one Mike linked in post #56 above.

https://www.ebay.com/itm/STEP-UP-Tra...itleDesc=0%7C0


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