I remember reading about annular boosters not performing as good as the regulat drop leg style. I was hoping somebody could tell me why? I have a holley 830 with the annular boosters and the engine seems to be running rich. I remember hearing that they don't flow as good because the booster area is much bigger and takes up to much of the venturi opening. But doesn't an 830 cfm carb flow 830 cfm whether or not what style it is? I would have thought Holley would have designed the larger center area in when they sized the flow? Any feedback would be appreciated! I am thinking about replacing my Holley to something like a 900 to 1000 HP. I love how the annular boosters make the motor run though. Nice throttle response.
I run an 830 HP with drop leg boosters. Running 12:1 on a 455. Jets are 80 front 84 secondaries. Going to jet down a little at a time to get to 13:1. Nice flat fuel curve. I am going to switch back to my SP1 manifold and see what happens to the fuel curve. I do not think the carb would be big enough for my motor with annulars.
Doug, I have the sp1 now and seems to go good with it. i just don't like how high it is. won't let me use fresh outside air!
This topic has come up a few times. Here's an article that points towards annular: http://www.carcraft.com/techarticles/116_0508_carburetor_showdown/index.html
You are not the only one with the hood clearance problem. I have been fighting this for a few years. I was trying the B4B but did not solve a lot of problems because I needed to add an inch spacer to make my TV/throttle cable work (200r4 tranny.) Also boosted the bottom end torque so much that I could not get traction off the line like I was with the SP-1. The only air cleaner that fits is that triangle one from edelbrock. Run a vacuum guage and see what you are pulling at WOT (might need a passenger to check this, I tend to be busy at WOT :spank: ) Any more than 2 and you have a restriction or too small a carb. Less than 1 is good. What jets are you running? It would seem to me if you have to run below 75's you are out of the norm for what most of us are running. Another thing that I have noticed since running an AF meter is that if you are showing traditional rich on the plugs you are way rich. At 12:1 my plugs look lean. I think that is why so many people say that Buicks like to run lean, the plugs need to look lean to have good Air Fuel ratios.
i'm using the 830 annular holley also.i am not ready to give up on it yet, the throttle response is to good. on my car the a/f ratio follows the rpm richer as the rpms climb. stock jetting is 78 squared if you have a power valve in the rear. i had to increase my jets 2 sizes when i switched to 3" exhaust. when i get my wideband back(my friend is using it) i plan on messing with the emulsion holes and air bleeds to flaten out the a/f curve.
We should have an 830 hp group. :idea2: More people are using this carb than I thought. I will let everyone know what jets it took to run 13:1. Then will switch to the SP-1 and see what difference that makes. Dave tell us more about the air bleeds and emulsion holes. The air bleeds I know are used to change the upper end characteristics. Know nothing about the emulsion holes.
the emulsion holes are in the metering block. depending on the metering block there can be from 2 to 5 holes. the hole sizes and placement change the fuel curve,(make very small changes .001) the top holes are earlier in the rpm range and the lower holes are higher up in the rpm range. i haven't had a chance to test this myself but have been reading a lot. innovate motorsports(wideband o2) has a great tunning forum. you can find pics and detailed info for tunning emulsion holes and other parts of your carb. also great before and after results from other members. right now i'm at 80 primary and 91 secondary with the rear power valve plugged and jet extensions and .028 main air bleed. i have 13 to 1(in 3rd gear) a/f but in 1st and 2nd gear the a/f goes fat(12.2 to 1) as the rpm climbs. i wouldn't make any changes to these circuits without a way to verify(wideband o2 or dyno) what the outcome is.
Doug, I will test my vacuum at WOT. I need to buy a good vacuum gauge. I was hoping somebody to tell me what aircleaner they have on the SP1 intake. I can only fit a 2 1/2 inch high filter in mine. I really should have 3". I don't know much about the s/f ratio's yet but would like to dial mine in someday. As i said before i have the 830 annular carb and is all factory. I have not done anything with the jets yet. I just noticed how black my exhaust pipes are. I raced it last week and got a 13.7 @ 104.7 MPH with 3.08 rearend and street tires. I thought that was decent for the MPH, but my 0-60 time was bad at 2.4 sec. Gary
