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Author
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Topic: bench racin'
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Dusty Kiser
Gearhead Posts: 191
From: Bethel,Oh USA
Registered: Mar 2002
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posted 04-18-2002 07:59 PM
 
I have several dumb questions and comments I'd like to throw out and see where they land. #1 I hate the sound of a powerglide equipped car. They sound like a drone airplane. My question is, How can a two speed be fast in a relatively heavy car? An ultralight altered or something would seem to be a better application. #2 With all the sophisticated computer technology why don't head flow experts use variable pressure drop levels in evaluating flow instead of relying on valve lift increments to predict potential torque characteristics? #3 My son-in-law's stock '69 Mach w/ near stk 351C 4v picked up 4tenths and three mph by switching from a 3310 to a box stk 750DP Holley. ( From 12.90 @ 107mph to 12.5 @ 110mph.) A Holley rep I met says if it liked it that much, to put an 830 HP series carb on it and we'll likely see a similar increase over the 750 DP. Any comments on that?
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kid vishus
Gearhead Posts: 7251
From: middle of NC
Registered: Oct 2000
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posted 04-18-2002 09:42 PM
First part, not all cars are faster with a powerglide. My racecar went from running mid 6.30's in the 1/8, to low 6.60's when I put a powerglide in (and the car weighed 2835 lbs with driver). All the trans companies I talked to prior to that told me the convertor and trans ('glide) I had was a perfect match, and that it would run just as fast, if not faster than my C4. Well, they were waaaaaayyy wrong. It made it a dog and very inconsistant. I took the 'glide out, put my c4 back, and it went right back to 6.30's again and would run the same number all day long. Your second question went right over my head.  Third, I bet that motor would like the 830 too. It also might really like a 950HP. I put one on a mild 351C 4v motor, (took off a 750 DP), and it picked up around 3 tenths in the 1/8 with no other changes. [This message has been edited by kid vishus (edited 04-18-2002).]
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SundanceKid
Gearhead Posts: 1302
From: UT
Registered: Feb 2001
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posted 04-19-2002 05:17 AM
#2 As far as I know they do, but I haven't seen any companies release their data. I know that they use the standard of CFM @ 28" H20 at each vavle lift height for comparison reasons only. In reality even if the pressure drop was variable who is to say that each engine will have the same pressure drop? When the original pressure drop standards were made they were made soley for compairing a 2brl to a 4brl carb. 1.5 and 3.0 respectively if memory serves? I would guess that each and every engine has a differant pressure drop at any given RPM. And with the millions of engine combinations possible It would seem to me that there are far too many variables to get that specific on airflow. I'm sure that given a specific Engine with fixed variables it would be very advantatious to use the variable pressure drop in design consideration, but maybe not in evaluation purposes?
This is just a stab at it, I am kinda confused as to what you mean? Hope I touched light on what you asked?
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Daniel Jones
Gearhead Posts: 972
From: St. Louis, MO
Registered: Aug 99
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posted 04-19-2002 04:51 PM
>With all the sophisticated computer technology why don't head flow experts use
>variable pressure drop levels in evaluating flow instead of relying on valve
>lift increments to predict potential torque characteristics?Do you mean variable pressure drops to mimic the pressure drop (across the
valve) change with RPM or to mimic the cyclic nature of the pressure?
Either way, I don't think it's an either-or situation. Valve lift still
needs to be part of the test. Ideally, you'd like to flow test the head
with an oscillating pressure drop that mimics the suction of a piston over
the RPM range of interest, with intake and exhaust manfolding, flowing an
air-fuel mixture. You'd want the valves being actuated by the cam too.
Hmmm, add in combustion and I think we call these dyno tests :-) If I follow your question correctly, I think you'd want to control the
pressure drop of the flow bench to provide the same port velocity as a
given range of RPM. I wonder what sort of pressure drop the valve sees as
a function of RPM? It might be that a 10" drop is a better predictor for
low RPM flow than 28". It would also be important to know if your at or
above the critical Reynolds number (determines the transition from laminar
to turbulent flow). I think port velocities are on the order of 0.6 Mach,
so my guess would be turbulent at higher RPM. Did you know that water benches have been used to design cylinder heads?
Wings, too. >When the original pressure drop standards were made they were made soley
>for comparing a 2brl to a 4brl carb. 1.5 and 3.0 respectively if memory
>serves? The reason is primarily historical. Early on, venturi size (area) was
used for carb comparisons. By the time 4 barrel carbs came onto the scene,
2 barrel carbs were being flow rated at a pressure differential of 3.0
inches of mercury (Hg). However, due to the larger (total) venturi area,
the vacuum pumps used to rate 2 barrel carbs were unable to pull the same
pressure differential across a 4 barrel carb, so it was agreed to rate 4
barrel at a lower pressure drop (1.5 inches Hg). Flow ratings from one standard can be related to flow ratings from another
standard. For 2 and 4 barrel carbs: Flow @ 1.5 In Hg = (CFM Rating @ 3.0 In Hg)/SQRT(3.0/1.5) Which is approximately: Flow @ 1.5 In Hg = (CFM Rating @ 3.0 In Hg)/1.414 This relationship is derived from the fact that, for incompressible flow, the
volumetric flow rate through a venturi is proportional to the square root of
the pressure differential: Q = K1*A2*SQRT(2*Gc/Rho)*SQRT(P1-P2) or more simply: Q = K2*SQRT(P1-P2)
where: Q = volumetric flow rate
K1 = flow coefficient
A2 = downstream area of the venturi
Gc = gravitational constant
Rho = density
P1 = inlet pressure
P2 = pressure at venturi minimum area
K2 = K1*A2*SQRT(2*Gc/Rho) Computing the relationship for volumetric flow rate at the two flow
differentials and equating yields the conversion formula. A similar conversion can be done for flow benches (i.e. converting 10"
numbers to 28" numbers) but it is important to know that the character
of the flow can change (particularly above and below the critical
Reynolds number) so the conversion may not be accurate. Dan Jones
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JCQuinn@work
Gearhead Posts: 998
From: Lakewood, CO, USA
Registered: Jun 2001
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posted 04-19-2002 05:16 PM
Dan
regarding the conversion from one flow bench pressure, ie 10" to 28". I once had a long conversation with the guy who started Superflow, the flow bench and dyno company. He is also the design engineer. They made two versions of the flow bench, the smaller one did not have enough power to flow heads at 28" and could not even pull the pressure used to flow a chevy head when testing Clevelands. I owned one of the small benches and was asking him if I should upgrade. He claimed that the conversions were very accurate. I asked him if you can do all the work you need on the small bench then why do you make the large one. His reply was that if he didn't make the larger model, someone else would and take away his business.The bottom line, he believed the conversions are very accurate and he is a whole lot smarter than I. John Quinn
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Dusty Kiser
Gearhead Posts: 191
From: Bethel,Oh USA
Registered: Mar 2002
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posted 04-19-2002 11:29 PM
quote:
Originally posted by kid vishus:
First part, not all cars are faster with a powerglide. My racecar went from running mid 6.30's in the 1/8, to low 6.60's when I put a powerglide in (and the car weighed 2835 lbs with driver). All the trans companies I talked to prior to that told me the convertor and trans ('glide) I had was a perfect match, and that it would run just as fast, if not faster than my C4. Well, they were waaaaaayyy wrong. It made it a dog and very inconsistant. I took the 'glide out, put my c4 back, and it went right back to 6.30's again and would run the same number all day long. Your second question went right over my head. Third, I bet that motor would like the 830 too. It also might really like a 950HP. I put one on a mild 351C 4v motor, (took off a 750 DP), and it picked up around 3 tenths in the 1/8 with no other changes. [This message has been edited by kid vishus (edited 04-18-2002).]
Kid, You've confirmed what I only suspected, which begs the question Why install one in the first place, especially when there are so many options? ('Glide vs 3 or 4 spd AT's) I liked the sales pitch Holley made on the HP carb especially after reading that Ford helped develope the annular boosters for the Dominator / Boss 429 project. I'll have to convince Johnny to get one.
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Dusty Kiser
Gearhead Posts: 191
From: Bethel,Oh USA
Registered: Mar 2002
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posted 04-19-2002 11:56 PM
quote:
Originally posted by Daniel Jones:
>With all the sophisticated computer technology why don't head flow experts use
>variable pressure drop levels in evaluating flow instead of relying on valve
>lift increments to predict potential torque characteristics?Do you mean variable pressure drops to mimic the pressure drop (across the
valve) change with RPM or to mimic the cyclic nature of the pressure?
Either way, I don't think it's an either-or situation. Valve lift still
needs to be part of the test. Ideally, you'd like to flow test the head
with an oscillating pressure drop that mimics the suction of a piston over
the RPM range of interest, with intake and exhaust manfolding, flowing an
air-fuel mixture. You'd want the valves being actuated by the cam too.
Hmmm, add in combustion and I think we call these dyno tests :-) If I follow your question correctly, I think you'd want to control the
pressure drop of the flow bench to provide the same port velocity as a
given range of RPM. I wonder what sort of pressure drop the valve sees as
a function of RPM? It might be that a 10" drop is a better predictor for
low RPM flow than 28". It would also be important to know if your at or
above the critical Reynolds number (determines the transition from laminar
to turbulent flow). I think port velocities are on the order of 0.6 Mach,
so my guess would be turbulent at higher RPM. Did you know that water benches have been used to design cylinder heads?
Wings, too. >When the original pressure drop standards were made they were made soley
>for comparing a 2brl to a 4brl carb. 1.5 and 3.0 respectively if memory
>serves? The reason is primarily historical. Early on, venturi size (area) was
used for carb comparisons. By the time 4 barrel carbs came onto the scene,
2 barrel carbs were being flow rated at a pressure differential of 3.0
inches of mercury (Hg). However, due to the larger (total) venturi area,
the vacuum pumps used to rate 2 barrel carbs were unable to pull the same
pressure differential across a 4 barrel carb, so it was agreed to rate 4
barrel at a lower pressure drop (1.5 inches Hg). Flow ratings from one standard can be related to flow ratings from another
standard. For 2 and 4 barrel carbs: Flow @ 1.5 In Hg = (CFM Rating @ 3.0 In Hg)/SQRT(3.0/1.5) Which is approximately: Flow @ 1.5 In Hg = (CFM Rating @ 3.0 In Hg)/1.414 This relationship is derived from the fact that, for incompressible flow, the
volumetric flow rate through a venturi is proportional to the square root of
the pressure differential: Q = K1*A2*SQRT(2*Gc/Rho)*SQRT(P1-P2) or more simply: Q = K2*SQRT(P1-P2)
where: Q = volumetric flow rate
K1 = flow coefficient
A2 = downstream area of the venturi
Gc = gravitational constant
Rho = density
P1 = inlet pressure
P2 = pressure at venturi minimum area
K2 = K1*A2*SQRT(2*Gc/Rho) Computing the relationship for volumetric flow rate at the two flow
differentials and equating yields the conversion formula. A similar conversion can be done for flow benches (i.e. converting 10"
numbers to 28" numbers) but it is important to know that the character
of the flow can change (particularly above and below the critical
Reynolds number) so the conversion may not be accurate. Dan Jones
Dan, Kid, Quinn great stuff. You can't get this kind of rational thinking and experience from reading the second and third hand drivel in the rodding pubs. You're right on target with my thinking. Whether you can compensate for every variable or not, is irrellavant when performing a static flow test on a head. It seems much more practical to check flow at lesser pressure drop if you want to predict low speed torque characteristics. We know cam timing (ie valve lift) doesn't change appreciably with RPM, so we consider that a constant. What does change dramatically? Piston speed, which dramatically impacts on the efficiency of the"pump" thus the velocity of the incoming charge. In other words REDUCED PRESSURE DROP. To my befuddled mind, the passion for predicting low speed torque based on low LIFT flow numbers makes as little sense as selling torque converters by RPM ratings. Why don't converter manufacturers say IF your engine produces 300ftlb torque at 3500rpm this converter will stall at 3500. Keep the good stuff coming guys. Thanks.
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SundanceKid
Gearhead Posts: 1302
From: UT
Registered: Feb 2001
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posted 04-20-2002 05:05 AM
quote:
Originally posted by Daniel Jones:
>mimics the suction of a piston over
the RPM range of interest, with intake and exhaust manfolding, flowing an
air-fuel mixture. You'd want the valves being actuated by the cam too.
Hmmm, add in combustion and I think we call these dyno tests 
Agreed  Great info as usual Dan! I would like to learn more To me there are just too many variables to consider. The end result can be tested in real world physics on a dyno. I'm kinda thinking what would be the point? IMHO??
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Dusty Kiser
Gearhead Posts: 191
From: Bethel,Oh USA
Registered: Mar 2002
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posted 04-20-2002 10:33 PM
quote:
Originally posted by SundanceKid:
Agreed Great info as usual Dan! I would like to learn more To me there are just too many variables to consider. The end result can be tested in real world physics on a dyno. I'm kinda thinking what would be the point? IMHO??
Hell, why waste time on a dyno? Let's throw it in a car and flog it, that's the ultimate dyno. Or better still, let's all call Kuntz and have him send his latest and greatest, and we can sit on our hands and congratulate ourselves on what fabulous mechanics we are. The whole concept of the fow bench, is to make comparisons without having to commit to one configeration. Harry Weslake was instrumental in adapting gas meter ( flow measuring ) technology to measure changes he made to his motorcycle engines. His work, and the work of a mere handfull of mechanical geniuses laid the groundwork for all the so-called hi-tech crap we use today. The people who question convention and don't settle for the easy path are still the ones who make the greatest contribution to the sport. Let's all drive small block Chebbies and be content with mediocrity!
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TomP
Gearhead Posts: 6376
From: Delta BC Canada
Registered: Dec 99
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posted 04-20-2002 11:46 PM
quote:
Originally posted by Dusty Kiser:
Kid, You've confirmed what I only suspected, which begs the question Why install one in the first place, especially when there are so many options? ('Glide vs 3 or 4 spd AT's) I liked the sales pitch Holley made on the HP carb especially after reading that Ford helped develope the annular boosters for the Dominator / Boss 429 project. I'll have to convince Johnny to get one.
Heres trannies more suited to going fast... http://www.jericoperformance.com/
Holley and Ford have a long history, the Holley 4 barrel as we know it today was used on 1957 Fords, the Dominator was a Ford-only carb for it's first season and the Holley 4 barrel was used up to the mid 80's on Fords, and i think it still is on Ford marine engines.
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kid vishus
Gearhead Posts: 7251
From: middle of NC
Registered: Oct 2000
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posted 04-21-2002 11:49 AM
quote:
Originally posted by Dusty Kiser:
[QUOTE] Kid, You've confirmed what I only suspected, which begs the question Why install one in the first place, especially when there are so many options? ('Glide vs 3 or 4 spd AT's)
Well, it was what came in the car when I bought it. And when I decided to use it, I had had a slight problem with my C4, and didnt want to miss a points race. And since I had everything to put the glid back in the car, (transmission, crossmember, adaptor,shifter, and convertor) I figured it would be a good way to still race, and find out if the glide was indeed faster like all the "experts" said it would be. Afterwords, they (transmission "experts") all told me the convertor I had was too tight and it needed loosened up to around 6500 rpm to work well with my motor (the glide convertor flashed to 5500 while my c4 convertor flashed 6200).
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SundanceKid
Gearhead Posts: 1302
From: UT
Registered: Feb 2001
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posted 04-21-2002 11:46 PM
quote:
Hell, why waste time on a dyno? Let's throw it in a car and flog it, that's the ultimate dyno. Or better still, let's all call Kuntz and have him send his latest and greatest, and we can sit on our hands and congratulate ourselves on what fabulous mechanics we are. The whole concept of the fow bench, is to make comparisons without having to commit to one configeration. Harry Weslake was instrumental in adapting gas meter ( flow measuring ) technology to measure changes he made to his motorcycle engines. His work, and the work of a mere handfull of mechanical geniuses laid the groundwork for all the so-called hi-tech crap we use today. The people who question convention and don't settle for the easy path are still the ones who make the greatest contribution to the sport. Let's all drive small block Chebbies and be content with mediocrity!
First off Dusty I meant no offence.
If you want to know what power an engine makes and be as accurate as possible and consider as many variables as possible...hmmmph build the engine and find out how the combo does!
If you want to compair parts individualy you don't need all the variables just those that are the most significant. The most important thing is that when compairing likes with likes that the test procedure is the same for both.
The internal combustion engine is so inefficient at it's current level today anyway. Why flog a dead horse? Show me a ceramic engine with valves actuated by computer controled solinoids with pre-combustion fuel vaperizeation adjustable compresion and intake then we'll have something worth toying with.
I guess I feel at our current point in technology the testing procedures and mathmatics involved are good enough?
Are you planning on building and designing such a program to contribute to the "sport" or just ramble on about it here? Oh and ah yeah I'm conventional  [This message has been edited by SundanceKid (edited 04-22-2002).]
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Alex
Gearhead Posts: 148
From: Melbourne, Vic, Australia
Registered: Jun 99
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posted 04-22-2002 12:20 AM
Dan,Interesting thread. I put some numbers into Moody's plot one time, and you're way, way, into the inertial regime. I'm not sure of the nature of the turbulence however, It'd be interesting to see some CFD? I think the Mach number is a little lower than that. I've got an interesting reference at home, and from memory the flow gets pretty throttled by about Mach 0.6. I've heard quotes around 200 fps for intake flows, but I'm not sure how they arrived at that number. I completely aggree with your comment about needing a pulsed flow - I'd have thought a steady state experiment would be a poor approximation. Isn't this sort of what the method of characteristics is trying to get a handle on?? Alex
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jsracingbbf
unregistered
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posted 04-22-2002 02:31 AM
Kid, I ran a power glicth behind my 351C and I run one now behind the BBF. I didnt like it then and I don't now, but it would cost too much to go back the other way now. Just to mention though I had a 6400 stall PTC convertor behind the 351C and I launched it at 5600 - 5800. I also had to run 6.00 gears. Along way from the set up I have now. but it worked best in that RPM area. The clevland, power-slush ( glide) combo just needed allot of gear and RPM to work.
------------------
Jerry Smith
69 Pro ET Mustang
514 cid Alcohol/ Enderle injection
5.60's@ 119 MPH 1/8th
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TomP
Gearhead Posts: 6376
From: Delta BC Canada
Registered: Dec 99
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posted 04-22-2002 02:47 PM
hey it can be worse... there was that (hopefully finished with) experiment with the high gear only Powerglide. It made a race car sound like a truck with a bad muffler climbing a long hill 
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kid vishus
Gearhead Posts: 7251
From: middle of NC
Registered: Oct 2000
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posted 04-22-2002 05:56 PM
quote:
Originally posted by jsracingbbf:
Just to mention though I had a 6400 stall PTC convertor behind the 351C and I launched it at 5600 - 5800. I also had to run 6.00 gears.
I was figuring, (plus I was told) I needed a convertor in that area too. Plus that 6.00 gear is a long ways from the 4.88 I have now, and the 5.00 I had at that time (would still have the 5.00 but I broke three teeth off the pinion gear)
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Dusty Kiser
Gearhead Posts: 191
From: Bethel,Oh USA
Registered: Mar 2002
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posted 04-22-2002 06:00 PM
Thanks guys, great stuff. Sundance your arguments are valid and thanks for sharing. Like I said at the onset, we have some experienced and articulate persons here and it's nice to have this kind of medium to use to stimulate conversation& new ideas. The piston engine does waste a hell of a lot of energy for sure, but it still provides a lot of thrills for old farts like me! I still say there are better ways to utillize tools at our disposal in our quest to get the most from an antiquated design. I'm primarilly a circle track fan/participant. The only reason I ever personally got involved in drag racing was to have a legal outlet for my street cars, and get an idea how they compared (ET) to the blow hards in the area. Recently, my son-in-law has revived my interrest with his piddly efforts in his stock bodied "69 Mach 1 with a 351C 4V & C6. In spite of having a bad missmatch of components, the old Ford is giving the bowtie bunch night mares and he put it together 8 yrs ago when his rationale for choosing a camshaft was making it lope! We're kicking around some ideas for a racer and it's fun bouncing stuff off you fellas. Thanks again.
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SundanceKid
Gearhead Posts: 1302
From: UT
Registered: Feb 2001
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posted 04-24-2002 05:29 AM
Dusty, Much respect, I gave an open invetation to flame me and you kept your cool. Much respect.
I would like to learn more on this. Maybe others would as well? I'm almost at speed with you guys, but I'll be honest when I originaly read and answered the question I down played it as a much simpler question then you intended. I have now realized that this is above my "current" level of knowledge and I would realy like to learn more. Are there any places on the net or books that you guys may know of? Maybe something written by Vizzard? (sp?)I dono call me silly, but the aftermarket and billion dollar race teams have the resources at their command to do what it takes to win. We for the most part at our level can only wait for the technology to trickle down and become available and afordable in that order. What I still to this day wonder is why the aftermarket hasn't provided us with quad overhead cam heads or variable valve timing for our antiquated OHV engines? Or why Turbo's have taken such a long time to be an accepted as a viable means of power production? One thing I have noticed is that we as domestic car owners have not embraced change. That said why are most the part today the same parts that were available 30 years ago? Sure you have companies marketing new spins to old ideas but in reality they are the same design with a twist. Two such products that come to mind are the Edelbrock AirGap series, and Nology Sparkplug wires. Remeber split fire plugs? Now we have Platnum 4's ....are we realy progressing in our technology? electricity only follows one path, so why do I need four electrodes when one will do and when one electrode shrouds the spark less then four? I agree we need more people that inovate instead of imotate.
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SundanceKid
Gearhead Posts: 1302
From: UT
Registered: Feb 2001
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posted 04-24-2002 05:33 AM
Oh, I just want to go on the record as I do think the AirGap is a quality product. The above post may have made it sound as if I thought it wasn't.Thanks
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jkilroy
Gearhead Posts: 1811
From: Vicksburg, MS
Registered: Dec 99
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posted 04-24-2002 11:11 AM
There are several reasons why the aftermarket giants like Edelbrock or Holley, have not produced 4 valve over head cam heads or variable valve timing. The primary reason is that people seem perfectly content to spend their money on the current technology. Why spend the huge R&D bucks to make the parts? (Reason #2) Variable valve timing you want? One word, Patents. Most of the viable methods of doing variable valve timing are patented for at least another 10 years. Another reason is that the current state of production multivalve heads is very very good. At one point Edelbrock was going to produce a single cam head for the Ford 4.6 modular. About the time they were going to finish R&D and start marketing, Ford came out with the 99 engine with the *new* heads. The Edelbrock parts could not better the new Ford part, and there isn't any way in the world Edelbrock can compete with Ford on economies of scale. No there are some smaller companies that have attempted, over the years, to produce multi-valve heads for american v-8's, and they work great. Why they haven't prospered is probably an economic matter. ------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"
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JCQuinn@work
Gearhead Posts: 998
From: Lakewood, CO, USA
Registered: Jun 2001
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posted 04-24-2002 01:04 PM
I have to agree with jkilroy that the cost of the overhead cam conversions has been a large part of why they never were popular. Another reason is they typically make peak power above 10,000 RPM. When you make power up there, you are solidly in the unreliable zone.
Another reason for pushrod engine popularity is the respective torque curves of overhead cam and pushrod engines. If you look at the Ford engine torque curves you see that the Triton engines make more torque than the old pushrod engines but they do it about 1000 RPM higher. If you are going to compete for any contest where low RPM torque is important the pushrod engine will win.
There is a relationship between torque RPM and drag racing that I don't fully understand but cars with flat torque curves generally run faster and break much less than the higher RPM cars. Just look at Pro 5.0 racing. The sanctioning bodies are having to give the Mod motors advantages and they still are not competitive.John Quinn
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SundanceKid
Gearhead Posts: 1302
From: UT
Registered: Feb 2001
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posted 04-25-2002 03:56 AM
To my knowledge Honda and Toyota are the two front runners in VVT both have completely differant designs. One I have not seen yet, are Variable ratio rockers. A rocker that increases ratio as oil pressure rises. Another thought I had awhile back is a carberator throttle body that opens and closes like a camera shutter. That way there would be no butterfly shaft to upset the flow and cause turbulance. I would think a stronger fuel signal would result? Lots of neat ideas come to mind, but like I and others have said most people are content with current offerings available.
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Dusty Kiser
Gearhead Posts: 191
From: Bethel,Oh USA
Registered: Mar 2002
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posted 04-25-2002 07:52 PM
quote:
Originally posted by SundanceKid:
Oh, I just want to go on the record as I do think the AirGap is a quality product. The above post may have made it sound as if I thought it wasn't.Thanks
You make some valid points, again. Moser built some 4 cam heads for the small block Chev 15 years ago, and some of the high buck California sprint car contingent ran some and had minor teething problems, with valve stems and the like. What kills most of these projects is the lack of funding needed to develope the WHOLE package. I can't just build a head and expect John Force to jump on it, build induction systems camming etc to fit his application, and in effect develope the true potential of the head. Then the block and assemblies undergo different stresses that cause more developemental hangups. Jim Fuelling is finding this out with his big block heads for truck applications. First, only the truely dedicated gearhead ( and there aren't that many of us ) will shell out 5 grand for the privelage of owning these limited production pieces even if they are better than the factory offerings. What happens when you break down in Montana and the only parts are in L.A.? Even in racing, the majority rules. A few years ago the Cosworth midget engine was kicking butt. At 120 cubic inches it had to compete against 145 cu.in. pushrod engines and outpowered and outlasted them. Then Ed Pink, Brayton, Gaerte and Fontanna started developing stronger inline four pushrod engines to take advantage of the displacement advantage. The sanctioning bodies limited the Cosworths and like engines because they felt it would be cost prohibitive for everyone to have to switch to get competitive and they were a little more costly up front at about $15G's ea. Now, the same jokers are paying $40G's for 160 cu.in. pushrod motors! Where's the logic?Ford and USAC are promoting a series now, using the Focus engine. That should help awaken some interest in a fresh approach to an old issue. It's that level of involvement that will eventually break down those old barriers and soften the resistance of the timid.
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Larry Jennings
Gearhead Posts: 540
From: Redwood City, Ca. USA
Registered: Apr 2000
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posted 04-25-2002 08:15 PM
Have you ever heard of the McGee? It was a top fuel effort using new tech with old materials and (IMO) it's failure probably set 4 valve development back, in the 80s as much as the SOHC that I love set the OHC back in the 60s.
I have a friend that's been working with varible rockers and fulcrum systems for over 15 years. He has a small engine running without a carb, the engine is throttled with valve opening and we've run several different fuel systems on it for power and economy and it shows promise.
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Dusty Kiser
Gearhead Posts: 191
From: Bethel,Oh USA
Registered: Mar 2002
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posted 04-25-2002 08:15 PM
quote:
Originally posted by SundanceKid:
Oh, I just want to go on the record as I do think the AirGap is a quality product. The above post may have made it sound as if I thought it wasn't.Thanks
I agree, for the most part. I like the dual plne, long runner unheated aproach to high performance street induction, but let me share a little WAR story with you. While attending the Street Rod Nats @ Louisville last year, a fellow parked near us was sweating over a BBC with an Air Gap and Holley dbl pumper. He eventually got the Holley rep to look at it, and he diagnosed an air leak and sold him a new base gasket. It made no difference. Fast idle, lean missfire etc. I got curious and had to put my two cents worth in. After much perusing, sweating and cussing I found a casting flaw in the bottom of the #7 runner that left a hole big enough to stick your little finger tip in!The worst part was The Edelbrock rep was not at all interested, he told him when he got home to call Jegs and have them replace it! We epoxied a patch on it, reset the carb and made the balance of his drive much better. I understand a defect once in a while gets past QA, but I don't understand the Rep's attitude.
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