"Best" carburetor choice(s) on which to focus tuning efforts?

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BradH
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Re: "Best" carburetor choice(s) on which to focus tuning efforts?

Post by BradH »

BradH wrote: Wed Jul 11, 2018 5:09 pm
steve cowan wrote: Wed Jul 11, 2018 4:23 pm ... and you know your stuff...
More accurate to say I ask a lot of reasonable(?) questions...
Hmmm... based on some comments posted on another forum, even that's being debated. :lol:
Last edited by BradH on Thu Jul 12, 2018 5:50 pm, edited 1 time in total.
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Re: "Best" carburetor choice(s) on which to focus tuning efforts?

Post by Mike Laws »

Given the carburetor/combinations that you have; the overall best for your BB Mopar and street/strip is probably going to be the 1.425 BG/Gold Claw/Braswell boosters carb. The 1.5 QFT/Proform/Braswell boosters should also run well. I'm generally not a fan of the large venturi/smal throttle bore carbs...

Those BB Mopars like a bigger carb, but only with a favorable venturi/throttle bore ratio. Your engine would run the best with a small Dominator or a Twin Blade, however it's noted that you're carburetor-heavy as it is.

As to the analog vs digital, efi thoughts; you can now have both with the ECI from K&N. I have much experience with it and it's going to be a game-changer for sure...

Best of luck. You're going to enjoy the testing of these...
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Re: "Best" carburetor choice(s) on which to focus tuning efforts?

Post by shoedoos »

^^^^^ Mike, is this the item you are talking about? Any insider info you can give us on the "game changer" status?

https://www.youtube.com/watch?v=BPLhN9Rd4BI
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Re: "Best" carburetor choice(s) on which to focus tuning efforts?

Post by andyf »

Brad, how are you going to go about testing the carbs? Bolt them on and drive them or are you going to try them all at the track too? I still think that the one which drives best around town might not make the most power. If they are both setup with the same fuel line and linkage then it only takes a few minutes at the track to swap from a street carb to a race carb so that isn't the worst outcome. Not sure any of those carbs are going to have great street manners but you might be able to get one of them to work halfway okay on the street. I'm guessing that most of them will work pretty well at the track.
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Re: "Best" carburetor choice(s) on which to focus tuning efforts?

Post by Mike Laws »

shoedoos wrote: Thu Jul 12, 2018 7:00 pm ^^^^^ Mike, is this the item you are talking about? Any insider info you can give us on the "game changer" status?

https://www.youtube.com/watch?v=BPLhN9Rd4BI
Yessir, however there is much more to it than the video lets on. Let's not derail Brad's thread though. I can PM you or you might start another thread about the eci...
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Re: "Best" carburetor choice(s) on which to focus tuning efforts?

Post by PRH »

For a "street carb", knowing I had a bigger race carb to install at the track....... I'd just buy a used 4779 and maybe put a HP body into it.

My experience is that those old school type DP carbs have a more street friendly low speed calibration.

It's worth noting that although not nearly enough time was available to sort out each of the carbs that were tested(which could have easily altered the rankings from best to worst), the biggest carb didn't make the most power. The smallest one put on the motor that day did.....barely. But it highlights that how well the carb does its job of mixing the air and fuel is important too.
Somewhat handy with a die grinder.
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Re: "Best" carburetor choice(s) on which to focus tuning efforts?

Post by BBO Omega »

I know a larger Carb can be tuned to run well at the track and still have pretty impeccable street manners......just not by me. I have a 1000hp [wet flows 992cfm] unit from Pro-Systems that runs really great straight out of the box. This is on a 468 Olds in a street car [11.32 at 118.7mph NA, 10.4 at 129.3mph 150hp N20]. I have sat still in traffic for 2+ hours in a parade on the boardwalk in OC without a single hiccup or fouled spark Plug. In fact the same plugs were in it for a later trip to the track. It is more responsive on the street than any carb I have ever owned [including a 830cfm Pro-Systems unit I had earlier].
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Re: "Best" carburetor choice(s) on which to focus tuning efforts?

Post by BradH »

I expect my testing will go pretty much as what I've done before, with the exception that I'll be using a wideband O2 setup to keep from going off the deep end:
--> Do initial car setup w/ the BG Gold Claw, since it ran decently before on the street; the QFT/Proform 1.45 would be a good street test, too
--> I've talked with a friend about going in on another track rental to work on the new combination; I want try out the other carbs on the track to see what gains may be found over the "street" carb
--> If I find a "winner" as far as on-track improvements, then my focus will shift to seeing how cleanly I can get it to run on the street, too
--> Ideally, I'd be down to one carb and the rest could be sold off to recoup some $$$
--> If I can't get the "Track King" carb to also run well enough on the street to suit my tastes, then I'll be keeping two carbs in the long run; swapping 'em ain't no biggie

It could be a lot fun and eye-opening. It could also be a major frustrating PITA. We'll see...
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Re: "Best" carburetor choice(s) on which to focus tuning efforts?

Post by BradH »

PRH wrote: Fri Jul 13, 2018 10:39 am For a "street carb", knowing I had a bigger race carb to install at the track....... I'd just buy a used 4779 and maybe put a HP body into it.

My experience is that those old school type DP carbs have a more street friendly low speed calibration.
I think I can get one of the two smaller carbs to suffice, and have a couple of tweaks to help keep 'em happier during normal street use. The Gold Claw 1.425 config drove pretty well, for the most part.
PRH wrote: Fri Jul 13, 2018 10:39 am It's worth noting that although not nearly enough time was available to sort out each of the carbs that were tested(which could have easily altered the rankings from best to worst), the biggest carb didn't make the most power. The smallest one put on the motor that day did.....barely. But it highlights that how well the carb does its job of mixing the air and fuel is important too.
I think the QFT/Proform 1.50 w/ the BLP boosters made a couple more HP than your PRH-modified 80496 (686 to 684?), but you're correct that none of my carbs were very close to being sorted out that day. Two carbs we "should" have had to try were my BG Gold Claw and your CFS 905... but that's 20/20 hindsight.
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