Technical ***September 2020 Banger Meet Thread - Four Months of 2020 to go***

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the man has a science question and everyone's mind immediately goes to sex..146 foot pounds of money shot at 2250 rpm,its why hookers cost money.

 

Got some pinstripe work done by a friend.

 

Also because they are worth it!! much less hassle to rent............
I was looking at fuel curve, if reading correct, I wonder what it would do if leaned up a little.
J

 

we did 5 pulls and only one recorded, they had issues with the dyno.
I had 38 jets in on that pull, The guy at the shop said I should add more for the lean at wide open. I put in 40's and raced it, my ET's were .8 slower than my old average times from years passed.

 

Gotta ask because I don't know, what crankshaft are you using for the stroker? what size stroke?

 

Do the 81's have a power valve or economizer circuit? I don't know Strombergs. It may be just too much enrichment. If that was a Holley, I would pull the Power valve and jet up 1 or 2. It looks too fat to me. The slower ET kind of reinforces my opinion.
Opinions are just like that, I look at the AFR and see it far too rich for the majority of the power band.
Dataloggers are like a curse, the more you can analyze the more places you see where improvements can be made. My Son raced for years with me in karts and then sports cars. We used data every time the car was on the track. With his feedback and the data there was always improvement to be made. Sorry for going off base some, I am looking for a new datalogger for the BVille car.

John

 

Strombergs have a power valve,Mechanically operated at the end of the accelerator pump stroke. The stromberg is less efficient than the Holley,which is dependant on vacuum signal to operate the power valve.IMO a shade fat is good for the street..

 

Great video thanks for sharing it! Looks like it was an awesome event!

 

Yeah, I don't understand the Stromberg, the Holley is a vacuum signal which is load dependent.
We don't know if the AFR was reading correctly, leaded gas always shortens the life of the sensors and it is possible the sensor was not up to temp properly. The fuel curve makes no sense, it just transitioned off and went clean. It could have also been pooled gas in the bottom of the manifold.
John

 

2 inch journal "C" 1 peace crank,
mains ground down to Model A size, rod journals off set 1/4 inch and ground down to 1 1/2

 

One thing that affects the stromberg fuel delivery is the float level,or more accurately the fuel level in the full bowl.Strombergs are emulsion tube style carbs,fuel level dictates how much fuel is available to be drawn from the tubes..just a skosh of high level they run rich,and low they run lean..

 

Yes I’ve been meaning to check the float level I think they may be just a tad high.
I appreciate all the input thanks guys


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My "Carb Guy", Jere Jobe, has worked on my Strombergs since we were teenagers! He's several years older than me; so he's "Older than Dirt"! When it comes to carburetion (including manifolding) he's forgotten more than most will ever know. He set my Stromberg 97's float levels "Spot on"; and they work fine. My only "Dyno" is on a race track. My lap times are steady to higher (depending tires and ambient temp)! I'm running .o45's in the front and .047's in the rear!

 

Hey guys. I have been thinking for awhile about removing the muffler and go with straight pipes but after thinking about it more, I am looking at the possibility of installing a cutout in front of the Aries Muffler and run a dump tube. This way I can have a choice on how loud I want to be. Has anyone else out there done this? Thanks.

 

Thats a pretty darn good carb guy you got.His article on matching engine and carburetor CFM is pure gospel.

 

Its in the back copy's of 'secrets of speed'..its also in Tex Smith/s flathead V8 book..he explained the inefficiency of running a fuel system that flows at a higher rate than the engine..a very touchy subject but Mr Jobe has the experience and 'chops' to spell it out.

 

I made it home with my hood and seat. I had to start mocking it up today

 

If you ever want a steel seat, look for heavy equipment parts dealers that specialize in recycled parts. My seat came from a euclid r15 truck, although mine was free, they wouldn't be too expensive as not many want old seats, and many older pieces of equipment have similar seats.

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I am looking thru the pile of SOSS mags for the articles, but should also mention that Carb CFM ratings have evolved over the years. What I am referring to is the test vacuum standard. By changing this, the CFM rating changes drastically. Take for instance a Holley 4BBL 650CFM carb, compare the venturi and butterfly dimensions against a 2BBL 500 CFM. The sizes are the same between both carbs, so why doesn't the 4 BBL flow 1000 CFM or the 2BBL only flow 325? It has to do with the test pressure.

John

 

SOSS, July 1993 vol. 3 number one, page 36. Jan 1994 vol. 3 number three, page 38. Gary

 

2020 is the worst year !! be so glad when its over ...............

 

Its critical for racing to have an accurate set point to measure. I'm a street guy,like Old Dawg I don't put much credence in dynamometers... strictly controlled and calibrated they accurate tools for maximum performance,I get their value,but I don't need one to achieve what I want to do with my car.I've yet to see any published Holley 94 or Stromberg 97 flow ratings that deviate from the 160 to 170 CFM range for flow.A model a flathead engine flows at 160 cfm or so. Jobe's point is the matching of the two flow rates yields the best all round performance.I agree with his theory,as do many who washed out rings running two carbs on an engine that can tolerate one effectively.
This is ham and egger stuff,like I say I'm a seat of the pants tuner,and have set limits on what I want from a build,with a heavy emphasis on modest..I appreciate the time and devotion it takes to run the salt (money too). It's your innovation that drives the hobby..

 

Read from bottom to top...

 

Thank you railcar mover for posting the Jere Jobe attical! I do not have a flat head V-8 or a flat head Banger, But do have an overhead Chevy Banger running multiple Strombergs, so this is good info!

 

Railcar,

Thanks for posting article, I agree with it. My street coupe is a single 94 right now and a EBU 1"venturi and an ECG 1 1/16" venturi on the shelf.
The biggest takeaway from the article is that in order to maintain the proper vacuum signal to the venturi and ports the carb must be sized properly.
When I was working on the flowbench with cylinder head designs and lots of clay, I found a significant amount of flow could be increased by dropping the amount of vacuum drop thru the carby. This lead to a 650CFM 4BBL sitting on the manifold. This was also improved by going to a 2up/2dn crank to isolate the intake port pulses. It ended up taking quite a bit of work to get the harmonics induced fuel control (or lack of) and the low vacuum signals to work but ran pretty good. Still, not for the street.

Best, John

 

You did a 'Winfield'? 2 up 2 down? Id like to hear that spinup..bet it wakes the dead.Got an 8BA 94 on mine,prefer it to a Stromberg.
Have you done any volumetric effciency calculations? The stuff you do tosses the baseline flathead CFM numbers out the window.."boldly go where no man has gone before" or as an old racer buddy said to me "if the kids get hungry they can eat the putty out of the windows"

 

Railcar,
no VE calcs or numbers, like I mentioned, Jobe's article is spot on for keeping the carby working correctly, which means having the proper vac signal to the ports to feed fuel at correct ratio. What I was doing was taking the restriction of the carb and minimizing it. This means much less signal to the ports to feed the fuel, sort of like making the motor an injected setup, no vac signal required. In short, the carb will not work on another street motor, it has too many extra holes in it.
The 2up motor had some thin spots in the ports and after all kind of attempts at sealing, I just filled the ports with epoxy and bolted down an overhead assembly and removed the 2up crank. But here is what it looked like...............and you are right, it did not sound like a Model A anymore. J

 

He whittles stuff like that in his sleep.

(But he spends hours getting it ready to go.)

 

So if I understand you correctly your pouring fuel at a metered rate,basically stuffing instead of allowing the engine to draw..sounds simple..till you try to make it work,imagine you slept at the flow bench.