Interesting and very informative. Better flow, cooler air, more air but something is missing I just can't remember what it is.

 

I strongly dis-agree with this whole premiss of the IC being only partly used. Absolute rubbish fellas!

***under boost*** The lower plenum and therefor the IC reaches a equall pressure. On a pressurized air chamber the intake port and the blower exit is very close to being the same pressure. Velocity is NOT. But the pressure IS. Remember air is highly compressible.
When each intake valve opens and the pressure from this large pressurized cavity is allowed to flow... then the velocity at a given point in the IC increases. And that point would be the closest to that now open valve. It would NOT pull air only (or mostly) from the leading edge/area of the IC. Under boost conditions it's all about delta P.

I speculate that the Apten port job is truely a modification that make the blower more efficient. Efficiency for this conversation being defined as rpms put in vs air flow and air temp put out. It simply is more *Efficient*. Not the IC.



It's this kind of reason why we "bench test" designs in the first place. You cannont measure IAT2 temps and conclude that one component in a SYSTEM is affecting another. To get an apples to apples understanding you have to look at the apple itself. Not the poop that comes out the other end.

Rich

 

Sorry Rich, I disagree with you. I understand exactly what you are saying, but as much as we would all like to believe it, things don't always happen in the real world as they do in a lab on a bench. I learned that as a dealer tech, having to talk with engineers on the Ford hotline. They knew exactly how things were "supposed" to work, but they rarely worked that way .

Case in point... I have two trucks here with the blowers off for porting. Both heat exchangers on these trucks are much cleaner right under the blower outlet, than towards the rear of the blower. If the outgoing air from the blower truely was evenly distributed through the intercooler, then the top of the heat exchanger would have a uniform finish, and not have a nice shiny area under the outlet port.

 

What your seeing is a residue from the high vacuum situations. NOT the positive pressure situation that I clearly stated.

"***under boost***"



Sal with all due respect. I've got 8+ years of fluid and air handling experience. Including intake manifolds for Ford. Not just text book training. I fully understand how the "real world" works.

Rich

 

I'm with kerno on my line of thinking.

Would it make sense to say that the greater velocity of the open part of the blower pushes more air over the front section of the intercooler, but the area under the intercooler where the valves reside is under the same amount of pressure? So both arguments are correct.

I would assume the restrictive intercooler slows the air velocity, along with a lower intake design that aids in even distribution? otherwise the high velocity over the front part of the intercooler only theory would make the front cylinders run leaner.

 

yes the IC is not being "partly used" in a ported or unported applcation. It takes what the pump sends it which is more mass in a ported application,...more air per piston stroke

 

So what you're saying is that you can't imagine a more efficient blower with lower dicharge temps, in a non-intercooled application?

Testing stock vs ported blower without an intercooler would show which blower had cooler discharge temps

 

Rich, don't take my posts as saying you are wrong. I am just posting my experiance, and what makes sense to me. When I see something, I like to know what caused it. I try to use my own knowledge to figure it out, but I don't know everything, and I certianly don't have your airflow dynamics knowledge. I welcome your (and any other experts) repsonses to tell me why my theory is wrong, so I can learn myself. But I will continue to debate the situation until I hear an answer that makes sense to me.

You are saying the 40 degree drop in air charge is from the porting making the blower more efficient. That means you are saying the air charge out of the blower is 40 degrees cooler. Can you explain how it has become more efficient? The rotors have not changed, the clearances have not changed and the rpms have not changed. What's your thoughts on that?

 

Great thread BTW. The old text book/lab vs. real world war. I too have an Engineering degree and this war frustrated the pi$$ out of me in school. Keep in mind that most of respected authors of texts are Professors in graduate programs. Lifelong men of science and most likely couldn't function in the real world. Hell, we asked a Chemical engineer one time to explain what octane ratings meant for us at the gas pump (before I had the L). He rambled on for minutes going down to chemical formulas and chit and never said "resistence to self combustion".
Please no one jump in an bash anything on this thread so the debate can continue. It is very informative to have maybe two of the best on both sides having a conversation about this issue. We all win.

BD

 

....well.... yes I cant imagine it.... the blower is a positive displacement pump that takes a fixed volume of ambient air per revolution and the mass air flow is determined by the induction into the blower and the "mass"will not be affected by anything downstream of the rotor .............but, the intercooled application reduces temperature and pressure for the exact same mass of air...so you still get the same mass but its easier to put as you are pumping the same mass at a lower pressure... in a non-intercooled application it will pump less air than an intercooled application everytime.



stock vs. ported discharge temps

I dont know what the compressibilty is for throttled air but I do know what it is for an Ideal gas and with a pressure drop there will be no change in the amount of heat contained in a given mass quantity of air, but since this constant amount of heat is expanded into a larger ported blower, due to the drop in pressure the temperature would drop....but of course oxygen and nitrogen are not Ideal gases....so this fact will not apply.. so I would have to go back to my stance on the IC being the culprit for the ported blowers HP increase....

 

good point, no bashing ... sometimes engineers dont have the patience to answer questions and get very defensive when challenged.....Rich is not like that and from what I have read seems like a pretty sharp guy

imfamous quote: Engineering is the art of not constructing......of doing that well with one dollar what any bungler can do with two after a fashion.

 

Yes I believe so. I've not done the bench testing to find out. But YES this is exactly what I believe.

Friction. It now takes less energy (heat is the result) to move the air through the ported blower assembly. I'd also look for a decrease in torque required to spin the blower after a "Apten" porting job.

I am of the (unverified) opinion that the HP & TQ we all see on these ported blowers come from a combination of: less power consumption to spin the blower, cooler output temps, and more air being moved (at the higher rpms).


One very interesting side note: My eaton had 10mm thick walls at the openings before being ported. But yet the overall generall wall thickness was 4.5-5.0 Generally speaking an aluminum casting would NOT have that big of a thickness difference. Kinda makes me *guess* that someone at eaton gave us "a little somethin somethin" to have fun with. Or maybe.....?

Rich

 

I see. So you're saying there's less resistance on the rotors because after the air is compressed there is a larger hole for it to exit. So there is basically less backpressure on the blower, that it would normally be fighting against. There is no increase of incoming air, as the rotor setup is the same, but it's easier for the air to get out. I guess that would be like opening a restricitve ehxaust port, without changing the cam. You are trying to move the same amount of air, but it's easier to get out now, so your EGTs would drop (in the exhaust port example).

Am I understanding correctly? That would make sense to me.

 

Very cool observation. Makes sense, but with my manufacturing management experience now, I can add this. I doubt and haven't seen a plant where the tech people pulling stunts are allowed to get away with it. Engineers usually lose in name of money. The extra cost of that extra casting thickness would be significant to the bottom line, especially in today's metal markets. It would take a snowed over GM to allow it. Anything's possible though. I need to go over to Eaton and be a hero on their costs!

BD

 

Great thread ... Keep it up ...

The bean counters have taken over the design of just about
everything. One of our products suffered an almost 40 percent failure because a plastic part was spec'ed to save money.

They broke unfortunately.