I was researching for a good carb and ran into this from Barry Grant web-site and I just Validate exactly what UDHarold has been preaching about the 1/2 fuel lines. :D
Now Barry Grant has Vaildated Harold point. After reading this you will clearly understand the need for a 1/2in fuel line :D
Fuel Delivery
Many racers experience fuel delivery problems without ever being aware that something is wrong in their race car’s fuel systems. Today’s state-of-the-art engines produce a lot more power than a race engine of ten years ago. The process of producing horsepower revolves around the conversion of fuel into energy. The more pounds of fuel an engine can burn efficiently per hour, the more horsepower it produces. Even though your car may not miss, pop, bang, skip or do anything else peculiar, it may not be getting all the fuel it needs to make maximum power.
In oval track applications, a BG Belt Drive or Hex Drive Fuel Pump is preferred where use of a mechanical fuel pump is specified. These pumps offer the highest fuel delivery volume of any mechanical pump yet maintains low fuel pressure at low engine speeds. This feature alleviates “loading up” of the spark plugs. The BG Six-valve and Super Speedway mechanical fuel pumps will also deliver ample fuel volume when used according to recommendations.
For drag race cars, a BG400-2 Electric Fuel Pump is the best way to guard against fuel starvation. If a car is “lazy” or “lays down” at mid-track then pulls well in a higher gear, the engine may be experiencing intermittent fuel starvation.
Why? Typically, the carburetor bowls are full at the starting line so the car leaves hard but in the process, drains the bowls dry. In the lower gears, the car accelerates rapidly with the engine picking up rpm very quickly. This rapid acceleration increases the demand for fuel. When the float bowl fuel level drops, the car “lays down” because of fuel starvation. In high gear, engine speed increases more slowly allowing the bowls to fill again.
The Fuel Can Test
To assure adequate fuel delivery, the fuel system should be capable of filling a one-gallon metal gas container at the carburetor fuel inlet in 25 seconds or less. Do not use a plastic jug of any kind - they are not accurate. Large displacement, high horsepower engines should have a fuel system that can pump a gallon in less than 20 seconds. Remember that to get fuel into the engine, the jets must be covered. Whenever a race car slows for no apparent reason, fuel delivery is the first thing to check, both for single and dual four-barrel installations. In fact, single four-barrel applications frequently have more severe fuel starvation problems than dual four-barrel installations. This is because a single four-barrel has only two fuel bowls and two inlet needle and seat assemblies. With dual four-barrels, there are four needle and seat assemblies and four fuel bowls. This doubles the fuel handling capability.

That article is typical of any advertising gimmick and just because it's "out there" doesn’t mean that it is correct!

Yes, proper fuel delivery is necessary, but to blindly say you need a leaky POS offshore Barry Grant fuel pump and 1/2" line is dead wrong!

Common sense and a good fuel pressure gauge is all that is needed!

Think about it!

If you have two .110 needle and seats (which BTW, flow allot less than 3/8" fuel line can supply) in a single carb setup, and you maintain a constant 7lb's pressure from the regulator to the carb.

What more can you add! More pump and line? Noooo, the regulator will still maintain the same 7lb's to the carb.

Marketing, pure and simple!

This topic draws a lot of attention and discussion every time it pops up. Not to start an argument or take sides, but consider my setup:
I have a fuel pressure gauge and an air/fuel gauge on my car. Both have memory recall features. After I make a pass, if I see that my fuel pressure never dropped below 6 psi and my air fuel reading never showed a lean condition throughout the pass, wouldn't it make sense that I had sufficient fuel delivery? That is currently what I go by. Does anyone see a flaw in this logic?

smile.gif That's not logic Jim, it's stone fact! Are you running that UD 288/296 +4/6? If not, then that would also be an excellent experiment on your platform, being all digital and such. :cool: Advance it, get a new best!( or at least a few more mph ) and see what the data shows at the top end.

Do not use a plastic jug of any kind - they are not accurate.

I think I'm going to have to recalibrate all my plastic jugs. Is there a standard metal jug we can calibrate from?

I wonder if the more accurate 'weigh' to measure fuel flow would be in lbs/hr, since most engine efficiencies are expressed in these units. Just don't use a plastic scale - they can be inaccurate....

Ditto what Gateway Racer said graemlins/thumbsup.gif Most know that Ed has gone from mid 11's with his UD hydraulic cam to low 10's using the same fuel system with factory 3/8 fuel line,and Mallory Comp 140 pump. Ed is meticulous with his record keeping,thats why he tests for Pro Systems,ATI and soon to be BTE, right Steve ;)

Originally posted by 427L88:
smile.gif That's not logic Jim, it's stone fact! Are you running that UD 288/296 +4/6? Yep, I run the 288/296 hydraulic cam. I have it installed with a +4 bushing in the cam gear. Using Harold's +/- .050" from max lift method of degreeing, it is installed on a 105 ICL. This gives me a 8.53 DCR for what it is worth.

I wonder how much I would pick up with a solid flat tappet cam or a roller? Ahhhh, nevermind, who am I kidding. That would make me dip in the 11's and then I'd need a cage, assuming the M20 survived.

This is a good topic...

In another recent post I asked Harold about my Comp Cams 292R solid roller and if it was one of his designs or if it would experience the same fuel supply problems he describes for a number of his UD designs. I am hoping he can get back and comment.

This spring I will be performing a test comparing ET and MPH with the fuel delivery from my Carter 172 compared to a Mallory Comp 250 regulated at 7 psi. Both will use the -10 braided line system I have.

As Bob said Ed uses the stock 3/8 and I have seen the system in person as I spent the good part of a half hour under his car last year.

As for BG...Well, I agree with the previous comment and that's from personal experience as well..... graemlins/angry.gif

I'll say one comment on this and many other things. What works on one car may not be the same on all cars. Just because one thing works well on one car may not be the same on another. There are too many variables.

Real world experience is very good, but if you don't have the hard data to back up that experience you don't have all the facts. In this case hard data would be actual fuel flow, A/F ratio, pressures monitored throughout the system. This would all require a typical data acquisition system. Since most people don't have access to a fully instrumented car, they just use real world experience and get their car working properly which is fine.

I've learned from my work that a lot of strange things happen that you would never see unless you fully instrument something and make sure it is fully calibrated. I've seen gauges be way off.

Most people just look for an easy answer.

If what you have works for you then great, if someone changes to what seems like overkill and their car goes faster then good for them too.

I've yet to see anyone give any real good factual data other than what they think works good for them. I do agree an ET slip tells a lot, but the hard data does too.

Bucket tests work fine, you are just missing any real dynamics that happen when a car is launching and goint down a track.

Originally posted by Epistuff:
I wonder how much I would pick up with a solid flat tappet cam or a roller? Ahhhh, nevermind, who am I kidding. That would make me dip in the 11's and then I'd need a cage, assuming the M20 survived. Never mind is right , IMHO Jim. Going solid would bring it up some for sure, but then there's always the hassle and probabililstic nature of a bbc cam change. A SR would really pick it up, but then you whack the tranny in short order. ( and drop big coin on lifters springs pushrods) I don't know how mr.68 runs deep 11's in a stick car man; I'll gladly take my 11,90 and drive home. The right solid grind would likely get you sub 12 without anymore tuning as well. Good goal anyway!

Hey guys, Here are a few good links for reference on this subject, if interested.

Also if upgrading your fuel system, 1/2" line should be good to around 1000HP or so and would be easier to maintain the correct 15-20 PSI between the fuel cell/tank and the regulator. When using a high pressure/volume electric pump, this is the critical adjustment that most seem to overlook.

As far as the "free flow" test. It is just that, free flow and means very little. If you maintain 7lbs at the needle and seat, then you need to flow test the system at 7lbs through the N&S. If more flow is required, then upgrade the N&S to .110 or .130 from the stock .097. Then if you can't maintain 7lb's at the new N&S you need more line pressure which could be a simple adjustment of the bypass setting on the fuel pump, or a larger regulator or, maybe a new fuel pump.

Tom, the -10 an system must have cost a bundle, very nice though I'll bet.

Holley Technical Information (http://www.holley.com/HiOctn/TechServ/TechInfo/FMFPTech.html)
Century Performance - How to set up your fuel system (http://www.centuryperformance.com/fuel.asp)
Magnaflow fuel systems - Performance Tips (http://www.magnumforceracing.com/store4/magnaflow/fuel_system_technical_notes.htm#How%20much%20fuel% 20pressure%20is%20necessary?)

Originally posted by gatewayracer:

Tom, the -10 an system must have cost a bundle, very nice though I'll bet.

It will meet the needs of anything I might put into my paperweight so I went -10. I put in a new gas tank ($130) because I am slowly restoring my car and the old one was covered with undercoating I wasn't going to spend 20 hours scraping to then spend $80 for a clean and seal. As far as cost, Yes it can be on the pricey side especially with all of the -10 and -8 fittings but Swap Meets are a nice thing smile.gif , the key is to plan ahead for your ride if possible, find the deals or a lot of times they find you and then squirrel them away for future use. I bought a big box of AN fittings mostly -10 and -8 for about $2 a fitting at a swap meet last year.

Here is something else to think about.

Whether you run an electric or mechanical fuel pump will influence the required fuel line size.

The gerotor style electric pumps pump fuel continuously through the fuel line to the carburetor.

The mechanical pump is a plunger pump that is only drawing fuel into the pump 1/2 the time, and discharging it to the carburetor the other half.

Also, the rate of discharge (and filling) of a plunger style pump as a function of stroke follows some what of a sine curve. Thus, the peak discharge and pump fill rate is about two times the average.

Couple this with the above statement that the plunger pump is only drawing fuel into the pump 1/2 the time and you end up with peak flow rates for the mechanical pump being four times that of the electric pump.

For example, let's say that an electric pump supplies the needs of a given engine at 50 gph. Every minute and every second the electric pump is supplying 50 gph.

The mechanical pump will supply the same 50 gph. However, due to the reasons discussed above, the rate of flow through the fuel lines will vary between 0 to 200 gph, averaging 50 gph.

As the fuel flows through the line, friction between the fuel and the inner walls of the fuel line provide resistance to flow. Think of it like sucking a milk shake through a straw. This is particularly important for mechanical pumps that must "suck" fuel from the tank.

Once the "suction" pressure equals the vapor pressure of the fuel, the fuel will vaporize in the line and the pump will no longer pump fuel at that high instantaneous rate.

For this reason, the fuel line must be sized to accommodate the peak flow produced by the mechanical pump. The larger the fuel line, the less the resistance to flow, and a greater volume of fuel can be pumped without vaporizing the fuel in the line.

That is why the Carter 172 gph mechanical pumps require 1/2" fuel line, and why many others get by with 3/8" line and a single gerotor style electric pump.

I've been thinking about this situation for awhile and I think the secret for adequate fuel volume at the big end of the track with a marginal mechanical pump system would be to mount the regulator as close to the carb as possible, then use some 5/8" hose from the pump to the regulator. The 5/8 hose would serve as a storage area of pressurized fuel. How much fuel would be in 3ft. of 5/8 hose?- enough to fill the bowls twice? The largest amount of pressurized fuel before the regulator the less chance it would run dry. Make sense? Makes sense to me, but I don't have any first hand experience with high fuel demand engines.

Unless you have a compressible medium in the 5/8" line it won't retain any useable pressure once you remove the source.

Originally posted by Rapid Robert:
Ed is meticulous with his record keeping,thats why he tests for Pro Systems,ATI and soon to be BTE, right Steve ;) Man...thats going to be a record breaking post...if/when Ed does test Steves BTE converter..I really think it started out on the wrong foot..when ED decided against testing it this year

For the 40 zillionth time, here's my thoughts....

Whatever cam and fuel system you are running, if it pulls your head off at high RPM, you DON'T have a fuel delivery probllem.
On the other hand, if whatever cam company you are using told you that their cam had a strong top-end and would pull hard at high-RPM, and instead it gets flat and lazy, revving slowly, then SOMETHING or the other is wrong.
Maybe they lied. If not, then something else is wrong. Let's face it, you've bought a cam, maybe spending $250-$300 for it, and something's wrong. If you ask your cam company and they say you're running out of fuel, you can either fix it, or tell them you think you need a bigger cam. If you spend another $250-$300 for the bigger cam, and it still is flat and lazy, you have paid $500-$600 for what? To insist your fuel system is OK? Now you have to change cam companies, and spend another $250-$300 for another cam, to hope that this one doesn't go flat and lazy on the top-end.
If you're in this situation, make sure to ask if their cams are symmetrical, because symmetrical cams DO NOT HAVE this problem; Their high-RPM reversion kills off their demand for high volumes of fuel, and allows them simplier fuel systems.
Companies that have symmetrical cams only, or a high proportion of symmetrical ones, are Competition Cams, Cam Motion, Bullet, and LSM.

Just my thoughts,

UDHarold

Originally posted by UDHarold:
Whatever cam and fuel system you are running, if it pulls your head off at high RPM, you DON'T have a fuel delivery problem.
UDHarold :cool: !!!

Originally posted by 427L88:
</font><blockquote>quote:</font><hr />Originally posted by Epistuff:
I wonder how much I would pick up with a solid flat tappet cam or a roller? Ahhhh, nevermind, who am I kidding. That would make me dip in the 11's and then I'd need a cage, assuming the M20 survived. Never mind is right , IMHO Jim. Going solid would bring it up some for sure, but then there's always the hassle and probabililstic nature of a bbc cam change. A SR would really pick it up, but then you whack the tranny in short order. ( and drop big coin on lifters springs pushrods) I don't know how mr.68 runs deep 11's in a stick car man; I'll gladly take my 11,90 and drive home. The right solid grind would likely get you sub 12 without anymore tuning as well. Good goal anyway! </font>[/QUOTE]

hey gene, running deep into the 11's with my m20 is easy. a stockpile of parts and many evenings putting it back together again., and again, and again. lol!

I don't understand why people are insisting that the needle/seat restriction is what utimately determines flow. Given that logic, a 3/16" fuel line 'should' suffice.

A Q-Jet with larger primary throttle bores will flow MORE, even though the venturi size remains the same - velocity is increased at the restriction. Even though people haven't maxed out their combos, they've discovered that better flowing heads net noticeable gains. I'd also like to point out that combustion chamber shape can affect your BSFCs. Alter the intake runner lengths and plenum size and you will have to re-jet accordingly. Hell, even your exhaust plays a vital role...

It is evident that there will come a point that these cars will benefit from an upgrade. Where that point is depends on how much fuel you need.

When we test using the "bucket" method we test for weight and convert it to volume. First you use an accurate measuring container like a graduated cylinder and weigh it (with a very accurate scale). From there you get the specific density of the liquid you are flowing. Then you flow the liquid into a container for a specific time. Then you weigh it with a good digital scale. Using the density you convert it to volume. This is a very accurate method.

You always use the pressure you will be running the system at. Most pump flows are rated at 0 PSI, or freeflow and will flow a lot more than when at higher pressures so most manufactures pump ratings are useless unless at the desired system pressure.

The bucket test, no matter how carefully you take it, does not accurately reflect what happens under a hard launch. The rear mounted electric fuel pump must overcome the weight of fuel in the fuel line that is under the force of gravity at launch. Assuming 12-feet of horizontal fuel line between the pump and the carb, the pump must produce about 4 psi of pressure per 1 G launch. So an electric pump in a car with a sub 1.5 second 60-foot time which is launching near 2-G's must produce 8 psi just to overcome the G-force. Add 7 psi desired at the needle and seat plus a few psi for friction losses in the fuel line and you need a pump capable of 16-18 psi.

Gotta bite. UDHarold is not really talking about this. All I have seen him advise is most of his grinds do better with more fuel on the long end... right? No argument with me on that at all. If I had known him 10 years ago and tried that my stuff may have picked up....Anyway a few comments: Seems like to do the free flow "bucket" test, the best you can under non race conditions, you would want to remove the float bowels and hold that over the "time volume measurement tank". That way you are testing as much of the system as possible. For me experience is an important teacher. My '70 back halved (Dana 60 strong like bull :D ) 3000+lb Vett I raced in the early 90's, had a 12.5:1 505 BBC with nice ported (by Tommy at Champion) Brodix -2 and a stock 1050 Dominator 9375. I ran 1/2 tube from the rear mounted single Holly Blue via a giant Russel filter and into a single Holly regulator. I had jet extensions and ran 92 square jets. This car ran on 100LL gas. R274 Crane roller, Callis crank on C&A steel Super Stocker +400 rods. Dart intake. This car was nothing special for sure, but just as described and at a density altitude of 500ft it ran 8.93's at 154. Summer time it would run 9.2' at 147. My point is simple, if the combination is correct you can haul ass with small pump. You do not have to buy into the hip about needing a 400gpm pump unless you want. graemlins/thumbsup.gif

I'm sure many other have done the same or better. I think this 505 made about 820hp on the HBR Dyno.

Here's one last ditti.. I never saw these Germans in my life. They came over here just to by a race car. They saw my junk run on a regular Sat race night here, made me an offer on Monday and owned it Wed. It was in a Sea Crate off the mother-land Friday! graemlins/hurray.gif They said they like the super stocker 3ft wheels stands. Big laughs! They had tons of money.... They wanted to go fast and I got very luck! I wish they would come back on by my Horton so I could get one with springy things. OK that's it good night... graemlins/boring.gif

Hey Harold,,remember me? :D With all your talk about buying bigger cams and bigger cams,spending 250-300 a pop....so... what if we do this and the car continues to pick up with this smallish( by your standards) fuel system?...the cams keep gettin bigger and the car keeps going faster without two fuel pumps and a fire hose going to the front. How many cam companies out there today recommend the larger fuel system? I know you have to know that answer too,since you were in the business,and ought to know everyones marketing ploys.

I don't think Harold ever sold fuel pumps so recommending a fuel system didn't do any good for him from a monetary standpoint.

Roadknee,
I agree, that is why having a simple data acquisition system on a serious car is a good idea.

RapidRobert/Bob,

Let me explain this ONE more time.
I DON'T DESIGN OTHER COMPANIES' CAMS. I did in the early-mid 70s, but they were all SYMMETRICAL designs.
If you doubt me, buy a Lunati 501C1LUN. This is my favorite, 288/296 at .020, 255/263 at .050, .626/.626 valve lift, and 106 LSA. Run it with a Mallory 140 and 3/8" line. IF it gets flat and lazy above 6000---Remember, I say PEAK POWER in a 12.5:1 355 with 210 AFRs with this cam occurs at 7200---Call me up and I'll sell you another cam. Maybe a 501C8LUN, 302/310 at .020, 271/279 at .050, .640/.640 valve lift, and still 106 LSA. A LOT bigger cam, right? So the top end should really increase. However, if it won't go over 6000 either, without being flat and lazy, CALL ME UP AGAIN, and again, and again. You could help me retire.......
This advice does not hold true for any other company's cam that I know of. My advice concerning THEIR cams is for you to ask them what their cams need for fuel. I will not give you advice on what a LSM need, other than, "Not Much...".
In 23 years I have never made ONE dollar off of recommending 1/2" fuel lines, or Carter 172-gph mech pumps, or using 2 Holley 110s. This must be the worst marketing ploy of all times.

UDHarold

UDHarold, Just for curiosity sake and if you or anyone else has this two blue pump set-up as UD had described . Try making a pass with one of the two pumps off. I'd be interested to see the MPH change on a 1/4 mile pass.

For what it's worth, I know a guy that ran NMCA Hot Street when the class first began several years ago. It was basically a Comp motor (SBC) in an old Super Stock chassis (80's Camaro). When he bought the chassis it had 2 Holley Blue pumps feeding into a Y-block at the rear. The car ran low 9's turning close to 9000 RPM. He said if it ain't broke, don't fix it.

Originally posted by UDHarold:
RapidRobert/Bob,

Let me explain this ONE more time.
I DON'T DESIGN OTHER COMPANIES' CAMS. I did in the early-mid 70s, but they were all SYMMETRICAL designs.
If you doubt me, buy a Lunati 501C1LUN. This is my favorite, 288/296 at .020, 255/263 at .050, .626/.626 valve lift, and 106 LSA. Run it with a Mallory 140 and 3/8" line. IF it gets flat and lazy above 6000---Remember, I say PEAK POWER in a 12.5:1 355 with 210 AFRs with this cam occurs at 7200---Call me up and I'll sell you another cam. Maybe a 501C8LUN, 302/310 at .020, 271/279 at .050, .640/.640 valve lift, and still 106 LSA. A LOT bigger cam, right? So the top end should really increase. However, if it won't go over 6000 either, without being flat and lazy, CALL ME UP AGAIN, and again, and again. You could help me retire.......
This advice does not hold true for any other company's cam that I know of. My advice concerning THEIR cams is for you to ask them what their cams need for fuel. I will not give you advice on what a LSM need, other than, "Not Much...".
In 23 years I have never made ONE dollar off of recommending 1/2" fuel lines, or Carter 172-gph mech pumps, or using 2 Holley 110s. This must be the worst marketing ploy of all times.

UDHarold =
Hi Harold,

Does the term "P!ssing into the wind" bring fond memories :rolleyes:
And here I thought your retirement fund was being funded by the Berry Cant (oops,Grant)/ Mallory / Holley fuel pump fund :D :D
To everyone that dissagrees with Harold's ideas, my question is,,,,why???
Why is it a bad idea to have a fuel system that you do not have to question?
What exactly is a good fuel system going to hurt?
Now what is a poor one capable of hurting??

If you have a small fuel system & feel it works & you already know all things important in the universe by all means do not try something different. Instead just continue to argue a mute point.
Can you run good with less fuel system,, very probably.
Might you run better if you upgrade,, hey here's a thought, try it & see.
Even if it makes no difference you have caused no problems & on the off chance that someday you should decide you want to go faster which of course none of us have even considered :eek:
guess what, you have a fuel system that will support it.

And before someone says what about the "waste of money", if you have never "wasted" money on something in performance that didn't help you ain't been doing this very long.

Exactly as stated above, what`s the harm with a little bigger fuel line anyway? It won`t hurt anything so who cares??
For those wondering why Rapid Robert constantly pesters and badgers Harold so much and where he gets his motivation to do so, just stop on over at DRR and you`ll see for yourselves :rolleyes: .
You might also be surprized at some of the comments made about this site while doing a search there very interesting...!!

No harm at all running 5/8" fuel line and the biggest pump on the market. But to go spend $800.00 for an upgrade that may not be needed is foolish. If you are installing a new system and you are purchasing anyway, by all means, it would be foolish not to install ˝” line and an adequate pump to meet your goals.

Yes, inadequate fuel supply can cause a lean/lazy condition, but there are test that can be done first to check you're current fuel system and see if an upgrade is needed and where. The problem may not be the pump or line.

How about finding that out after you spend the $800....!

My post was merely point out where gauges are needed along with links to information on pluming the proper system, and that the article IS a marketing article printed directly from the Barry Grant site, not to argue with anyone.

I totally understand why a cam designer would recommend that you make sure you have adequate fuel supply. But if you are telling me to blindly upgrade to the biggest pump without doing any testing then sorry, you are “pissing in the wind”
:D

I never tell anyone to 'blindly' upgrade their system. What I tell them is that if they use my cams, and at high engine speeds they have a flat and lazy condition, they are running out of fuel. This has been the case for 23 years, not "sometimes you may be running out of fuel.".
I know of no oother condition that could cause this problem, AND be solved by a fuel system upgrade. The 288/296F5 runs 4412 Holleys out of fuel half-way down the straight IF you use a 3/8" line from mech pump to carb, and most people report over .1 gain in lap-time replacing the 3/8" line with 1/2".
If you use my cams, and you experience the flat and lazy condition at high-speed, you must either live with it, or up-grade your fuel system. I generally tell customers when there is a probablity of running out of fuel at high-speed, and how to correct it. If they have doubts, I tell them to run the fuel system they have, and IF they feel the flat and lazy condition, they know what I will tell them to do.
No one has to spend any money they don't want to.

UDHarold

Hey Nickel333 :rolleyes: You aint worth it. I was asking a question. Ed is running the stock fuel system with a comp 140 and has since upgraded his cam several times and his car keeps getting quicker with the same small fuel system,so the upgrade is not something that has to happen. What do you care what I make myself look like anyway? Did you contribute to this post or just put your nose where it don't belong? and while you're at it,wipe the brown stuff off it :D Harold recommends that everyone using his cams upgrade their fuel system and I say it don't have to happen along with a select few that do actually drag race quite frequently if I was building a drag car from the ground up,I'd probably plumb it with 1/2" line to the front,but why take it out of there now when 3/8" serves its purpose? No,I'm not setting any track records either,but I did add a Comp140 pushing to a Carter street/strip mechanical pump with no improvement to be had with my current setup wolfplace tongue.gif ...Harold contributes that to be an older Lunati solid cam, read "symetrical". Ya know,I'm no engine builder,,,I've put together 3 or 4,I'm no cam designer,I've installed several...I enjoy drag racing,been doing it full time the last two years logging close to 400 passes down the track,finishing 17th and 6th in points respectively the last two years. I don't claim to be anything I'm not,I don't recommend stuff you don't need,I just suggest whats worked for me,and occasionally voice my opinion when I disagree with blanket statements...thats me,,,just Bob :D

1/2" fuel line is cheap smile.gif

Bob,

There's no problem on my part. You say "Don't install it if you don't need it.". I say the exact same thing. It's just that over the past 23 years, I've seen tens of thousands of racers who did need it.
Do not use Ed as proof I am wrong. If anything, Ed's example PROVES what I've been saying all along. When Ed bought that cam, it recommended being installed 6° advanced. Ed had insufficient piston-to-valve clearance, so he installed it around straight-up, possibly even slightly retarded. At THAT position, the cam was flowing LESS air than it could have, and Ed's Mallory 140 and 3/8" line was sufficient. Over these past 23 years, I have had a number of people who tell me my cams run just fine straight-up, with THEIR fuel system. But dyno tests tell us the cams like to be advanced 4 to 7 degrees for the BEST overall power curve, and on the track, a cam in that position is very demanding of fuel supply. And yes, it still delivers decent fuel economy... The cam is USING that fuel to make BHP, not wasting it. After all, when I invented and designed the original High Energy cams for Comp Cams, the secret was----- I WAS DESIGNING THEM EXACTLY LIKE I DESIGNED MY ROLLER CAMS---Unsymmetrical, fast open, gentle close, etc, etc, etc... Reducing reversion increases airflow, and increased airflow means increased torque, and increased torque means a more efficient engine, both with more power and with better fuel economy. Once again, use whatever fuel system you want. If your car pulls hard in high gear, you have no fuel problem. If you are using one of my designs and the engine gets flat and lazy past peak torque, wellllll, you know what I'll say....

UDHarold

UDharold I totally respect your judgement and recomendations. I enjoy reading your posts/replies. It is amazing how far this post has gone. I plan to install the larger line in my car because it only makes sense. This has been very interesting. I'll be asking for a cam recomendation for my bigblock after I do a trial assembly and get my actual static compression ratio figured out along with the remainder of the parts selection bought. graemlins/beers.gif

Bob,

Thanks, I always appreciate words of kindness....
Give me a call when you're ready.

And to everyone else, Good Night, I have a busy day tomorrow, involving Pro-Stock cam design, so I'm---- Outa Here!!!

UDHarold

Robert, smile.gif
I don't doubt your accomplishments & certainly respect what Ed has done & the way he has done it.
As I said in my previous post, if you have a system that works for you that's great.
What I take issue with is every time Harold recommends his preference in fuel systems for his cams someone has to argue with him.
I just feel he has been doing this stuff for a couple of years now & has had enough feedback from his customers along with a fair amount of testing of his own that when he says he feels it is in the best interest of the person buying a cam of his design to either have a good fuel system or upgrade to one it serves no useful purpose to say it isn't necessary or is wrong.
You obviously have a bit of experience at the track.
Well, I have done my share of track time also.
In everything from 15 second cars to 5 second dragsters & won my share including the division championship. & have built & had a few engines on the dyno but that does not make me an expert on much of anything but I can tell you that they will not all run on 3/8 fuel lines :D
The point is, why not give the man the respect he deserves given his experience.
If you can make your deal work with a hand pump & straw great but that does not make it the only way to do it & it could be that there are better ways to go about it ;)

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That's alright, Think of Robert just like 'Stewie' on Family Guy...