Hot Rod says a carb will usually make more HP than EFI
#41
Drifting
Since O2 sensers are typically installed in the collectors, and not the primary tubes, you will get an average readout of all 4 cylinders on that bank.
#42
The O2 sensors respond pretty quickly too, especially at lower speed you can pick up a problem from a individual sensor.
these two facts and some other tricks allow for check engine codes like "misfire on cylender 3"
nevermind high tech stuff like SAAB trionic that fires the sparkplug a second time and uses some feature of the spark signial to identify burn quality.
#43
Drifting
if you have a knock sensor or two, you can correlate a knock event with an individual cylender pretty easily.
The O2 sensors respond pretty quickly too, especially at lower speed you can pick up a problem from a individual sensor.
these two facts and some other tricks allow for check engine codes like "misfire on cylender 3"
nevermind high tech stuff like SAAB trionic that fires the sparkplug a second time and uses some feature of the spark signial to identify burn quality.
The O2 sensors respond pretty quickly too, especially at lower speed you can pick up a problem from a individual sensor.
these two facts and some other tricks allow for check engine codes like "misfire on cylender 3"
nevermind high tech stuff like SAAB trionic that fires the sparkplug a second time and uses some feature of the spark signial to identify burn quality.
Are you say that isnt the case?
#44
you can hear knock throughout the block, just like a mechanic's stethoscope can hear a rod knock anywhere in the block, even if it might be louder and quieter at certain locations
#45
Le Mans Master
It's not going to be all that long until there are sensors at each cylinder, and actually within the cylinder itself. Many high-performance general aviation aircraft already have EGT sensors in each exhaust.
We'll clearly end up at some point with direct injection fuel injection with the injector in the combustion chamber - the Cadillac CTS already has this and there are likely others I don't know about. Virtually all diesels use direct injection.
The technology path is pretty clear - EFI, including aftermarket EFI gets better and cheaper all the time. I worked with the early aftermarket stuff, and it was - in a word - junk. And it's not like all the early Detroit stuff was a lot better. But the factory stuff now is pretty impressive and the aftermarket stuff is getting better all the time. This latest generation of aftermarket EFI is pretty impressive as well.
We'll clearly end up at some point with direct injection fuel injection with the injector in the combustion chamber - the Cadillac CTS already has this and there are likely others I don't know about. Virtually all diesels use direct injection.
The technology path is pretty clear - EFI, including aftermarket EFI gets better and cheaper all the time. I worked with the early aftermarket stuff, and it was - in a word - junk. And it's not like all the early Detroit stuff was a lot better. But the factory stuff now is pretty impressive and the aftermarket stuff is getting better all the time. This latest generation of aftermarket EFI is pretty impressive as well.
Last edited by billla; 12-12-2009 at 02:12 PM.
#46
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if you have a knock sensor or two, you can correlate a knock event with an individual cylender pretty easily.
The O2 sensors respond pretty quickly too, especially at lower speed you can pick up a problem from a individual sensor.
these two facts and some other tricks allow for check engine codes like "misfire on cylender 3"
nevermind high tech stuff like SAAB trionic that fires the sparkplug a second time and uses some feature of the spark signial to identify burn quality.
The O2 sensors respond pretty quickly too, especially at lower speed you can pick up a problem from a individual sensor.
these two facts and some other tricks allow for check engine codes like "misfire on cylender 3"
nevermind high tech stuff like SAAB trionic that fires the sparkplug a second time and uses some feature of the spark signial to identify burn quality.
I am open to correction if the newer ones actually fire the plug twice.
#49
Le Mans Master
I can't imagine that quote being used out of context to try and "prove" exactly the opposite of what the article found.
But it just shows how important it is to check sources and read articles fully.
But it just shows how important it is to check sources and read articles fully.
#50
Race Director
Just read the article completely. It's findings are the exact opposite of the original post. What amazed me was the difference on the chassis dyno. Peak HP increased by 10 and Peak Tq by 20. This is on an engine with well under 200 HP to begin with and about a 30% increase in fuel mileage.
#51
Race Director
So what are we looking at here, converting to EFI for 10hp if that, maybe the other way around an lose 10hp ?
Buy an LM-1 and tune your carb correctly and you will be surprised how well it works. Like I said before not many know much about carbs anymore, they are gone or going. Anyone ever change their emulsion bleeds, anyone even know what they are. ( I know only a little about them so don't worry about it )
As for the European and his superior EFI setup if I was going to spend 2 -3 grand to change over I would expect this superior setup to net me some real power, not something you wouldn't even feel in the seat of your pants.
As for throttle response and drive-ability, I again have to go back and say get the correct carb for your motor and get it tuned correctly. As far as I am concerned there would be little advantage for someone like me driving around the same area in the same weather every year.
I do like that Dual Throttle body FAST EFI setup though
Buy an LM-1 and tune your carb correctly and you will be surprised how well it works. Like I said before not many know much about carbs anymore, they are gone or going. Anyone ever change their emulsion bleeds, anyone even know what they are. ( I know only a little about them so don't worry about it )
As for the European and his superior EFI setup if I was going to spend 2 -3 grand to change over I would expect this superior setup to net me some real power, not something you wouldn't even feel in the seat of your pants.
As for throttle response and drive-ability, I again have to go back and say get the correct carb for your motor and get it tuned correctly. As far as I am concerned there would be little advantage for someone like me driving around the same area in the same weather every year.
I do like that Dual Throttle body FAST EFI setup though
#52
A good EFI always knows which cylender its firing. So it just needs one knock sensor. when it fires a cylender and hears knock right afterwards, it can retard timing or add more fuel to that cylender for the next firing event.
you can hear knock throughout the block, just like a mechanic's stethoscope can hear a rod knock anywhere in the block, even if it might be louder and quieter at certain locations
you can hear knock throughout the block, just like a mechanic's stethoscope can hear a rod knock anywhere in the block, even if it might be louder and quieter at certain locations
When tuned properly a carb is the peerfect atomization/emulsion machine.An injection system is a proper air to fuel delivery ratio machine. When a carb is tuned to do both things at the correct time its desgn is an inherent advantage at making peak power. Golden, save your book worm EFI seminars for a different forum preferably one only the UK can access. Out
#53
Race Director
I don't buy this EFI; Great, Carb; poopy stuff either.
Don't get me wrong though EFI is here to stay and the future
When I want to get groceries on a cold night I jump into my fuel injected daily driver, don't even warm it up.
But when I go to the track I want to take something with a carb, unless I take a rental again
Don't get me wrong though EFI is here to stay and the future
When I want to get groceries on a cold night I jump into my fuel injected daily driver, don't even warm it up.
But when I go to the track I want to take something with a carb, unless I take a rental again
#54
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We use thermal couples at each exhaust header tube as well as multiplexed O2 sensors. A special header setup for our engine types support the engine dyno tuning setup.
#55
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Hey guys...I'm going to be testing this soon. My 540 will be getting some neat EFI stuff and it will be dyno tested as well as street evaluated.
It's going to be fun...because my 'ole Dominator actually works well...but I know EFI can do better overall.
Look out for upcoming reports!
JIM
It's going to be fun...because my 'ole Dominator actually works well...but I know EFI can do better overall.
Look out for upcoming reports!
JIM
#56
So what are we looking at here, converting to EFI for 10hp if that, maybe the other way around an lose 10hp ?
Buy an LM-1 and tune your carb correctly and you will be surprised how well it works. Like I said before not many know much about carbs anymore, they are gone or going. Anyone ever change their emulsion bleeds, anyone even know what they are. ( I know only a little about them so don't worry about it )
As for the European and his superior EFI setup if I was going to spend 2 -3 grand to change over I would expect this superior setup to net me some real power, not something you wouldn't even feel in the seat of your pants.
As for throttle response and drive-ability, I again have to go back and say get the correct carb for your motor and get it tuned correctly. As far as I am concerned there would be little advantage for someone like me driving around the same area in the same weather every year.
I do like that Dual Throttle body FAST EFI setup though
Buy an LM-1 and tune your carb correctly and you will be surprised how well it works. Like I said before not many know much about carbs anymore, they are gone or going. Anyone ever change their emulsion bleeds, anyone even know what they are. ( I know only a little about them so don't worry about it )
As for the European and his superior EFI setup if I was going to spend 2 -3 grand to change over I would expect this superior setup to net me some real power, not something you wouldn't even feel in the seat of your pants.
As for throttle response and drive-ability, I again have to go back and say get the correct carb for your motor and get it tuned correctly. As far as I am concerned there would be little advantage for someone like me driving around the same area in the same weather every year.
I do like that Dual Throttle body FAST EFI setup though
EFI is always going to at least equal a carb at the top of it's game, if not beat it, for about the 4th or 5th time, if EFI doesn't out perform a carb, you've either fitted the wrong system or not tuned it properly.
As far as gains go, even if EFI gives a smallish PEAK gain over what's probably a reasonably expensive carb with dyno time. It's not just about PEAK, it's about BHP and torque across the rev range and that's where EFI really kicks a carbs ***.
Also what about guys who want to junk their 30 year old, 250,000mile carbs. I suspect the gains there are going to be a lot more than 10bhp, the driveability will by like night and day, plus they'll have a system capable of accepting much more future development than a carb.
As for cost, I've said all the way through this thread that a good, bolt on carb is good value for money, that's if it works out the box. Some people though keep comparing EFI to tests done with carbs that cost 2 or 3 times a basic Holley or Edlebrock. The thing is that a 600cfm carb that's perfect for a mild SB won't cope with a fast road 383 conversion, where as a 750cfm EFI system will run both.
As for your comments on atmospheric change, in Toronto you have a annual temperature range of 30-35 degrees, a variation of 15% in air density and as much as a 45% change in humidity in a single day! Do you really believe your carb is optimised for all those conditions? Drag racers will change their fuelling for as little as a couple of degrees temp change.
Here's a quote taken from jetting specialist http://www.jetsrus.com showing how many vairiables drag racers allow for. These are vairiables that a good EFI system adjusts for 24/7 365 days a year.
Holley carbs are calibrated for sea level operation and an inlet air temperature of 70 degrees Fahrenheit. Once you know the correct stock jetting for your particular Holley carb, you can determine whether you live or race at an altitude above sea level. For every 2000 foot increase in altitude, you can reduce the jet size by one size. If you had a carb which has a stock jet size of 80 and you live or race at 2000 feet above sea level, then you would use a #79 Holley jet in the carb. Similarly, a change in the carb's inlet air temperature may require a change in the jet size from the stock calibration. Many racers go a step further by combining all of the weather varibles, temperature, barometric pressure, dewpoint and humidity with the altitude of the track they are racing at to determine the "density altitude". This is a "corrected" altitude above sea level. From there they can determine whether a jet change is necessary to maintain performance or whether to change their "dial in" (if they are bracket drag racers).
#57
Melting Slicks
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Hey guys...I'm going to be testing this soon. My 540 will be getting some neat EFI stuff and it will be dyno tested as well as street evaluated.
It's going to be fun...because my 'ole Dominator actually works well...but I know EFI can do better overall.
Look out for upcoming reports!
JIM
It's going to be fun...because my 'ole Dominator actually works well...but I know EFI can do better overall.
Look out for upcoming reports!
JIM
Hey Jim, you going to try out that new Holley EFI?
#58
#59
Race Director
Thread Starter
Thanks for the replies! I was away yesterday, and i figured if i was completely off base, this topic would go to the bottom of the page. I am pleasantly surprised to see solid points made on both sides. Keep up the good responses! I'm reading and learning.
.
To correct the public record, i should have stated the 4165-6210, not a 4165. It is a Double Pumper, my street favorite, because Holley has tuned it for 327, 350 and 402 Chevy engines 1965-1970. The primarys do not need oxygen sensor tuning. Just put it on and drive, as long as it idles at 800 or lower and has 12" vacuum or higher.
I agree a generic carb that needs tuning is a big waste of time; the holley catalog is full of application specfic carbs; I'd not put a "universal performance" carb on any street car. Common mistake. Reports here on CF are that they run too rich. here is my article http://community-2.webtv.net/MATTGRU/carb/page2.html
Just checked the mpg in my 355 61 4.11/ no overdrive.
got 19.0 mpg. What mpg could i expect with EFI(be specific as to what system) ?
I am listening closely. and what would my payback period be? My insurance limits me to 1,000mi/yr, and i rarely go 500.
Thanks for the lively discussion
.
To correct the public record, i should have stated the 4165-6210, not a 4165. It is a Double Pumper, my street favorite, because Holley has tuned it for 327, 350 and 402 Chevy engines 1965-1970. The primarys do not need oxygen sensor tuning. Just put it on and drive, as long as it idles at 800 or lower and has 12" vacuum or higher.
I agree a generic carb that needs tuning is a big waste of time; the holley catalog is full of application specfic carbs; I'd not put a "universal performance" carb on any street car. Common mistake. Reports here on CF are that they run too rich. here is my article http://community-2.webtv.net/MATTGRU/carb/page2.html
Just checked the mpg in my 355 61 4.11/ no overdrive.
got 19.0 mpg. What mpg could i expect with EFI(be specific as to what system) ?
I am listening closely. and what would my payback period be? My insurance limits me to 1,000mi/yr, and i rarely go 500.
Thanks for the lively discussion
Last edited by Matt Gruber; 12-13-2009 at 10:04 AM.
#60
Race Director
Hey guys...I'm going to be testing this soon. My 540 will be getting some neat EFI stuff and it will be dyno tested as well as street evaluated.
It's going to be fun...because my 'ole Dominator actually works well...but I know EFI can do better overall.
Look out for upcoming reports!
JIM
It's going to be fun...because my 'ole Dominator actually works well...but I know EFI can do better overall.
Look out for upcoming reports!
JIM