thoughts????? - odd combo flow help

[Otto]

OK heres a sheet for a current build just some thoughts from someone else on what i am seeing i know there is str flaws of course using the new pts 12 blower bench for the first time.

Comments or suggestions on the sheet are welcome also.

[Otto]

sorry check this sheet might be easeir to figure out by looking at page 2

[bruce]

Looks ok to me, I did not look at each formula though just a general look-over of the sheet.

[FTCH]

Otto, I am probably missing the question,
However if your asking about the sheet and what I would add I would want.
Name
Head Type
Runner length
Runner Volume
Engine cubic inches (bore stroke ect)
Bowl size, Minimum crosssection, entrance size, manifilod ent size,
I also like average low lift flow, mid and high.
If you end up with dyno figures all of this information become very handy.
Looking at the flow figures, it would be good to have more information so as to be able to make a comment.

I do like what you have done, its very good, I would just want to add to it.

cheers
FTCH

[FTCH]

Entry Probe pressure FPS
13 12.3 14 238.69 232.17 247.70
10.7 11.5 16.4 216.55 224.50 268.09
12 11 17.9 229.32 219.56 280.08
STR Probe Pressure FPS
9 17.3 10.3 198.60 275.35 212.46
12.7 17.5 12.4 235.92 276.93 233.11
32 38 27.3 374.48 408.08 345.89

Average STR 284.5369126 Intake
Average Entry 239.6281973 CFM
Could you please explain this a little more please, like does the entry probe mean port entry and the reading are taken top, middle bottom?

cheers again
FTCH

[Otto]

being a hd aftermarket head entry would be manifold gasket surface probe from left to right top to bottom just layed out with a custom flow staightener basically a extra section from custom biuldt manifold and then probed at the turn
i should add actual measured dimensions not having that sheet in front of me i believe IN CL port lenght 3.75 seat ID 1.850 with a 1.800 round port entry manifold runner has a 2* taper
the averaged readings in FPS are of all 9 readings in each position

[Otto]

some rough early Pics

[Otto]

Like i said these are early pics i know there is some turn problems and high lift deficiancies this pic shows some of the flaws in the early stages

[FTCH]

Thank you Otto, I am going to write a little on exhaust ports on the thread I have going, maybe a couple of things to consider.

cheers
FTCH

[Otto]

my problem with this particular combo has me alittle concerned because of the total package
4-1/8 bore 4-1/4 stroke 7.680 rod lenght 11.2:1 static comp
intake 263 dur with .645 lift LC 103 ex haust 266 .615 lift LC 105
in my eyes it already has more air flow than it really needs for the street but then to correct some of the problems that (poor high lift numbers & odd intake velocity readings) still exist it will be worse but vehical owner wants it maxed out. And of course the exhaust port is alittle lazy but runable I.M.O.

[larrycavan]

Otto

If it were me [and I realize it's not] I'd put some more radius on the intake bowl. If you have the material to do so or a junk head to try it on, getting back under the seat will make generally make the CFM pick up at upper lifts.

I know a lot of people say to taper it down up toward the seat. I have multi cylinder 2V engines that will scoff at that theory though....

JMO - Nice work, thanks for sharing the pics and data:D



Edited By larrycavan on 1217554980

[Otto]

thanks for the input heres a sheet done from the begining to the point of photos done with the old bench stock as cast and then cleaned up. which promted the new bench build poor little thing just couldn't pull anymore air so it got retired to the rafters so to speak

[FTCH]

Yes larrycavan if I read you correctly, I dont like to taper it down to the seat, quite the opposite. My view is as something contracts, airspeed rises, static pressure drops, As area expands, air slows, static pressure rises, Higher static pressure likes to move to lower static pressure, pistons like to creatate low staic presuure.

if I read you right
cheers
FTCH

[Otto]

well i have the intakes straightend away well enough but the exhaust is still poor IMO there is more to be had but with evening out the in velocity profile. by adding a little width at the turn and squaring up the floor abit and of course getting rid of a couple of minor flaw lines on STR now if the exhaust would just jump i would be really happy