The JDM lower pulley is here
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From: SD, CA
BfB: just a thought, but I'm pretty sure that some chips out there are revving the motor closer to ~5600 right at the shift. If this is the case, and the #'s you listed are right , then:
7.5" dia lower pulley / 3" dia upper pulley = 2.5 ratio
5,600 rpm (crank) = 2.5 * 5,600 rpm = 14,000 rpm blower speed
Personally (yes, I know that this is going to sound ludicrous to some of you), since my L is my daily driver, I would rather give up the possibility of a little bit more performance for the sake of reliability. If what you said is true, and Eaton will "sign off" on these things to 14,000 rpm- then thats the # i'd be shooting for. Now, I'm not advocating one tuners design over the other, and for the record I'm not specifically for OR against ANY tuner out there (since I like stuff the all of them offer), but assuming that the aforementioned info holds true, I think the JDM pulley would be the best bet FOR ME. However, if your L is your Nth vehicle and only sees the strip on sunny days, then you're probably not as worried about the possibility of decreasing the overall life of the engine or blower over time as I am. Again, I'm not trying to sell anything, just giving my opinions as to the possible design intent behind the slightly smaller lower pulley. later...
7.5" dia lower pulley / 3" dia upper pulley = 2.5 ratio
5,600 rpm (crank) = 2.5 * 5,600 rpm = 14,000 rpm blower speed
Personally (yes, I know that this is going to sound ludicrous to some of you), since my L is my daily driver, I would rather give up the possibility of a little bit more performance for the sake of reliability. If what you said is true, and Eaton will "sign off" on these things to 14,000 rpm- then thats the # i'd be shooting for. Now, I'm not advocating one tuners design over the other, and for the record I'm not specifically for OR against ANY tuner out there (since I like stuff the all of them offer), but assuming that the aforementioned info holds true, I think the JDM pulley would be the best bet FOR ME. However, if your L is your Nth vehicle and only sees the strip on sunny days, then you're probably not as worried about the possibility of decreasing the overall life of the engine or blower over time as I am. Again, I'm not trying to sell anything, just giving my opinions as to the possible design intent behind the slightly smaller lower pulley. later...
Last edited by MXRacer; Jul 10, 2001 at 02:36 PM.
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From: Northern VA, USA
My thoughts:
1) I own the PSP pulley and like it. Its lighter by stock than 11 lbs. I dont have any concerns about weight on the crank. With the PSP, I really don't think the spider bracket is needed. Maybe it does reduce noise....
My Q: What are the effects of added boost on charge temps??? Is the added boost worth the added heat?? Especially in the Hotter southern temps???? Any gain above x lb's boost may be negated by the heat generation.....
While the Metco/ASP changable upper is a great idea...I'm still not that convinced that there is no concern with belt slip.
My Q #2: Has anyone (Vendor or User) tested both pullies in similar conditions and monitored temps, boost etc..etc..????
I can't believe that such a small difference in size would make a great difference in temp, but I ain't the mind behind the pullies........
Sal...JL...JDM....BABolt....
1) I own the PSP pulley and like it. Its lighter by stock than 11 lbs. I dont have any concerns about weight on the crank. With the PSP, I really don't think the spider bracket is needed. Maybe it does reduce noise....
My Q: What are the effects of added boost on charge temps??? Is the added boost worth the added heat?? Especially in the Hotter southern temps???? Any gain above x lb's boost may be negated by the heat generation.....
While the Metco/ASP changable upper is a great idea...I'm still not that convinced that there is no concern with belt slip.
My Q #2: Has anyone (Vendor or User) tested both pullies in similar conditions and monitored temps, boost etc..etc..????
I can't believe that such a small difference in size would make a great difference in temp, but I ain't the mind behind the pullies........
Sal...JL...JDM....BABolt....
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Thanks for the info,
Sounds like you just want to make sure your chip is tuned for the pulley you have. Personally I think I would rather have the boost come on harder and shift at 5300 as opposed to the smaller puuley and reving to 5600 RPM. On a street machine you want the power there as instantly as possible. Of course we are talking about a very minor difference, but from what I've read on this board the tranny's seem to last longer shifting at 5300. Its my opinion that the extra 500 RPM won't hurt the blower at all and I doubt the 2lbs of boost will hurt the engine either. Ford wouldn't have any of the components running at maximum tolerance from the factory.
Sounds like you just want to make sure your chip is tuned for the pulley you have. Personally I think I would rather have the boost come on harder and shift at 5300 as opposed to the smaller puuley and reving to 5600 RPM. On a street machine you want the power there as instantly as possible. Of course we are talking about a very minor difference, but from what I've read on this board the tranny's seem to last longer shifting at 5300. Its my opinion that the extra 500 RPM won't hurt the blower at all and I doubt the 2lbs of boost will hurt the engine either. Ford wouldn't have any of the components running at maximum tolerance from the factory.
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From: Mobile, AL, USA
Originally posted by 2002Lightning
Thanks for the info,
Sounds like you just want to make sure your chip is tuned for the pulley you have. Personally I think I would rather have the boost come on harder and shift at 5300 as opposed to the smaller puuley and reving to 5600 RPM. On a street machine you want the power there as instantly as possible. Of course we are talking about a very minor difference, but from what I've read on this board the tranny's seem to last longer shifting at 5300. Its my opinion that the extra 500 RPM won't hurt the blower at all and I doubt the 2lbs of boost will hurt the engine either. Ford wouldn't have any of the components running at maximum tolerance from the factory.
Thanks for the info,
Sounds like you just want to make sure your chip is tuned for the pulley you have. Personally I think I would rather have the boost come on harder and shift at 5300 as opposed to the smaller puuley and reving to 5600 RPM. On a street machine you want the power there as instantly as possible. Of course we are talking about a very minor difference, but from what I've read on this board the tranny's seem to last longer shifting at 5300. Its my opinion that the extra 500 RPM won't hurt the blower at all and I doubt the 2lbs of boost will hurt the engine either. Ford wouldn't have any of the components running at maximum tolerance from the factory.
I explained the reasoning for this here: https://www.f150online.com/forums/sh...hlight=optimal
The beauty of using a pulley is the fact that we can gain more rpm lower as well which in turn will increase the power curve even greater!
BfB
Last edited by BfB; Jul 10, 2001 at 03:03 PM.
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From: SD, CA
My bad...
My B...I just realized that #'s I used in my previous post were for the stock setup; not JDM nor PSP. So although I'm an idiot, I guess what all that really just meant is that a stock pullied L that shifts at 5,600 rpm isn't hurting the blower (but you can take Eatons word for it...cause I'm not signing anything! jk). Just out of curiousity (I'll try my best to stop turning this forum into Math 101), does anyone know what the actual diameter of the JDM is (and are 7.5" for stock and 8" for PSP the correct #'s)? thanks, later...
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Re: My bad...
Originally posted by MXRacer
My B...I just realized that #'s I used in my previous post were for the stock setup; not JDM nor PSP. So although I'm an idiot, I guess what all that really just meant is that a stock pullied L that shifts at 5,600 rpm isn't hurting the blower (but you can take Eatons word for it...cause I'm not signing anything! jk). Just out of curiousity (I'll try my best to stop turning this forum into Math 101), does anyone know what the actual diameter of the JDM is (and are 7.5" for stock and 8" for PSP the correct #'s)? thanks, later...
My B...I just realized that #'s I used in my previous post were for the stock setup; not JDM nor PSP. So although I'm an idiot, I guess what all that really just meant is that a stock pullied L that shifts at 5,600 rpm isn't hurting the blower (but you can take Eatons word for it...cause I'm not signing anything! jk). Just out of curiousity (I'll try my best to stop turning this forum into Math 101), does anyone know what the actual diameter of the JDM is (and are 7.5" for stock and 8" for PSP the correct #'s)? thanks, later...
I'm not sure what JDM's is, but it would be nice if any of them would state before they sell a product that could have extreme effects on the motor. Not saying they all haven't but there are some who have not. How bout someone measure it before they put it on?
BfB
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From: New Orleans
JDM post:
The stock pulley 7inch 400 thousands.
Our pulley 7inch 800 thousands.
Weight stock pulley - 7lbs
Our pulley - 3lbs
Our pulley boost increase with our chip over the stock pulley min 2lbs
Yes, our pulleys use the factory cage.
Hope this helps.
Jim@JDM
The stock pulley 7inch 400 thousands.
Our pulley 7inch 800 thousands.
Weight stock pulley - 7lbs
Our pulley - 3lbs
Our pulley boost increase with our chip over the stock pulley min 2lbs
Yes, our pulleys use the factory cage.
Hope this helps.
Jim@JDM
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From: SD, CA
The answers...
This was posted by Jim@JDM over at SVTperformance.com on 7/7/01:
The new machine shop that manufactured our pulley has produced us a perfectly balanced pulley. They are 4lbs lighter than the factory. The factory pulley specs are 7inch 400 thousands. Our pulley is 7inch 800 thousands. It produces exactly 2lbs of boost. We tested it on Bill's truck last nite at E-town. He has our warm weather program, 90mm, full Basani exhaust, our electric fan, TB. The reason why I mention these mods is b/c most of you are running these. Even with the shorty headers the pulley produced 2.3lbs of boost. With stock exhaust manifolds it will produce around 2.7 at shift points of 5500, air charge temp increased by 9 degrees. With our original design of 8inch, the air charge temp increased 22 degrees.
By "7inch 400 thousands" I would have to assume he means the stock pulley is 7.4" (the last two zero's are included just to show the level of machining tolerances), and his is 7.8". Regardless, I guess all my previous speculation as to why he chose to go with making a smaller lower pulley have been answered by the man himself (only 9 degree increase with the 7.8", instead of 22 degree with the original plan of an 8" pulley).
Again, I'm not saying the JDM one is superior (because right now I have neither), but I'd be interested to see why JDM and PSP got different measurements for the stock pulley (0.1"), and what boost vs. intake temp results Sal got. Sal (or anyone), care to comment?
The new machine shop that manufactured our pulley has produced us a perfectly balanced pulley. They are 4lbs lighter than the factory. The factory pulley specs are 7inch 400 thousands. Our pulley is 7inch 800 thousands. It produces exactly 2lbs of boost. We tested it on Bill's truck last nite at E-town. He has our warm weather program, 90mm, full Basani exhaust, our electric fan, TB. The reason why I mention these mods is b/c most of you are running these. Even with the shorty headers the pulley produced 2.3lbs of boost. With stock exhaust manifolds it will produce around 2.7 at shift points of 5500, air charge temp increased by 9 degrees. With our original design of 8inch, the air charge temp increased 22 degrees.
By "7inch 400 thousands" I would have to assume he means the stock pulley is 7.4" (the last two zero's are included just to show the level of machining tolerances), and his is 7.8". Regardless, I guess all my previous speculation as to why he chose to go with making a smaller lower pulley have been answered by the man himself (only 9 degree increase with the 7.8", instead of 22 degree with the original plan of an 8" pulley).
Again, I'm not saying the JDM one is superior (because right now I have neither), but I'd be interested to see why JDM and PSP got different measurements for the stock pulley (0.1"), and what boost vs. intake temp results Sal got. Sal (or anyone), care to comment?
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From: Billings, MT, USA
I believe that JDM reduced the diameter of the original pulley because of the heat generated, if my memory is correct, the original pulley raised the charged air temp 22 degrees, and the new pulley raised it only 9 degrees at max boost.
I guess I am to slow at posting.
I guess I am to slow at posting.
Last edited by MID_12s; Jul 10, 2001 at 03:18 PM.
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From: Mobile, AL, USA
I'm not sure how they measured, but if Sal's is .5 larger than the factory pulley then that means his is only .1 larger than JDM's regardless that JDM states his is 7.8 inches and Sal states his is 7.5.
Now comes the "?" of what actual rpms these things do spin now? Obviously they are getting two different measurements so it's kindof got me going "hmmmm" BfB
Now comes the "?" of what actual rpms these things do spin now? Obviously they are getting two different measurements so it's kindof got me going "hmmmm" BfB
Last edited by BfB; Jul 10, 2001 at 03:29 PM.
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Originally posted by JeffsLightning
You go BfB and get your slide ruler and calulator and gives us the numbers we are all looking for... L8r
You go BfB and get your slide ruler and calulator and gives us the numbers we are all looking for...
L8r
BfB
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From: NJ
Re: The answers...
Originally posted by MxRacer
By "7inch 400 thousands" I would have to assume he means the stock pulley is 7.4"
By "7inch 400 thousands" I would have to assume he means the stock pulley is 7.4"
Originally posted by BfB
I'm not sure how they measured, but if Sal's is .5 larger than the factory pulley then that means his is only .1 larger than JDM's regardless that JDM states his is 7.8 inches and Sal states his is 7.5.
I'm not sure how they measured, but if Sal's is .5 larger than the factory pulley then that means his is only .1 larger than JDM's regardless that JDM states his is 7.8 inches and Sal states his is 7.5.
Unless if Sals is .5 over stock that would make his 7.9" and JDM is 7.8" that would be over by .1.