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For the auto enthusiast a quick quiz


maddmaxx
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2 hours ago, Philander Seabury said:

Bottom ones have air filters, because that is good for them!

That's all I noticed.  Except for the 2-barrel carbs I rebuilt on the old 283-V8 Chevy's I drove in high school and college, I can't tell you much except that some people say that replacing a dirty air filter isn't such a big deal anymore because the computer system adjusts the fuel/air for it.

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11 minutes ago, jsharr said:

fuel starvation under heavy acceleration?

Ta da.  Almost full points.

The example that shows the float bowls fore and aft is a normal street or road racing setup.  The sideways setup is for drag racing.

Why?:  Because the bowls are the same, the float assembly on one side (or end) of the carb is opposite the other.  In the road setup, the bowls are set up to behave the same under the more common lateral acceleration of going around corners.  If used for drag racing this would result in the float on one end of the carb forcing the mixture to be richer and the other end of the carb to be leaner.  Placing them sideways causes all the floats to behave more or less the same.  On the other hand, the drag racing setup in a road racing car would cause the rich/lean condition during cornering.

This is the sort of tech that makes big differences in one's ability to make good horsepower for the intended application.

You may or may not believe it but acceleration even matters inside the intake manifold where fuel/air mixtures can be forced by acceleration to cause the rearmost cylinders of the engine to be richer than the front cylinders.

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3 minutes ago, maddmaxx said:

Ta da.  Almost full points.

The example that shows the float bowls fore and aft is a normal street or road racing setup.  The sideways setup is for drag racing.

Why?:  Because the bowls are the same, the float assembly on one side (or end) of the carb is opposite the other.  In the road setup, the bowls are set up to behave the same under the more common lateral acceleration of going around corners.  If used for drag racing this would result in the float on one end of the carb forcing the mixture to be richer and the other end of the carb to be leaner.  Placing them sideways causes all the floats to behave more or less the same.  On the other hand, the drag racing setup in a road racing car would cause the rich/lean condition during cornering.

This is the sort of tech that makes big differences in one's ability to make good horsepower for the intended application.

You may or may not believe it but acceleration even matters inside the intake manifold where fuel/air mixtures can be forced by acceleration to cause the rearmost cylinders of the engine to be richer than the front cylinders.

what about oil pan baffling?  Or do you run dry sump?

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7 minutes ago, jsharr said:

what about oil pan baffling?  Or do you run dry sump?

Oil pan baffling also varies with the type of racing.  Higher horsepower cars work better with dry sump.

Back in the day, one of the good investments in HP for a big block Chrysler engine was called a windage tray.  On the 383/440 it was a $2.98 metal stamping that sandwiched between the oil pan and the block.  It had slots and scoops designed to strip the oil that was rotating with the crankshaft (windage) and dump it into the pan.  The HP penalty for allowing that oil to rotate around with the crankshaft was about 15HP at higher rpms.  Other engines have similar trays but in many cases they are held in place by the main bearing cap bolts and are a much more complicated install.  $2.98 and 2 oil pan gaskets is an inexpensive price for 15 HP.

As for pan baffling, drag cars tend to pick up oil at the back end of the pan.  Road racing cars have compartments and trap doors to keep the oil near the pickup under acceleration from any angle.

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The float bowls fore and aft is for normal street or road racing setup.  The sideways setup is for drag racing.  In the road setup, the bowls are set up to behave the same under the more common lateral acceleration of going around corners.  If used for drag racing this would result in the float on one end of the carb forcing the mixture to be richer and the other end of the carb to be leaner.  Placing them sideways causes all the floats to behave more or less the same.  On the other hand, the drag racing setup in a road racing car would cause the rich/lean condition during cornering.

i didn’t always believe it, but acceleration matters inside the intake manifold where fuel/air mixtures can be forced by acceleration to cause the rearmost cylinders of the engine to be richer than the front cylinders.

Now, don’t get me started on oil pans....

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18 minutes ago, Prophet Zacharia said:

The float bowls fore and aft is for normal street or road racing setup.  The sideways setup is for drag racing.  In the road setup, the bowls are set up to behave the same under the more common lateral acceleration of going around corners.  If used for drag racing this would result in the float on one end of the carb forcing the mixture to be richer and the other end of the carb to be leaner.  Placing them sideways causes all the floats to behave more or less the same.  On the other hand, the drag racing setup in a road racing car would cause the rich/lean condition during cornering.

i didn’t always believe it, but acceleration matters inside the intake manifold where fuel/air mixtures can be forced by acceleration to cause the rearmost cylinders of the engine to be richer than the front cylinders.

Now, don’t get me started on oil pans....

No points for you.  :nyanya:

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1 hour ago, Razors Edge said:

Aski him about the oil pans!!! Go on. Give him a shot at redemption!

Oil pan baffling also varies with the type of racing.  Higher horsepower cars work better with dry sump, while drag cars tend to pick up oil at the back end of the pan.  Road racing cars have compartments and trap doors to keep the oil near the pickup under acceleration from any angle.

Back in the day you could gain big horse power (we called it HP!), with the insertion of a cheap metal stamping that removed oil from the crank shaft and put it back into the pan. I calculated you could get 5.033 HP for every dollar spent (up to about $3) for that trick, plus some gaskets.

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6 hours ago, maddmaxx said:

You may or may not believe it but acceleration even matters inside the intake manifold where fuel/air mixtures can be forced by acceleration to cause the rearmost cylinders of the engine to be richer than the front cylinders.

I was late to the game...    I read the thread and I knew @jsharr was on the right track (1/4 mile long).

I just read where engine computers, direct injection, and variable valve timing are being used to just about eliminate the problem of individual cylinder mixture balance problems in high hp motors.  If I recall, it was an article about the new flat plane crank that will be used in the Z06 version of the C8 Corvette, and how computers will help make for a more even cylinder pressures, therefore less engine imbalance. 

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6 hours ago, Bikeguy said:

I was late to the game...    I read the thread and I knew @jsharr was on the right track (1/4 mile long).

I just read where engine computers, direct injection, and variable valve timing are being used to just about eliminate the problem of individual cylinder mixture balance problems in high hp motors.  If I recall, it was an article about the new flat plane crank that will be used in the Z06 version of the C8 Corvette, and how computers will help make for a more even cylinder pressures, therefore less engine imbalance. 

Yes.  Computers have made the modern internal combustion engine able to do things we could only dream of back in the day.  Who would have thought that a modern high performance car could get 30 mph cruising and still make lots of power.  The Daytona got 6mpg in stop and go driving around town.:o  At the same time it didn't make as much horsepower as a modern 5.0 Mustang engine.  Times have changed.  Even NASCAR uses computerized fuel injection now.........

I want one of the new Corvettes by the way.........but then it's on a list of many things that I can only want.

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Hey @maddmaxx I was just looking for a purple Baracuda to go with the hemi in the picture in the OP, and I found this.   The guy is not using an original hemi.  

In the first race, I noticed the guy hitting the brakes before the finish line.  Years ago... (ok decades) my friend needed to do that too.

 

  

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4 hours ago, maddmaxx said:

Yes.  Computers have made the modern internal combustion engine able to do things we could only dream of back in the day.  Who would have thought that a modern high performance car could get 30 mph cruising and still make lots of power.  The Daytona got 6mpg in stop and go driving around town.:o  At the same time it didn't make as much horsepower as a modern 5.0 Mustang engine.  Times have changed.  Even NASCAR uses computerized fuel injection now.........

I want one of the new Corvettes by the way.........but then it's on a list of many things that I can only want.

Yep.  The 305 V-8 in my Nova made 140ish HP in 1976.  The 3.6 liter Pentastar V-6 in my Chrysler makes 292 hp.  Paired to an electronically shifted 8 speed it gets well over 30 mpg on the highway and is still fun to drive in the city, but mileage drops into high teens or low 20s.

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1 hour ago, Bikeguy said:

Hey @maddmaxx I was just looking for a purple Baracuda to go with the hemi in the picture in the OP, and I found this.   The guy is not using an original hemi.  

In the first race, I noticed the guy hitting the brakes before the finish line.  Years ago... (ok decades) my friend needed to do that too.  I would always sandbag by a 10th or so and rely on my starting line reaction to allow me to slow before the finish line and still not get caught.

 

  

It was routine for me back when I was winning brackets week in and week out.  I was always on the brakes near the lights to avoid breaking out.

This was the purple hemi to use though. Carbs even.  This was the original goal for Plum Crazy but I blew the silver flame masks and settled for plane purple.

 

50443545-042-70-HEMI-Cuda.jpg

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1 minute ago, Prophet Zacharia said:

You mean to exceed the maximum distance of the paved track area?*
 

* I can probably write a long dissertation on this later after you’ve elaborated on your terms and experiences. :D

No, in some race classes you have a time or speed that you cannot go under or over.  So many drivers have to lift off the gas or even apply the brakes to avoid "breaking out" or going faster than their preset time.

 

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1 minute ago, jsharr said:

No, in some race classes you have a time or speed that you cannot go under or over.  So many drivers have to lift off the gas or even apply the brakes to avoid "breaking out" or going faster than their preset time.

 

Bracket racing is always like that.  You set your own estimated ET.  Go faster you lose.  Handicap starts are based on the difference between the two cars.

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Just now, Prophet Zacharia said:

Why can’t you go as fast as you can go? I mean, of course, I know this but want to make sure you’re on top of both the “what” and the “why”.

To keep races fair.  If you bring a car that will run 7s and dial it in at 11s then you have a good chance of winning.  This makes it harder.

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Just now, Prophet Zacharia said:

So each racer sets their own handicap? No PHRF-equivalent to objectively set this based on equipment? :scratchhead:

depends on the type of racing.  Sor of like adjusted start times for slower boats on around the buoy races.  Times are compared and the slower car is given a head start.

https://www.onallcylinders.com/2012/06/22/bracket-racing-101-learn-basics-then-get-out-race/#:~:text=A good bracket racer can,in than the other guy.
 

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4 minutes ago, jsharr said:

To keep races fair.  If you bring a car that will run 7s and dial it in at 11s then you have a good chance of winning.  This makes it harder.

Actually if you do that your chances are pretty poor.  If the other car is running close (very close) to it's dial in and you are guessing they will probably beat you to the line or force you to break out more often than not.  Good bracket cars can run within a couple of hundredths every run. 

Now back in the day we were hands, feet and eyes only.  Except for throwback bracket racing, the cars today are computerized.  As long as you, the tuner can adjust the car each run to be on it's dial in then the race is often determined at the starting line by reaction time.

I won't run in the computer classes.  IMO it's just a video game.

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5 minutes ago, Prophet Zacharia said:

So each racer sets their own handicap? No PHRF-equivalent to objectively set this based on equipment? :scratchhead:

Yes.  This type of racing is mostly for people who bring their street drivable car to the track for the fun of racing.  Most serious classes run heads up no handicap.  They are grouped however into things like 9 second classes. 8 second classes etc.  There isn't much room for sandbagging here but you must not run under the group time.  If you can consistently then you run for more money in the next fastest class.

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