Irocss85

iTrader: (1)

ok, i ported one int and exh. port, took the head to ET performance, had them flow test that cyl. and critic my work. even give me pointers on how to do the rest of the ports same or different. he recomended I get a valve job and mill the heads. but the port work was pretty good for a home job (only 2nd set Ive ever ported). I was happy with the initial flow #s being.

I E
.100 91. 83
.200 168 125
.3 223 157
.4 268 180
.5 272 196
.550 277 202
.600 281 205
.650 285 210

now this is before the valve job/milling. after I finished all the ports(some 5 weeks later), brought them in and dropped them off and had the valve job done and reflow same cyl. (supposedly) which is cyl. 3.
and got totally diff (lower) numbers. these

I E
.100 65 54
.2 143 106
.3 206 141
.4 245 166
.500 248 183
.550 254 190
.600 257 194
.650 262 198

thats around 23 cfm on the intake side and 15cfm exh. side drop on average, all the way across the board. so either one of the tests were flawed/not accurate (possible wrong bore size on first test? its not noted what they used, and they wrote 4.8/5.3L head, sec. test says 3.9 bore) or, could the small step created when the valves were sunken in for the valve job created that much drop in cfm? I expected a little at low lifts, but not that much all the way across the board like that. I have since gone back and blended in the valve job (on both sides of the seat) as suggested by cary. that should help pick some back up, but I expected to gain some low lift #s, not lose . Im goin to take it back, for a third flow test, and see whats up now. too bad its gonna cost another $75. they were nice enough to do the second test for free for me (thanks ETP!) since I was spending some cash with them.

just wanting to hear some opinoins on what ya'll think of this, and if the loss is directly related to the step in the chambers around the valve seats created by the valve job.

chris

Studytime

iTrader: (15)

Chris,


https://ls1tech.com/forums/generation-iii-internal-engine/587011-ported-my-heads-getting-valve-job-should-i-use-aftermarket-valves.html

I'd forget the first numbers they gave you. I honestly believe they are erroneous. Look at the flow at .300". That's off-base for a home-ported head with stock valves and with the stock valve job. I wouldn't want to accept that if I were you, but look at the results AFTER a valvejob. A good valvejob should only help low-flow numbers. Your low-flow numbers were down and peak flow numbers were down.

There's also the chance your heads got mixed up with another set / someone else's flowsheet.

Good luck,
Ben T.

Irocss85

iTrader: (1)

holy crap thats one hell of a memory you got there ben. lol. I figured Id ask this in a tread just for this, to get more idea's. I will know soon though as Im goin to get them retested again. as for the getting the wrong flow sheet, I doubt it due to how the flow#s follow the same curve. what about the after vavle job #s? these things just barely outflow my LT1 heads that I also ported a couple years ago, w/o doin a valve job? cant see how that would be possible. esp. since i didnt go that extreme on those, and didnt even raise the roof enough to expose the rocker stud holes.

Tony Mamo @ AFR

iTrader: (13)

Throw away the first results....something was wrong with the test.

The .100 and .200 numbers on the intake tell the story. They are both essentially impossible to achieve thru anything less than a 2.300 valve, and even with a valve that big are pretty damn good. Check out my flowthread for an overview of mixed numbers for a Gen III head....you will see some figures that are all over the map, but NONE of them are in the ballpark you are quoting in the lower lift ranges and Im surprised whoever conducted the test didnt stop to see what was wrong when he or she recorded the numbers(missing sparkplug, too weak a spring on the exh valve and it was slightly opening skewing the results which is actually a fairly common problem).

I will post a link later....no time now

Tony

Irocss85

iTrader: (1)

id be interested to see your thread when you get a chance to post the link. and, I myself thought something was weird when I saw my chart and compared it to what the pro's were getting down low. figures though. hopefully I'll get the last test done in a day or two so I can see my final results after the blending. however Im now not expecting to see the first test results again.

Tony Mamo @ AFR

iTrader: (13)

Here is the flow info copied and pasted from my thread. Note these represent the better of all the Gen III heads I have tested....the list would be twice as long if I included all of them. Most of these heads have larger valves as well so keep that in mind....(and still didnt muster the results you initially got which were/are essentially un-attainable). Just focus on your real baseline (the last test) and try to learn and progress foward from there.

Here are the numbers....

INTAKE FLOW

Head…………Int. Valvelift…………………..........Runner
…..….200….300….400….500….550….600…….Volume…………Comm ents……….

“A”….136….199….257….294….305….313………232 cc’s
“B”….134….195….239….267….280….289………229 cc’s
“C”….131….189….240….275….287….282………221 cc’s…(LS1 castings)
“D”….141….206….259….291….303….313………231 cc’s
“E”….145….203….253….295….309….321………246 cc’s….Stg 3
“F”….141….206….263….300….315….332………245 cc’c….Stg 3
“G”….135….201….260….304….316….”T”………239 cc’s……Stg 3
“H”….140….211….260….285….286….287………243 cc’s……Weak for size
“I”…..137….207….252….290….306….318………242 cc’s……Stg 3
“J”.….126….186….231….263….277….290………228 cc’s
“K”….121….190….246….278….293….306………230 cc’s
“L”….146….208….264….301….314….323………237 cc’s.Stg.3 (good overall)
“M”…137….207….252….290….306….318………242 cc’s……Stg 3
“N”….136….190….249….288….301….312………241 cc’s……Stg. 3
"O"...147....213...264...300....308...304..... .249 cc's.....Stg. 3
"P"....144...205...259....299....316...330......24 9 cc's....Stg. 3
"Q"....129...200...258...295....305...308..... .232 cc's
"R"....135...200...251....293....311...317......25 4 cc's....Stg3 (BIG!)
"S"....148...200...247....289....301...304......23 1 cc's...LS6 head w/ 2.02
"T"....132...195...240....283....296... "T"......227 cc's...LS1 head w/ 2.02
"U"....136...194...248....267....275...281......23 4 cc's....5.3 head/weak #'s
"V"....128...186...238....274....287...293......23 1 cc's
"W"...141...206...256....299....315...324..... .236 cc's ...LS6 Casting/Good#'s
"X"....143...207...265....298....313...."T'......2 40 cc's....Ported 6.0 Casting
"Y"....136...197...242....281....294....293.....23 0 cc's...Stg 3 (soft #'s)
"Z"....137...211...270....310....324....336.....24 0 cc's ..New "Best" peak #'s
"a"....138...205...259....295....304....309.....25 4 cc's ..CNC Ported Dart/BIG
"b"....160...240...305....342....N/A....368.....2XX cc's ..."b" for BAD AZZZZ!
"c"....141...214...267....303....306....311.....21 5 cc's....Very good #'s (11')
"d"....138...215...264....304....317...."T"......2 29 cc's....Rolled Valve (13.5')

AVG..137….200….252…..289….302….308....…237 cc’s

AirFlow Research #’s
205….145….210….257….290….301….308………205 cc’s...(205 w/ 4.125 #’s)
225….151….221….270….306….315….322………229 cc’s


EXHAUST FLOW w/ 1.875 pipe (curved to simulate header)

Head………….Exhaust Valvelift…………………..Runner
……...200….300….400….500….600............Volume

“A”….113….150….180….208….230…………….84 cc’s
“B”….107….147….196….218….228…………….85 cc’s
“C”….107….153….184….205….217…………….82 cc’s
“D”….112….165….195….215….228…………….86 cc’s
“E”….111….156….202….235….246………...…88 cc’s
“F”….126….170….204….226….236…………….85 cc’s
“G”…117….164….201….229….242………………87 cc’s
“H”…113….156….189….221….231………………85 cc’s
“I”….114….145….179….211….237………………87 cc’s
“J”…..97….133….166….193….213………………89 cc’s……Very weak for size
“K”….117…157….194….218….228………………83 cc’s
“L”….114….155….214….238….252……………..90 cc’s……Big, but good #’s
“M”…120….177….219….240….251……………..87 cc’s….....good #’s
“N”….105….144….177….208….222……………..89 cc’s……Very weak for size
"O"....115...166...202...228...241............ .88 cc's
"P"....116...163....211...236...241........... .84 cc's
"Q"....109...156....208...224...227........... .89 cc's.....Weak for it's size
"R"....113....156...195...227...241........... .91 cc's......(BIG!)
"S"....108....146...188...226...235........... .84 cc's....Soft low/midlift #'s
"T"....120....171...200...217...224........... .84 cc's...1.570 vlv, good low#'s
"U"....111....147...189...209...224........... .84 cc's
"V"....111....144...168...186...194........... .86 cc's....VERY weak Exh #'s
"W"...126....177...215...230...241............ 82 cc's.....Good #'s
"X"....115....150...177...194...208........... .89 cc's....Very weak for size
"Y"....119....160...182...195...200............83. 5 cc's..Small port/Very soft #s
"Z"....117....170...215...241...253........... .95 cc's.....BIG port / strong #'s
"a"....114....153...193...220...233........... .90 cc's.....BIG port / avg. #'s
"b"....120....176...205...221...230........... .XX cc's.....Needs MORE!
"c"....118....164...207...232...245........... .96 cc's.....Good numbers / BIG
"d"....110....174...213...231...240........... .84 cc's.....Good #'s

AVG...113….157….194….219….230…………….86 cc’s

AirFlow Research #’s
205….118….171….206….226….240……………..84 cc’s
225….120….180….220….241….250……………..85 cc’s

Hope this info helps you out...

BTW....A realistic .100 lift # on the intake port would be between 68-76 CFM or so....obviously my test results featured here starts at .200 of lift

Good luck,
Tony

Irocss85

iTrader: (1)

cool. thanks. do you use a superflow like ETP's? wondering if the #s are comparable like that or would be slightly diff. cause if they are comparable, then it turns out I got pretty good low lift/mid lift #s for stock valves, and prolly a small port size. I didnt do much reshaping of the ports, so Im assuming I have a small port. what could be done to help out .500-.650 lift #s that I prolly missed? obviously bigger valves would help, but what else? and on that note, what size would you feel is the right size for stock short block LS1? 2.02Int. valve? the next set I'll try and improve upon this port shape.
BTW, i dont think there was a pipe on the exh. side. not noted on the chart.

thanks for all the help tony and ben.
chris

Studytime

iTrader: (15)

You already got the easy gains, further gains are going to be tougher. They'll involve a flowbench and further reshaping the short side radii.

Ben T.

Tony Mamo @ AFR

iTrader: (13)

Dont have much time to get into any real detail (heading to PRI for the next week), but what Ben had to say was correct and I would add that enlarging the bowl a little (shaping it correctly) and the right valvejob profile can net you a reasonably small port (215 cc ish) that can flow somewhere in the 280's with solid low and midlift flow.

Much further work from here though requires small moves and a flowbench to guide you if you dont have alot of past experience to draw from.

Good luck....try to enjoy the process

Tony

Irocss85

iTrader: (1)

whish i had a flow bench and a couple extra sets of heads to play with. I'll keep all that in mind next time around.
chris

Beaflag VonRathburg

iTrader: (176)

I've seen some threads here and other links online where people have built their own flow benches rather cheaply. Might want to consider that if you're dropping $75 every time to get them flowed at ETP.

Irocss85

iTrader: (1)

actually, got them retested today. a big thanks goes out to craig at ET Performance for helping me out. and he didnt charge me to reflow them. twice. he even took a stock valve, cut it for me at a different angle just to see if it would produce more flow out of my port. if you see this thread, thanks man.
I was still too scared to open them up, but I did clean them up better through out, blended in the ridge left behind from the valve job, did much better job blending back and opening up the throat of the valve seat into the chamber, took the guide down a bit more then before. gained around 5-10cfm everywhere except max lift.

here's the new #s.

.100 70.3 54.7
.200 150.9 111.2
.300 2.8.6 151.1
.400 250.1 179.5
.500 253.3 194.1
.600 261.9 202.5
.650 263.9 205 w/o pipe

its too bad I didnt get any better high lift #s like I wanted, but Im sure these heads will do just fine. not like this is a competition engine or anything like that. next set I'll make the ports wider and see what happens. I'll add some pics later.

I highly recomend ETP for there great customer service.
chris

Irocss85

iTrader: (1)

these first two are actually a port in my next set of heads, but it matches this set. thats why its not clean, valve jobs not done, not milled, chambers not clean, ...

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this is a pic of the head. just no good pics of these ports yet.
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