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Interesting and proved what I thought. Mostly it's just the size not the name. They tested Holley, Summit, Qjet, Edelbrock and one other all 750 CC street oriented versions. All basically made the same peak and average, no run away winner.
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TomOverdrive is overrated
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CFM Ratings are all over the place with carb manufacturers. It would be easier if they all listed venturi and throttle blade size for a better comparison. I have a fixture for my flowbench to test airflow on carbs, hope to make it a winter project this year to learn some new thingsNick Smithberg
www.smithbergracing.com -
I would not have expected a big winner. Same basic size, except for manufacturer variances, all tuned correctly should produce pretty equal power.
To me, it's more a matter of preference and better driveability. My Holleys have better driveability than my Proform 750 DP. The Proform needs more time to idle and needs a richer idle mixture to run right. Have no idea why.Last edited by Scott Liggett; August 6, 2012, 09:35 PM.BS'er formally known as Rebeldryver
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The QJet was apparently not put back together well, typical of reman carbs. For it to use the most fuel means someone had no clue what they were doing. Other than that, I liked the article and it made for fun reading.Comment
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I was sort of surprised the quick fuel ran the leanest through the cruise portion.
I'd like to try one of those bathtub holley/summit carbs on a mild street engine.There's always something new to learn.Comment
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Originally posted by Scott Liggett View Post
I'd venture a guess that cylinder-to-cylinder distribution is the reason the Proform needs to idle richer to keep the engine happy.www.realtuners.com - catch the RealTuners Radio Podcast on Youtube, Facebook, iTunes, and anywhere else podcasts are distributed!Comment
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they used to list it. a simple example is a 250cfm monojet at...just 3 inches of vacuum. At 18 inches someone deciphered 280. Should be the same today.Originally posted by BOSSMAN View Post
another thing is the height of venturi, how long is that restriction with the same diameter comparing to another?
and if the venturi is smaller diameter, but height from one end to the other end of restrictor (speed increaser) is less..it ends up the same as a taller one.
like offsetting a square and a rectangle..but doing it in a way to end up the same..as round of course but you get the idea.Last edited by Barry Donovan; August 7, 2012, 08:37 AM.Previously boxer3main
the death rate and fairy tales cannot kill the nature left behind.Comment
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I agree, .......... well,..... i have no experience here other than the 3 q-jet carbs i've had in the last 25 yrs or so... but all of them got exceptional mileage... compared to the Holleys i tried - 2 of them - and i was unable to get them to match the consistency of the q-jet....I'm no expert tuner, that's for sure, but i did spend considerable time ( and resources$$) trying to get the holleys to work. I ended up selling them both to folks who swear they ran almost perfectly for them...Originally posted by Thumpin455 View Post
The holleys just never seemed to run with consistency. they were a bitch on cold mornings and vapor lock/stumbled lean when extra hot. also condsider, i don't race 'em, i just drive 'em to work and back...and sometimes stomp on 'em
I love the quadrabog and was very suprised when they didn't get the best mileage out of that group. That test sounded like it was kinda short in the testing department though... i would like to see something a lot more comprehensive. I also can't seem to get it outta my head that a lot of income for that mag comes from the holley/derivative sellers....not many ads for Q-jets. don't hate me Dulcich
Mike in Southwest OhioComment
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Cliff has always said that the reman Qjets are usually a mess. Its like the parts are all thrown in a bucket then they just pull stuff out and stuff it in a carb. There are so many variations of Qjet you really have to know the difference in the parts, you cant just mix and match everything. Sure they will run, but they will usually run like crap. Build it the right way and they will work great.
Admittedly with all the adjustability in them they are a bit of a pain to convert to ethanol and make them run right compared to a Holley. Its fun for me to mess with them, and after doing the conversions I can make one run freakishly awesome on gas.Comment
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HOLLEY WILL ALWAYS WIN WITH TUNING
q jets work ok right out of the boxComment
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Look what they did for the Hemi over the Carters!Originally posted by SpiderGearsMan View Post58 Plymouth Sport Suburban. 526 cubic inches of angry wedge! Pushbutton shifted 9 passenger killer!!"Comment
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this is true, Holleys will always be first to stop for more gasOriginally posted by SpiderGearsMan View Post
of course, that said, I don't do q-jets because they're such a pain to recalibrate.Doing it all wrong since 1966Comment
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Hmmm..., the Holley 3310C in the test had the lowest peak and average BSFC's at .432 and .447 respectively, where the Q-jet's peak and average BSFC's were .519 and .527, which was also the highest of all the carbs tested.......Originally posted by SuperBuickGuy View Post
So again who's stopping for gas first??......
Last edited by TC; August 8, 2012, 08:06 AM.Comment
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Originally posted by TC View PostHmmm..., the Holley 3310C in the test had the lowest peak and average BSFC's at .432 and .447 respectively, where the Q-jet's peak and average BSFC's were .519 and .527, which was also the highest of all the carbs tested.......
So again who's stopping for gas first??......
The one who spends more time in the secondaries....Comment
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Not for nothing but isnt a 750 a kinda big for the test motor? Everyone always says use a 650 or smaller on a 350. I know a q jet is a 750 cfm carb but it has those small primaries.Comment
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