Questions about Porting heads

[riotwarrior]

Turbo VS Na too different beasts...

NA is all about the velocity maintained with atmoshperic pressure only....Turbo is more about much more pressure and volume as velocity is beyond what atmospheric pressure on back of valve can produce.


This could become a very intersting thread...well beyond what it already has!

 

[IDIoit]

This could become a very intersting thread...well beyond what it already has!

agreed

 

[laserjock]

I'll toss this in. Take it for what it's worth. I was talking to my buddy the other day about this. He runs in the Porsche crowd. Anyway he mentioned that the NA guys spend tons of time and money squeezing every drop out of the heads but he always wondered why the turbo guys didn't. One of the better know forum members told him that basically there was no need on the turbo cars because they just turned up the boost pressure to make up for the losses in the heads.

Without a bench test, or extensive CFD modeling, as you go, the problem is you are guessing (albeit maybe educated guessing). While I think it's absolutely true that smoothing things out may help a little, it's been shown that these heads flow very well in stock form. It's also been shown that boost in excess of 10-15 psi is quite achievable. If you pull it all together at the end of the day, the average Joe will run out of fuel probably long before extensive head work will make a sizable difference. That being said, with the pumps that are coming on the market, that might not continue to be the case.

No reason to limit the conversation to the average Joe type situation though. IDIoit has shown quite clearly that he is far from average. [emoji6]

 

[IDIoit]

No reason to limit the conversation to the average Joe type situation though. IDIoit has shown quite clearly that he is far from average. [emoji6]

this guy, he just called me retarded!

from what ive learned on this thread,
screw the porting, i need to go out and get a set of heads and put em on the bridgeport

think we would see more gain out of hogging out the exhaust manifolds.
hell, makes me want to build a set of headers too!

 

[The Warden]

60 thou is basically nothing!
i can tell you first hand, going from the 7.3 hard lines (which have the pulse bulb, or wtfever it is) to the 6.9 lines with that bulb out of there gave me no trouble.
altho i did install a better IP and injectors.
as long as the lines are the same?
one can easy manipulate 060 out of the injector hard lines.

I've never done any measuring, and frankly I never looked closely at this (didn't have a need to), so I could be wrong...but, from the diagrams and the engines I've seen, when Gary's talking about the injectors being repositioned in the precup, the difference is in the precups themselves. I think the injectors are still in the same position relative to the cylinder heads and to the injector lines. But, as you pointed, 60 thousandths is nothing...and, it doesn't really matter how long the injector lines are, as long as they're all the same length relative to each other. And, keep in mind that a 6.9l injector without the bulb is the same length as a 7.3l injector with the bulb.

I'll toss this in. Take it for what it's worth. I was talking to my buddy the other day about this. He runs in the Porsche crowd. Anyway he mentioned that the NA guys spend tons of time and money squeezing every drop out of the heads but he always wondered why the turbo guys didn't. One of the better know forum members told him that basically there was no need on the turbo cars because they just turned up the boost pressure to make up for the losses in the heads.

Without a bench test, or extensive CFD modeling, as you go, the problem is you are guessing (albeit maybe educated guessing). While I think it's absolutely true that smoothing things out may help a little, it's been shown that these heads flow very well in stock form. It's also been shown that boost in excess of 10-15 psi is quite achievable. If you pull it all together at the end of the day, the average Joe will run out of fuel probably long before extensive head work will make a sizable difference. That being said, with the pumps that are coming on the market, that might not continue to be the case.

No reason to limit the conversation to the average Joe type situation though. IDIoit has shown quite clearly that he is far from average. [emoji6]

I expect that you're right (again, without having really looked into this), although I suppose one could argue that, if the the air flow is smoother, the turbo's working less hard to stuff air in at the same pressure, which might increase efficiency. I have a feeling that that increase would be too minimal to notice, but again, I never really looked.

FWIW (which probably isn't much )...

 

[laserjock]

this guy, he just called me retarded!

But in a good way [emoji6]

Seriously though, this is a good conversation, please don't take my opinions as gospel. Just presenting a side as best I can and with the tiny bit of understanding I have. I'm learning a lot here to. [emoji106]

 

[IDIoit]

now the flow numbers that are posted are at 28" of water pressure.
from what ive read, 28" of water can be converted into PSI.
I.E.
http://en.wikipedia.org/wiki/Inch_of_water
(yea had to bust out a wiki)
so, if 27.7 inches of water equates to 1 psi, are these tests being performed correctly for a turbo application?
what we see are numbers on a low pressure environment, if you add 10 psi, im thinking these numbers would be alot higher!

now another thing i cannot grasp my cranium around (and i never have) is that an engine being diesel or gas, is nothing more than an air pump.
why are we using a non compressable element to test for flow rates on a pump thats being fed compressed air to begin with??!?
maybe its too damn early and my coffee hasnt made it way to the correct places yet, i hope someone can set me straight.

 

[laserjock]

now the flow numbers that are posted are at 28" of water pressure.
from what ive read, 28" of water can be converted into PSI.
I.E.
http://en.wikipedia.org/wiki/Inch_of_water
(yea had to bust out a wiki)
so, if 27.7 inches of water equates to 1 psi, are these tests being performed correctly for a turbo application?
what we see are numbers on a low pressure environment, if you add 10 psi, im thinking these numbers would be alot higher!

That looks like the correct conversion. Not sure but I'm guessing that's a standard test condition.

now another thing i cannot grasp my cranium around (and i never have) is that an engine being diesel or gas, is nothing more than an air pump.
why are we using a non compressable element to test for flow rates on a pump thats being fed compressed air to begin with??!?
maybe its too damn early and my coffee hasnt made it way to the correct places yet, i hope someone can set me straight.

What non-compressable element are you refering to? The 28" of water? That's just an equivalent measurement for pressure, like inHg or PSI or torr or pascals or atmospheres....

Have another cup of coffee.

 

[riotwarrior]

I will add that in Justins and my conversations about the heads he did test, the ported one did not receive any signficant amount of reshaping, his info to me at the time was it was minor bowl blending and port matching nothing to change overall shape/configurations.

The big change was unshrowding of valves from what we discussed. This would play out well in higher revving or forced induction. How it would play on the lower valve lift I'm not sure.

Again without a good valve grind and such those numbers though good may have changed subtle amounts by having correct valve grinds.

Take into account that as I mentioned small improvements in a NA head have different affects in a boosted engine, in essense in theory it's compounded the increase in cfm from NA to Forced induction.

The balance is cost vs improvement.

Plenty of aftermarket heads for SBC and BBC and SBF etc exist and really don't need any touch same with Porshe heads for example, so porting any of these for a small increase of 10 cfm may not yeild much over what they already where, however an IDI with a 10 CFM gain is quite an improvement. If you have the fuel and enough boost, it can have a profound effect on the engine in question.

Just sayin...

 

[BDCarrillo]

Well if anyone feels like scientifically monkeying with ports I have some spare heads with cracks between the valves and a piston kiss.

Shipping cost only, with possibly cutting them down to individual cylinders.

 

[riotwarrior]

Great offer...got heads here too..NO flow bench..ifn I can find a way to MAKE a home made bench I would be very inclined to do so, thus being able to have repeatable and quantafiable data...

Just saying a cheap home made flow bench would be great...

Back in 80's??? IIRC one of the car mags I read at the time, had two article spread on home made flow bench...Hmm..

guess google could locate something a fellow could build...


Anything that gives data would work...a vacuum and slopped tube with a ping pong ball even...just saying

 

[laserjock]

Simple ball air flow meters aren't that expensive. I'm not sure if you want to push air or pull air or even if it matters but you would need to also know the pressure differential between the top and bottom. If someone could tease out exactly what needs to be measured, it shouldn't be hard to come up with a reasonable way to measure it. Even if you are only making relative measurements rather than absolute measurements.