Gas guzzling alternatives

[Monte's62]

Originally Posted by Blessed66

While I don't disagree, there is one word that comes up in the EFI vs. Carb debate I always felt was a tip in EFI's favor. Consistency.

Not wanting to derail this into a debate, but I'll put my money where my mouth is soon enough. MS TBI conversion in the works.

I also agree with the consistency aspect. I would like to hear more about your throttle body conversion results. Happy truckin blessed66

[patrickk1]

EFI can be done cheap. A standard GM EFI TBI setup can be done on pretty much any carb'd engine. If your going to big HP you'll need an aftermarket throttle body. Just looked on CL by me and found an entire stock setup with an engine for $150. Tuning Software is free online and tuning is pretty simple.

[LostMy65]

Originally Posted by patrickk1

EFI can be done cheap. A standard GM EFI TBI setup can be done on pretty much any carb'd engine. If your going to big HP you'll need an aftermarket throttle body. Just looked on CL by me and found an entire stock setup with an engine for $150. Tuning Software is free online and tuning is pretty simple.

Does TBI handle ethanol gasoline okay?

[patrickk1]

Originally Posted by LostMy65

Does TBI handle ethanol gasoline okay?

If you're talking normal gas (E10), there's no problem. There's tens of thousand of people still driving around there late 80's early 90's vehicles on the road with TBI. If you're talking E85 or 100% ethanol then you would have to modify the software running on the ecm or buy a conversion kit from someone. Change out some fuel hoses also.

[joedoh]

Originally Posted by patrickk1

A properly tuned quadrajet will get the same mpg as Fuel Injection.

sure, when its tuned for mpg, and then your peak power will suffer. and only if you are only comparing steady running on the highway mpg between carb and efi, most wasted gas is used when warming up the engine in cold weather, where efi shines. I have spent a lot of time in a freezing truck just feathering the throttle for 10 minutes.

if carbs are trumpets, with specific valves for specific notes, efi is a slide trombone, able to hit all the sharps and flats with equal energy.

[argonaut]

I don't think that is really true for quadrajets. Their small primaries and large secondaries are what make them a uniquely versatile carb when compared to some others. You can get great mileage when only into the primaries and then scream when you open up the secondaries. The problem is there are a lot of old, crusty, unmaintained Q-jets out there on cars that aren't running properly. A simple rebuild, clean and mild tune yields pretty darn good results for most street cars.

Also, a fuel injection system needs to be programmed and tuned just like a good carburetor. But it is a fact that a carburetor is not as "infinitely tune-able" as a multi-port fuel injection system. Throttle body injection units are basically a half way point between a single carb and multiport injection.

The problem is that these days carb tuning is more and more of a lost art because of the availability of FI parts and the availability of tuning software that wasn't as readily available 10-20 years ago.

I would agree that, ultimately, a properly tuned multiport FI system will outperform a properly tuned quadrajet in efficiency and power. However on a street motor, you can get darn close with a quadrajet at a fraction of the cost.

[LostMy65]

Originally Posted by patrickk1

If you're talking normal gas (E10), there's no problem. There's tens of thousand of people still driving around there late 80's early 90's vehicles on the road with TBI. If you're talking E85 or 100% ethanol then you would have to modify the software running on the ecm or buy a conversion kit from someone. Change out some fuel hoses also.

.
I'm just talking about the gas you get at the pump.
Doesn't ethanol tainted gas cause issues with carburetor engines?

[siggyfreud]

Originally Posted by argonaut

I don't think that is really true for quadrajets. Their small primaries and large secondaries are what make them a uniquely versatile carb when compared to some others. You can get great mileage when only into the primaries and then scream when you open up the secondaries. The problem is there are a lot of old, crusty, unmaintained Q-jets out there on cars that aren't running properly. A simple rebuild, clean and mild tune yields pretty darn good results for most street cars.

Also, a fuel injection system needs to be programmed and tuned just like a good carburetor. But it is a fact that a carburetor is not as "infinitely tune-able" as a multi-port fuel injection system. Throttle body injection units are basically a half way point between a single carb and multiport injection.

The problem is that these days carb tuning is more and more of a lost art because of the availability of FI parts and the availability of tuning software that wasn't as readily available 10-20 years ago.

I would agree that, ultimately, a properly tuned multiport FI system will outperform a properly tuned quadrajet in efficiency and power. However on a street motor, you can get darn close with a quadrajet at a fraction of the cost.

I agree with this statement. FI, just like carbs, requires tuning, and at times, more tuning than a carb to really dial it in. But the amount of precision you can get (if you want to go to that length) is crazy (awesome).

What carbs don't provide is a feedback loop. You tune it, drive it, and then adjust based on performance, smell, plugs, etc. With FI, that feedback loop can be incorporated into the tuning much easier. Many computers now allow for autotuning, where you command the air:fuel ratio you want to see at given loads/RPMs, and the system will adjust other parameters accordingly.

Even without the tuning you can get real-time data and adjust parameters much more precisely than with a carb. If the carb could do what FI does, both in terms of power and efficiency (without sacrificing one or the other), automakers wouldn't have made the change.

[joedoh]

edited: not really a reply to argonuat



even if you get the same mpg on the highway, the mpg average for the rest of the trip will be significantly lower. if you cherry pick the statement to say ONLY the highway portion will be exactly the same, I will counter by saying you could rewrite the EFI code to keep it extra lean at high vacuum top gear low tps and blow the carb mpg out of the water.

the O2 sensor feedback loop, as been said, is the key. no matter how off your open loop program could be or is, the O2 feedback will always be trying for stoich in closed loop. with a heated O2 it gets there even faster, which is why cars are required to have heated O2 sensors, it gets into closed loop that much faster and will pass emissions in the crucial start up phase.

I always see these mpg threads and there is always some guy getting just outstanding mileage with his carb. this can be considered the exception, if not outright wishful thinking. most will use their needles ( I have half tank left, thats y gallons, and traveled x miles x/y=holy crap I got 22mpg!) instead of their gallons (I traveled x miles since filling up and it took y gallons to fill back up so x/y= 12.7mpg)

but others are so happy to read it, so excited that they can have the simplicity of a carb and the mpg of an efi system, that they believe it and even perpetuate it. If you want mpg and a carb, get one, and only measure mpg when you are on the highway. count those extra stops for gas every week/month as friendly to your bladder instead of what they really are, lower overall mpg which includes start up and warmup and acceleration.

if you want actual better mpg, with fewer gas station stops as a side detriment but being able to drive away almost instantly even in the coldest weather, get yourself an EFI system. tuning it is only necessary with changes, and that big cam and performance exhaust isnt going to help mpg anyway. power out = power in - efficiency.

if you just want to save gas and dont want to change anything, slow down. air resistance is exponential as speed goes up. on a 30 mile trip the time difference between 60 mph and 70 mph is four minutes.

[LostMy65]

I learned that lesson about 15 years ago.
I had about a 20 mile trip home from a job site on back roads. I would drive in a hurry and could even feel the stress and tension needed to drive at that increased speed.
I slowed down 10 miles an hour and found the drive a lot more relaxing down those back country roads. - I got home 3 minutes later.
10 miles an hour even slower, and I could lean back and admire the country scenery. - Got home 6 mins later.
.
Even my CRV I increased 3 miles a gallon by just enjoying the drive.
Listen to some music, or an audio book and enjoy the drive and save fuel and extend your life.

[LostMy65]

I've been trying to find some way to calculate just how many miles you'd have to drive to pay for an upgrade from a basic crate engine with a carb, to something that might get me 18mpg.

[joedoh]

Originally Posted by LostMy65

I've been trying to find some way to calculate just how many miles you'd have to drive to pay for an upgrade from a basic crate engine with a carb, to something that might get me 18mpg.

but its more than just the sunk cost, how do you quantify not sitting in the truck for 10 minutes every day warming it up 4 months out of the year? how do you quantify not dealing with vapor lock or hard starts 2 months of the year? how do you quantify drivability? cars and trucks to me are more than highway cruising and WOT, if I choose to drive something else out of town, or to work because I just dont want to deal with the foibles, how do you factor that in on your spend? how do you quantify the excitement of installing new parts and the sense of accomplishment?

in mpg payback only it could take a very long time. I like to save on recurring costs and spend on sunk costs that do just that.

[argonaut]

Anyone having the issues you describe above, with a carbureted motor, means that they haven't properly tuned or maintained their carburetor. And they probably also have neglected their ignition system, as carbs often get blamed by lack of understanding of tuning the ignition system. For example, a fuel injected motor doesn't come up to temperature faster than a fuel injected motor; that is a function of thermodynamics and heat transfer, not the fuel delivery system, and really shouldn't effect drivability if both systems are properly tuned.

Plenty of people get excitement from learning how to build a purely mechanical system that functions pretty darn close to the way a computer controlled system does.

Look, Joedoh is right, it is no question that a fuel injection system with custom tuned computer controlled fuel maps and ingnition maps can outperform a carbureter and a distributor. But the original poster asked about ideas to improve fuel mileage, with the ultimate goal of saving money. And the fact is that with only a couple hundred dollar investment one can have fun building and tuning an older tech carb abd dizzy system that will perform surprisingly well. Or one can spend a couple thousand on buying FI conversion components (or a compete motor), custom wiring harness, new fuel tank/pump/return system, computer reprogramming and tuning, etc.

Now another big thing that we should mention here is that when people comoare FI versus carb they are often comparing apples and oranges. A motor's efficiency is based on much much more than fuel delivery system alone. Its about comoression ratio, intake/head/exhaust flow characteristics, combustion chamber design and flame proportion, camshaft timing/lift/duration, spark timing control, mechanical pumping losses due to machining/bearing tolerances, and many many other factors. For this reason we can't fairly compare a sbc 327 from 1966 with a carb and a dizzy to a 5.3l vortec from 2006 with full electronic controls. Even if you convert the 1966 motor of the same physical displacement (327ci = 5.3l) with electronic controls it still won't be as efficient at using fuel and making power as the 2006 motor. Similarly if you put a carb on the vortec it will always perform better than the old gen one sbc.

This doesn't make anyone right or wrong. These decision are all about balancing the relative desired outcome and the amount of money soent and enjoyment had achieving that outcome.

I simply want to make sure that when people compare carbs to FI they arent just comparing an improperly tuned/maintained carb to a properly tuned FI system. Let us be scientific and compare apples to apples.

[LostMy65]

Yes, the user experience is surely a factor.
I see the neatness and advantage and reliability of all the new technology in an old truck, but I also see the pure feeling of nostalgia with an old truck and an old small block - which maintained properly can be just as reliable.

[joedoh]

its not thousands of dollars for EFI unless you buy a ready made kit, and only the super show systems cost that much, atomik and fast both make 4 barrel type kits for under $1000. you can get a stock setup almost free from guys who would rather tune a carb. you can build an entire megasquirt system for under $600. thats not heresay or wishful thinking, I have done it! the latest megasquirt system will even handle spark control (extra) and 12x12 maps and will auto tune with the O2.

a quadrajet is almost 500, and if you need to put on an intake to replace your two barrel and buy the linkage kit, well, I wouldnt bother telling anyone you were doing a carb to save money at that point.

this isnt about being right or wrong, I agree. but there are so many myths about efi, expensive, hard to work on, etc. every day these same people get in their modern fuel injected cars and trucks ad drive them thousands of miles per year but say "oh no, wiring!" on their custom trucks. its baffling.

[LostMy65]

This brings me back to my question earlier.
Does a Fi unit that I can install for under $1000 handle fuel that is tainted with ethanol without the issues of a carburetor. I'm not trying to debate, I really would like to have the simplicity of FI, but even my daily driver CRV only is driven 5000 miles a year.
When I sold my 2000 Tacoma in 2010 to get a CRV, it only had 50,000 miles on it.
So, if i could get a system that hasn't an issue with ethanol tainted gas, and could boost my mpg up atleast 3 or 4 mpg, I would seriously consider putting FI on my 327.

[argonaut]

I don't see why a fuel injection system would be bothered by ethanol any more than a carb.

[Blessed66]

Originally Posted by LostMy65

This brings me back to my question earlier.
Does a Fi unit that I can install for under $1000 handle fuel that is tainted with ethanol without the issues of a carburetor.

In short, yes.

Depending on how electrical-abled (is that a word?) you are, there's this; MegaSquirt-I - this is entry level or MegaSquirt II - more bells and whistles, more tunability to 1 microsecond or if you happen to find a TBI unit (I bought one for $30 on ebay, I will rebuild it, but that's far easier than a carb), and a harness for TBI (like this one on eBay), you could use a a MegaSquirt plug and play computer that would plug right in to the delpi 56-pin harness.

I am about to do this for my 84 (sidelining the 66 because of Texas title issues), and will post a very, very detailed build thread when I do. To my understanding, the TBI unit plays nice with pump fuel, and aside from the required sensors and a good fuel system, I am expecting that I will have no problems once I get everything buttoned down.

EDIT: A GM PCM from an 87 TBI truck (ending in 7747) is also something to look for. They go for relatively little money. No need for Megasquirt if you go that route, really, but MS helps with tuning. I am hooked on the product, admittedly.

[Blessed66]

Originally Posted by joedoh

if carbs are trumpets, with specific valves for specific notes, efi is a slide trombone, able to hit all the sharps and flats with equal energy.

As a former high school trombone player, this made me laugh.

[LostMy65]

Originally Posted by Blessed66

In short, yes.

Depending on how electrical-abled (is that a word?) you are, there's this; MegaSquirt-I - this is entry level or MegaSquirt II - more bells and whistles, more tunability to 1 microsecond or if you happen to find a TBI unit (I bought one for $30 on ebay, I will rebuild it, but that's far easier than a carb), and a harness for TBI (like this one on eBay), you could use a a MegaSquirt plug and play computer that would plug right in to the delpi 56-pin harness.

I am about to do this for my 84 (sidelining the 66 because of Texas title issues), and will post a very, very detailed build thread when I do. To my understanding, the TBI unit plays nice with pump fuel, and aside from the required sensors and a good fuel system, I am expecting that I will have no problems once I get everything buttoned down.

EDIT: A GM PCM from an 87 TBI truck (ending in 7747) is also something to look for. They go for relatively little money. No need for Megasquirt if you go that route, really, but MS helps with tuning. I am hooked on the product, admittedly.

Thank you. I'll be watching for your thread.

[Mackie]

I posted elsewhere that I got 14 mpg in my C10 Shorty on a 675 mi. trip, loaded and pulling a loaded trailer thru mountains a third of the time. Total miles divided by gallons, not needle reading. It has a freshened roller cam 305 upgraded with an LT1 cam, Edel Perf intake and 500cfm Edel 4 Bbl, block huggers, T5 and OE 3.73 rear.
I got the core 305 with all the TBI stuff and plan to eventually convert it back to the EFI using this GM ECU modifier for tuning.

http://www.dynamicefi.com/EBL_Flash.php

I looking for even better MPG and performance.

[joedoh]

lostmy65, my senior engineering project was an ethanol E85 (85% eth, 15% gas) conversion for OBDII equipped cars and trucks and the bulk of that project was a hardware piggyback that had code to add a fuel line sensor (for % of E85) and maps that took that into account. otherwise stock EFI components. Because E85 requires longer pulse width on the injectors (higher fuel to air ratio for stoichiometric operation) there is a slight drop in fuel economy. E10 is only 10% eth and all cars can use it without issue, but still have a small drop in mpg.

did you know there isnt E100 (100% ethanol) because it would be grain alcohol? drunks would line the pumps 24/7 the 15% gas is not necessary in a car that can run E85, it is necessary to make the fuel lethal. True story. Although drinking grain alcohol would be sufficiently dangerous.

Any grain alcohol is hygroscopic, and the problems people report with ethanol gas is usually from leaving it in a system for a long time, where it absorbs water out of the air and turns into goo. this is why you need a stabil type additive in your mowers. It can also attack some seals, but in our research for the project it is usually only when using generic o rings and hand made gaskets, the oem and most replacement parts are oil and gas rated.


very long story short, you wont see a problem running E10 on your EFI or your carb, except a very small decrease in fuel economy.

Originally Posted by Mackie

I posted elsewhere that I got 14 mpg in my C10 Shorty on a 675 mi. trip, loaded and pulling a loaded trailer thru mountains a third of the time. Total miles divided by gallons, not needle reading.

thats good gas mileage, you arent one of the guys I was referring too though. more often its the over 20 mpg crowd, especially the guys who pull a late model 5.3 and talk about getting 10+mpg over the donor, and then their argument is that corvettes get 30mpg. yes, a 3200lb corvette with the frontal area of a lawn dart and two deep overdrives get over 30mpg on the HIGHWAY. what does that have to do with a 3800 lb truck with the aerodynamics of an unladen cinder block and average mpg?

[Blessed66]

Originally Posted by joedoh

thats good gas mileage, you arent one of the guys I was referring too though. more often its the over 20 mpg crowd, especially the guys who pull a late model 5.3 and talk about getting 10+mpg over the donor, and then their argument is that corvettes get 30mpg. yes, a 3200lb corvette with the frontal area of a lawn dart and two deep overdrives get over 30mpg on the HIGHWAY. what does that have to do with a 3800 lb truck with the aerodynamics of an unladen cinder block and average mpg?

What's that take, a 2.08 axle ratio? :P

[siggyfreud]

Originally Posted by Blessed66

In short, yes.

Depending on how electrical-abled (is that a word?) you are, there's this; MegaSquirt-I - this is entry level or MegaSquirt II - more bells and whistles, more tunability to 1 microsecond or if you happen to find a TBI unit (I bought one for $30 on ebay, I will rebuild it, but that's far easier than a carb), and a harness for TBI (like this one on eBay), you could use a a MegaSquirt plug and play computer that would plug right in to the delpi 56-pin harness.

I am about to do this for my 84 (sidelining the 66 because of Texas title issues), and will post a very, very detailed build thread when I do. To my understanding, the TBI unit plays nice with pump fuel, and aside from the required sensors and a good fuel system, I am expecting that I will have no problems once I get everything buttoned down.

EDIT: A GM PCM from an 87 TBI truck (ending in 7747) is also something to look for. They go for relatively little money. No need for Megasquirt if you go that route, really, but MS helps with tuning. I am hooked on the product, admittedly.

I'll be running a Megasquirt on my motor. I've had the computer and wiring over a year now, just haven't gotten far enough along to start wiring and installing, but I plan to soon. Will be running sequential fuel and spark through it on a Gen I block.

[patrickk1]

ALL gas from the pump has some amount of ethanol in it. It usually varies by delivery but can be up to 10%. Some brands are consistently on the higher end of that spectrum than others. I know I get better mpg with some brands than others.