911 fan belt sizes, 2.7 |
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911 fan belt sizes, 2.7 |
mate914 |
Aug 28 2023, 04:27 PM
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#1
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Matt Group: Members Posts: 793 Joined: 27-February 09 From: Eagles mere, PA Member No.: 10,102 Region Association: North East States |
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mb911 |
Aug 28 2023, 04:32 PM
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#2
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914 Guru Group: Members Posts: 7,213 Joined: 2-January 09 From: Burlington wi Member No.: 9,892 Region Association: Upper MidWest |
I believe stock is 710. That said there likely is a mismatch of your belt doesn’t fit. You have to either match the pulleys or buy 4 different size belts until you find the right fit.
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mate914 |
Aug 28 2023, 05:07 PM
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#3
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Matt Group: Members Posts: 793 Joined: 27-February 09 From: Eagles mere, PA Member No.: 10,102 Region Association: North East States |
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brant |
Aug 28 2023, 05:29 PM
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#4
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914 Wizard Group: Members Posts: 11,771 Joined: 30-December 02 From: Colorado Member No.: 47 Region Association: Rocky Mountains |
Once upon a time I saw this discussed on the pelican 911 forums
Not sure if there was a chart or just comments about them We tested the large pulley in a non oem combination to increase fan speed Played the belt game a half dozen times Loving the hole in the firewall |
mskala |
Aug 28 2023, 05:33 PM
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#5
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R Group: Members Posts: 1,926 Joined: 2-January 03 From: Massachusetts Member No.: 79 Region Association: None |
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mskala |
Aug 28 2023, 05:34 PM
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#6
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R Group: Members Posts: 1,926 Joined: 2-January 03 From: Massachusetts Member No.: 79 Region Association: None |
And some text I saved a long time ago:
--------------------------------------------- Guys: There's still some misinformation floating around here .... the small fan pulleys are 3.125", or 3.25" ( 80 vs 83 mm). Why such small change was ever made we'll never know. Notice that the pulleys are "pulley-halves". You can't simply change the upper fan pulley without also changing the mating fan ( which has the other "pulley-half" surface on it). From my notes...and this is inconsistently shown in the various parts books, so don't hold me to it, it may be one model year "off": 1965-74/75.. 110 mm crank pulley..95 mm fan pulley 1976-77... 130 crank...83 fan ( may be 80?) 1978-79....130 crank... 80 fan ( or was that 83?) 1980-89.....120 crank....83 fan ( or was that 80?) for fan sizes / blades / air flow: 1965-74/75....245 mm / 11 blade... 1.3:1 ratio..1390 liters air/sec 1975/76- 77.....245 / 5 blade.......1.8:1 ratio....1265 l/sec 1978-79...........226 / 11 blade ...1.8:1 ratio...1380 l /sec 1980-89.........245 mm / 11 blade...1.67:1 ratio...1500 l/ sec Turbos used the 245/11/ 1500 set up. Interestingly... the later curved fans for the 964 were quieter ( by being curved)...but resulted in lower flow: -- 1.6:1 ratio..1010 l /sec (!). fan belt sizes: 1965-75....9.5 x 710 1976-77.....9.5 x 725 1978-79....9.5 x 725 1980-on.... 9.5 x 710 There are "borderline" years where these specs don't quite match...and the goofy 80 vs 83 negligable fan size difference doesn't help to sort this out either. It won't make a difference in performance but watch out of you mismatch a 80 and 83 pulley half. BTW....aftermarket will sell 9.5/10x 710 as being "equal" to 9.5. Don't buy it. There have been reported problems with this. If possible, buy from dealer or Pelican and ask for the right size. --Wil __________________ Wil Ferch 85 Carrera ( gone, but not forgotten ) Early 911 245 mm fan 1.3:1 pulley ratio 1390 ltr/sec @ 6100 rpm 1976-77 five bladed fan 1.8:1 pulley ratio 1265 ltr/sec @ 6000 rpm 1978-79 226 mm fan with 1.81:1 pulley ratio 1380 ltr/sec @ 6000 rpm Turbo fan 1.68:1 pulley ratio 1500 ltr/sec @ 6000 rpm 964 fan 1.6:1 pulley ratio 1010 ltr/sec @ 6100 rpm New twin turbo 1.8:1 pulley ratio 1210 ltr/sec @ 6100 rpm The crank alternator pulley sizes range as follows: 1. 2.0 thru 2.4 - 116 mm 2. 2.7 - 131 mm 3. 3.0 SC - 126 mm 4. 3.2 and 3.3 - 127 mm The factory used the same 245 mm fan and fan pulley for the 2.0 thru early 2.7 motors. This represented about a 13% change in fan/alternator speed for the same engine speed. This variation is small compared to the variation in engine speed over the operating range of the engine. The early 116 mm single crank pulleys can be used on all later model motors through the 3.2. __________________ Tom Butler 1973 RSR Clone |
windforfun |
Aug 28 2023, 05:34 PM
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#7
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Senior Member Group: Members Posts: 1,962 Joined: 17-December 07 From: Blackhawk, CA Member No.: 8,476 Region Association: None |
Wrap a string around the setup & measure it's length.
(IMG:style_emoticons/default/beer3.gif) (IMG:style_emoticons/default/beer3.gif) (IMG:style_emoticons/default/beer3.gif) |
mate914 |
Aug 28 2023, 06:58 PM
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#8
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Matt Group: Members Posts: 793 Joined: 27-February 09 From: Eagles mere, PA Member No.: 10,102 Region Association: North East States |
And some text I saved a long time ago: --------------------------------------------- Guys: There's still some misinformation floating around here .... the small fan pulleys are 3.125", or 3.25" ( 80 vs 83 mm). Why such small change was ever made we'll never know. Notice that the pulleys are "pulley-halves". You can't simply change the upper fan pulley without also changing the mating fan ( which has the other "pulley-half" surface on it). From my notes...and this is inconsistently shown in the various parts books, so don't hold me to it, it may be one model year "off": 1965-74/75.. 110 mm crank pulley..95 mm fan pulley 1976-77... 130 crank...83 fan ( may be 80?) 1978-79....130 crank... 80 fan ( or was that 83?) 1980-89.....120 crank....83 fan ( or was that 80?) for fan sizes / blades / air flow: 1965-74/75....245 mm / 11 blade... 1.3:1 ratio..1390 liters air/sec 1975/76- 77.....245 / 5 blade.......1.8:1 ratio....1265 l/sec 1978-79...........226 / 11 blade ...1.8:1 ratio...1380 l /sec 1980-89.........245 mm / 11 blade...1.67:1 ratio...1500 l/ sec Turbos used the 245/11/ 1500 set up. Interestingly... the later curved fans for the 964 were quieter ( by being curved)...but resulted in lower flow: -- 1.6:1 ratio..1010 l /sec (!). fan belt sizes: 1965-75....9.5 x 710 1976-77.....9.5 x 725 1978-79....9.5 x 725 1980-on.... 9.5 x 710 There are "borderline" years where these specs don't quite match...and the goofy 80 vs 83 negligable fan size difference doesn't help to sort this out either. It won't make a difference in performance but watch out of you mismatch a 80 and 83 pulley half. BTW....aftermarket will sell 9.5/10x 710 as being "equal" to 9.5. Don't buy it. There have been reported problems with this. If possible, buy from dealer or Pelican and ask for the right size. --Wil __________________ Wil Ferch 85 Carrera ( gone, but not forgotten ) Early 911 245 mm fan 1.3:1 pulley ratio 1390 ltr/sec @ 6100 rpm 1976-77 five bladed fan 1.8:1 pulley ratio 1265 ltr/sec @ 6000 rpm 1978-79 226 mm fan with 1.81:1 pulley ratio 1380 ltr/sec @ 6000 rpm Turbo fan 1.68:1 pulley ratio 1500 ltr/sec @ 6000 rpm 964 fan 1.6:1 pulley ratio 1010 ltr/sec @ 6100 rpm New twin turbo 1.8:1 pulley ratio 1210 ltr/sec @ 6100 rpm The crank alternator pulley sizes range as follows: 1. 2.0 thru 2.4 - 116 mm 2. 2.7 - 131 mm 3. 3.0 SC - 126 mm 4. 3.2 and 3.3 - 127 mm The factory used the same 245 mm fan and fan pulley for the 2.0 thru early 2.7 motors. This represented about a 13% change in fan/alternator speed for the same engine speed. This variation is small compared to the variation in engine speed over the operating range of the engine. The early 116 mm single crank pulleys can be used on all later model motors through the 3.2. __________________ Tom Butler 1973 RSR Clone Thank you |
mate914 |
Aug 28 2023, 06:59 PM
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#9
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Matt Group: Members Posts: 793 Joined: 27-February 09 From: Eagles mere, PA Member No.: 10,102 Region Association: North East States |
Wrap a string around the setup & measure it's length. (IMG:style_emoticons/default/beer3.gif) (IMG:style_emoticons/default/beer3.gif) (IMG:style_emoticons/default/beer3.gif) Will do, thanks |
rgalla9146 |
Aug 29 2023, 06:21 AM
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#10
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Advanced Member Group: Members Posts: 4,641 Joined: 23-November 05 From: Paramus NJ Member No.: 5,176 Region Association: None |
The old standard 911 belt sizes were 9.5 x 710 or 9.5 x 725 On my 911 SC engine for some reason a 735 or 740 seems necessary |
mate914 |
Aug 29 2023, 10:17 AM
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#11
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Matt Group: Members Posts: 793 Joined: 27-February 09 From: Eagles mere, PA Member No.: 10,102 Region Association: North East States |
The old standard 911 belt sizes were 9.5 x 710 or 9.5 x 725 On my 911 SC engine for some reason a 735 or 740 seems necessary I think I’m going to get a few belt sizes tomorrow. My SC engine used 710 or 725. I am going to measure the pulleys tonight and post. Matt |
rgalla9146 |
Aug 29 2023, 05:28 PM
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#12
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Advanced Member Group: Members Posts: 4,641 Joined: 23-November 05 From: Paramus NJ Member No.: 5,176 Region Association: None |
oops
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