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No blow hard here ...:-) HVAC Fan power

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Old 09-29-2013, 08:29 PM
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Crazy Eddie

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Default No blow hard here ...:-) HVAC Fan power

Hey all
I was over Tom's today trying to do a A B comparison on the HVAC fan blowing capability of each system
Well.....
Turns out Tom blows much harder
Like 2x + more powerful than mine
He was kind enough to swap out the resistor pack in his and we tried that swap resistor pack on mine, but really did see much of a difference if at all ... Mine was still under-powered compared to his
I wish I asked others when we had a small meet last week to sit in their car and see the difference as to how theirs blows ..
What's even stranger, is that I think this has always been the way the fan speed pushed the air in my car ...
Tom's is like on steroids !! His # 2 speed is like my #4 speed
Any insight from you guys out their would be greatly appreciated ..
Possible causes and places to look ( as to why mine fan speed is so under-powered
BTW I should be clear on one issue. My A/C compressor is not hooked up to the Alternator belt, so its just idle, as in not running .... ( I have no idea if that would make any difference in affecting the fan speed, but just wanted to mention it)
Also, I did a number of searches both on Rennlist and Google, and came up with very little
Thanks in advance
Ed
Old 09-29-2013, 08:34 PM
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gruhsy
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All of the polished parts are causing severe air turbulence under your hood
Old 09-29-2013, 08:37 PM
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Crazy Eddie

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Originally Posted by gruhsy
All of the polished parts are causing severe air turbhttps://rennlist.com/forums/944-turbo-and-turbo-s-forum/778914-no-blow-hard-here-hvac-fan-power.htmlulence under your hood
LOL
Jeezz.... how did I miss that
Old 09-29-2013, 08:57 PM
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Tom M'Guinn

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After you left I looked in PET and it shows the same part number for the blower motor/squirrel cages between 86 and 88, so it doesn't look like they intentionally changed that. I found the motor connector (right in front) so we could always test the resistance of your motor (mine was less than half an ohm). Looking at the schematic, I'd be inclined to switch out relay G1 to see if that has any effect -- that's where the blower gets 12v so if the contacts are poor inside the relay, that could explain your low fan output. Also check ground MPIII, which is where the climate control/fan gets ground. If we try applying 12v directly to the fan and it blasts away like mine, then somewhere you're power is finding resistance -- ground, relay, or (drum roll....) in the climate control box/switch...
Old 09-29-2013, 09:54 PM
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Crazy Eddie

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Originally Posted by Tom M'Guinn
After you left I looked in PET and it shows the same part number for the blower motor/squirrel cages between 86 and 88, so it doesn't look like they intentionally changed that. I found the motor connector (right in front) so we could always test the resistance of your motor (mine was less than half an ohm). Looking at the schematic, I'd be inclined to switch out relay G1 to see if that has any effect -- that's where the blower gets 12v so if the contacts are poor inside the relay, that could explain your low fan output. Also check ground MPIII, which is where the climate control/fan gets ground. If we try applying 12v directly to the fan and it blasts away like mine, then somewhere you're power is finding resistance -- ground, relay, or (drum roll....) in the climate control box/switch...
OK.... so I just came back from Tom's again. He was able to figure out how to bypass everything and go to the motor directly and still the output is the same
Tom has a HVAC blower that is on steroids !!!
I am thinking of reporting him to the anti doping commission
Does anyone have both an 86 and an 88 and see differences in the fan blowing capability ? ? Maybe the part numbers are the same but the motors put out different CFM's
Regards
Ed



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