using the charts,calculators and basic math



using the charts,calculators and basic math

Postby grumpyvette » November 10th, 2014, 9:25 pm

theres a hundred threads on this site answering various questions about how to properly select or installation of various components and its rather obvious that the most common questions are some variation on how to either build a decent running performance engine at low cost or trouble shoot various issues with engines that are already built.the key is and always has been to carefully match the components being selected to provide and slightly exceed the expected required and carefully calculated, air flow, rpm range and expected stress levels so you can make and maintain the power expected with a margin for extended durability,so you overcome the inevitable minor air flow and friction losses.
its rather obvious most guys would rather be boiled alive than read what they see as near endless links or sub links but you might be amazed at what youll learn, I know I WAS AS I DID YEARS OF RESEARCH, and RESEARCHED HOW to do things correctly ....yes usually after finding out how NOT to do things, or spending far too much money, like most guys!.
it should be rather obvious that after 60-80 plus years since Chevy,Pontiac,Buick,Olds, Plymouth ,Ford and mopar first produced a v8 engines that a great deal of research and engineering time has gone into building and modifying those engines and that the more popular of those engines that have longer production runs lasting decades like the Chevy,Pontiac, and many Ford and mopar engine have had significant research done and parts produced. thus a bit of research into what HAS worked and what HAS BEEN successful and what has been shown to be the most successful trends should lead anyone whos willing to do some research to several previously successful combos that can be copied, or at least closely duplicated once the basic operational details are understood and logically one should understand the basics of why the basic components function like they do, and what previous combos or modifications failed miserably, as well as what succeeded , so previous mistakes can be avoided.

I was asked several dozen times for a good basic combo that won,t break the bank that would result in a nice street engine based on your basic first generation sbc, keep in mind low cost is relative and low cost and quality and long term durability may not be compatible, so I,m talking about a total fresh rebuilt where you have a good rebuild-able 350 block, and decide to build a fresh 383, that will produce over 430 hp at the fly wheel and should last 100K miles or more,ALL THE FACTORS REQUIRED IN THE BUILD CAN BE CALCULATED and it will be designed for street use where it will spend the vast majority of its life at under 4000rpm, and rarely see north of 6300rpm, so low speed torque is important just as upper peak power, so it should push you back in the seat easily if you floor the throttle but not be a problem if you want to drive across the country (well gas mileage will not be great) and compromises were made, but theres a big difference between building a performance engine you might reasonably expect to go 100K miles with minimal maintenance, and an all out race engine that will be rebuilt after each race or at least at the close of the season, that would be expected to spin 7000rpm and not be expected to perform below 4500rpm.

well, to start with a low cost build and I mean to minimize the cost every place I reasonably can, Id strongly suggest we keep cost to a minimum and start with a basic 350 first gen block thats no more than .030 over bore as the stock blocks are not all that rigid, Id maximize the blocks displacement with a SCAT CAST STEEL CRANK, BASED ROTATING ASSEMBLY, YES YOU WANT THE 7/16" CONNECTING ROD UPGRADE as its significantly stronger, 5.7" or 6" your choice ID prefer the 6" rods myself but either will work.
forged pistons are preferred but hyper-eutectic pistons will work ok if you keep the engine rpms reasonable (with a mild performance 383 thats generally about 6200rpm max) and the engine out of detonation.
Id select and edelbrock air gap intake and a 600cfm-700cfm vacuum secondary carb
http://www.flatlanderracing.com/scatsr-chevysbcast.html
on a street car Id prefer a manual transmission, and at least 3.35:1 rear gears but 3.73:1 are ideal
ID want about 9.5:1-10.5:1 static compression to maximize torque but obviously youll need to carefully select the cam timing to get a dynamic compression near 8:1 to run pump octane fuel and aluminum heads that flow at least 250 cfm at .0500 lift,to flow enough air to adequately fill a 383 cylinder at 6300rpm. and Id select a solid lifter flat tappet cam, or if forced into it a hydraulic flat tappet cam, with at least a .500 lift and a 235-245 dur. at .050 lift cam to maximize performance per dollar are about mandatory for maximizing performance , roller cams are great but they are expensive.
Id damn sure put the time in to find a decent 7-8 quart baffled oil pan with a effective windage screen,that fit the car because maintaining consistent oil pressure is mandatory for durability
heres a calculator to calculate ideal port cross sectional area
on a street driven 383 Id design the build to put that some place in the 4000rpm-4500rpm band
youll generally dump 30%-40% of your budget into good cylinder heads because they hold the key to much of the engines performance potential, on a 383, youll want a 195-215cc port size , if your intent on max power Id go with a larger port cross sectional area, a smaller port will restrict upper rpm power but result in more mid rpm torque ,your choices depending, mostly on gearing, and cam selection and intended operational rpm band.
now keep in mind this is NOT intended to be a max performance build , and you could rather obviously boost peak power with a with more compression, larger port heads, a well designed single plane intake and a larger carburetor and perhaps a wet nitrous plate, and a serious roller cam, but that would also add significantly to the engines cost and tend to make it far less likely to be useful for daily transportation.

http://www.rbracing-rsr.com/runnertorquecalc.html
Image
COMMON SBC INTAKE PORTS
felpro # 1204=Port Size: 1.23" x 1.99"=2.448 sq inches

felpro # 1205=Port Size: 1.28" x 2.09"=2.67 sq inches

felpro # 1206=Port Size: 1.34" x 2.21"=2.96 sq inches

felpro # 1207=Port Size: 1.38" x 2.28"=3.146 sq inches

felpro # 1209=Port Size: 1.38" x 2.38"=3.28 sq inches

felpro # 1255 VORTEC=Port Size: 1.08" x 2.16"-2.33 sq inches

felpro # 1263=Port Size: 1.31" x 2.02"=2.65 sq inches

felpro # 1266=Port Size: 1.34" x 2.21"=2.96 sq inches

felpro # 1284 LT1=Port Size: 1.25 x 2.04''=2.55 sq inches

felpro # 1289 FASTBURN=Port Size: 1.30" x 2.31" 3.00 sq inches
http://users.erols.com/srweiss/calccsa.htm
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there are quite useful ,cam selection soft ware programs that get you in the ball park, but the final selection is based on far more factors than most of those software programs address
http://www.camquest.com/

http://www.strokerengine.com/SBCHeadsFlow.html

http://www.wallaceracing.com/Calculators.htm

Image

if you read thru the links theres a ton of detailed info, but the charts and calculators in the links and sub links will all tend to guide you to a similar conclusion, a semi mild 383SBC can use a cam with about a 235-245 duration at .050 lift with about a 108-110 LSA and ideally about 520- 530 lift so youll generally run 1.6:1 roller rocker to get the required lift at the valve, with a flat tappet cam, obviously if you have the cash exceeding that lift but keeping the duration tends to result in more power potential but it costs more., do the required calculations so the cam you select and the engines compression ration allows you to get to about that 8:1 dynamic compression, and discuss the cam selection with the cam manufacturer.
Id also point out that the closer you are geared to that base 3.336:1 range the lower the cam duration should be, and the closer you get to lets say 3.73:1 the closer you can get to the 245 duration end of the cam range, while all the cams in the range will work, its best to maximize power where the gearing maximizes your average rpm band at cruising speeds

you can use calculators to figure out the best header config, but generally youll find its a 1.75" primary about 38-39" long with a 3" diam, 18"-20" long collector

http://www.wallaceracing.com/header_length.php

http://www.bgsoflex.com/auto.html
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it should be rather obvious that youll need to know the exact distance the piston deck sits at TDC ,above or below the block deck surface and the valve notch recess or pop-up dome volume of the piston to do accurate quench or compression calculations
heres a chart FROM THE BOOK,HOW TO BUILD BIG-INCH CHEVY SMALL BLOCKS with some common cross sectional port sizes
(measured at the smallest part of the ports)
...........................sq inches........port cc
edelbrock performer rpm ....1.43.............170
vortec......................1.66.............170
tfs195......................1.93.............195
afr 180.....................1.93.............180
afr 195.....................1.98.............195
afr 210.....................2.05.............210
dart pro 200................2.06.............200
dart pro 215................2.14.............215
brodix track 1 .............2.30.............221
dart pro 1 230..............2.40.............230
edelbrock 23 high port .....2.53.............238
edelbrock 18 deg............2.71.............266
tfs 18 deg..................2.80.............250

http://users.erols.com/srweiss/calcehp.htm


related info
viewtopic.php?f=44&t=38

http://www.rbracing-rsr.com/calculations.htm

http://airflowresearch.com/articles/article085/A-P1.htm

viewtopic.php?f=44&t=392

viewtopic.php?f=52&t=333&p=37705#p37705

viewtopic.php?f=52&t=2630

viewtopic.php?f=55&t=10494&p=44284&hilit=port+tuned+restriction#p44284

viewtopic.php?f=69&t=519

viewtopic.php?f=69&t=9930

viewtopic.php?f=52&t=462

viewtopic.php?f=54&t=615&p=820&hilit=+baffled+corvette#p820

viewtopic.php?f=54&t=2187&p=29042&hilit=baffled#p29042

viewtopic.php?f=52&t=5078

viewtopic.php?f=55&t=10494&p=44299#p44299

viewtopic.php?f=52&t=8460

viewtopic.php?f=52&t=322

viewtopic.php?f=52&t=11119&p=49638#p49638

viewtopic.php?f=52&t=10947&p=48126#p48126

viewtopic.php?f=52&t=796
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theres lots of charts in the links like this one that provide info, if you have a 383 thats about 48 cubic inches per cylinder, divided by intake valve diam. we get 23.7, looking at the chart we see a LSA of about 106 should be the most efficient
THIS CHARTS RATHER CONSERVATIVE ON SUGGESTED CAM DURATION BUT IT CERTAINLY SHOULD BE A USEFUL GUIDE
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the chart above can be used as a rough guide to match cam duration at .050 lift and static compression in engines obviously other factors come into play so its only a rough guide, when you use a cam with significantly more duration than suggested drive-ability and lower rpm power can suffer
Image
4000 feet per minute in piston speed is generally considered a safe make on a mild performance build with upgraded components, a 383 with its 3.75" stroke would see that as about 6400rpm,but hydraulic lifters tend to float a bit lower so call it 6200rpm, look at the chart and we see a engine with the 383 roughly 48 cubic inch per cylinder needs a 230-240 duration to match that power band
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: using the charts,calculators and basic math

Postby grumpyvette » November 11th, 2014, 10:48 am

as an example lets take this advice,if you want to build an old school 383-406 first gen SBC, on a reasonable budget for the power level reached, IT WON,T BE DIRT CHEAP BUT IT WILL BE A REASONABLY GOOD VALUE, youll generally be expecting too dump 30%-40% of your budget into good cylinder heads because they hold the key to much of the engines performance potential, an engine similar to this should easily produce respectable results in a fairly light weight car with a manual transmission as described

and we will select a crower 00226 hydraulic flat tappet cam (because I know most of you guys hate lashing solid lifters)
http://www.crower.com/chevy-262-400-ser ... -7067.html
Lobe center 108
Advertised Duration: Intake / Exhaust 290 / 298
Duration @ .050" Lift: Intake / Exhaust 242 / 250
Rocker Ratio: Intake / Exhaust 1.5 / 1.5
Gross Valve Lift: Intake / Exhaust .507 / .522
OR
crower FLAT TAPPET SOLID LIFTER 00304
http://www.crower.com/chevy-262-400-hig ... -core.html
Duration @ .050" Lift: Intake / Exhaust 236 / 244
Gross Valve Lift: Intake / Exhaust .522 / .510
OR
a CRANE 114681 if you want to go, a bit hotter with a solid lifter combo
Image

ID go with 1.6:1 roller rockers to maximize lift. Ive used ERSON extreme duty, 1.6:1 SBC 3/8 stud rockers on at least 10 engines now with good results
http://www.ebay.com/itm/Erson-SBC-Chevy ... 9c&vxp=mtr

SCAT INTERNAL BALANCE 6" ROD 383 rotating assembly with 9.8:2 forged pistons $1160
http://www.jegs.com/i/Scat/942/1-90505B ... oreDetails

you have several options on cylinder heads
brodix 200cc IK heads $1,308.33
http://www.jegs.com/i/Brodix/158/1021001/10002/-1

http://www.summitracing.com/parts/afr-1054

Image

edelbrock air gap intake $227
http://www.jegs.com/i/Edelbrock/350/750 ... ProductId=

demon 625 cfm carb $330
http://www.jegs.com/i/Demon-Carburetion ... ProductId=

youll obviously want a decent 7-8 quart baffled oil pan and a Z28 style oil pump to fit the chassis you select, because consistent pressurized oil flow protects the bearings and does most of the internal parts cooling and wear protection
Image
obviously the components selected , how well they complement each other and the care taken during assembly maters but heres what DD2000 predicts for a similar flywheel hp result, but if you read thru the links and sub linked info and understand the concepts youll have a very good chance of avoiding many common mistakes and building an impressive performance engine.
keep in mind the combo above is for an old style muscle car engine with a manual transmission and a carburetor, the links below have more info if your building a TPI combo


YOU MIGHT FIND THESE LINKS INTERESTING

http://www.superchevy.com/how-to/148-0506-gm-bow-tie-vortec-small-block-engine/

http://www.strokerengine.com/SBCHeadsFlow.html

http://airflowresearch.com/articles/article032/A-P1.htm

http://airflowresearch.com/articles/article096/A-P1.htm

http://airflowresearch.com/articles/article085/A-P1.htm

viewtopic.php?f=55&t=10494&p=44299#p44299

viewtopic.php?f=32&t=601&p=1216&hilit=+first+porting#p1216

viewtopic.php?f=55&t=641&p=1004&hilit=+first+porting#p1004

viewtopic.php?f=71&t=741&p=1048&hilit=+first+porting#p1048
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: using the charts,calculators and basic math

Postby grumpyvette » November 18th, 2014, 11:36 am

Now Im reasonably sure this may not be what any of the newer guys in this hobby want to hear, but,unless you sit back and think things thru,and make a logical assessment of your skills, budget, and goals,your tools and where you have too work, your doomed to spending far too much time and money to get decent results by making many COMMON mistakes, keep in mind your hardly the first guy to want to build a killer combo on a limited budget with out a full understanding of how to correctly match components ... WELL WE ALL..... ALL STARTED THAT WAY , but the smarter guys, in any group learn from other guys mistakes , and try too avoid making as many as they can themselves. .... so avoid making as many mistakes as you can by understanding the basic concepts ,please under stand I,m trying to help and save you a great deal of time and wasted cash, you need to do some research before throwing cash at the potential engine build problem,youll need a better understanding of what factors like duration, lift LSA, and port flow rates compression ratio, etc. have on engine performance. what basic suitability of a cam design has on how it will effect the car or trucks engine and how gear ratio compression ratio and displacement and converter stall speed all must be matched to the application to build the engine correctly, yeah you can ignore this advise and think I'm F.O.S. here but in the long term youll see I'm trying to help , simply slowing down and doing a week or two of serious research into whats required,and the cost involved and having a realistic assessment of what you can afford to do, and have the skill too accomplish will save you a ton of cash and months of wasted effort.

start by buying these books and watching the video

viewtopic.php?f=50&t=11026&p=48766#p48766
http://www.themotorbookstore.com/resmchstvi.html
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HOW TO BUILD MAX PERFORMANCE CHEVY SMALL BLOCKS ON A BUDGET by DAVID VIZARD
Image
.
JOHN LINGENFELTER on modifying small-block chevy engines
Image


READ THRU THESE LINKS, AND SUB LINKED INFO.....yes it will take some time, but it will save your thousands of dollars and weeks of work and give you a good basic back ground knowledge
http://www.rpmrons.com/Rebuild.html

http://www.chevyhiperformance.com/tech/engines_drivetrain/complete_builds/0608ch_race_engine_building_tips/index.html

http://www.racingheadservice.com/Information/ArticleDetails.asp?ID=1160755224

http://forum.grumpysperformance.com/viewtopic.php?f=50&t=46&p=55&hilit=+software+books#p55

http://forum.grumpysperformance.com/viewtopic.php?f=53&t=509

http://forum.grumpysperformance.com/viewtopic.php?f=52&t=10705

http://forum.grumpysperformance.com/viewtopic.php?f=87&t=10415&p=43240&hilit=what+makes+good+engine#p43240

http://forum.grumpysperformance.com/viewtopic.php?f=50&t=10363&p=42683&hilit=what+makes+good+engine#p42683

http://forum.grumpysperformance.com/viewtopic.php?f=71&t=741&p=39629&hilit=what+makes+good+engine#p39629

http://forum.grumpysperformance.com/viewtopic.php?f=69&t=9930&p=38054&hilit=what+makes+good+engine#p38054

http://www.speedomotive.com/t-faq.aspx

http://www.mre-books.com/sa21/sa21_10.html
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: using the charts,calculators and basic math

Postby grumpyvette » November 19th, 2014, 7:27 pm

theres hundreds of related threads about various components , but it not simply the components you select alone, but the requirement to carefully match and fit components, correctly, theres a huge differences between bolting parts together out of the box and taking the time and effort to correctly clearance and fit components to reduce flow restrictions, increase oil flow rates reduce heat and part wear rates stress and fatigue.
some excellent info well worth reading thru

READ THRU THIS LINK
you might have somehow gotten the IN-CORRECT idea that the valve center-line and CYLINDER center-line are exactly matched in a sbc, they are NOT!
plus the valves are angled at a 23 degree angle so the outer valve edges close to the cylinder walls do not drop strait down into the bore as the valves open at the point of the cylinders largest diam. moving the head center-line to move the valve center- line to maximize flow at max valve lift potentially helps performance.
Image

http://www.circletrack.com/enginetech/1 ... ch_engine/



http://www.hotrod.com/how-to/engine/061 ... d-porting/

http://www.motortecmagazine.net/article.asp?AID=30&AP=1

http://www.eurospares.com/graphics/engi ... 0Time!.pdf

http://www.gofastnews.com/showthread.ph ... rt-Volumes

http://www.rbracing-rsr.com/runnertorquecalc.html

viewtopic.php?f=52&t=8460&p=29682&hilit=curtain+flow+angle#p29682

http://users.erols.com/srweiss/tablehdc ... _Big_Block

http://www.j-performance.com/index.php? ... view&id=48

http://www.cfmperformance.com/cfmproducts/flowbenches

http://racingsecrets.com/speedtalk_head_porting.shtml

http://www.diyporting.com/Shrouding.html

viewtopic.php?f=27&t=3379&p=8922&hilit=+shop+filter#p8922

viewtopic.php?f=50&t=3422

http://www.circletrack.com/enginetech/c ... index.html

http://victorylibrary.com/mopar/chamber-tech.htm
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valve seat and back face angles ,valve diameter and valve lift and duration effect the flow thru the curtain area
Image
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restrictive, as cast
Image

less restrictive after unshrouding the valve

Image
heres some old fuelie heads with the chamber slightly un-shrouding the intake valve pocket walls
polishing the combustion chambers and smoothing contours tends to reduce detonation and improve power, combine that with port and bowl area clean-up and careful blending of the port walls. and a back cut on valves with a multi angle valve job, etc. and its not unusually to gain 25-40 hp or more, from port work and combustion chamber mods that improve air flow rates
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BTW HERES SOME REWORKED BIG BLOCK HEAD COMBUSTION CHAMBERS, TO UN-SHROUD THE VALVES, SMOOTH THE COMBUSTION CHAMBERS

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STOCK
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SIGNIFICANTLY IMPROVED FLOW
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
grumpyvette

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Re: using the charts,calculators and basic math

Postby philly » November 19th, 2014, 8:08 pm

since you are talking a bit about porting and the like i thought this would be a good place to post this.... dont think that because you bought an aftermarket intake that there isnt room for impovement!

Fairlane_Magazine_Article_2 5.0 intake forum resize.jpg
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-phil

There's never enough money to build it right, but there's always enough to build it twice!
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