Damn Holley

1969_Mach1 · October 29, 2014

I think with 35 nozzle you may need a hollow nozzle screw per Holley's recommendations.

If everything is correct on a Holley, sometimes is takes a 50cc accelerator pump to overcome a stumble. This is more common on single plane intakes since each cylinder draws from both sides of the carb, the velocity through each booster is less, therefore, they do not start up as soon. If in the future you look into a new carb I would recommend, if at all possible, get something with Annular Boosters. They are the most sensitive, start up with lower air velocities, atomize fuel better, eliminate some drivability issues, and provide crisper throttle response when compared to a down leg or straight leg booster.

Edited October 29, 2014 by 1969_Mach1

barnett468 · October 29, 2014

I don't want to run 14 plus degrees of initial timing, there really is no need for it I don't think..., plus I have no way of detecting detonation on acceleration its just to loud inside.

put your finger over the vacuum port on the passenger side of the carb . . if there is noticeable vacuum then your butterflies are too far open as mentioned.

if this is the case, you can drill holes in the front plates or open the rear plates slightly and try that but because you will still be getting the same air flow i doubt it will change anything .

if your rpm increase with more initial timing then advance the distributor and then you can close the plates more. . this will make it idle smoother and run cooler at idle and may reduce or eliminate the dieseling if lowering the gas level has no affect.

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no test = no results

plus I have no way of detecting detonation on acceleration its just to loud inside.

if your rpm increases noticeably and the engine does not run rougher it is not dieseling. if increasing the timing reduces dieseling then simply reduce the mechanical advance in the distributor by the same amount you advance the timing then install 1 slightly stiffer spring on the advance to slow the curve down a bit . . very easy, very simple.

Edited October 29, 2014 by barnett468

barnett468 · October 29, 2014

I don't want to run 14 plus degrees of initial timing, there really is no need for it I don't think..., plus I have no way of detecting detonation on acceleration its just to loud inside.

put your finger over the vacuum port on the passenger side of the carb . . if there is noticeable vacuum then your butterflies are too far open as mentioned.

if this is the case, you can drill holes in the front plates or open the rear plates slightly and try that but because you will still be getting the same air flow i doubt it will change anything .

if your rpm increase with more initial timing then advance the distributor and then you can close the plates more. . this will make it idle smoother and run cooler at idle and may reduce or eliminate the dieseling if lowering the gas level has no affect.

.

no test = no results

plus I have no way of detecting detonation on acceleration its just to loud inside.

if your rpm increases noticeably and the engine does not run rougher it is not dieseling. if increasing the timing reduces dieseling then simply reduce the mechanical advance in the distributor by the same amount you advance the timing then install 1 slightly stiffer spring on the advance to slow the curve down a bit . . very easy, very simple.

Edited October 29, 2014 by barnett468

barnett468 · October 29, 2014

am considering going to a Double pumper with electric choke it just seems that this thing may need double 50cc Accelerator pumps to perform at its best LOL...

50 cc pumps won't make any difference for your dieseling problem.

Gonna get some good 91 Octane gas with no Ethanol OR should I just go with 93 Octane with Ethanol.....Both are sold at the pump by my house, Along with Sunco 110 plus LOL

ethanol reduces detonation. if your dieseling is due to your cheap 87 octane gas the 93 will reduce it more than the. 91 will.

barnett468 · October 29, 2014

am considering going to a Double pumper with electric choke it just seems that this thing may need double 50cc Accelerator pumps to perform at its best LOL...

50 cc pumps won't make any difference for your dieseling problem.

Gonna get some good 91 Octane gas with no Ethanol OR should I just go with 93 Octane with Ethanol.....Both are sold at the pump by my house, Along with Sunco 110 plus LOL

ethanol reduces detonation. if your dieseling is due to your cheap 87 octane gas the 93 will reduce it more than the. 91 will.

barnett468 · October 29, 2014

if you are running heat range 5 you can try the next colder plug.

if your water temp is over 200, it will likely contribute to dieseling.

.

barnett468 · October 29, 2014

if you are running heat range 5 you can try the next colder plug.

if your water temp is over 200, it will likely contribute to dieseling.

.

Max Power · October 29, 2014

There is nothing wrong with street avenger carbs. They are not very different from the previous edition vacuum secondary carbs except some adjustability and lighter weight. No idea why people would be afraid of them.

I often crack the secondary plates at idle to make up for big cams. The biggest problem I have with that is that the adjustment screw points straight down, meaning you have to pull the carb for every adjustment. I hate that. Still better than drilling though. The fast idle cam for the choke is also really annoying.

Max Power · October 29, 2014

There is nothing wrong with street avenger carbs. They are not very different from the previous edition vacuum secondary carbs except some adjustability and lighter weight. No idea why people would be afraid of them.

I often crack the secondary plates at idle to make up for big cams. The biggest problem I have with that is that the adjustment screw points straight down, meaning you have to pull the carb for every adjustment. I hate that. Still better than drilling though. The fast idle cam for the choke is also really annoying.

1969_Mach1 · October 29, 2014

I agree, on vacuum secondary carbs it is difficult to adjust the secondary throttle plates. They make a lever for DP carbs to adjust the secondary throttle plates from the top. Why they don't offer something for vacuum secondary carbs is beyond me. Most people set the primary throttle plates where they should be and use the secondary throttle plates to fine tune the idle speed.

1969_Mach1 · October 29, 2014

I agree, on vacuum secondary carbs it is difficult to adjust the secondary throttle plates. They make a lever for DP carbs to adjust the secondary throttle plates from the top. Why they don't offer something for vacuum secondary carbs is beyond me. Most people set the primary throttle plates where they should be and use the secondary throttle plates to fine tune the idle speed.

barnett468 · October 29, 2014

.

One main reason it is better to drill the front plates instead of simply opening the secondaries to increase idle is because there is no idle circuit in the secondaries.

It has been std practice to modify some carbs this way for st least 50 years that I know of.

The following is an excerpt from Drag Race Magazine 2013.

"When all idle mixture and throttle plate position adjustments are exhausted, we must move on to modification.

…drill holes in the primary throttle plates.

Holley recommends starting with a 3/32-inch bit drilling carefully into the mid-point between the center and the outer edge of the plate on the front half."

http://www.dragracermag.com/solve-idle-dilemmas-without-misusing-throttle-plates/

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Edited October 29, 2014 by barnett468

barnett468 · October 29, 2014

.

One main reason it is better to drill the front plates instead of simply opening the secondaries to increase idle is because there is no idle circuit in the secondaries.

It has been std practice to modify some carbs this way for st least 50 years that I know of.

The following is an excerpt from Drag Race Magazine 2013.

"When all idle mixture and throttle plate position adjustments are exhausted, we must move on to modification.

…drill holes in the primary throttle plates.

Holley recommends starting with a 3/32-inch bit drilling carefully into the mid-point between the center and the outer edge of the plate on the front half."

http://www.dragracermag.com/solve-idle-dilemmas-without-misusing-throttle-plates/

.

Edited October 29, 2014 by barnett468

1969_Mach1 · October 29, 2014

You are correct in that they all do not have a adjustable secondary idle mixture circuits. All the Holley's I've seen without adjustable secondary idle mixture circuits have fixed secondary idle mixture circuits. Sometimes referred to as a constant bleed circuit. I've read the reason is to maintain a constant fresh fuel supply in the secondary fuel bowl during time periods when the secondaries do not get opened. That seems reasonable. But in extreme cases you can have a situation where the secondaries are open too far to obtain a desired idle speed. Then as you mentioned drilling or installing Holley's predrilled throttle plates are needed to let more air into the motor at idle.

1969_Mach1 · October 29, 2014

You are correct in that they all do not have a adjustable secondary idle mixture circuits. All the Holley's I've seen without adjustable secondary idle mixture circuits have fixed secondary idle mixture circuits. Sometimes referred to as a constant bleed circuit. I've read the reason is to maintain a constant fresh fuel supply in the secondary fuel bowl during time periods when the secondaries do not get opened. That seems reasonable. But in extreme cases you can have a situation where the secondaries are open too far to obtain a desired idle speed. Then as you mentioned drilling or installing Holley's predrilled throttle plates are needed to let more air into the motor at idle.

BuckeyeDemon · October 30, 2014

i think you need more initial timing (especially if you only have a mechanical advance).

BuckeyeDemon · October 30, 2014

i think you need more initial timing (especially if you only have a mechanical advance).

sportsroof69 · October 30, 2014

You don't have enough initial timing for your combo. If you get the initial closer to 16, I'd bet your problems will get better.

sportsroof69 · October 30, 2014

You don't have enough initial timing for your combo. If you get the initial closer to 16, I'd bet your problems will get better.

MikeStang · October 30, 2014

Well didnt get a chance to mess with it last night, I decided to go ahead and finish hooking up My AC hoses and pull a Vac on the system and let it sit overnight, then charge it this evening.

I will try a few more degrees of timing and see if it helps.

We have 91 Octane NON Ethanol gas and 93 Octane WITH Ethanol...whats the better choice? I would think the 93 would be better.

The car Idles Very smooth to have a cam the size that it does even at 650 RPM's "I have video just gotta post it"

I have Electric fans set to come on at 190 and it cools it down just fine...temp stays at 180 in traffic and cruising....

I Like the Street Avenger Carb dont get me wrong I just would like to get it tuned right. It seems to provide all the get up and Go that I need and I dont know that installing a bigger carb with 50 cc pumps would provide a noticeable difference in terms of performance.

I think I would get more performance gain by removing the 3.25 gears and installing 3.73s or 4.11s with my New 4R70W "Loving the Transmission..Thanks for the persuasion from board members to make the swap"

Guess I gotta get some timing tape or borrow a dial back timing light so I can see what the total advance is once I dial up the initial timing.... Uggghh I hate messing with this thing especially after I had it dynoed and all was perfect LOL

MikeStang · October 30, 2014