Holley question
Since I have never raced a car with a Holley on it or owned one, I have question.
I am working on a 440 6bbl car for the street everything I read says take idle vacuum and divide it by 2 to figure out the correct power valve. Is there any benefit running a high flow PV? How about on a race engine. I have my old stocker engine on a run stand and am playing with the 340 6pack setup just to learn a bit about it. Any suggestions? Thanks |
Re: Holley question
Sorry can't help, I have zero knowledge on drive ability. Only care about WOT and air-fuel.
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Re: Holley question
So Larry in your race setup do you use a Power Valve? Regular or high flow?
The more I mess with the Holleys the better I like my Thermoquad. |
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He is the guy that knows the in's&out's of the 6-bbl. |
Re: Holley question
A reasonable suggestion is to equip them as Chrysler did originally. Also, in high-performance street trim, a 6.5 valve is common with a single carb. I estimate a 6.5 or 5.5 will be just fine.
I expect you already know, no matter what level of tune or refinement you attain, it will get "yardage" not mileage :) |
Re: Holley question
OK I have decided I need to step out of the dark ages and get an wide band AFR gauge.
I am thinking An Innovate LM-2 Looking on their web site and e-bay there are many options, What recommendations would you guys have? I would use it on my street cars as well as the race car. |
Re: Holley question
Rod,
Before you choose the Innovate LM-2, take a look at the Daytona Sensors WEGO and the NGK. My experience is that their reading are more reliable than the Innovative and AEM. http://www.daytona-sensors.com/wego-...---8-cyl..html https://www.ngksparkplugs.com/produc...-ratio-monitor |
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On paper, the LM-2 looks good. I bought one and have had problems from day 1. Tech support ranged from decent to pretty sad. If I buy another, I'd give daytona a shot.
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It seems that guys either love the LM2 or hate it. I posted this same question on another website and they can't say enough good things about Innovate. Makes it difficult to decide. The Daytona is a bunch more money and I had never heard of them until now. Maybe I should just buy a Racepack and make it portable.
Keep the suggestions coming guys. |
Re: Holley question
I was told decades ago to remove the power valves on Holley carbs being used for all-out drag racing and simply jet the carb up 3 or 4 jet sizes. The rationale I was given (and it seems to make sense) is that power valves are devices that provide part throttle enrichment (i.e. they open when you depress the accelerator and vacuum drops to their approximate opening point), and drag race engines spend the entire run at WOT.
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Re: Holley question
The picking a power valve method of idling in drive makes no sense. The PV has no part in idling, so why idle in drive to pick a PV? If your PV is opening or effected by idle vacum something is wrong. Wrong PV could close at WOT if vacum rises. Not worth having a PV in a race engine.
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Therefore, if cost is the issue, I would recommend the NGK unit. It works great and very affordable. I can assure you there are many that have been disappointed with the LM-2 units due to issues and not being reliable. |
Re: Holley question
My problem with the LM-2 was with rpm. It would not display, record, or playback anything over 2K rpm. I tried multiple work arounds as per their tech support. After a year of playing around with it, I accepted the fact it didn't work as advertised. AFR displays ok.
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Re: Holley question
The amount of jet change needed when blocking off the power valve is determined by the PVCR (power valve channel restriction) - the 2 little holes under the power valve in the metering body. That can be as high as 10. But I never used the formula.
As for using the vacuum reading "at idle, in gear", it's just a reference to make sure that the power valve you start with isn't opening at idle, in gear. If the reading is 7" of vacuum, you'll need a power valve below that to avoid a constant over-rich condition - i.e.: 6.5, 5.5, etc.). It's simply an on/off switch. But as mentioned, it's often eliminated in a race application with success. It's more important in a street application that spends more time idling. |
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