Amusing.

 

It's too bad you have to resort to rudeness and bullying tacticts to get your point across. This could be an interesting discussion.

 

There are certain rules and laws which govern how any system- mechanical, electrical, fluid, chemical or nuclear- works. ONLY when you understand those rules, will you know how to push the envelope...

I've not bothered spending the time to test 300 carbs on a particular engine. I mean, I've got better things to do with my time... For a particular engine combination, it is relatively simply to calculate the maximum airflow that an engine can utilize, and have a carb slightly bigger. (Assuming 100%.)

For example, say I have a 400 SBC. The conventional thumb-rule as already stated would dictate a flow capacity of 694.444 CFM at 6000 RPM. Simple, right?

If you use stoichiometry, you'll find the that the thumbrule applies exactly. (I'm sure any engineering student worth his salt will know how...)

The point is, if the engine can only pull it (at 100% volumetric efficiency) 694 CFM at a redline of 6000 RPM, then what is the benefit of putting on a Dominator, or even an 850 CFM carb? More airflow? More horsepower??? (See Lars Rule #2).

Of course not, that is preposterous. The engine cannot attain 100% efficiencies unless you're relying on some sort of ram-air system (including very specialized high-RPM cams), or forced induction (which brings up a whole NEW series of discussion, with regard to adiabatic efficiencies, and the resulting headaches and compromises of positive-displacement versus centrifugal impellers, parasitic losses, etc.)

So we're back to the 694 CFM that this engine demands, and that's assuming perfect efficiency. Since we're not there, what ARE the ways to improve it? Better scavenging of the exhaust system, better-flowing heads, more favorable camshaft profile (another line of debate, depending on low or high-RPM efficiency), better intake manifold, etc...

The catch is flow velocity. The velocity must stay sufficiently high to keep the fuel droplets entrained in the air. Too slow, and the fuel will start to come out of solution, like morning dew on grass... If it gets VERY slow, then it will puddle on the bottom of the intake manifold ports. At that point, your engine is getting plenty of air, but no fuel. It leans out the engine (leading to possibly catastrophic results).

See Lars Rule #1.

As you get bigger and bigger ports on top of the engine (carb venturis), the airflow velocity will decrease correspondingly. The smaller the ports for a given amount of fluid flow, the higher the velocity, and the better the throttle response. But the problem is, if you put a Holley 600 on top of that engine that can use 694 CFM, when you reach 600 CFM of flow, the carb is maxxed out... Oh, it may flow a little more, but the problem is that the carb starts to be restrictive, not allowing all the air in that the engine can use... So, at this point it will limit horsepower (See Lars Rule #2).

Theoretically, you can put on a monster carb onto a tiny engine, and have it do a decent job... (Lars Rule #3). BUT.... if you're at low RPMS (small volume of fluid flow at high velocity), the big venturis, when you jam your foot into the pedal, will suddenly open up the port through which the fluid is moving... Now remember, the engine cannot instantly swallow a doubling of air and fluid flow- the vacuum is remaining (essentially) constant, and so when the ports open wide to atmospheric pressure, your flow velocity drops dramatically... If the carb venturis are TOO big, the flow drops enough to where the fuel (again) comes out of solution, your engine leans out, and you have a bog... This bog will be even more noticeable under load, unless you downshift and rev the engine to gain much higher RPMs (and therefore higher fluid velocity- See Lars Rule #8) There are only a few possible ways to overcome this: either limit how fast you open up the butterflies on your carb (i.e., push down slowly), or use a bigger fuel pump shot and better squirters. But either way is a band-aid approach, because the underlying problem- that the carb venturis are too big- remains...

So where would that leave us on the example engine I mentioned? Probably a 750 CFM carb, and no bigger... Because while you *could* go for a bigger CFM carb, there's nothing to be gained, and a lot to be lost in throttle response...

Simple fact is, flow velocity is what counts. The higher you can keep it at all points in the operating range, the better you are... Going bigger then necessary decreases that velocity...

ALL of these issues are not my personal opinion, they are simple facts based on physics. Quote whomever you like, it doesn't particularly matter... I'm just stating how the carb sizing effects the performance of an engine...

You may think I'm a know-it-all, or whatever... But as I said, these are immutable facts... Of course, I'm not trying to sell myself, either...

Well... My TKO-600 arrived, and now I can go to sleep... (Graveyard shift really sucks, sometimes.)

 

Frankly speaking, I LIKE a good technical discussion- and I've learned a lot from these forums, on a variety of issues (and headaches I've had to face). Yeah, I know... you still think I'm a know-it-all... I visit nearly every thread, but rarely get involved in them, unless I have something I can contribute to the mix... So most of the time, I just read... I rarely get into tuning threads, because... well, I don't need help in that area....

So Lars comes in laughing, clearly thinking I don't know... spit from shinola... He makes statements that are simply impossible to believe, even on their face. His own rules completely contradict his statements...

(BTW, with the exception of his particular recommendations as to carb sizes, I agree with his rules- as I have previously inferred.)

Calling him on his contradictions is no more rude or "bullying" then his behavior merited.

 

 

I'm not an engineer by any measure, but I am a scientist, and currently in graduate school, so I've had some experience with the scientific method...basically science would be a lot easier if everything worked according to theory...equations don't always explain the behavior...thus more complicated explanations must be offered to explain the situation. Experimentation must be used to verify the results. My experience has taught me that real world results are what matters, not what a hypothesis suggests. If one can do it experimentally, that's what matters.

breathial-you're right, there are certain laws that apply, but I believe that there are too many variables for the equation to be solved as simply as you have presented it, therefore I will believe in the real world results that lars can offer from experience along with trial and error.
just my own opinion,
trw

 

Better things to do with your time? Like make personal web pages all over the internet about yourself so everyone can see what a tool you are?

Lars gives freely of his own time unselfishly contributing to other forum members. He travels all over the world and often gives up his weekends to help out his friends. He's taken the time to test and tune these carbs and we all learn and benefit from it. It's apparent that your only goal is to prove to everyone how big your ego is.

Having the good fortune of living close to Lars, I've personally seen him tune over 30 carbs that would be considered "too big" by your standards to incredible performance levels. I'll take that personal real world experience over your postulates.

 

Yes, I've read all of those things at various times, but certainly couldn't rattle it off of the top of my head. I don't disagree with you here, but I also think there must be more variables in real world situations. When I see actual dyno results with the only variable being the carburetor I must believe them. Again, I do have a mild 351w running a mechanical secondary Speed Demon 750. It does need some fine tuning but runs pretty well for the most part. The only thing I did was set the butterfly openings to .020, otherwise it's setup as "out of the box". Idles at about 800 rpms and has great off idle responsiveness.
We should be able to discuss these things with some level of civility as most of us here are adults. Congrats on the TKO.

 

Man I go to work and class for one day, get home at 8, and look at you guys!

It's alot to catch up with but I do this because it's fun, it's a labor of love Let's begin with the personal and move to the technical.


How did you say it... "judging by the quality of your contributions here"...
okay, unless we're playing semantics here, please interpret this in a way that doesn't sound like "I'm a know-it-all" :
How very generous of you. People like Lars know so much because they have taken the time to help others and have gained something for themselves in the process. I contribute to this forum as best I can in the subjects that I have experience in (suspension in practice and theory, auto transmissions, exhaust, vintage racing) Others know more than me, but I can help alot of the time and do, for their and my benefit, not to mention the forum community as a whole.
about the cam-specs or the torque convertor? I never said where the cam specs came from and the convertor has always been in my signature which you must have read to know my cam and that my engine is so badly put together
Under my skin? I'm still having fun, so no. It is annoying what you assume about all young people, but I know many many kids who match perfectly with your assumptions, just not all. Dug? Well your name is in your profile... I pasted it into google... a personal ad was the one and only thing that came up. Nothing came up from the Navy, maybe your heroic deeds are still classified? If that is intense digging to you, I really wonder how you can question my research abilities?

Your comments on checking for vacuum leaks. I'd say thanks if it not for the backhandedness! I understand how it works. Actually I already read that suggestion elsewhere, maybe it was you, perhaps someone else. Either way, logical good advice which I will follow when I have the time next week to start fiddling. If you'd stick to this kindof info...
Seriously? Wow, that is way more than I was expecting to get from this combo! Not a screwed up combo doesn't sound like your proclamations earlier.

Thank god, this is what I was trying to say when I said that low speed air/fluid-dynamics are super-complicated and that the formula had too many assumptions. How does one argue against reality? What is, Is.

I agree. I admit I've had a big part in aggravating breathial, but I really have very little tolerance for arrogance. I enjoy spirited discussion but I'm not angry at anyone here, just exchanging blow for blow. That in itself is childish, to need the "last word" but like I've said, I'm just having fun here while trying to learn and prove some things.

stoi·chi·om·e·try n. Calculation of the quantities of reactants and products in a chemical reaction.

uhh, sorry but that does not apply to CFM of a carb. There are subtleties but the air requirements of the engine would be the same if you drove the crankshaft and made the engine an air pump. Chemistry not involved. So yes, perhaps your lack of an engineering background is hampering your understanding here! By the way, if engineers did nothing but "think for themselves" we'd be banging rocks together trying to cook toast. You learn from authorities (not follow blindly) and develop from there. "On the shoulders of giants" so to speak.

Think man think! If they recommend a certain engine size and expect you to be using it, of course the carb is going to be tuned near the requirements for such an engine out of the box.

Yup, I understand that, but I knew it'd work with some effort and would meet my needs for a long time to come. Hence, same monetary output when I would be outgrowing a 650 before too long and needing a 750 anyhow. Again I am not ashamed to admit that cost is a huge concern at this point, but notice I am still trying to buy the best quality products so it's worth it in the long run. If they didn't tell me it was unnecessarily large, that would be undercutting their recommendations and like you said making it difficult for them when people without the support of something like this forum constantly need help. Once again breathial those are recommendations! Not "will NOT work below this precise displacement."


I know sometimes you miss things that I say (and trying to keep up with your tangled web of bad logic leads to some really long responses) but you need to read this next part.

As promised. I have not pasted in my email for brevity but it contained their questionaire filled out accurately and in whole, a brief description of my troubles, and the question "is there a minimum CFM requirement for idle that would make this carb not work on my engine?":

Judging by your already high tension level, I believe your heart may have just exploded. No, they don't agree with you. If they did they would say "you should really considering stepping down to a 650" rather than "we should be able to help you." The low CFM threshhold you defined from their recommendations does not apply. Sorry. You now have a rediculously experienced tuner and the company that designed, built, tested, (I assume they have a racing team?)race, and have decades of experience in tech support (including the Holley techs that have undoubtedly carried on with BG.)

So let me do a little more predicting... if you are anything like the illogical overzealous in the religious debates that I mentioned you will now do one of the following:

1. Tell me why this does not apply to me.
2. Tell me this is "absurd" just like Lars' experience.
3. Faced with overwhelming proof that you can't fight well, you will weaken on your original point and start attacking other lesser topics... oops that already happened. ("you guys will never know why your cars run so well if you don't understand the concepts" I personally care to know the Why's very much, that's why I contemplated the idea of minimum CFM needed.)
4. Disappear completely, but if you were going to do that I suspect you would have by now. Further forays into the unexplored regions of human illogic are anticipated (see above)

You could admit you were wrong without some kind of qualification that undercuts it, but I suspect that you've dug your hole too deep... here's a hint, you'll hit mantle and core before you get to China!

Damn, that took awhile, chalk one up to procrastination for me. That response is rather out of order, but I think I included everything. This has been fun, let's keep it up. Thanks to everybody who posted substantive info. That goes for those who posted about running small carbs successfully on their large engines too, I value all opinions posted with logic, experience, and common courtesy.

-Chris

 

One does not need to perform a multiple-regression analysis to infer certain correlations... Granted, performing such an analysis does tend to sometimes give correlations that simply cannot pass the "sniff" test... That being said, Lars DOES post his results in his "rules." But then making statements which can't possibly pass the sniff-test, and cannot even make it past his first rule, then I ask, which of "the real world results that lars can offer from experience" are we to believe???

Since his proclamations on this thread don't make it past the sniff-test, can't make it past his first rule, can't make it past everything I've ever learned and applied of fluid theory and chemistry, I have no choice but to reject his statement.

Looking up "stoichiometry" on a high-school webpage does not make for good research... i guess when all you can offer are superficial answers, though...?

Engineers must often utilize the methodology of Stoichiometry (originally derived to deal with chemistry conversion problmes) as a quick-and-dirty way to crunch out numbers and get conversion ratios (such as cubic inches at a given RPM to the CFM drawn by that engine). It is a very common means of mathematical computation, and used in countless applications...

Do a Google search on "stoichiometric" +gasoline. How MANY hits do you see??? Or even better, do a google search on "stoichiometry" +carburetor.
You wanna' try again???

There's LOTS of good stuff in there, maybe you'll actually learn something...? Unless vacuous answers are all you are capable of.

The only thing I am not understanding, is what you're trying to say... That an engine is not about chemistry? Or that, if the engine were an air pump (aka "compressor"), that chemistry would not be involved...? Actually, even in an air compressor, there is chemistry... But since you're not an engineer (and clearly not even close) such subtleties are still beyond your grasp...

Since you didn't post your questions nor their responses, your answer was insufficient... You've never been concerned with brevity in your previous bloviations, so why now???

I called their tech line 706-864-8544, extension 2), and talked to Mike, one of their carb techs (of course, I also wanted to see what they'd say regarding a single-carb setup on my engine, in case my packaging goals for the future fuel injection cannot be attained). The relevant questions I asked him were:

1. Is there a specific CFM for a given carb, that is required for the idle and off-idle transitions to operate correctly? His answer: No, because a specific number is meaningless, due to the vacuum variables due to the camshaft profile.

2. I mentioned an acquaintence (I was being kind) who has a 350 SBC, with a cam of 218 degrees @.050" lift, symmetrical profile, lobe CL of 112 (since you've claimed so many different things about your cam, I just went with that), and he's using the 750 Speed Demon carb, and he's having lots of idle issues. His answer was simple:
"I would NEVER use a carb that big- the vacuum signal is breaking in the carb, and it won't work. I would have told him to get a 650, because he'd have better driveability and much better performance."

3. I asked him if I should mention his name, when I order my carb (I wanted to see if there was any monetary incentive in his recommendations)? His answer:
"No, you don't need to mention anyone's name, because we don't get commissions. My job is to help you out, that's all..."

So, where does this leave us??? To the first question, I concede the point. I failed to consider the vacuum variables due to cam profile itself. Easy to overlook... And yet... The smaller the camshaft (and the wider the lobe separation), the higher the vacuum... which would tend to boost vacuum in the idle areas, and increase vacuum signal to the carb... But then again, it can idle much lower (which will tend to decrease the vacuum, depending on how low you set it). If you go with a monster cam, close lobe separation angles, high lift and long duration, the vacuum drop off... And the higher you must keep the RPMs, just to get any idle signal... An interesting subject for debate, all on it's own... Too bad DD2000 doesn't have the sophistication to use the iterator to this level... The results might prove interesting...

With regard to #2, this is absolutely no suprise to me... It's what I have been saying all along...

With point #3... I already knew this answer, as I've talked with BG previously (though it's been a few years).

Your position that a tech guy will only recommend what'd be best "out of the box," or "what makes his job easier" is counterintuitive. Consider:

A. If all they cared about was telling you what to run "out of the box" (which call OB, cause I'm tired and don't want to keep writing it out), then they wouldn't have techs, they'd only have salesmen...
B. If the BG carbs all ran perfect OB, then the techs would be redundant... A tech is a trouble-shooter. His job is to help people (such as yourself) who have problems, and ultimately his responsibility is to solve YOUR problems...

Ridiculous is right...... when confronted with his own contradicting statements, his simply goes silent...... Disappointing, but not unexpected. After all, what can he say???

That company, while correcting me on my extrapolation of baseline CFM, also verified what I told you regarding your carb... So.... what are you going to say??? They're stupid, or their correct??? You can't exactly rejoice over answer #1 (wow, they're so SMART!) and then say they're stupid about answer #2... After all, how can they be credible for one answer yet not the other...?

Hmmm..... Now I understand, why you didn't post the questions or answers...

At this point, it doesn't even matter, whether you post anything at all... Anybody can call up BG, even talk to the tech that I talked to, and discuss all of the questions I asked him (ah, the beauty of free nationwide cellular service)...

Checkmate, kid. You're done... and so is this thread. Buh-BYE...

 

i'm not sure i understand most of what you guys are bantering about especially the engineering jargon so let me first ask what is the educational credentials you guys have, which degrees and from where? perhaps that will help me understand your positions. thks bob

 

Now that the size of the carb has been throughly beaten into the ground again.....I can surely see that in some Engineering schools that tact is not tought...or at least learned...back to the origional problem.
Did you get your problem with idle fixed?
There are three areas I normally check for idle problems.
One Carb butterfly opening....sounds like this one has been covered.
Timing....timing at idle...that is moving around sure can cause problems.
The third...and usually the culprit is vac leaks...either under carb or in some other system. They will cause all types of problems....lean...then rich....then high idle...then wont idle.
Have you put a vac gauge on the manafold vac port on the carb.....is it somewhat steady...or all over the place?
And my last comment...He who argue with Lars about carb...not very smart.
Dave62 An Old Engineer who knows he does not know everything.

 

 

 

Wow! I just read this whole thread and can't wait to see how it all turns out. Of course, I know something that only Lars and Chris know... This debate should be resolved at a Tuning for Beer in the near future, an event which I (and my lowly quadrajet) are psyched to be attending.....

 

bobs77vet,
I am a 3rd year engineering student (Mechanical) planning to go into racecar engineering. Oh, first 2 years at Kansas State University, currently attending NC State and taking a few non-engineering classes I needed at a larger community college. It's going to take me an extra year because I: 1. started as a Physics major 2. was very distracted by certain "extracurricular college activities" 3. cleaned up and instead became distracted by a fantastic girl with whom I'm now approaching the 3-year mark. She wants a green C2 drop top I have been working at an Italian car shop that also races vintage Italian cars and BMWs and various vintage dedicated race cars, especially Sports 2000s. www.krauseandengland.com Yes, if you "dig really hard" you'll see me noted as assistant mechanic at the recent races, not super-glorious. I have served at 5 race weekends, recently getting into data aquisition. With the incredibly talented fabricators, technicians, and racers I work with, I'm lucky just to be there. My boss Pete can jump into anything and turn the fastest laps the car has seen (Sports 200 to M3 to Fiat 850 to ex-F1 car). We produce tons of winners and advise everyone (i.e. the eastern seaboard) including our opponents. If you go to a vintage race on the East coast and don't know Peter Krause, you will probably be laughed at But that doesn't really have to do with me (other than the respect of experience and attention to detail I've learned there) plus it should be noted that I am trusted with our customer's lives essentially and we have extremely few failures. Besides that minimal education I spend every second I can reading. Everything by Carroll Smith, and the usual by Yunick, Vizard, Lingenfelter, anything I can get my hands on with regard to my car's current problem , Racecar Engineering magazine religiously. Have had my car going on 3 years, forum member same time, possibly the least experienced hot rodder in this thread but very interested in learning. Oh yeah, I was accepted as a member of MENSA for a year but let my dues run out because I didn't have any desire to hang out with know-it-alls.....

Eric does not have an engineering degree but does have technical experience in a few fields. I'll let him speak for himself, however I will note that people in technical positions are taught to rely on rules of thumb, while engineers must understand the concepts behind things in greater detail. Mr. Woodell, do you have any calculus? Engineering classes are often calc-based technical classes, the difference is far more than "details" or rather the devil's in the details. Once you get outside the assumptions of basic formulae, everything goes to hell for the technician who was 'tuned' for a certain purpose. Pardon the pun.

Sorry I guess the subtleties of my word use lost you there. There is chemistry obviously, that is far too general a term, barely more specific than the word physics! What I meant was chemical reactions, there are no chemical reactions (nominally) in a non-firing engine. You are wrong about what stoichiometry is, maybe technicians use it incorrectly? I doubt it though. Again look at my definition and the others in any dictionary you wish (sorry the way you and your buddies use it isn't good enough)
Key words: reactants (and thus products), "chemical reaction"
Nope, no stoichiometry in a non-firing engine. To vaguely call it a method of conversion is inaccurate. It is of course relevant to tuning and carb choice as those products and reactants are gasoline and oxygen (plus any ancillary reactions).

Actually I just asked my father--BSME grad of VaTech, MS from Drexel, professional engineer certified, 22 years experience since graduation in power plant design primarily steam and heat transfer stuff (yeah he saved the government millions when he designed some parts of those subs you worked on or ones similar) now Chief Mechanical Engineer of his office managing many others. He says stoichiometry is only used to refer to chemical reactions, most commonly combustion.

My definitions came from www.dictionary.com which accesses many respected dictionaries. My stoich definition came from "Source: The American Heritage® Dictionary of the English Language, Fourth Edition" High school website As a student that has excelled in several english classes involving research (just finished aceing British Literature Monday) I am quite well versed in chosing reliable references. If I have a computer question I go to www.arstechnica.com or www.anandtech.com or www.tomshardware.com, if I have a writing question I go to a previous teacher I've kept in contact with or my girlfriend who pumps out brilliant prose like it's her job (actually, next semester it is), if I have a carb question I go to the most experienced carbureted-engine tuner I have access to, Lars.

Have any of your jobs required critically reading and understanding... anything? I just can't comprehend why you are having so much trouble with my basic points. I did not say they all run perfect out of the box (there is a range of engine sizes... how could it be perfect for them all?) I said: see that? that is the word near. It means not perfect, but close. Thus, if they expect you to have a certain engine, they will tune it near to an average of what those engines will require. If you have a different engine, more tuning will be required. If you put a 650CFM carb on a 502bbc I wouldn't know but I would wager it would not be optimally set up out of the box. Comprende?

From my post, page 2, the stock cam ('77 base engine is called a L48, but you knew that?) followed by my current cam to show that the two were not the same (and thus idle RPM would be higher). Former is from Crane Cams catalog, second is from CompCams catalog:
from my sig which you have read: I have never claimed to have anything but the Competition Cams High Energy 268 hydraulic camshaft. Your confusion of 112* LSA can only mean that you cannot read and understand very clear and basic statements. This explains why you did not understand you were wrong when I proved your formula irrelevant long before BG informed you. How can you be so quick to call someone a liar when you can't even understand a direct quote from a catalog? Every time you have asked "where did I say..." I have responded with direct quotes. Every incorrect point you have brought up I have disproved with references to qualified authorities or directly disproved myself. I'm at a loss. Fortunately aggravating the arrogant never gets old.

Now I am a little thrown as to why two of their techs clearly disagree. Perhaps... it's not so clear cut as you make it out to be? Perhaps it's in the way you ask the questions? Judging by the way you ask every question in this topic, the answer is implied as "known" by you already.
eh? I posted the entirety of their response, I summarized my questions accurately. I didn't put the whole thing in there the first time because it should have been unnecessary. Since you seem to think I'm a liar, I guess you'll need the whole email huh? Their reply contained my entire email, that okay or do you need photocopies of each in triplicate? By the way, I was nice to you, I called you a 'friend'


rom : Tech Line <tech-sales@barrygrant.com>
Sent : Tuesday, April 26, 2005 3:24 PM
To : "Chris Newport" <ruxper1enced@hotmail.com>
Subject : Re: 750 on 350

| | |
Inbox
Chris Newport writes:


I am using a Speed Demon 750 with vacuum secondaries on my 350 SBC. As seen below it is modified a fair amount although I realize it is not perfectly balanced at this point (cam and intake specifically). I have some people trying to convince me that this carb will not work properly with my combination, and that it is the reason for my idle problems. The idle troubles are: universal high idle, extreme hunting idle, strong hesitation from idle under hard acceleration. Transition slots are at .020" and floats are close but need double checking. In any case, the question I would really like answered is what the minimum flow at idle is that this carb needs to operate properly and whether that could be the cause of my trouble as my 'friends' claim or whether I will be able to successfully tune it.

Thank you,
Chris


Name Chris Newport
City Holly Springs
St NC

Email RUXper1enced@hotmail.com

APPLICATION INFORMATION :
USE
Drag (1/4 Mile or 1/8 Mile) Occasionally

Oval (Asphalt or Dirt) None
Track Size

Autocross Monthly

Road Race Will be occasional

Street Primary use


ENGINE

Mfg Chevrolet

Cubic Inch 350

Compression Ratio 9.5:1


HEADS

Mfg World Products Sportsman 2 200cc 64cc

Ported (Yes or No) Yes lightly


INDUCTION

Mfg Edelbrock

Model Performer

Type: Dual Plane

Ported No


CAMSHAFT

Mfg CompCams

P/N 268HE

Flat Tappet Hydraulic

Intake Lift .454

Duration Advertised 268

Duration @ .050" 218

Rocker Ratio 1.5

Exhaust SAME


IGNITION

Brand Chevy HEI

Timing @ Idle 20

Timing @ Full Advance 36


EXHAUST

Headers

Primary Size 1 5/8"

Collector Size 3"

Pipe Diameter 2.5"

Muffler Type Flowmaster 50 Deltaflow

Muffler Size 2.5" inlet


FUEL SYSTEM

Gas

Pump Type stock

Pump Size stock

Regulator or Bypass bypass


VEHICLE

Type '77 Corvette Coupe

Wt. 3300

Transmission TH350

Number of Gears 3

Trans Brake No

Stall Speed 2000

Rear Tire Size 255 60r15

Gear Ratio 3.08




The carburetor seems a little large for this combination, but we should be able to help you get it to run better. To make an accurate recommendation we're going to need some more specific information about your combination, and where you have all of the settings/adjustments on the carburetor. If you'll contact our technical department directly at (706) 864-8544 we can walk you through this situation.

Thank you

Technical Support

Barry Grant, Inc.
BG Fuel systems, Demon Carburetion, Nitrous Works, Rush Performance Filters

1450 McDonald Road
Dahlonega, GA 30533

Phone (706) 864-8544
Fax (706) 864-2206

Mon to Fri 8am to 6pm EST"


Finally, these repeated denials of Lars' experience are "Amusing. " You talk about research, well the search function is working well enough for you to search for his previous posts and the photo-summaries of his tours. I personally used the loaner-carb program he runs and have seen countless posts of carbs and distributors he has setup for people, plus the odd body-off or engine pull completed in an afternoon for a CCC club member, plus his current resto that just reeks of craftmanship and attention to detail. He is not lying, it's all sitting right in front of you.

What's next? norvalwilhelm doesn't know fabrication. Jim Shea (ex-GM) doesn't know steering systems. Insert any forum member with a lifetime of experience and skill and their respective subject of expertise.

Checkmates only happen once in a game, perhaps since you are having multiple checkmates they might just be 'check?' Maybe you are not even playing this game? Yahtzee, backgammon, battleship? How's your lifeboat holding up? (Anyone remember that Far Side with the guy in the liferaft (oddly) watching TV "A-1 Liferafts has just recalled 10,000 of their products for faulty glue..." Can you swim as well as you ride?)

-Chris

 

I forgot I'm an engineer too, must of lost my pocket protector somewhere, maybe it fell under the vette while I was trying to adjust my carb. Dave 62 with your comments regarding Lars, he's been very helpful to many Forum members including myself.....anyone want to discuss hydraulic engineering now....

 

+

=


?

 

Forgot to include, nope haven't solved anything yet, just driving through it until my last final Wednesday. I will try all of what's posted here, beginning with float levels at operating temp, then searching for vac leaks with the several methods presented, verifying timing again etc. Getting home while it's still light outside is going to be weird...

-Chris

Didn't want to let this one go to waste:

Like arguing for days with a kid on the internet?

 

This whole "carb is to big" argument belongs in another thread. This engine can run with it's current carb. Whether or not it's the best carb for the engine is an entirely different question.