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What is the bearing life expectancy of an alternator not designed to have the mass of a 911 fan attached to it ? Is this a non issue ?



EDIT: I didn't previously notice that the housing , etc. were non OEM and made for the application. Judging by Jonny's other products, i'm sure bearing capacity was considered in design.

Last edited by LJ851; 03-13-2018 at 08:50 AM..
Old 03-12-2018, 05:36 PM
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I believe this alternator was designed to take the lid of the fan. As for other alternators made to fit, I’d guess not super long.
Old 03-13-2018, 07:06 AM
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Quote:
Originally Posted by Jonny H View Post
Sorry for the slightly negative response but we are dedicated to providing fully integrated and elegant solutions for these beautiful machines.
Amen to that!! No reason to apologize. Keep up the great work!
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Old 03-13-2018, 07:46 AM
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Quote:
Originally Posted by LJ851 View Post
What is the bearing life expectancy of an alternator not designed to have the mass of a 911 fan attached to it ? Is this a non issue ?



EDIT: I didn't previously notice that the housing , etc. were non OEM and made for the application. Judging by Jonny's other products, i'm sure bearing capacity was considered in design.

Yes, the billet casing has been designed from scratch to be a direct fit to the early fan housing. We will provide billet spacers for mid year and C3.2 applications.

The shaft is custom too, allowing direct fit of the standard fan.

There is nothing special about the bearings in the standard alternator. The extra side load caused by the fan is insignificant compared to that of the belt. We did have concerns about the fan causing extra drag on the belt at higher loads, but this does not appear to be a problem, even at 145A.

The 911 is unusual (no surprise!) in that the belt is in contact with almost 180 degrees of the the pulley which helps a great deal. Having that amount of 'wrap' allows a single V belt to transmit greater load than ina typical 'triangular' belt arrangement.

Porsche's design of the split pulley and its shim stack is engineering genius.
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Old 03-13-2018, 10:59 AM
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The split pulley s great unless you try to change a fan belt in a 914-6. It can be done, but might be less frustrating to simply drop the engine, adjust the valve and replace the fan belt, then reinstall the engine. Great work on the alternator and AC system- keep up the wonderful upgrades!
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Old 03-13-2018, 11:21 AM
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Jonny H,

It's interesting reading your other AC thread that someone pointed out to you the benefits of a better alternator in place of the original compressor 2 years ago.

And you responded with

Quote:
Originally Posted by Jonny H View Post
That's something we have considered and is straightforward enough to do but I don't think it is necessary. I currently run a 3.2 90A alternator in my SC, which gives me a 70A headroom for the A/C. Even in the test chamber at 115F, we were only drawing 50A.

Classic Retrofit: Lightweight Electric Air Conditioning

Did the beta testing change your mind ?

I'll invite you to share those technical findings based on the real world tests so this technical forum can benefit from your experiments. There's nothing wrong with learning by trial and error, BTW.
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Old 03-13-2018, 12:21 PM
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This alternator project is more about enabling electric heat and other projects to be a possibility. E.g. Heat needs double the amount of power that cooling does for the same kW output.

Sure, it means you can drive the AC harder.

Stronger, harder, better, faster...
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Old 03-13-2018, 02:12 PM
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Johnny,

Not a customer yet, but very much appreciate the cool things you’re working on for these cars.

If you’re taking requests, an engine management computer that can be mounted in the engine compartment would be sweet- mounting an unprotected unit under the seat of a targa has moisture risks and wiring is a hassle.

Best,
Rutager
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Old 03-13-2018, 02:16 PM
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With the belted in place, the inline alternator can be removed I would think. Helps preserve the fan housing with the reduced load and decouples the fan speed from alternator, better in slow traffic. A dedicated pulley will also drive a bigger alternator than the inline given the single belt limits and additional space on the side compared with shoehorning into the fan. Your replacement already requires a new harness so that's a wash.

I'll sacrifice some engine compartment aesthetics, which won't be a lot given I'm running a stock CIS system now , for better cooling and cheaper maintenance.
+1. Salient points in favor of separating the fan from the alternator. But yes, with an AC compressor and an alternator on either side of the fan, that would add stuff to the engine compartment unless future tech provides us with smaller, more efficient units.

At any rate, the benefits would outweigh the minuses and probably minimize maintenance and overstressed fan housings (e.g. want momentary +5 HP? Switch alternator charging off or install an AC-like clutch pulley). Just think of an external alternator as a beloved long lost EGR pump.

JohnnyH. Sorry to digress. The high capacity alternator does provide certain advantages.

Sherwood
Old 03-13-2018, 02:36 PM
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Guys, this idea of having an external alternator, so many issues.

1) You'll have to run a gutted out alternator... That's not a fun job.
2) Or make a precision shaft and bearing carrier for the fan. 3 of them in fact for the different shaped housings.
3) And make a mount and adjuster for the alternator. Where, how?
4) If you leave the original alternator and run it unplugged, it will be destroyed electrically.
5) if you leave it plugged in, it will not play nice with the external one. It certainly won't 'add' power, rather just make the weaker one 'lazy'. The igniton light won't work properly either.
6) How will you tell if your fan belt has snapped? Igniton warning light would be on external alt.
7) Not all cars have an 'accessory pulley'. Have to buy a new crank pulley and fit.
8) Can't fit to a car with an air pump and AC.
9) Won't fit any Turbo (pretty much all have AC and intercooler blocks the other side)
10) You'd have to get the wiring harness out of the shroud , reroute, extend it and fit a plug. Ugh.

I haven't even got to the bit about ugly...

If you want to pursue this, please go and do it. Talk is cheap.
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Old 03-13-2018, 03:14 PM
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Quote:
Originally Posted by Jonny H View Post
Guys, this idea of having an external alternator, so many issues.

1) You'll have to run a gutted out alternator... That's not a fun job.
2) Or make a precision shaft and bearing carrier for the fan. 3 of them in fact for the different shaped housings.
3) And make a mount and adjuster for the alternator. Where, how?
4) If you leave the original alternator and run it unplugged, it will be destroyed electrically.
5) if you leave it plugged in, it will not play nice with the external one. It certainly won't 'add' power, rather just make the weaker one 'lazy'. The igniton light won't work properly either.
6) How will you tell if your fan belt has snapped? Igniton warning light would be on external alt.
7) Not all cars have an 'accessory pulley'. Have to buy a new crank pulley and fit.
8) Can't fit to a car with an air pump and AC.
9) Won't fit any Turbo (pretty much all have AC and intercooler blocks the other side)
10) You'd have to get the wiring harness out of the shroud , reroute, extend it and fit a plug. Ugh.

I haven't even got to the bit about ugly...

If you want to pursue this, please go and do it. Talk is cheap.
Numbered items to address:
2. Yes a bearing carrier for the fan, now devoid of a weighty rotating stator. Stress is reduced due to minimized rotating inertia.
3. A mount would work as if there were an A/C compressor on the pass. side. Obviously those two can't occupy the same space, thus A/C-equipped car lose; or install a similar mount to the left of the fan housing.
4/5. Alternators require current flow through the stator to generate a magnetic field (and electricity). Assuming elec. connections to alternator are deleted, w/o current flow, it's merely dead weight. Chuck the factory alternator or use just a shaft to support the fan assembly.
6. An issue, but not insurmountable. Both fan and remote alternator could share the same drive belt (V or serpentine belt), or install a sensor to monitor belt tensioner position and/or fan speed.
7. Agree unless a single belt drives both
8. Agree
9. Agree
10. Agree. Bypass the shroud. Chassis harness connects directly to the alternator harness.

Agree, and the admission price to exchange ideas here is cheap. We're not in the engineering/prototyping stage, just tech brainstorming. It's not as though this hasn't been done before. To avoid confusion, I'm not attempting to circumvent/minimize your worthy product, and yes, we did segue from the main topic. Sorry. At this point, your high output alternator sounds like a more viable product than a non-competing fantasy external alternator.

Reminds me of several attempts to build a flat cooling fan. If naysayers prevailed, no one would ever attempt it.


Air-cooled Porsche Flat Fan Kit in Testing (Video) - Ferdinand
Old 03-13-2018, 06:43 PM
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Yeah, the belted comparo is a digression. However, in all engineering work, there is no solution without challenges to be surmounted so it is good to hear your technical rationale for not selecting that design.

As Sherwood pointed out, 4 is a nonissue. In the alternator, there's no current to create the magnetic field to induce the current from the rotation.

Quote:
Originally Posted by Jonny H View Post
Stronger, harder, better, faster...
Totally agree.

Going back to discussing your inline design, what is the practical limit in your estimation for future improvements ?
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Old 03-13-2018, 11:27 PM
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^ Nice Motor.

I was just trying to illustrate that an external alternator is a more complex solution. What is the advantage to it? Stress caused by alternator inertia? That's an assumption. The fans crack as well remember.

The idea was put forward as 'just fit a second unit' like it was a walk in the park and the inference was a cheap solution. The reality would be very different.
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Old 03-13-2018, 11:54 PM
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I have a rash idea here. Jonny & Co are building a high out put alternator to replace the factory ones. They chose this route for the whole host of reasons they have listed, and many others I am sure, and this is their thread.

Why don't we leave this thread about their product, and all the "arm chair engineers" can start another thread talking about their own ideas on how to make an external one work. I am sure Jonny would chime in on that one and lend his experience in a positive manner. If you don't like Jonny's path forward, if other ideas are so good, build a better mouse trap yourselves in another thread.

It is so frustrating to see an actual business with actual real & great products, bring us a good new product in the latter stages of development so we can have some input into the final product, and others have to "think they know better," and clutter up the OP's thread with their own ideas. Most of these people have no products in this marketplace, and have no clue how to bring them to the market in a profitable and well received manner....wonders of the internet I know. No one pee'd in my cheerio's, it's just that this is the third thread, on the third board today, that I have been reviewing where this exact behavior manifests itself. I am also not trying to bust anyones balls in this thread, as this is written a bit tongue-in-cheak. I am more trying to offer up a suggestion.
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Last edited by Duc Hunter; 04-13-2018 at 05:24 AM..
Old 04-04-2018, 09:16 AM
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Please keep us updated on when this might ship as a Beta or actual product. Keep on building great new products for our old cars!
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Old 04-04-2018, 09:42 AM
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We are looking at some time in May for production units.
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Old 04-04-2018, 01:32 PM
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Oh I can't wait... my car is once again having alternator problems so I'm holding out for this baby.... replacing the alternator was a pain the back...literally, so I'm only looking forward to doing this once more...

Can you provide any estimates on cost?
Old 04-12-2018, 09:46 AM
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Old 05-22-2018, 11:51 AM
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Pretty sweet. Is the voltage regulator adjustable at all? It'd be nice to clear 14v at the battery.
Old 05-25-2018, 11:24 AM
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Pretty sweet. Is the voltage regulator adjustable at all? It'd be nice to clear 14v at the battery.
It is but you're seeing my in dash meter which is 0.3v below the battery voltage. You'll always get some voltage sag on high continuous loads. Drop a feather on the throttle and you're above 14V.

Most 911's struggle to hold 12v with all the toys switched on at idle
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Old 05-25-2018, 11:37 AM
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