|
Author
|
Topic: 393 Vs 392, What・s the Dif
|
68 S-code GT
Gearhead Posts: 2962
From: Sayreville, NJ, US
Registered: Mar 2000
|
posted 02-13-2005 04:35 PM
   
Is it just a mater of rounding off or is it the compression height?
IP: Logged |
69 Sportsroof
Gearhead Posts: 2124
From: Valley, Alabama, USA
Registered: Mar 2002
|
posted 02-13-2005 06:57 PM
1? 
IP: Logged |
68 S-code GT
Gearhead Posts: 2962
From: Sayreville, NJ, US
Registered: Mar 2000
|
posted 02-13-2005 07:56 PM
but is it really 1?
IP: Logged |
69 Sportsroof
Gearhead Posts: 2124
From: Valley, Alabama, USA
Registered: Mar 2002
|
posted 02-13-2005 09:45 PM
Not sure, thus the question mark. 
IP: Logged |
indyphil
Gearhead Posts: 2690
From: Senoia, G.A. USA
Registered: Jul 2002
|
posted 02-14-2005 07:30 AM
displacement is not affected by compression height, its a swept volume and is only affected by bore and stroke - not piston bowls, head volumes or compression ratios.I would imagine the difference is just rounding up Vs rounding down. ------------------
'68 coupe, '66 289 C code
engine, edel 600cfm carb, performer intake, dual exhaust http://www.geocities.com/ottouk_77/68mustang.htm
IP: Logged |
MrWesson22
Gearhead Posts: 1286
From: Dacula, GA
Registered: Sep 2000
|
posted 02-15-2005 08:31 PM
4.030" bore, 3.85" stroke, V8 = 392.87cidTake the bore, divide by 2, square the product... (4.030/2)(4.030/2) = 4.060225
Multiply this by pi... 4.060225 x 3.1415 = 12.7552
Multiply the product by the stroke to get the cid of each cylinder (volume of a cylinder). 12.7552 x 3.850 = 49.1075
Multiply that by the number of cylinders, and voila! Engine cid... 49.1075 x 8 = 392.86cid It's just the rounding. Hope that wasn't too much math for you. You can also use this to find out that by going to a 4.040" bore, you get 394.81cid, and going to a 4.060" bore gets you 398.73cid. An aftermarket block with a 4.125" bore and a 3.85" stroke gets you a fun, high revving 411.06cid.
------------------
Neal 69 Gulfstream Aqua Grande
351C/4sp
https://mustangsandmore.com/ubb/MrWesson22.html 99 GT 5 sp coupe
IP: Logged |
bob6364
Gearhead Posts: 275
From: griswold,ct usa MCA#59447
Registered: Dec 2004
|
posted 02-15-2005 10:01 PM
OH THanks!! There goes another blood vessel,math...and right in plain sight too...
IP: Logged |
MrWesson22
Gearhead Posts: 1286
From: Dacula, GA
Registered: Sep 2000
|
posted 02-16-2005 01:57 AM
At least I didn't take the time to explain that I was using pi rounded off to 4 decimel places in the calculation of the area of a circle and using that multiplied by the height of a cylinder (or stroke in this case) to find the volume of each cylinder. ------------------
Neal 69 Gulfstream Aqua Grande
351C/4sp
https://mustangsandmore.com/ubb/MrWesson22.html 99 GT 5 sp coupe
IP: Logged |
68 S-code GT
Gearhead Posts: 2962
From: Sayreville, NJ, US
Registered: Mar 2000
|
posted 02-16-2005 07:46 AM
Thanks,If you only carry two decimal places you get something like 392.4. I guess if Ford had this as a production engine they would have called it a 393 so it would sound like it is bigger and better. I could have done the math but what can I say but that I was thinking the other day and got lazy. 
------------------
Ed S. 68 S-code FB GT 4spd(now C6)/3.25 PS PDB
68 J-code(now 289) Cp Sprint"B" C4/3L00-9" PDB PS AC Bla-Bla-Bla
99 F150 XLT Ext/cab, 4X4, 5.4L, 3L55
IP: Logged |
Mustangsandmore Forums
