Carb'd vs EFI era Supras... What do you prefer??

[michael hunter]

If I recall GM got rid of carbs in 83. I was a ASE certified auto mechanic from 1971 to 1991 . During that time I saw the rise of electronic
Ignition and fuel injection . In the early years the FI systems were problematic and difficult to repair . Now pretty much all the manufactures have solid trouble free systems. The reason points and carbs are no longer used is because they dont work as well.
Staying with the simple basic systems because you dont understand the more complicated systems is fine . But dont try to say they are just as good or more reliable . All systems break down if your mechanic isn't capable of repairing it its not the systems fault .

[cavilry]

I guess it depends on what you want. Admittedly I am more knowledgeable with car applications, but for general use I would say EFI hands down. More reliable, more efficient, more powerful (okay, thats a bit of a tough one to say), and yeah, there is a reason manufacturers went to them. Generally speaking I would go with EFI all the way if I had the money and it was a newer boat with a polished EFI system. The early ones were definitely a bit iffy.

That being said, am finishing up my 1972 Alfa Romeo GTV and I just went to the dual webers. Granted, that was for nostalgia and the fact that my car had the SPICA mechanical fuel injection...

[cadunkle]

Michael, when you add complexity you add points of failure. Carbs just work and have very few points of failure. EFI has MANY points of failure and MANY more things that can cause the system to not run properly or not run at all. Beyond that, those many additional components are expensive and complex, requiring additional money and time to diagnose and repair. Carbs (depending on the model) can get the same fuel economy and driveability as EFI, but with far less complexity and cost. Simplicity is beauty is reliability.

[pap]

That is a beautiful theory, but reality is starkly different. Again, the market speaks to efficiency and economy and expense: nobody uses carbs anymore.... and it isn't because the new stuff looks better: a dual carb system sitting on top of a big block is a thing of beauty, but functionally....

[docdrs]

Michael, when you add complexity you add points of failure. Carbs just work and have very few points of failure. EFI has MANY points of failure and MANY more things that can cause the system to not run properly or not run at all. Beyond that, those many additional components are expensive and complex, requiring additional money and time to diagnose and repair. Carbs (depending on the model) can get the same fuel economy and driveability as EFI, but with far less complexity and cost. Simplicity is beauty is reliability.

If this was the case then why did we ever go from 2 stroke motors to 4 stroke. Way more parts to fail and more costly to rebuild. The efi motors today are far more efficient than carbed motors. The atomization of fuel and fuel to air ratio parameters can not be matched on a carbed engine. Plus , unless you have a perfectly tuned intake manifold, the distant cylinders will always run leaner than the closer cylinders. For 95% of the population efi is most practical , but for the gear heads I can see why a carb is the only way to go.

[michael hunter]

Cadunkle I have to call you out on to your last statement. No way any carbureted system can match fuel economy,drive ability and performance of EFI.
You say the EFI systems are costly to maintain . I have a 05 GMC 75k miles 02 Lexus 157K miles 08HHR 58K miles 08 350 EFI boat 380 hours .To date the only thing that has been replaced on any of them is filters and spark plugs [in the Lexus] not much money or time spent here. I have worked on thousands of cars and rebuilt hundreds or carbs over the last 30 years and I can say without doubt the best engines and systems are the ones being used today . As a professional mechanic you make most of your money doing maintenance . With the EFI , high energy ignition , serpentine belts and silicone gaskets there is very little maintenance to do anymore . Now since there are very few carbureted engines around the parts are getting rare and expensive. We all dream of a simpler time but you cant stop progress especially when its in the right direction.

[DAFF]

I remember when I got my first Supra back in 1990... Boat was running very bad and need the points cleaned up. I asked my friend an old school mechanic why in the this modern world boats still run points??? Thinking back, adding a electronic ignition seemed the only logical thing to do. He replied due to the reliability issue and how things can go bad in the water at least points will get you back.

IN the modern world of today my Android can be used as a scanner on any OBDII based system. Reading the codes it doen't take much to diagnose the issue or at least possible causes. Very rarely will a computer based system completely fail other than a bad crank sensor. So simplicity to me says the old carb and a cleaner running more fuel efficient engine EFI.

So are the new boats also OBDII based??

[DAFF]

Getting rid of the old v belt system is a great positive too !!!

[cadunkle]

If this was the case then why did we ever go from 2 stroke motors to 4 stroke. Way more parts to fail and more costly to rebuild.

Many reasons why two strokes are not practical in every application. The main reason being they don't exactly wear nicely, so have a lot shorter life between overhauls. They also create a crapload of heat especially as you scale up into heavier applications. There are other reasons too, but you're talking totally different scenario than carb vs EFI.

The efi motors today are far more efficient than carbed motors. The atomization of fuel and fuel to air ratio parameters can not be matched on a carbed engine. Plus , unless you have a perfectly tuned intake manifold, the distant cylinders will always run leaner than the closer cylinders. For 95% of the population efi is most practical , but for the gear heads I can see why a carb is the only way to go.

Depends on what you're building the engine for. I have yet to hear of anyone else with new lifted EFI truck getting the towing MPG I get with my old heavy carbed truck. 10.8 at 65-70 MPH towing and 12.5 at 70-75 MPH. I expect a slight increase in both figures due to some tweaks over the winter, but haven't tested yet. Everyone I hear with a modern EFI truck is getting worse MPG, and most of them aren't lifted. Unloaded, year some are better... But before the lift I was getting about 16 MPG highway.

Fuel distribution issues are real. Can be mitigated with better intake designs, dual carbs, or if you really want you can go with a Weber setup or similar for one carb per cylinder. Real world experience shows with a decent intake the fuel distribution issues are relatively insignificant.

[cadunkle]

Cadunkle I have to call you out on to your last statement. No way any carbureted system can match fuel economy,drive ability and performance of EFI.

See above about my truck's fuel economy. Most guys I talk to with EFI gassers don't get anywhere near that towing MPG. A properly tuned carb setup just plain works, same as EFI. Cold weather will require choke adjustments for extreme cold or significantly colder than where you had it adjusted for... Or just use a manual choke to simplify that aspect of it.

You say the EFI systems are costly to maintain . I have a 05 GMC 75k miles 02 Lexus 157K miles 08HHR 58K miles 08 350 EFI boat 380 hours .To date the only thing that has been replaced on any of them is filters and spark plugs [in the Lexus] not much money or time spent here.

Your three brand new vehicles run like brand new with only minor maintenance? No surprise there. Come talk to me in 10-30 more years and let me know how all those electronics are holding up, how many sensors have failed and left you without a ride. Try driving your GMC through deep water enough to dip the engine compartment, or even halfway up the engine, let me know how that works out for your EFI.

I have worked on thousands of cars and rebuilt hundreds or carbs over the last 30 years and I can say without doubt the best engines and systems are the ones being used today . As a professional mechanic you make most of your money doing maintenance . With the EFI , high energy ignition , serpentine belts and silicone gaskets there is very little maintenance to do anymore . Now since there are very few carbureted engines around the parts are getting rare and expensive. We all dream of a simpler time but you cant stop progress especially when its in the right direction.

High energy ignition, serpentine belts, and silicone gaskets are fine. These things are totally different from EFI, and can be put on any engine. For clarification, all my vehicles do have carbs, but they also all have electronic ignition pickups. Serpentine belts make sense when you're running high amp alternators or other high draw accessories. There are plenty of advances in technology that makes it easier to build better engines, using the same blocks they used 50 years ago. EFI though? No thanks. You keep your progress and I'll keep my carbs, they just plain work every time.