Whats the price going to be for a complete set with a 650 lift springs?

 

In that 40 or so heads shipped (mind you with sbc valves,etc) I wish someone would slap a set (out of the box) on something that has been dynoed for a heads only comparison.

I currently have an LS1 that I am looking at and the stock heads lifted at around 10 PSI.

Thicker deck + larger valves + reasonable $$$ =

Under 1 hour with the polishing rolls = pretty nice looking chambers

A little bowl work and port clean up and it looks like a nice high perf street head (and maybe better).

Seems like a winner for at least a good portion of the LS1 market.

my 2 cents

 

I have a 402 on the dyno that we have been trying some cams and two different heads on (317 6.0's and 862 5.3's by ET). I will try and run the Darts on Monday to compare.


Kurt

 

Workin on that man.... got other things in the shop to do as well!

 

While no one is obliged to do anything, I just thought that by now someone would have.

 

You might be looking at turbulence in a different light....I don't believe that statement is true, there are allot of heads out there that get turbulent but still make great power. If you get turbulent on a flow bench at a given lift, lets say .590" but then you bolt the manifold on and it is clean to .700" would it make a difference in power if it had pulled clean to .700" without the manifold? Now take this exact same scenario and only give it a .550" lift cam....what is the problem with the turbulence and .590"?

 

I thought the Darts only had around a 1/2" deck??? If so, that's not a thick deck guys! The AFR's and ETP heads I believe are around 3/4".

 

how do these compare to LS6 heads ported in the same manner?

http://users3.ev1.net/~black_ops/hea...2009-09-03.htm

according to this, very similar with LS6 heads having a hair more midrange.

 

I didnt say that a head that stalled or got turbulent didnt make power. I just said that the head should increase flow under optimum conditions. For a head to get turbulent without an intake, and be clean with one, would be unrealistic. Intakes can make airflow worse going into the head(compared to a flow bench), not better. Bottom line, if a head flows well at a given lift and maintains good velocity, it will make power, stalled or not. I think Jason at thunder proved that a few years ago, when he cracked 500whp with a head stalling at like .550

Brandon

 

How much time have you spent on a flowbench? It can and allot of the time will clean-up, because the intake doesn't allow the full airflow potential of the cylinder head it doesn't go turbulent.

 

Less airflow doesnt change the characteristics of the port. Unless you are talking about crippling the flow of yout head, its still going to stall or become turbulent. Most of the LSX intakes hold about 90% of the cylinder head potential, up top. With that same 90%, you are going to maintain the same events in the runner. How much time have you spent on a flow bench?

Brandon

 

You gotta look at the base material and the heat treatment..... The Dart is stronger because of that, you really dont need .750 deck thickness anyways.

FWIW on the turbulence.... If you have any at all you will make more power without it. If it goes away with a intake on the head, then you aren't moving enough air thru the head, turn up the bench and see what happens, betcha it will come back.

Bret

 

Agreed Bret. Thats why alot of the best guys test flow from 25-30". No matter what you do, an engine pulls more air than a flow bench anyway. Especially in the larger bore motors.

Brandon

 

What are you talking about 90%???? So if a head flows 200cfm then through a manifold it will go 180. But then put a really nice ported piece behind that same manifold that flows 350cfm and now it goes 280??? What if that manifold is only capable of 250cfm, why would there be a 10% loss....that is like the 15% drivetrain loss I guess some random internet number that is close to correct for the average guy because the average guys are making the same number....

Take your 10% and apply it to this: A Fast 90mm intake was bolted to 3 heads the first flowing 308, the second flowing 326 and the third flowing 341 all before this manifold. Bolted on the intake and the numbers were 280, 286, and 290.....hmmmm, not 10% loss, maybe because the manifold was MAXED out. Which is why the manifold can clean-up the flow, you have a larger opening (I.e. valvelift) with less air having to go through it (Because the manifold is restricting it), therefore you don't have the same turbulent effect as if you simply had the head there. Feel free to tell me I am wrong Brandon, after all you are a local cylinder head porter that has his own flowbench, right? If you do, we wouldn't be having this conversation.

 

You dont prove anything with that previous statement. I said about a 10% as a ROUND number and stick to it, maybe I should say 10% in case A, 12.75% in case B and 16.44555% in case C. No doubt ANYTHING has limitations. Would you now explain to me why a 300 cfm head makes less power than a 330 cfm head, even through a LS6 intake? Obviously it isnt possible to flow anymore air, since the intake gets "maxed out". I get what you are trying to say, but you are wrong about an intake relieving turbulence. If your head goes sour at .500 lift with 320 cfm, it will do the same with 280 cfm. Not saying it doesnt produce the numbers you say it does, the flow is just more chaotic doing it. Do I have a flow bench, nope. I mess with heads on the side, and btw, dont claim to be a pro. However, I do have a bench at my disposal, and use it frequently.

Brandon

 

Meanwhile ... anyone seen any Dart heads floating around?

 

I love linear thinking, applications to extremities to prove a point and arguing technicalities.

Being the local head porter, you'd think that you would try to be a bit more... professional. If you are as good as you think you are- well, I'll just say that typically I've found that those who use thier assumed expertise to prove their expertise (yay circular reasoning) tend to lack it.

 

Wow, you have a problem with my "Assumed" expertise, by what, doubting me with yours? tell me what I said is false, who cares? Prove it....

 

I understand your way of thinking, but why would that same port go south with less air moving through it, the air is not as tightly confined, it isn't as fast, therefore is less sensitive and less likely to go turbulent. Stop telling me I am wrong and just test it, I will be right, trust me. Enough theory, tell me you have done this and I am wrong, PLEASE! I will gladly admit this may not happen in all cases, but it has happened everytime I have done it.

 

First off, what is "real" is simply a conclusion you deem necessary to be true because the data came up with because the evidence/data supports it.

For example, let me draw a parallel. He fell over, therefore his drunk. Although falling over may indicate intoxication, it is not enough to come to that conclusion. I am not saying you wrong (you incorrectly deducted that as well), but one is not enough to claim the other. Because you found volume flow numbers to decrease significantly by bolting on an intake manifold, you decided that the intake manifold was the major source of pressure drop/restriction. A bottle neck if you will. But what if the intake manifold, on a flow bench, could flow 375cfm? (by the way, I doubt an intake manifold is more restrictive than a 2’’ valve opened 0.550” but again, who cares?)

This “bottle neck theory,” however, is not the only explanation for why the head flow numbers dropped. What if the intake, when joined to the head, created a massive amount of turbulence. What if, a hundred other things. But whatever.

Second, you cant ******* multiply. If you are going to call someone out for having unrealistic numbers in the manner you did, at least multiply correctly. 350* 0.9 = 315, not 280. That’s not even a typo. You don’t fat finger or miss a decimal place when trying to type 315 and end up with 280


Second, your numbers


280 is 9.1% 308
286 is 12.2% of 326
290 is 14.95 of 341

Doesn't seem like his 10% is unreasonable. Certainly its not a constant number but he expressed that here. The 280 range is also a fairly reasonable number to be working around.

and I made that assumption on my own, before reading that.

In just the same way no one ever said 15% was some kind of God handed magical powertrain loss number- but for ***** and giggles, its pretty damn close for a manual and good enough. But what you are saying is that there is some hard fixed number that it just wont flow past, and (in continuing the parallel) there is a fixed powertrain loss with a given powertrain.
Very few things are constant. I guess to be accurate, I’ll start factoring in the effects of slowing of time due to changes in velocity when calculating my commute time.

The main problem I had was you calling out the stupid 10% when that wasn't his point in the whole post. What he is saying is that the addition of an intake to a turbulent head is not going to increase the flow/ make airflow more laminar.


Let me draw another parallel.

"I was walking down the street and saw this guy, 6'4'' in a suit. Not very normal for a guy to be walking down an abandon road with suit on so I turned around to offer the guy some help. turns out it was Michael Jordan and his car broke down! He was looking for a lift!"

"Michael Jordan is 6'6'' so therefore, you are wrong and it was not Michael Jordan"

A minor detail which is irrelevant to the point being made.

Anyway,
Id have to agree. Typically- adding length is NOT going to make it more laminar, although it is possible. To bank on a manifold to reduce turbulence in a turbulent head is rather brave without CFD. that’s just my two. Typically something that creates more head loss will increase turbulence, not decrease it. Or so my fluids project said. Length usually does the same. But I'm not a fluid dynamics expert, or nearly as smart as you, so I'll leave that up to the experts.

the technical accuracy of whether or not an intake manifold will increase or decrease turbulence at .550 lift wasn't why I made that comment. My comments were based on your calling him out on the "10% loss "thing and ignoring the other 99% of his post, which included his point.

I guess what I'm trying to say here is- I really dont care what you think about the intake manifold as a restrictor or relief of turbulence or whatever you want to say. I probobly wouldn't take it too seriously anway. I just though it was funny that you were being a jerk about some small point while abandoning the gist of the conversation and didn't even bother to check out the numbers

Regardless, I just thought your comments were funny I'll listen to the smart people continue to tell me how dumb I am now.