Posted By: emarine01
Jetting? - 12/18/12 06:21 PM
Whats the deal with Holley jets #s 88 /89 /90.... they all have the same size hole 
Jetting?
Posted By: Cab_Burge
Re: Jetting? - 12/18/12 06:41 PM
Quote:The diameter is the same the, the angle (taper) on the back side of the hole is not
Whats the deal with Holley jets #s 88 /89 /90.... they all have the same size hole
According to Holley that is why they, the bigger numbered jets, flow more 
Posted By: Thumperdart
Re: Jetting? - 12/18/12 06:56 PM
And measured, those holes in that range are larger than stamped........
Posted By: emarine01
Re: Jetting? - 12/18/12 07:20 PM
Thankx guys It seems when I jet down from 90s to 88 there is very litle change - LM1- I go to 87 and go way lean, some what the same when I go to 91s
It seems when I jet down from 90s to 88 there is very litle change - LM1- I go to 87 and go way lean, some what the same when I go to 91s
Posted By: Thumperdart
Re: Jetting? - 12/18/12 08:52 PM
Quote:Have you fine tuned w/bleeds?
Thankx guys
Posted By: emarine01
Re: Jetting? - 12/18/12 10:33 PM
Yep... went from 31 to 29 on the HSAB after the first jetting from 88 to 90 showed no change, this make it too fat so I went down to 87s which made it too lean 
, the air temps were all over the place that week also so I switched to another carb that worked but was too small cfm wise its a demon 850 w/annular boosters which limits my rpm, We just stopped racing for the winter so I have some time to get it right, don't have that many HSABs to test with right now or too much experience fooling with the bleeds.
, the air temps were all over the place that week also so I switched to another carb that worked but was too small cfm wise its a demon 850 w/annular boosters which limits my rpm, We just stopped racing for the winter so I have some time to get it right, don't have that many HSABs to test with right now or too much experience fooling with the bleeds.
Posted By: Locomotion
Re: Jetting? - 12/18/12 11:27 PM
Standard Holley jets have some percentage of production tolerance, but i forgot what it is. But some may actually overlap in flow.
There are some close-tolerence jets that are available through Comp Cams and I believe Holley has some as well.
Myron
There are some close-tolerence jets that are available through Comp Cams and I believe Holley has some as well.
Myron
Posted By: Cab_Burge
Re: Jetting? - 12/19/12 02:31 AM
Which carb, brand, size and type, are you working on? If it is a stock Holley which List number is it with the dash number, IE List 4781-9 ?
Posted By: emarine01
Re: Jetting? - 12/19/12 04:15 AM
Quote:Its a BG race demon 1000, the best that I can tell its the same as the 850 annular I have but has down leg boosters & has +5 jets larger
Which carb, brand, size and type, are you working on? If it is a stock Holley which List number is it with the dash number, IE List 4781-9 ?
Posted By: Cab_Burge
Re: Jetting? - 12/19/12 06:12 AM
Quote:I would want to try #88 jets with a #30 HSAB. You really need to keep in mind when the weather is changing it is almost impossible to tune the carb. to perfection due to the changing temps, humidity and barometric pressure changes
Yep... went from 31 to 29 on the HSAB after the first jetting from 88 to 90 showed no change, this make it too fat so I went down to 87s which made it too lean
Humidity is a real big deal on tuning, water molicules really spread the oxygen molicules out, as you know water don't burn worth a hoot 
, even in alcholol 
I haven't play with any of the B.G. King Demons to speak of so I'm not much help, sorry
Posted By: emarine01
Re: Jetting? - 12/19/12 10:33 PM
Thakx Cab that sounds about right.... I am waiting on the air bleeds to show up, I used a friends LM1 and learned a lot, we will hunt down a LM1 or 2 @ this point.... I dont know how I got this far without one 
Posted By: Thumperdart
Re: Jetting? - 12/19/12 10:45 PM
I would even go as small as .026`s or 28`s on the high speed bleeds............ 