After reading thru many PROM articles for the last hour my head hurts and I have serious second thoughts about putting an exhaust on my 88 IROC let alone new cam, heads, headers, and intake. I dont want to hurt the motor by running it lean or by drowing it either. To get a chip programed that really makes all these things work in harmony really seems hard, from all the reading. One of those 5min to burn a chip, 5yrs to master it.

So wouldn't it just be easier to rip off all the computer stuff and run a carb? I dont mean to sound like a smart ***. I rewired my 69' roadrunner from head light to tail light, everything even the engine bay and it was really simple. No ECM or "brains" of the car just start and run. The cam worked with the heads and the intake with the carb and out thru the exhaust, simple. Only tunning was the carb and the advance.

What are the draw backs of going to a carb on these f-bodies? Losing MPG? Cold starts and reliablity? I wonder....

 

Not if you wanted to tune the carb to the same degree.

 

I too would switch over to a carb before touching that computer. It does seem a lot easier. And if you go to the tech article section there's a whole article that shows you how to swap over to a carbeurator. If you tune it right, the MPG shouldn't drop that much.

And you can put an exhaust on your IROC without worrying about the computer. I'm not too sure about the other mods you listed though...

 

Wouldn't be easier to just leave it alone?.
Why bother with trying to change things?. GM paid a fleet of engineers millions of dollars, and spent years working on EFI.

Yes, *you'll* never get a carb'd engine to do everything as well as EFI. Reworking carbs to get anywhere near as good as EFI is, takes YEARS, and YEARS of experience. Unless, *you're* talking about something as primitive as a Holley. By the time you get a Holley close, and that means redoing the emulsion circuits, you'll have more time in learning them, then EFI. Spend some time seriously investigating Webers, and then check back in about what time consuming can mean.
Not to mention you tune EFI with Key strokes, not tearing off a float bowl to make the smallest of changes. In the time it takes you to change mains, I can run 8 different chips. Who do you think will get done first?.

Not to mention when you get past N/A, and start making some real HP.

Yes, you can spend 5 years learning about *Chips*, but, in doing so you'll develope a thought process, that will extend into every facet of your life. Being able to think clearly, and analyse things is always a *good thing*.
BTW, it's easy to wrap up 5 years in learning to really tune a good carb.

BTDT.......

 

Grumpy has his Ts crossed and his Is dotted. I played with a Q-Jet for more than 2 years and had it running decent. I swapped to TBI and tweaked on the Tune for another 2-3 months. It idles better, runs cleaner, has better throttle response, delivers more mid-range torque, and gives better fuel mileage than the Q-Jet ever did.

 

If you know how to tune a carb then it will be easier than the PROM and all that. But the other guys are trying to say that if you don't know how, then stick with EFI.

 

Well tuning proms is easier than tuning a carb, period. Prom tuning will always be much simpler. (I have done both and can tell you this with confidence). If you are running 10% to rich in one area and 20% too lean in another, you simply change some numbers, reburn the chip, and life is great. You can't tell a carb to add fuel here and pull it here without pulling it apart, drilling, filing, etc. The problem most have with EFI over Carb is really simple. Most that hate fuel injection do so because there are no jets to change, no screws to turn (late model stuff anyway), etc. A definition file, .bin file, and a burner give you control over essentially everything though.

 

Exactly. Some of us like to fix our cars with nuts and bolts, not codes and bytes.

 

I think most people JUST want:
X*Money + 0*time = X*Power

If only life were so simple.

Also, EFI gives TOO MUCH control for some people's tastes (read as - they don't want to learn so much).
That, and it takes smarts to actually know how to use that control. It's not for the average high-school dropout.

Then there's the viscous circle of having soo much control that perfectionists never are "finished" with the calibration.

EFI is a wonderful and expensive adventure. If you're the kind of guy who just wants the car to run on little money, carbs are for you. If you want to impress yourself with challenging task, and maybe end up with an awesome running engine, and a lighter wallet, try EFI.

 

I agree, but alot of us are bound by emissions laws.

 

trust me, I know. Both my cars are in California. My post wasn't recommending carbs, it's just my ramblings on why people chose to do them.

More ramblings:
It hurts my feelings when people get impatient and throw carbs on. My career is EFI, and I wish it were cheaper, and easier for the masses. I don't like seeing people getting in too far over their heads (500hp daily driver first projects). They learn nothing, blame the darn computer, and scrap the project, or go broke trying to throw money at the problems. That, or they build a $6000 engine (long block), and then wonder why it's still slow as stock with the stock intake and calibration - then they install bigger injectors, TPS enhancers, IAT relocation kits with a resistor mod, ported MAFs, crank up the fuel pressure, MSDs, TB bypasses, headers, EGR delete, AIR delete, port the plenum, siamese the base, etc... and wonder why it's still a 14 second car and drives like crap. Then they get a mail order chip. It picks up a few tenths. Then they blow a piston because the stock fuel pump was dying before the build.

 

For some people tuning EFI is a hobby and do it for the learning aspect and for a better running engine. Ask any of those guys and they will be sure to say go with the EFI. Many of them have it running just about as best as it can but still try out new EFI things to see if it could be better.

I never owned anything that came with a factory EFI on it. All my stuff had carbs and ran OK. I am by no means a good carb tuner and a marginal EFI tuner. Every time I drove something with EFI it made my carb setups quite embarrassing. Finally, one by one I started converting them to EFI and never looked back. I still have one that is Holley carbed and every once in a while I drive it to remind myself why the others have EFI on them. The reasons I went EFI was for mostly the cold start thing and wanting more reliability. Once I realized that the EFI was tunable it got even better....better MPG. Eventually, I was curious how the thing worked and it became a hobby. Now I waste too much time on it.......maybe the carb was better in that respect.

This is all coming from a person that couldn't get a carb tuned quite right. I bet if I put the WBO2 on it I would be even more disappointed in my carb tune. It all depends on what you are after. I like EFI for a daily driver and for a race car. No way would I put a carb on a daily driver, but would on a race car that is always at WOT. WOT was about all I could get right with the carb setups. That is just my experience.

 

for me tuning efi is a hobbie, plus I make a couple bucks on the side to buy stuff like WB O2 etc.

tuning a carb is complicated too, as well as getting the right curve in a mechanical advance distributor, takes hours on a dyno to get a carb and timing right, my bros Harley is carbed and he can't wait to get my WBO2 on it,
if you understand how to tune a motor, weather its carb or EFI, it make your life alot easier, just relating it to numbers on a computer screen is the complicated part
MAF isn't far off from a carb, where fuel is determined by airflow, MAP can get abit more in depth but the overall drivabilty more then makes up for it

 

I would be willing to say that most daily drivers with a carb are not tuned properly anyway. Most use the butt dyno to feel if its ok.
Accel pump drilling or bigger cam operator to get the bog to go away...
Having data aquisition built in with EFI will SHOW you how bad it is.
If there's no ECM then you are only using external means like plug cuts to know what is going on.

I've got my totally changed setup (bigger cam, headers, exhaust, heads...)
This is now able to drive regularly after about 8 hours of tuning.
Basically 4 times around the block and the light throttle cruise is already pretty good. WOT will be another few romps to get it closer then the long term tweaking can begin.
As mentioned earlier, Mine will NEVER be done to my satisfaction.
I'm just that way
Most would drive the car now and not even think there was anything that needed to change. Has decent manners but has more power hiding in there.

Its definatly a hobby type thing.
You don't want to do either without the dedication to finish the job to a good level.
Carb does "seem" easier if your not shooting for the ultimate all around tune.
Tearing it apart constantly (and just as much reading BTW) is not my idea of fun.
Once EFI is together there is no reason to take it apart.
I don't like grease on my keyboard!

 

I have always had carb'd cars. I like to think I am a good carb tuner, and now I am even better at it with the addition of my wide band (that I really bought for tuning EFI). Ive got a 71 Nova 355/2004r/3.50:1 gears with a +.500 lift cam, single plane intake and Holley 750dp turning high 12's at 111 mph in the quarter That gets 16-17 mpg around town! It runs great but still has some cold start issue's that are fine by me but my wife hates it. Overall, it runs great.

Now, on the other hand I have an 85 Vette with a Procharger @10psi, and a 1993 GMC Typhoon (turbo/intercooled) that are both obviously EFI. Both are stock, but the vette has the aftermarker SC and a cat back exhaust. The vette will nearly put shame to the Nova. The EFI rules on these cars. Now you could say the SC has made all the power and it runs like stock because it pretty much is... but the EFI is so easy to make changes in fueling and spark that just cant be made on a carb and distributor setup. Having an Autoprom makes it just that much nicer too. The feedback from the ECM is very valuable, and nearly impossible to replicate on a carb'd car (to the degree of sampling).

Years ago I would say that EFI is too hard or no good. Today I have an open mind and love learning all this new stuff. Learning EFI has made me a better carb tuner, but I would take EFI over a carb any day.

 

im pretty good at tuning carbs, im ok at tuning EFI.
i really don't see anyway you could tune a carb to anywhere near the extent you can EFI, at least not without spending alot of cash & a lot of time on it. how many carbs would get trashed just from trying different things to see what works best? even if you did get a carb dead on right, make a change to the motor & you have to start over. of course its the same with EFI when you make a change to the motor, but with EFI i its quicker, & with less money involved.
what do i mean by right?, it runs right from the first start on a freezing cold mourning to a long highway run on the hottest of days, gets good gas mileage, & passes tail pipe emissions without cats. how many carbed cars are out there that can do that? in my book EFI is the only way to go

 

Everyone is missing the real reason not to use a carb. Any of you old enough to remember cars from the 60s and early 70s know that every car made needed a valve job at 60 thousand miles and maybe 5 out of 100 might make it to 100 thousand miles. I remember how people would brag about that 100 K. Spark plugs lasted 12 thousand miles, if you cleaned them every 4 thousand miles. Now we do a tuneup at 100k because we want to , not because we have too. A carb will never equal a fuel injected engine with computer controls and a feedback system that measures what is coming out the back and adjusts what is going in the front until it gets it perfect. You can't adjust a carb 100 times a second no matter what you do.

 

I don't think a carb or prom is easier than the other... I think most people are probably pretty familiar with carbs because they grew up with them... Those newfangled proms are the devil... not because they actually are - but because they're new and there's learning involved to know that "AE" in devil speak is really an accelerator pump shot.

<insert something about dog and new tricks>

Anyone that wants a carb can fill their car with non-detergent SAE 30 oil while they're at it. If it's good enough for a model A....................

 

these are common misconceptions about carburetors.

spark plugs didn't last is true.
the reasons they didn't last wasn't because of a carb though.
the 2 main reasons are,
1, points type ignition systems. they did not fire very hot.
the points type didn't produce much in the way of firing voltage, maybe 30,000 volts on a good day.
the first HEI systems could do to 35~ 40,000 on average. grab a loose plug wire from each system & you can feel the difference between a points type & the old style HEI ignitions, i promise you,.. the HEI will hurt a lot more.
the points started to deteriorate as soon as they were put in, they needed to be adjusted every 2~3000 miles or you were asking for problems.
leave the key in the run postion with the motor off for very long & you were lucky if it would start & run.

the plugs back then rarely had much wear on them when they were replaced.
most plugs get replaced today because they are worn out, & very seldom because they are fouled out. they also did not have platinum plugs back then either. platinum plugs don't fire better than plain R45s, they just last longer.

2, leaded gasoline.
leaded gas was bad on the plugs, it fouled them out long before they were worn out. along with weak spark from the ignition it didn't take long before the plug would cause a miss.
when the first electronic ignition systems came out, they doubled the life of the spark plugs even with leaded gas.


on the valve jobs, valve problems were seldom caused by the carb, but it did happen.

vacuum leaks & lack of maintenance are 2 good reasons,
fuel injected motors still need valve jobs today, dirty injectors on a PFI motor can kill the valves.
vacuum leaks are not such a big problem for valves now unless the motor uses a mass air flow sensor.
intake gasket leaks were quite common back then, the gaskets we have now (not including the newer plastic vortec type) are so much better than what they had back in the 60s, there is no comparison.

solid lifters that were not maintained also killed a lot of valves. the valve sinks into the head a little (see reason 3) & now its too tight, & if its the exhaust valve, which it mostly was, it gets burned up.

a third reason was leaded gasoline, i can hear it now, "your wrong,.. leaded gas is great, it makes your car run better & makes it last longer",... no, it does not. it causes more problems that it solved. "but what about all the valve problems when they took the lead out?" yes, there were more problems with valves after the lead was no longer added. but, those problems are no more, gasoline now has other additives that work much better & are cleaner than lead ever was.

a side note, lead also caused the motor oil to get dirty quicker (which helped to kill those cast iron rings they used back then) sooner than unleaded gas does. motor oil is also much better now than it was back then.

i wonder how many miles someone could get out of a LS1 that was switched over to a points type ignition system & ran leaded gas in it, but keep the PFI on it.

 

I have to agree, that forklifts MAF car is probably the easiest one to tune (provided your MAF scalar tables are setup properly). Other than compensating in PE when you "max the MAF" and working your spark tables, MAF requires a less effort to tune and often don't need any further work.

And, as mentioned by someone before, tuning the spark table in the eprom is WAY EASIER and WAY FASTER than your non-computer controlled distributor.

The biggest drawback to tuning EFI is the time you need to invest to learn how to do it and the cost of the equipment.