SUX2BU:

I wish you were a little closer as a good welder is hard to come by. I can weld. I do a pretty good job at that but I also know that it is an art form. There is so much to know about it that makes the quality and strength so much better.

Easy. Airflow.

Ask yourself this:

If airflow has cooled off the intake charge, what happens to the intake charge after that? Answer: The more airflow that goes throught he intake the more it cools off. How can it possibly heat up if air continously flows through it? It can't It can only get to a certain temp and then be maintained.

I'm not comparing the BBK with the Fast 90. There is no comparison. I would go Fast anyday if I was anything beyond stock and could justify the additional cost. I got my ported TB for $200 and my BBK new for $330. Plus I spray. No cam or heads yet. Cam coming soon. I still think it is a good stepping stone between the LS6 and the Fast.

PS. Again I'm not here to argue. Just trying to shed a little light on a subject that has been beaten to death. The only problem is that it isn't 100% accurate (my opinion).

 

hmm, i dont know HP differences, and i dont care about flow, but the difference in temp after the car is shut off is closer tot he the difference of temp the air going into the engine is, rather than while the car is running, the intakes are working as a radiator of sorts, when the car si running allt he air running through it is pulling the heat away from the intake into the engine, once the car is shut off, its no longer getting the cooling flow and you can get a more accurate idea of how much "heat soak" the 2 intakes accually get.

plastic does not conduct heat, granted they get warmer anything does, but its the head fromt he engine radiating the intake, wheras an aluminum intake works as a giant heatsink it accually pulls heat off the engine to dissapate it acrost its large amount of surfaces

and if i remeber correctly, aluminum is one of the best heat conductors out there in its ability to take the head, and throw it away into the air fast (this last part is the only part that i woudl consider option, just because i tihnk its true, everything before this is hard fact)

that being said, i would take the ls6 intake, i have no non opinionated reasons for this choice so i wont bother listing them

and to be honest its not really fair comparing these 2 perticular intakes because the difference is much more than the building materials, i think that the BBK should be compared to the fast intake, then you would have 2 intakes designed specifically for aftermarket flow and power wheras the ls6, while still designed for flow and power, was also designed as a stock part.

 

i think you made a good point there..im still a N E W B I E to ls1s....im only 17 and im still learning here day by day..i can care less about the "heat soke" debate..but moneys hard to come by especially when i have no job..theres NO WAY IN HELL i would drop that much money on a FAST intake..its just not happening id rather buy a decent flowing power producing intake such as the ls6 or BBK and have some spare change for a six pack. BUT if the BBK DOES produce a little more numbers then the ls6 i would have no problem trying out the BBK

 

Very difficult to read your post but you are way off base. The difference in the temps after the car is shut off is no where near what is going through the intake while running. Drive down the road on a hot summers day with the windows up. Now roll them down, see the difference. There is always cold air running through them keeping the temps down. The temps would not even be close. An intake is not designed to be a radiator. I understand your reasoning but you cannot compare the two. A radiator is designed to move heat and alwways has hot coolant running through it. An intake isn't. LSX motors don't have coolant or oil running through the intake like SBC motors do.

 

After all of these pages there still is nothing more than people theories. The BBK looks pretty good.

 

How bout we all just agree to disagree!

 

I guess my input on this subject is done. I have shown pics comparing the two manifolds, given my input on my heat soak theory & SOTP difference, given video on intake temps, shown my experience in the automotive field, qutoted CHP on proof that the manifold produces more power than the LS6. What else can I do? Nothing. I guess I'll just be one of the few that get's to enjoy what I have and be happy. The LS6 is a great manifold. No question GM finally did something right. I'm just tired of people beating up on the BBK who have no experience with it. It's not the Holley or Weiand by any means.

 

 

if not a radiator then a heat sink, it still has cold air pushing through it, it may not have "fins" but it has the surface area, as for driving with the eindows closed and open is the same thing the air is taking the heat away heat doesn't just dissapear when air moves through it it is only relocated, in the case of an intake, you dont see its relocation because it is thrown into the combustion chaimber.

basically when the car is shut down the air flwoing through the intake is not cooling the intake anymore, its the same thing when you shut down the entire engine, when the coolant stops flowing to cool the engine it also gets hotter
NOW, if coolent WAS running through the intake(post radiator, not post engine) the air taken in through the intake would not be heat soaked so bad since the coolant is taking away much of the heat, i dont know anything about SBC motors but i woudl immagine this is the case, if it pushes coolant through the intake after the motor, then it woudl make no sence, it would be using the air intake as a radiator, and you woudl get heat soak 10x worse than the intake acting soly as a heat sink.

just physics my freind.

and i appologize about typos, typing was never a strong point of mine. neither was spelling or grammer *shrugs*

 

just to clarify this, the bbk is clearly more flowing and woudl give more power, i stated it shoudl be compared to a fast, i was only clarifying my knowlege of physics to all this heat soak debate.

 

Do you have one? Do you know this for a fact? I do. It's not true and I'm tire of saying it. How can you post something about something you have no experience with? What do you think happens as air flows through it? It stays cool. It can't possibly heat up past a certain temp. Period. As you say, the air takes the hot charge into the combustion chamber. What happens with the air after that? It goes through a cooled down intake. Stick your head out the window while driving in 100* temps in Florida. Is your forehead 100*? NO it isn't.

 

im sorry but you really should take a physics class

you want an accurate temp of the alumum peice attached to the heads if air running through it wasnt pulling the heat off the intake? take a heat measurement from the heads whiel the car is running, subtract maybe 10 degrees for the distance fromt he heads. thats how hot your intake woudl be if the air being pulled in was not pulling the heat off all the exposed surface area within the intake manifold

i have no idea where your sticking the head out the window comes into place, you have me lost there,, and after the hot air is puled into the cumbustion chaimber it is pushed out even hotter, through the exhast, but i dont see what that has to do with anything

edit: accually if you are referring to the fact the air is not the temp of the intake you are correct tis far from it i wasnt arguing that, but the air will be significantly hotter passing through that aluminum intake pulling teh heat off of it, than it would be if you were pushing it through an intake that didnt work liek a heat sink, say, a plastic one?

and as for the inake not being hot because the air flows through it jsut agreed with my case, all that heat that should be there is no longer there because the intake works as a heat sink

 

Sounds good

 

Im done guys. Argue all you want. Please do me a favor and don't quote me anymore. I can't take anymore of people who know physics, or any other trade. If you don't do this for a living, please keep me out of the debate as I can't argue with you guys anymore. Most of what you guys are saying I agree is true. It just doesn't apply here as you think it would. Please no offense or hard feelings on my part, I just can't deal with physics or what would make sense based on the materials being used. I need someone with engine building or racing experience to jump in and give his 2 cents worth.

 

They did make me clean up under the hood for the final pics.

 

nomore quoting and this will PROBABLY be my last post as well, but, physics are physics, the rules of the universe dont change for an engine.

 

Guys I will give my observation of the heat soak. When the intake manifold was dynoed for the article the manifold was brought up to temp as they let the car idle for about 7-10 minutes before starting the tests. For the first back to back runs it gained power. The third lost a couple and the fourth lost some more power. BTW - this dyno session was in ~85* heat.

The problem by just looking at those observations, is that even the plastic manifolds start losing power after multiple back to back runs. The car is not moving so the radiator cant get fresh air to cool the engine down as quickly or as well. The other problem in assuming heat soak is the sole cause is that when the engine heats up, the computer starts compensating and pulling power regardless of what intake manifold is on the car. On the street or at the strip this wouldnt happen because the radiator would be working more efficiently. So, in dyno racing after the third or fourth run, the BBK will start losing power, but on the street I dont think this would be a problem.

I cannot notice a difference between the intake hot or cold on the street - that is truth. If there is a difference, nobody's butt meter would know. Running a 160* t-stat or EWP would guarantee more consistent results on the dyno and the street.

What I would really like to see is someone port out this manifold and match it to some big ETP 245+ heads and see what it can do compared to a Fast. As the back to back pics of BBK to LS6 show, there is a LOT of material that can be ported and definitely polished on the inside.

This post is just discussing my personal observations, I dont work for BBK or know any of the more detailed specs of the manifold. As to which manifold anyone should buy? that is up to what the person is looking for out of a manifold and what their budget is. Hopefully more people or shops will start testing with the BBK Intake to benefit the LS1 community.

 

I would vote LS6 manifold. What does BBK offer? Weight is up, cost is up, heat is up...doesn't sound like a good deal to me. Their real reason for making it out of aluminum is purely cost...they can't justify the extra cost of investing in the composite casting technology that GM used or the injection molding process used by FAST ($$$$.) They've been making things out of cast aluminum for years...their initial investments in casting tools have probably been paid off already...that's why.

As far as this heat soak theory debate goes, here is my take on it (based on solid engineering background not just purely speculation or what I read on the internet.) Heat soak is a problem…heat will transfer from areas of high energy to low and will continue to transfer until the system is in equilibrium...that's a fundamental law of heat transfer, not an opinion.

Heat soak does NOT come from the ambient air in the engine bay heating up the intake manifold. Think about it, ~30% of the combustion energy is turned into mechanical motion (in other words, power)...the rest is lost to pumping losses and the majority to HEAT.

Due to the laws of heat transfer this heat has to go somewhere (recall that nature will always try to maintain an equilibrium with its surroundings.) It will be transferred into the cooling system and the block itself. From there the engine transfers its heat to the intake manifold (heat transfer by conduction) because the intake manifold will be cooler than the engine block. Since the air flowing through the intake manifold is cooler than the surface of the intake manifold….going back to the fundamental law of heat transfer (transfer of energy from high to low)…the heat will therefore transfer from the intake manifold to the ambient air (heat transfer by convection.)

If you can limit the heat transfer by conduction (engine block -> intake manifold) you will limit heat transfer by convection (intake manifold -> ambient air) which in turn will lower the temperature of the air entering the engine and ultimately (as everyone well knows) will increase power.

Manufacturers from Audi to Lamborghini and even Honda (and no, not on the NSX) use magnesium intake manifolds in some of their vehicles...why? Even though the aluminum intake manifold will cost less than the high-pressure die-cast Magnesium manifold the benefit of the magnesium manifold outweighs the cost. They choose the Mg manifold anyways because it offers less weight and conducts less heat than Al which in turn leads to lower intake temps which in turn leads to better emissions, fuel economy and power. So tell me again why the aluminum intake manifold that weighs more, transfers more heat and costs more is a better choice? From a design/practical standpoint the LS6 manifold is simply a better choice. Follow the example of the automotive companies...they have put in far more money and research into it than any other aftermarket company..I should know...I do engine development for one.

 

thank you for explaining that in better detail than me, i was never good at choosing words.

 

From what *little* I have seen the BBK does offer some performance gain despite any associated heat soak issues. Now it's time to justify the price. BUT... If I was in the market *TODAY*, I'd probably go with the FAST and the Nick Williams TB since we know so much about that combo producing results.

In the future I would also like to see what a ported BBK would do. I just don't think it's fair to dismiss the product solely based on materials. I mean would you not use one of these intakes because they're made from aluminum?

http://www.katechengines.com/street_...s/DSCF0584.JPG (just the TB's are Al)

http://www.mycylo.com/(23sjl1eedhmcc...e.aspx?id=4999

http://users3.ev1.net/~black_ops/aus/dsc00037.jpg