Double Pumper Carburetor Video - Holley Install & Tuning DVD

[cbr900rr919]

i still like the Rochester quadrajet nothing like that sound when them huge secondaries open up

[kamphwagon1]

@cbr900rr919 Yeah it has a nice sound but nearly impossible to tune a fuel curve , the same thing with a Eddelbrock ,theres not many variations of parts , metering rods out there that you can readly get your hands on where as Holleys HP & Ulta series have infinate tuning capibilitys with changeable idle restrictions ,elmusion channel bleeds , power valve restrictions and screw in air bleeds ..... When someone can boast 2hp per cid with a quadrajet then I might consider looking at one.........

[Tunedup81]

Is there a benefit of having an electric choke vs manual?

[Muzicsallitsworth]

@Tunedup81 id rather a manual dont have to depend on electricals

[hydroMower]

as soon as she said the famous holley double pumper i was like god thats hot

[sweetwarmwrigglesree]

Is this compatible with a 1990 GMC Suburban?

[sweetwarmwrigglesree]

Is this compatible with GMC 2500 Suburban?

[456looky]

The black rubber diaphragm doesn't last long with 10% pump gas.

[kamphwagon1]

@456looky The green gill flex is much better with the 10% ethenol , this 10% crap also works on the viton needle tips and power valve diaphrams, Iv'e had the rivet become loose due to shrinking of the diaphram rubber, theres not much you can do about power valves , no one makes one out of the green gill flex materal that I know of I checked with holley , quick fuel, BLP, and Brasewell, you can put metal needels & seats in , I prefer the titanaim over steel , they react to float levels better.

[93Patriot]

Well I told my father who is much more of a mechanic then I am do to me only being 17 about what you suggested but he claims he already took it all apart, checked the needle and that it was fine. Is it possible that the damage is not visiable? Unfortunatley he already has a dislike for Holleys so it's becoming quite difficult for me to convince him to retry stuff such as replacing the needle which he feels isn't broken.

[BoxWrench]

@93Patriot The type of rubber that is used for the needle and seat assembly is a material called Viton. They are designed to seal well for a period of time, but when they reach their end-of-life span, it is normal practice to just replace the needle and seat.

There will be no visible wear or clogging that needs to be cleared. It's just the nature of the standard Holley service schedule to replace the needle and seat when they harden.

The problem comes from non-use of the engine over time...

[93Patriot]

@BoxWrench So even if the Holley is brand new?

[dest8629]

@93Patriot check to see if the seat is damaged at all

[71bee383]

@93Patriot Unless your dad is using the carb on a race application engine, toss that POS Holley in the trash & snag a good ol' Carter/Edelbrock AVS. much easier to tune & they won't give you the problems you'll continue to encounter with the Holley carbs.

[93Patriot]

I have a modified 350 and it has a Holley 700DP on it. We've been having trouble with it constantly loading up and flooding out. We have taken the carb apart, cleaned it, and frequently adjust the floats but it keeps flooding after running the car for a few trips. Unfortunatley it has come to the point that if we can not resolve the problem, the Holley will be coming off and being replaced with a Carter. Any ideas on what may be the problem?

[BoxWrench]

@93Patriot Sounds like the needle and seat assembly needs to be replaced, not just cleaned.

It's a standard procedure for any Holley carb as a regular service overhaul. The needle and seat is included with many of the complete rebuild kits as well.

Just start by getting a new pair of needle and seat assemblies and replace the one in each bowl. re-set the bowl level and your described problem should be solved.

Then you can think about the rest of tuning. Our Holley DVD can help if you like...

[93Patriot]

@BoxWrench Thank you for the help. I really appreciate it.

[BoxWrench]

@93Patriot Give the new needle and seat assemblies a try and let us know what happens...

there will be a need to be a round of tuning that you go into when you have new seat assemblies, but you should hopefully solve the flooding issue.

Keep us posted.

[5blacksmith5]

This is a very interesting video :P

[3MAN09]

whats so good about a double pumper?

[BoxWrench]

@3MAN09 Double Pumper carbs are most useful for use in higher horsepower engines with large camshaft profiles and/or manual transmissions.

They have four idle screws (one for each carb barrel) and also have dual accelerator pump systems (squirters) so you can more effectively tune the acceleration fuel demand curve for the higher HP types of engines.

They are most effective at eliminating 'flat' spots in the acceleration curve at the point where the secondary throttle plates open.

[adamslurch71]

@BoxWrench Or if you just have a really big engine. I had a 1970 Eldorado with the 500 in it, it ran OK on an edelbrock quadrajunk, but once I got a Holley Double pumper man that thing came alive.

[BoxWrench]

@adamslurch71 You would definitely need to have a larger displacement engine to even take advantage of a Holley Double Pumper.

The best way to determine if you've engine specifications are large enough to take advantage of the extra fuel delivery from a double pumper is to use the "Carburetor Calculator" at the Holley website. You answer some questions about your engine, RPM range and accessories, and it will guide you to the proper CFM size rating for your engine.

[adamslurch71]

@BoxWrench The double pumper was made for a 500 cubic inch engine, after a little fuel tweaking and a few timing adjustments I was making about 590 HP even though stock for that engine was only 400, I guess that what you get when you tune an engine just right.

[reptar1994]

Dude, BoxWrench rocks. :D

[wazii6]

dose holly make something for carburated hondas

[lablue350]

too much to learn.haha..thats why i had my mechanic tune my 650 double pumper..n really loved my carb setup,really liked the holley,but i love the way quick fuel and proform carbs look...so ill be gettin myself one of those.

[dannysauer]

@lablue350 - quick fuel and proform carbs are Holleys. They may have anodizing and / or chrome plating, but they're otherwise the same thing. It'd be cheaper to just get a can of spray paint... :)

[duggie666]

i have a carb question... Can i turn this carby around so the linkage are on the other side ....

[muchmoneyg]

very good video thanks for uploading!

[marcelomeazzini]

It´s impossible to tune without instruction manual

[BoxWrench]

@marcelomeazzini

That's why we produced a 3 1/2 hour in partnership with Holley. They used to include the DVD in every box with new carbs.

You can get the full DVD from our BoxWrench site, but also search here at YouTube for other BoxWrench/Holley carb tuning clips.

Everything you'd need to know for tuning a Holly or most carbs is in our videos.

[sh3lbot]

@BoxWrench Hello I'm running a holley 650 DP on a 1.3L rotary engine. I know it's abit big a 500 would be more what I need for my set up. The engine will idle fine with the choke on but as soon as I take it off the carb leans out, engine high revs and its sputters till it dies. Anyone know what my problem could be? I'm leaning on a air leak. It's getting fuel fine but as soon as that choke is let off game over.

[johnnycanadaballs]

Idle circuits plugged / incorrect adjustment?

[sh3lbot]

carbs are not my forte. i think i need a manual!

[End0fTheLine]

my compression is 10:1 btw

[End0fTheLine]

i have a carb question. i have a edelbrock 650 on ym current engine. i have a chevy hi torque 327 with double hump heads, a edelbrock performer air gap intake 1500-6500, comp cam thumpr seris 200-5800, ive got a 4 speed in it, with a 12 bolt chevy rear with 4.10 gears, should i buy a larger carb?

[BoxWrench]

Seems like it may be a good set up for you. Only thing is the secondaries of the carb. With a manual transmission, you would possibly benefit from mechanical secondaries if your carb currently has vacuum secondaries.

Not a requirement though, just make sure to get your carb tuned properly with the help of a vacuum gauge and the proper jetting and idle settings.

[racin468]

i would keep the 650. A bigger carb would only help you if you had a larger ci small block 383 or 400 or rpm aboove 6500. Putting a bigger carb will most liklely slow you down, foul plugs, bog off idel etc.. I had good luck with a edel 600 cfm on a 350 street motor. I put a 750 on my 406 small block but it had 11.5 cr and a .555 solid lifer cam rpms were 3-6500.

[stevenspimpin420]

dude lose that eddlbroke and get a good carb

[1mesterious]

what gives the carburetor the name mechanical? and would i not be able to use something like a vacuum canister or a vacuum distributor if i went with a mechanical carb?

[antisecondchances]

because its the secondaries openly mechanically instead of by a vaccuum and yes you can still use the vaccuum advance on the distributor

[racin468]

mechanical only means the secondaries are open mechanically not with engine vacuum. You can run vac dist and canisters with mechanical carbs. Note mechanical has pros along with cons as compared to vacuum secondary carbs

[Regislovato]

Holy crap! BoxWrench on youtube!? Nice! I can't find my tuning DVD anywhere, and this helps out so much!

[valcic1993]

boring

[BoxWrench]

I bet if we made a video tour of the exploded view of a Honda B16 you wouldn't think it was too boring...

Excitement is subject to the eye of the beholder.

[miataguy94]

so dont watch it and if u think its boring and u watch it then keep ur mouth to urself cuz this shit is helpful

[X2N18]

whats better a carburetor or a intake manifold?

[iceman0043]

I have a Holley 650 Performance carb with a mechanical secondary. I am having problems with the vacuum advance because for some reason there is a constant vacuum on the port that I am suppose to hook it to. What do I need to adjust?

[BoxWrench]

Which port are you connecting the distributor vacuum line to?

It should be the one that exits the passenger side of the primary metering block...not any of the ports on the base of the carb.

[mbiraguy]

I can see you guys put a lot of work into these videos, they really are top-notch. Thank you.

[kreigsmann]

i take it double pumper means it takes twice the gas?

would i also need to install a nother fuel pump?

or jusy a high velocity pump with split lines?

[BoxWrench]

At :21 seconds into this clip, the woman describes what "double pumper" means.

It just describes the fact that there are two accelerator pumps, one one the primary fuel bowl and one on the rear fuel bowl.

Two accelerator pumps also means there are two discharge nozzles.

The discharge nozzles (squirters) are solely responsible for making sure that enough fuel in introduced at the critical "lag" moment when the gas pedal is pressed.

Makes for better throttle response in a "Double Pumper"

[AGHHF]

im getting a buick 455 that can come with or with out one of these. 400 without --450 with. im taking the carb.

[shaikhdishgan1]

long time ago i modifid rochester for racing that worked muche beter on 350 chevy for drag and street racing i did not beleve it will but it was one of the best things i ever done .

[BoxWrench]

Does that mean that you did a comparison between a Holley and the Q-Jet?

Did you actually try to tune a Holley before working with the Rochester?

If you followed the instructions in our Holley DVD, you'd have any Holley carb running pretty incredibly well...

We've had the opposite experience when comparing a tuned Holley to a tuned Q-Jet, we preferred the Holley every time.

[shaikhdishgan1]

for small block chevy Q-jet workes allmost all the time beter ,i try tune holley it was fine but not very sharp some time you get flat spots in US you can have jet kits to fine tune it power valves but Q-jet is more responsive with small block and very important thing if you go street racing then Q-jet is realy shining.

[danieil12]

what do they mean by "the holley carbs" in my place you can only find bosch parts and its kinda different

any help will be appreciated !!

[BoxWrench]

Holley Carbs are one of the most popular carburetors for enthusiasts who like to build power and tune their higher horsepower large displacement engines.

If your engine has another brand of carburetor you still may be able to use the tuning info from our Holley DVD. You would just need to locate your Idle Mixture screws, idle speep screws and identify the power enrichment circuit for your Bosch carb. Sometimes there is are separate jetting systems for part throttle and wide open as well.

[spikonaleash]

ok i think i screwed up the adjustments on my carb.i think it runs a bit rich and when i mash the gas it damn near dies then goes

[levisnteeshirt]

it needs more fuel , not less

[BoxWrench]

You need more accelerator pump shot to squirt more raw gas as you touch the pedal, just before the power valve and jet systems kick in.

[angelicricky]

i have a tbi 88 chevy i want a 4 barrel carb,do i need a new intak manifold as well?or wat

[woltagziv]

Maybe someone can help with this. 351 cleveland, holley carb. Driving slowly 2nd gear, mash the gas, dead spot and then wooosh. Why does it go dead for a second? Any advice?

[BoxWrench]

Accelerator pump needs to be tuned.

You can do it by getting the Accelerator pump cam tuning kit and then find a cam that works well for your engine. You may also need to to to a larger accelerator pump discharge nozzle (squirter) to get enough gas to shoot in during the flat spot on initial "pedal mash".

Complete tuning for that system is covered in detail in our Holley DVD. It's over 2 hours long...

[Ryacuski]

Thank god I don't have a carbureted vehicle. That shit was confusing as hell. Lol! Thank you lord for EFI!!! Plus, with EFI, no warm up needed, since it's electrical.

[StreetLethalRacing]

You don't know what your talking about, carburetor's are just as easy to tune as fuel injection, if not easier. No warm up with EFI, ehh? Electronic Fuel Injection runs off of a predetermined fuel and spark table during what is called Open Loop, and once normal operating temperature is reached, switches to Closed Loop (O2 correction). It's bascially the same principle, it's just EFI is much more accurate. But to the experienced carb guy, the carb could be just as accurate....

[Xtraz00]

But with the ridiculous fuel prices these days, who wants a carbureted car? especially a double pumper..

[syco1100]

where i live ( minnesota ) gas is 1.99$ a gallon =P

[adiosk8erxxx]

gas prices r droppin by the second =D

[kurtass16]

ur damn right, i hate fuel injected i have a 85 camaro with a tuned port 5.7 and i hate it, i mean its fast and all but i have nothing but problems with it

[levisnteeshirt]

i'm about to pull the TPI off of my 89 vette , it has a problem somewhere in the wiring that can't be found , i've f@@ked with it for the last time

[kurtass16]

check your fuel line for a crimp. i was wondering why mine would bog when i reved it, the fucking motor pinched its own fuel line from rocking when under a load. crazy crazy shit.

i had it checked by a GM dealership and they said it was a bad wire that can not be located inside the wiring harness

[papadapolis74]

tpvalley your a novice because your explanations are vague and general. what you need to do is get specific, as in application specific. Just cause you cant tune a holley to save your life does not mean its not effective or better than a webber. and No I dont fuck cars, I build road race chassis and tune carbed motors for specific types of motoring for the last 27 years

[billy420c]

if you have a flat spot then you need a bigger power valve learn to tune before you blame the carburetor holleys will make more hp

[tpvalley]

Holley carbs should be called flat spotters!

just buy a webber.

[BoxWrench]

That may have been a widely spread opinion years ago but people that don't like Holley carbs usually don't know how to tune them.

If you feel a "Flat Spot" in a Holley carb, it's definitely out of tune.

That's why we made these videos. There's nothing like them out there, definitely not from Edelbrock or Weber.

Every Holley carb comes with the DVD and using it will give you more knowledge of their carbs compared to any other brand out there.

[papadapolis74]

tpvalley is a shmuk, double pumpers out of the box are an extreme performance upgrade that is very cost effective

[tpvalley]

I am just pointing out that hollies have a bad reputation for flatspots, thats why they have to give so much info with their carbs.

Why do u think the ford GT40 used a bank of webers and not holley?

holley is good for pouring fuel into big engines with so much torque that flat spots do not matter as much, but for quality, accuracy etc webber is far better.

Bizare that u would use insults to convey ur opinion, r u one of those wierdos that falls in love with objects? like men who fuck cars?

[Regislovato]

cool your jets, mate.

[tpvalley]

no! :-)

[theginacologist]

boxwrench is the shit.

[engineer15426378]

Wow, this is an awesome video. Very informative and made the carb easy to understand. Thanks Boxwrench.

[68ray]

That's a great video.  Thanks for posting.