FIGURES

[pssnmn1]

high all,

ive been playing around with desktop dyno 2000
for the last couple of hours and this is what i came up with...

now remember this is all theoretical based on this info

factory cam specs 1981
.269 lift stock 4 degrees adv
1.62 rocker ratio ivo(btdc) -18 -14
1.75 chevy rocker ratio ivc(abdc) 30 26
268 degrees adv. duration evo(bbdc) 22 26
192 degrees duration @ .050 evc(atdc) -10 -14

lobe center angle 110 cam degrees
intake center line 114 crank degrees(atdc)
exhaust center line 106 crank degrees(bdtc)

all these combo's are done with stock heads,valves,chambers and stock bottom end so in other words no machining
and as many other factory figures as i could get and there all correct and
confirmed.
here we go

bone stock
peak h.p. 147@3500 rpm peak torque 250ft/lbs@2000 rpm

bone stock +4 degrees adv.
143@3500 rpm 254ft/lbs@2000 rpm

bone stock +1.75 chevy rocker
148@3500 rpm 251ft/lbs@2000 rpm

same +4 degrees adv
144@3500 rpm 254ft/lbs@2000 rpm


350 cfm 2bbl offy-c efi exh.
163@3500 rpm 268ft/lbs@2500 rpm

same + 4 dergees adv
159@3500 rpm 271ft/lbs@2500 rpm

350 cfm 2bbl offy-c efi exh. +1.75 chevy rocker
164@3500 rpm 268-269ft/lbs@2000-3000rpm

same +4 degrees
160@3500 rpm 272ft/lbs@2500 rpm


390 cfm 4bbl offy-dp efi exh.
170@3500 rpm 296ft/lbs@2000 rpm

same +4 degrees
166@3500 rpm 299ft/lbs@2000 rpm

390 cfm 4bbl offy-dp efi exh. +1.75 chevy rocker
167@3500 rpm 297ft/lbs@2000 rpm

same +4 degrees
167@3500 rpm 299ft/lbs@2000 rpm

that is every combo of bang for the buck parts that you can just bolt on
and like i said this is theoretical numbers,desktop dyno doesn't give anything below 2000 rpm's there are just to many variables.

hope this is helpful too everybody

bill in indy

[pssnmn1]

i'm currently working on numbers with and without 1.94 in 1.60 exhaust valves,port work,.010 off the head,.010 off the block with a .030 overbore.

bill in indy

[Geezer 300]

Fascinating... more!

[pssnmn1]

geezer if you send me your other info i'll do yours specific


bill in indy

[pssnmn1]

mods
bored .030 over
.010 off the head
.010 off the deck
offy-dp
efi manifolds
comp raised to 8.82
stock cam with 1.75 rockers

the afore mentioned factory cam specs

h.p.@rpm 4 adv. tq@rpm 4 adv.
3500 190 187 2000 310 313
4000 197 190 2500 304 307
4500 192 180 3000 302 302

ive got a lot of different cam profiles i insert as well

bill in indy

[addo]

It's my understanding that later cam timings were around 4° retarded from factory. So, while we are seeing "improvements" of small amounts or so from straight up, in fact the gain may be more between the later factory cam position and aftermarket timing sets.

So - what about running a "stock" setup with 4° retard in the figures?

Regards, Adam.

[pssnmn1]

hey addo,

that is what line 2 in the list is.
i don't type fast enough to list the whole cam card here but,
not meaning to sound like a smarty pants but i listed all the
valve opening and closing events so you can see that its theoreticaly
advancing the cam +4degrees i tried to take everyones input into
account the flow changes come from the computer generated numbers
before and after port match and polish and in every circumstance i listed
4 degrees advance increased torque down low and decreased top end hp

now that being said these numbers were all done on the factory cam grind

if some one has a degree wheel and a engine on a stand and can give me intake and exhaust centerlines lift at peak and duration at .050 i can increase accuracy.

give me numbers i'll give you answers (theoretical of course)

[pssnmn1]

sorry about that i just read that again and you said retard and not advance

ooops

peak h.p 149@3500 peak tq 246ft/lbs@2000 -4 degrees
147@3500 250ft/lbs@2000 staight up
143@3500 254ft/lbs@2000 +4 degrees

[addo]

That's interesting! It seems people are definitely sensing the extra torque once retard is gone. Thanks for the calcs.

[mutt]

coooooollll.........i got sumpthin I can poit out to the Missus after me endlessly screwing around with something that was running to begin with.
Im interested as all getout what you get when you can plug in opening up the ports, tho I dont know how you would quantfy that short of a flow bench.
And Im sportin all the mods you quote, plus .030 off the head.....but then I eased the area of the combustion chamber that shrouds the intake valve, so I might well have ended up with a net loss of CR, the pistons I got being the listed "heavy duty" number for 1980-81. (Made in USA, $12. ea)
I hgather theres a LOT of pistons listed for these.
Anyhow, thanks for that, mate. Is there any way mpg increase as a percentage over stock can be distilled from your devil machine? thats whats so cool about these mods: not only do you get more useful power, your mpg goes up, in my case 30-100 percent, dependin on a lot of things.....

[pssnmn1]

no problem
i hope the awsome mod squad we have posts them in the facts


i can post and numbers with the right info.

my base info is all correct
so if i can get this cam info

intake center line
exhaust center line
duration @ .050 intake and exhaust
and lift
cam lift plus what ever rocker ratio your using
or valve lift

additional info if applicable
material in thousandths removed from head and or block
and how many thousandths over bore
wether or not there is port work
what you exhaust is manifolds,headers,etc.
carb size 2 or 4 bbl or cfm rating of your efi

thats about it
i can fill in the rest

bill like to crunch numbers

[pssnmn1]

sorry can't list mpg,but i can list volumetric efficency and cyclinder pressure at give rpm of any of the givin combos.

cylinder should be close to compression test readings
give or take 10-15% on a new or good running engine.

[xctasy]

Can you do a stock engine with
Cam +4 degee advanced,
1.75:1 Chevy rockers,
EFI exhast,
and three 500 cfm at 3"Hg carbs with 1.375" venturis and 1.6875" throttles.

Can you determine the percentage power and torque increase over the last 390 DP?

This will determine the improvement of an independent runner intake over a good 4-bbl intake and carb combination.


Then drop the stroke down to 3.45" with the same 6.21" rods and make sure the engine has the same compression.


Thanks in advance for the effort you are putting into this, its very much appreciated!

[pssnmn1]

yes i can do that but lets make sure ive got the numbers right

3 500cfm 2bbls ?
or stacks?
and which pistons are you using?

and bill likes a challenge

[xctasy]

Recappinmg the carbs. Three 500 cfm carbs, #4412 2300 series, (Basically like three down draft Weber IDF 43's with 35 mm chokes, if such things existed) All sequenced, sort of like the Barry Grant Demon Tripower set ups [BG 7540], but without the progressive linkage, and with 500 cfm carbs rather than triple 250 cfm carbs. Maybee add some stub stacks if it makes it easier. Intake is basically stock EFI lower with three deuces on the top.

Stock pistons with whatever cc dish (about 23 cc's, 230 thou deep dish or so for the 300, and whatever dish corresponds to 8:1 or whatever the stock compression is on a 300. With the 3.45" stroke crank 260 cube engine, just reduced the dish untill it has the same compression as the 300).

Basically, this is a stock engine with very good bolt ons, what every one wants when doing a project engine.

I know what the answers should show, as I've done a lot of research on this. I have made some claims before, but I'm currious to know what the data analysis shows.

[pssnmn1]

here you go X,

soory it took so long but i'm on the other side of the world.
had to sleep
combo 1

peak hp 194@4000 peak torque 309@2000

your combo

hp 208@4500 torque 278 @3000 straight up
199@4500 279 @3000 +4
213@4500-5000 273 @ 3500 -4

and the ve is at near 80%
and that was with efi manifold

hope this was what you where looking for

[Harte3]

Something to play with...

http://store.summitracing.com/partdetai ... toview=sku
You will find my cam specs there. As I recall there is a +4 built in.

Head and block milled minimum for clean up....010 each?
Pistons stock 8.3cr...don't know what cr ended up at with block/head milling.

Most of the specs are in my signature line.

[pssnmn1]

your comp ratio ends up as 8.58

peak hp 214@4500 tq 282@3000

but torque stayed above 270 between 2000 and 4000 rpm

i'd say good combo for a manual tranny

i'd love to be able to post the whole sheet for everybody.
but the program is being a pain.

[Harte3]

Many thanks! And very interesting.


When I get off the road this winter I'll be driving on a dyno and see what I'm getting at the rear wheels. And I have some more tinkering to do on that carb plus I have two other carbs I may set up and try just for kicks. One Holley 4010 600 cfm and a Holley 1850 600 cfm.

Thanks again.

[pssnmn1]

when i get back home i'll post 600 cfm numbers for you

9:15 pm eastern time

[Harte3]

Forgot to mention in my specs that it's bored .030. Saw a chart once that indicated that makes it 304 cid.

[pssnmn1]

ok .030 and a 600cfm carb

hp peak 222@4500 peak tq 291@3000

torque stayed above 280 from 2000 to 4000


hope that was what your looking for

once again just so everybody is clear
these are theoretical flywheel numbers

taking all requests

[xctasy]

Bill in indy, you are surely the man! That is an exceptional program.

167@3500 rpm 299ft/lbs@2000 rpm vs.

194@4000 rpm 309ft/lbs@2000 rpm

Pulse tuning in a 300 yields perhaps 16% more power over the better 4-bbl set-ups, perhaps 4% more torque.

If the 'port on port' carb sizing is too small for the combination, a 16% smaller engine will yield a lot more power!


Taken the other way, the best carburation is likely to yeild well over 16% more power, and a good increase in torque.

To corroborate, back in 1971 Chrysler Australia put out a triple carbed 265 cube I6 engine with a mild 260 degre cam, split exhast. They put out 248 hp gross at 4800 rpm. Allowing for the the conversion from gross to the net flywheel figures, thats the similar to the 208@4500 torque 278 @3000 ft/lbs you have there.

Thankyou for the effort involved.

[52'F-3]

interesting reading,
thanks "bill in indy".......

[pssnmn1]

yes this program shows an increase in value nearly every day

thanks for the compliments guys

and your welcome

[pssnmn1]

i'm going to post cliffords performance combos later today.

right now i have to go to work. it will show up around 4:30 eastern
standard time.

later

[pssnmn1]

i'm having a little trouble here....

i'd like to be able to post the numbers i've been giving you guys
in a speadsheet format so everybody can see the whole rpm range.

i've got it in an excel format anyone have any ideas?

the peak numbers don't tell the whole story.

helllllpppppp!!!!!!

thanks

[mutt]

so- if I gave you my cranking compression numbers, this would be useful to add to the mix? ill just average them out. Also, have you been able to quantify port matching & bowl work?
Thx! I bet between us all ya wouldnt have to buy a beer for quite a while.....

[pssnmn1]

sorry mutt i must have stated that backwards
the cylinder pressures are all perfect world mechanics
the program doesn't take into account things like clyinder wear
oil type varing tempurature and so forth.

what i meant to say was the cylinder pressures listed in the simulations should be close to want the reading on a compression tester would read
on one of these combos after a fresh rebuild 10% plus or minus.


as far as the head work goes... if you can some flow numbers in cc's
i can tweek the numbers the program gives and see what happens.

[Harte3]

Fascinating stuff! And I can tell you are having fun with it

[pssnmn1]

another word on port matching

i'm sure someone will correct me if i'm wrong

port matching and head porting is another form of blue printing
i.e exacting tolerances removing bottlenecks smoothing passage ways
and balancing components till they are as similar as possible.
i got my start in neighbors shop across the street (he built funny cars)
i kept hanging around the shop so much he put me to work doing bottom
end work so the seeming endless amount measuring,weighing,grinding,weighing,measuring,grinding oh crap i took to much off start over,assemble,check,disassemble and repeat the number crunching comes natural......but just like the drywall and paint
i don't do cylinder heads sorry

i'll openly admit bowl sizing and shaping confuses me
besides ive got friends for that that hate doing suspension work.

[pssnmn1]

yep i'm eating up

[mutt]

Well then: fresh rebuild. 80 block/head. head shaved .030, FI ex, thru y pipe, glaspak, Chev rockers, 357 cfm 2 bbl on offy c, cam straight up,
( cloyes adjustable) ......thats it....maybe someone like Strange Ranger or the FTF has flow numbers for modded heads.
THANKS!!!!!!

[pssnmn1]

peak h.p. 190@4000rpm peak tq 285@3000

torque stayed aboved 270 from 2000-3750 rpm

i was assuming your base comp is 8.4 if not let me know and i'll correct it

with .030 off the head that should reduce your chamber size to about 70cc
yeilding 8.88 comp ratio

tah daaa

[mutt]

YAYYYYYYY!!!! Im gonna print that out & glue it to the dashboard!

[pssnmn1]

high all bill here,

here are the numbers after a common rebuild and and every aftermarket
camshaft i could find in the in the 250-265 advertised duration range,
although i did use the .050 lift numbers to keep everything even.

the engine
bored .030 over
.010 off the deck and the block
yeilding a 8.82 to 1 comp ratio
390 cfm 4bbl
offy dp
efi exh manifolds

now mind you different intakes,carbs,compression ratios,head work and various headers are going to yeild different results both ways...

so i just used one engine profile.

here goes

stock
h.p. 194@4000 tq 309@2000

stock+1.75 chevy rockers
197@4000 tq 310@2000

napa cep2291840 basically stock replacement center lines are different
182@3500 311@2000

erson rv
209@4500 295@2500

isky mil-a-mor
195@4000 314@2000

isky 256 super cam
201@4000 302@2000

comp cams 252h
201@4000 304@2000

comp cams 260h
207@4500 300@2000

this is an interesting grind i found on the cc website
comp cams 264s-8
215@4500-5000 284@3000


if anybody has any others post the following
duration@ .050
lobe lift and rocker ratio
lobe seperation
and intake centerline

and i'll post it

there you go

[Harte3]

Good work

[pssnmn1]

thanks

[xctasy]

Okay, I've got a really good one for you. I can't find conclusive info elseware.

With the only change being a shorter piston to compensate, take the stock 6.21" rod, and shove an 6.58" rod in it, and then compare the ideal power increase for any application. I recon 3 hp gain at 147 hp stock, perhaps 4 hp gain for any 200 hp modifed combination.


This is a rod ratio sensitivelty test, and it seams to work best when the stock rod ratio isn't very good. David Vizard, Phil Irving and most specialist engine builders have often talked about the advantages, but I've seen no scientific 'apples matches apples' comparisons aside from SAE papers.

[pssnmn1]

it'll take a few i got to work today
but that is a very popular argument among builders.

bill like challange.

[pssnmn1]

lazy jw put a cam grind from reed cams in a basically stock engine

here are the numbers

peak hp 142@3000-3500 peak torque 262ft/lbs@2000

you didn't say if you bored it any so i did with stock bore.

[Lazy JW]

Forgot to mention .030" overbore. Sorry. Won't change much though.
Joe

[pssnmn1]

what was you stock compression supposed to be?
i also forgort to allow for for the porting.

i'll post corrected as soon as i get compression numbers.

oops

[pssnmn1]

ok this the figures for xctasy's 6.21 to 6.58 rod ratio question.

stock engine stock 6.21 rod
peak h.p. 147@3500 peak tq 250ft/lbs@2000

stock engine 6.58 rod
h.p. 151@3000 tq 261@2000

after rebuild stock rod
h.p. 197@4000 tq 310@2000

after rebuild 6.58 rod
h.p. 202@3500 tq 324@2000



interesting changes

[SR_Crewchief]

I'm missing something here. If the rod length is increased .37" don't you need to change the comression height of the piston to avoid hitting the head not to mention valve clearance?

[THE FRENCHTOWN FLYER]

I'm missing something here. If the rod length is increased .37" don't you need to change the comression height of the piston to avoid hitting the head not to mention valve clearance?

YES

[pssnmn1]

yes that's what i did

it took a bit of math
but i got there in the end

[xctasy]

This comfirms exactly what was calculated and discussed.

http://fordsix.com/forum/viewtopic.php? ... highlight=

By 2005, evidence I'd found showed that power increases half the algeriac increase in L/R ratio. So a 6% growth in rod length gives about 3% more power at best. I'm not sure on a dollar per hp ratio, but a longer conrod needs a special piston, and if 4 hp is worth US $2500, then knock yourself out!

[Lazy JW]

what was you stock compression supposed to be?
i also forgort to allow for for the porting.

i'll post corrected as soon as i get compression numbers.

oops

I think 8.5, dunno where it ended up being with the EFI pistons and .025" off the deck.
Joe

[pssnmn1]

ok lazy jw,

final with all the info you have supplied


peak h.p 160@3500 peak tq 274ft/lbs.@2000-2500