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Racing Fuel Systems • View topic - Car gearing and weight effect on tuning

Car gearing and weight effect on tuning

Re: Car gearing and weight effect on tuning

Postby Right hand drive » Sun Sep 05, 2021 9:28 am

Right hand drive
 
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Re: Car gearing and weight effect on tuning

Postby JETFAST » Sun Sep 05, 2021 8:35 pm

Checking out of your own thread huh....well check you out then....and go find out for yourself. Nobody has answers for what you do not care to understand. You guys are trolling....to validate your own speculations, while refusing to consider any all facts to the physics. I am not calling you names, or trolling you. But I am calling you a fool, and your friend over there too. You got to study, and apply, though to theory of these physics every day. Not just some seasonally, or nights and weekends, and when the weather is good.

I am here to give back to the forum, that has given me so much knowledge. This is a very advanced forum. Alot of great knowledge has been lost. And alot of that is lost, when we loose the people of knowledge, in forum, and real life. We have lost some great forums and people who gave free time to help others learn about this quickly fading art of the carbon foot print. It gets harder every year to build and calibrate any carburetor.

The struggle is real these days, and I am not here to make friends, I do not care what you troll of me, as that is any obvious sign of your weekness. Go back to YB if you want to be trolls. I do not care about your fickle feelings of who I am, what I have done, or what I do.

Have a day.
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Re: Car gearing and weight effect on tuning

Postby BradH » Mon Sep 06, 2021 4:17 am

Not sure there's much point in responding since this thread looks to be coming off the rails, but what the Hell.

Here are some things I would expect may benefit from changes by taking the same basic engine combo and changing the car:
- initial timing and/or rate of ignition advance
- accelerator pump cam choice and orientation, and maybe pump size itself
- emphasis on low RPM response under load
- how soon or delayed the main circuit should come into play

Here's something else to consider... if you make enough changes to the car in which the engine is used, the carb that was "right" for the original combination may no longer be the best performer for the new one. Hang enough additional weight, longer gears, & lower stall speed on the car and good driveability with the original carb may simply not be achievable.
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Re: Car gearing and weight effect on tuning

Postby jmarkaudio » Wed Sep 08, 2021 8:34 pm

Jetfast let's keep this more civil. Not everyone can grasp all that goes on in an engine, and that goes for most here me included. I'm here to learn as much as give out info for those that want to learn, whether just for their own understanding to make better buying choices or to build on their own.

The OP's question is a bit loaded, engine combinations have so many variables there isn't a correct answer, add converter stall, vehicle weight and gear, tire size, fuel type, and even winter/summer grade changes for pump gas throw curves. And it's even possible to build the engine with the same paper specs and change combustion chamber differences, dual and single plane, plenum volume... the picture looks bleak. Fortunately a carb built with the correct metering to provide a stable fuel curve over a range of throttle opening and load will usually be tolerated well as long as size isn't significantly off. And by fuel curve not the AFR you see on a meter, that can be skewed by incorrect timing at any point in load and RPM. Add insufficient octane and you can't burn the fuel correctly.

So with that said my starting point for either combo would be somewhere around a 750. I might lean a little bigger with a higher stall, but the end performance difference between the carbs would be minimal.
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Re: Car gearing and weight effect on tuning

Postby JETFAST » Thu Sep 09, 2021 6:40 am

1979 model 3G mechanic. I was turning wrenches as soon as I could hold one. I came up in a family shop, right threw the transition of carbs to EFI. Old school mechanics preaching EFI was the devil, and I was like .….hell no!!! EFI is the future! I got my first EFI .. speed density 1987 5.0 mustang GT in 1997 and I worked at super shops when it came to an end. I can tune just about any factory usa ford EFI system, SD, OBD1&-2, From 1987-2020. Run nhra, salt flats, sand dunes, off shore, mud, dirt, ect. A blessing and a curse, all at the same time.

The knowledge and arguments about EFI and carbs, always heald. A battle. I wanted to take carbs to the level they never got. Learn how to control one, like EFI. First carb I ever took a drill bit to, won a championship at the largest dirt track in the south 2007. I wanted to know more, and on speed talk, and YB, The Carb Shoot out was coming up at blp, and a guy name mark come out of the garage with a swap meet dominator, and smoked'em all.

I was like Holley~shit. Guy I seen, hanging around YB, just stood off in everyones sand box, with that back yard boogie! :shock:

I sent him a pm, with congratulations, and asked him if he could recommend a book, he did, and that was carburetors and carburetion by Larew. Took me 2-3 years to even begin to rap my head around all that, and I have still not read it all. Amazing book. If it was not for guys like mark, tuner, and some good ones lost, sharing there home work, notes, research, development, and thought to theory....I would not be here, and neither would any one else.

Thank You, everyone who contributes to the carbon footprint.
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Re: Car gearing and weight effect on tuning

Postby JETFAST » Sun Sep 12, 2021 11:52 pm

2.6g's on the dig. 1.29 60' on the back tires. no slip converter necessary. methanol/nitro 4150. on iron head SBC.
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TQ converter efficiency
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