I have always wondered.

How were engine tuned back in the day before electronic fuel injection, oxygen sensors, dyno's and all the really awesome stuff we have today that basically lets lets anyone determine in a matter of seconds whats going on with their engine?

 

Kinda wondered the same thing since I've never touched a carb.. I'd guess pinging and EGTs? I'm literally clueless on carbs.

 

Add fuel till it doesn't ping, keep adding until it doesn't go faster on the strip. Drink beer, knock up your brother's wife.

 

Actually,

Its a little known fact but Canary's were used to detect if the mixture was going lean or rich.

 

what's that old mopar saying? "a canary in your tailpipe and a gerbil in your ***"?

 

Reading the sparkplugs after a run (shut the engine down instantly after a pass) was and still is a great way to read a tune.

 

LOL I grew up on carburated engines. Just has Hindle stated read the spark plugs. If it pings add fuel. I would rather a good old fashioned carburated engine over FI any day. I think back when the Miata first came out there was a Weber dual side draft kit for them. Not sure if it is still available. My 240Z was a pure monster when it was running triple side draft Delortos. It was also only getting 8 mpgs, but it had an Isky cam, L28 head on a L24 block, and a MSD 6AL ignition.

heres a couple of my other carburated POSes that I have had




Bonus points if you know what this classic carburated bike is. Hint it was the fastest bike on the market in 1977

 

is that anderson lake?

btw, carbs may be emotionally enticing, but they sure aren't optimal for tuning.

 

I had this convo with a coworker who said they'd look for the "rich" shade of gray in the tail pipe, then advance as far as they could without knock. If they had knock at low rpm, they'd change the vacuum diaphram or whatever. He looked at the exhaust pipe in my green car and told me I needed to lean it out...after explaining why a solid rear is superior to IRS, lol.

LEAN IS MEAN, ************!!!

 

Anybody else ever fool around with a carbureted turbo setup? Several production cars came that way, but it wasn't hard to build your own. It was a guessing game and just like the fools who try to turbo Miatas without a wideband, you never really know what is going on in your engine. Unless you had a Colortune, but that was more for idle mixture. Anybody else ever use a Colortune?

Edit:Colortune lets you look at the color of the flame in your combustion chamber to determine if you are rich or lean. It lets you look through the spark plug hole while the engine is running.

 

The bike is an RD400.

 

Lake San Antonio

Congrats you get a cookie

 

Turbocharging gained popularity with the air-cooled VW crowd in the mid 80s. Or at least, that's when I first learned about it. The predominant carb on those engines was (and still is) the IDA/IDF Weber, though from a packaging standpoint they were not well suited to turbo use. Some folks diddled with sidedraft carbs in a draw-through application, though the greatest success was achieved with a more conventional progressive carb, enclosed in a pressurized box. To us today that sounds downright freaky, but back then it was pretty cutting edge.

That said, even though I cut my teeth on carbs and mechanical advance distributors, my loathing for them knows no bounds. Programmable EFI is the best thing to happen to hotrodders since Nicolaus Otto. No more ******* around with eleventy thousand different combinations of jets and emulsion tubes and diaphragms. No more casting runes over plug insulators, or sprinkling chicken blood over counterweights. Just point and click.

Profit.

 

If I drag raced, and that's all I used my car for, I'd take solid axle over IRS anyday of the week. As far as carbs, I believe nothing is easier or near as accurate as EFI. People who still run carburators and swear that they are better then fuel injection only say that because they are afraid of the technology. If you drive a 1970 GTO and you want originality, then run a carb. If you want to make big power, and get great fuel efficiency, you'd be a retard not to run a FI setup. I never knew anything about AFR's until I came to this board, and ever since I learned, I said to myself, "how did people tune anything without knowing exactly where their mixture was?" The name of the game is, go with the times or get left in the dust.

 

man you guys are young. I remember changing the little springs in the distributor to change the advance curve, tweaking carb jets, etc.

 

Tuning twin DCOE's or quad SU's on a race-cammed 4-cylinder engine will put all kinds of hair on your chest.

That being said, I'd rather not be pulling out all of that hair trying to figure out how to get the damn thing to run right.

One day I'd like to megasquirt the Fiat 1100 race engine back home and show the old man how awesome EFI really is.

 

come now, I still have unisyns, and 4 tube mercury sticks. Tuning doubles, triples and quads was easy stuff

Now what was fun was on the British cars if you forgot the little insulating washer when changing the points. People would cuss a storm because there British car would not start after changing the points.

Who remembers putting a book of matches under the 8 track cassette to shim it and make it work.

 

That matchbook was also useful for gaping points.

 

and for lighting the rag in the filler neck

 

Points are something I've never dealt with, we always ran aftermarket CDI ignition. God spared me from that clusterfuck.

Oh BTW, the most fun thing to do was tuning twin Solex on a manifold similar to this:



That's 1&4 going to the right flange tube and 2&3 going to the left flange tube.