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A quadrajet shines at an RPM the dyno can't even measure. So it's not ideal for power making youtube dyno tests.
Everything can be measured - There's no magic to the the Quad, or any other carb for that matter. You can see the power made at every nanometer of the dyno chart for any intake/carb combo out there if you have ready access to a dyno. I dig the the Quad, but I also watch Engine Masters, and they do some great tests with real numbers. Very informative. I like Eddy's, Rochester Quads, Holleys - they are tools to be used for a variety of applications
Last edited by Corvette-ZL1; Dec 21, 2022 at 07:21 PM.
I don't think that's true if you stay with a 3" air filter. Plus, nobody uses a drop base for aesthetics. They do it out of necessity to address any hood clearance issues. Depending on the setup, you simply may not have a choice if you want to go with any performance intake with higher than stock profile, and the BB hood (non-l88) doesn't give a whole lot of extra clearance over the stock small block hood.
Maybe an inch, as the rise really happens toward the front of the (BB) hood - well past the carb area... I have both to compare side by side, and there ain't much of a rise where you need it.
The LT1 had a hi-rise intake, which necessitated the use of the BB hood in the first place. Easy enough to measure when the OP installs the set up that he wants and gently closes the hood - Some Playdough and a tape measure or ruler should fit the bill.
A recent thread that dyno tested many different air cleaners proves differently.
I had to give some thought to why my 650 Holley 4165 works so well on my mild 383 stroker. I believe it's because the 4165 is a Quadrajet style with the big secondaries. The secondaries are far bigger than the regular 4150 style Hollies. Being a mechanical secondary carb, when you put your foot into it and those big blades open, it feeds a whole lot of air and fuel into that motor. At least that's my experience. Pulls hard to 6 grand and above, no flat spots and neck snapping response. Your results may vary.
A recent thread that dyno tested many different air cleaners proves differently.
I bet if there is ANY measurable difference, it will be at high RPM (like 6K on up). Can you link to the thread in your response? I'd like to read through it. I'm certainly not a know-it-all, and happy to correct myself if I'm wrong about something.
I bet if there is ANY measurable difference, it will be at high RPM (like 6K on up). Can you link to the thread in your response? I'd like to read through it. I'm certainly not a know-it-all, and happy to correct myself if I'm wrong about something.
the Edelbrock 2101 is set up for a hot air tube choke, mine is the divorced choke with a coil spring that mounts on the manifold. Does Edelbrock have one with that set up? to use with my q/jet? just looked at the 7104 and it has the correct choke set up and will take a q/jet
Last edited by 67tripower; Dec 22, 2022 at 12:58 AM.
Reason: adding the 7104
Thanks! Good video from Engine Masters. Didn't realize that the drop filter made any difference. If I can get away with the flat housing over the drop filter without clearance issues, I will. They were running a monster 750 HP that revs to 6500 RPM. My BPE SBC 396 stroker crate motor is dynoed at 500+ HP and torque at 6000 RPM max.
On their motor, it killed a bit over 12 HP with a 14x3" K&N, so the drop base and 3" filter on my motor realistically is probably only worth about 7 HP loss - Still more than I would like.
Everything can be measured - There's no magic to the the Quad, or any other carb for that matter. You can see the power made at every nanometer of the dyno chart for any intake/carb combo out there if you have ready access to a dyno. I dig the the Quad, but I also watch Engine Masters, and they do some great tests with real numbers. Very informative. I like Eddy's, Rochester Quads, Holleys - they are tools to be used for a variety of applications
Dyno's do not measure off idle response. They do not measure anything usable in regards to streetability really below 2500-3000. Nor do they measure throttle response at or below those levels.
And yes, there is magic in the Quad. You've apparently never experienced one tuned properly.
I don't think that's true if you stay with a 3" air filter. Plus, nobody uses a drop base for aesthetics. They do it out of necessity to address any hood clearance issues. Depending on the setup, you simply may not have a choice if you want to go with any performance intake with higher than stock profile, and the BB hood (non-l88) doesn't give a whole lot of extra clearance over the stock small block hood.
Maybe an inch, as the rise really happens toward the front of the (BB) hood - well past the carb area... I have both to compare side by side, and there ain't much of a rise where you need it.
The LT1 had a hi-rise intake, which necessitated the use of the BB hood in the first place. Easy enough to measure when the OP installs the set up that he wants and gently closes the hood - Some Playdough and a tape measure or ruler should fit the bill.
Nobody uses a drop base for performance either... It negates a lot of benefit of going with a taller intake in the first place. The element has to be tall enough to allow enough air to be able to have the most direct flowpath into the carb. from the tests ive seen done on dynos that means even a 2" tall air filter with less of a drop base will perform better than a higher drop base with a 3" because of the additional turbulence the drop base introduces... Seems 80% of the time none of this matters because these upgrades are done primarily for aesthetic reasons despite what owners tell themselves and others.
The filter top elements suffer the same turbulence issues which is why dyno testing found they perform better with the side element area taped off. I used one before and now use a drop base air intake ironically with a 4" tall element and solid lid... not ideal but it works best for my CAI setup and aesthetics since I dont race my car.
Last edited by augiedoggy; Dec 22, 2022 at 12:40 PM.
You better watch a few episodes of Engine Masters dyno pulls. You don't see Brule' slapping a Quadra on those high horse engines.
And if you are concerned about gas mileage, don't own a Vette.
Id argue that unlike the muscle cars most the c3 vettes were infact very much designed to be a more efficient grand touring vehicle but what fun is that unless you find yourself driving one of your other cars instead because its so impractical to drive getting 8mpg... personally efficiency is efficiency to me and no sense throwing it away unless your getting something greater out of it.
Anyway, engine masters also did a couple good intake comparision episodes that proved the only thing about an air gap that made it perform better than the standard rpm model intake after the engine warmed up was the cutout in the center divider... Once they modified the regular RPM by hacking out the divider the same way the dyno numbers were comparably the same. They did another episode to measure whether the air gap plenum helped lower air/fuel temps and found that because of design and runner length vs air speed, minimal gains were only true on a fairly cold engine that hadnt warmed up fully. They even tried the bag of ice sitting in the open air gap space trick some use on drag strips... In short the Air gap was a great marketing ploy to sell more new intakes into a market already flooded with older RPMs. I would imagine those of us running tapered or open spacers are also getting this benefit as engine masters also found.
Last edited by augiedoggy; Dec 22, 2022 at 01:23 PM.
Dyno's do not measure off idle response. They do not measure anything usable in regards to streetability really below 2500-3000. Nor do they measure throttle response at or below those levels.
And yes, there is magic in the Quad. You've apparently never experienced one tuned properly.
I grew up with Quad-equipped Corvettes. I always loved that wah-wahhhhhhhhhh (the RPM blip, then hesitation, then full RPM) of the Quad. Tuning them is a pain, though.
I grew up with Quad-equipped Corvettes. I always loved that wah-wahhhhhhhhhh (the RPM blip, then hesitation, then full RPM) of the Quad. Tuning them is a pain, though.
If you are getting a hesitation with a Quadrajet, then the air valve is not tuned right.
I grew up with Quad-equipped Corvettes. I always loved that wah-wahhhhhhhhhh (the RPM blip, then hesitation, then full RPM) of the Quad. Tuning them is a pain, though.
It was not tuned properly. Tuning them does require a higher level of knowledge and skill, perhaps effort, than most other carbs. If a guy doesn’t take the time to learn how to tune it then it’s not gonna perform properly.
Really? (not trying to be argumentative - just surprised and generally curious) My brand new dressed Blueprint Engines 396 SBC stroker I recently bought came with a 850 Holley, which is what they recommend if you just buy the long block from them. I bought the dressed motor, and that's the set up that BPE had on it when it was dynoed.
Not sure what you are putting out at the crank, but my motor was dynoed at 500+ HP and well over 500 ft lbs of torque, so 650 would be too light for that application. 650CFM is a bit light for a 383 stroker, unless it's a really mild build that doesn't have a terribly high rpm capability (say 5200-5500 RPM max). 750 CFM seems to be the magic number for ~400HP sbc strokers.
You are going to love that 396 blueprint motor there is a guy at are local cars and coffee that has one and it sounds very nice with the 110 lobe sep and he loves it .
It was not tuned properly. Tuning them does require a higher level of knowledge and skill, perhaps effort, than most other carbs. If a guy doesn’t take the time to learn how to tune it then it’s not gonna perform properly.
I'm probably not articulating the Quad mannerisms well enough - it's not like the old tech turbos that had lag where you were waiting a few moments for the power. The L46 Vette ran flawlessly, and had tons of power. When flooring it, that hesitation was a blink of an eye as the vacuum secondaries kicked in, and then BAM! - full power- almost instantaneous. It's like a boxer's quick jab before a lightening fast haymaker - the one where you have to watch the replay a few times because it happened so suddenly...
Every Quad-powered car I've been in and/or drove/owned has that characteristic, so I doubt all of them were improperly tuned. If that is improper tuning, then I want any Quad I end up using again to be tuned so improperly. The OEM motor that came with my '69 Vette when it rolled off the assembly line still has its Quad (replacing it with a 396 stroker). Same behavior..
IMO, that is a (cool) feature, and not a bug with the Quad... No one has ever noticed that? I find it hard to believe....
Last edited by Corvette-ZL1; Dec 23, 2022 at 10:20 AM.
You are going to love that 396 blueprint motor there is a guy at are local cars and coffee that has one and it sounds very nice with the 110 lobe sep and he loves it .
I can't wait! I read a bunch of reviews on the 396 before I ordered it and folks love it. Should have the car back together by April of next year (frame off resto)...
I'm probably not articulating the Quad mannerisms well enough - it's not like the old tech turbos that had lag where you were waiting a few moments for the power. The L46 Vette ran flawlessly, and had tons of power. When flooring it, that hesitation was a blink of an eye as the vacuum secondaries kicked in, and then BAM! - full power- almost instantaneous. Every Quad-powered car I've been in and/or drove/owned has that characteristic, so I doubt all of them were improperly tuned. If that is improper tuning, then I want any Quad I end up using again to be tuned so improperly....
IMO, that is a (cool) feature, and not a bug with the Quad... No one has ever noticed that? I find it hard to believe....
The Quadrajet does not have vacuum secondaries. 100% mechanical with air doors.
The Quadrajet does not have vacuum secondaries. 100% mechanical with air doors.
Not completely true....Quads do have vacuum secondaries, however, the throttle blades in the baseplates are opened mechanically by throttle position. The vacuum portion is controlled via the upper valves (secondary side) that you can push open with a finger. If you have a sensitive foot, you can feel the "tip-in" point where the secondaries are mechanically actuated. That's why you get that whoosh, and behavior I'm describing that is not from improper tuning...
Id argue that unlike the muscle cars most the c3 vettes were infact very much designed to be a more efficient grand touring vehicle but what fun is that unless you find yourself driving one of your other cars instead because its so impractical to drive getting 8mpg... personally efficiency is efficiency to me and no sense throwing it away unless your getting something greater out of it.
Anyway, engine masters also did a couple good intake comparision episodes that proved the only thing about an air gap that made it perform better than the standard rpm model intake after the engine warmed up was the cutout in the center divider... Once they modified the regular RPM by hacking out the divider the same way the dyno numbers were comparably the same. They did another episode to measure whether the air gap plenum helped lower air/fuel temps and found that because of design and runner length vs air speed, minimal gains were only true on a fairly cold engine that hadnt warmed up fully. They even tried the bag of ice sitting in the open air gap space trick some use on drag strips... In short the Air gap was a great marketing ploy to sell more new intakes into a market already flooded with older RPMs. I would imagine those of us running tapered or open spacers are also getting this benefit as engine masters also found.
There is one type of benefit to air gap style intake. In my opinion it's that thick base, helps griddle things a bit and is a heck of a lot easier to polish up the bottom, so hot oil doesn't stick to it. Also an engine bay is A lot hotter than a dyno room. My air gap runners measured bout 140 deg bolted on the iron heads, heat soaked but I set my car up to run cool and also why I prefer annular boosters.
