BOTTLE ROCKET

iTrader: (4)

I agree; we would love to see some heads that make geat power without the Corvette (camaro, firebird) Tax, but most would like to see some head to head test to confirm what the flow #s say. If they truely are a head that can produce close to the same #s for 1/2 the price, Dart will CLEAN UP!!

Rookie

I saw a 6.0 dyno sheet at 444RWHP were there any 346 dyno sheets posted with all the necessary info?

I'm also kinda curious how an 11 degree valve angle automatically guarantees a smaller cross sectional area. I see where it could be possible, but the blanket statment that it does is very "internetish"...........................

Fireball

iTrader: (21)

it stretches the runner length. for a given volume, if the length is longer then the x-sectional area has to reduce.

Dart331Stroker

God I hope someday people take flow numbers and throw them out the damm window, flow benches, engine dynos, and chassis dynos do not win races. Period end of story. A very reputable builder who you guys praise on here built a motor using the ET 215 heads and our as cast 225 amde more horsepower, unported out of the box! You guys keep talking about flow numbers, we can change the combustion chamber on the heads to kill 50 horsepower and never even affect the flow numbers. Sewer pipes flow awesome on a flow bench but dont make horsepower. There are so many things that have an affect on the flow numbers, bore size, radiused inlet, calibration of bench, altitude the bench is flowing it both corrected and uncorrected, barometer, I am sure there is something I am missing. Anyways get off flow numbers a decent built engine should make an easy 450 horsepower with the 225 heads. The stock heads even ported have limitations, the chamber needs serious help, and the way they flow when tested at 55 inches with fuel added wont even compare to the Dart heads. If you want to get into flow numbers, then ask people what their heads flow on a wet bench at 55 inches of fluid, this is where the real numbers matter and this is where the reality sets in, what works on this equipment will work on the engine. Period!

P.S. If your goals are higher than the Dart heads for power then greast get the big runners made by ET, AFR whoever, but runner volume for runner volume the dart heads as cast are awesome.

ceo44

Bravo and well said Dart!

Malihoochie

I have a nice pic of our wet flow bench if someone could host it - it is a pretty impressive machine. 55 - 60" is representative of what goes on in the engine when you're on the pedal. 28" is a industry standard that is not accurate once the motor is accellerated. It's enough to make you go !

CBX

Or you can do what I did, buy a fluted carbide bit and some WD40 for $25.00, grind the **** out of your stock heads and cross your fingers.

pdd

iTrader: (3)

Fireball

iTrader: (21)

So you compare a 215 ET head to a 225 Dart

Nate_Taufer

iTrader: (1)

- who did the motor and who did the tuning? Same dyno? engine dyno or chassis dyno? If you have access to both of those graphs that would be appreciated.

Nate

Nate_Taufer

iTrader: (1)

If you search for "ETP" in the dyno threads you'll find a few 5.7 liter results.


The runner is longer because of the fact that the valve is 11 degrees vs 15 degrees and the valve is place farther from the intake opening. based on simple geometry, when you have a longer (not larger) runner with the same port area, cross sectional area is diminished.

I guess simple math is very "internetish" though.

Nate

Ed Curtis

How come when I say this I get nasty PM's from sponsors????

Ed

Nate_Taufer

iTrader: (1)

Because everybody knows that off the shelf grinds are just as good as custom jobbies

Nate

itchygomey98

iTrader: (2)

This is true, so what do you suggest? Maybe we should all just take your word that these are great - never ask for any kind of proof - and pray to the quarter mile gods that our cars are fast. The only things we have to guage the quality of a head are flow and horsepower. Unless somebody wants to spend the cash to run a number of different heads on the same motor on the same day - that's what we have to go by.

Was this an "apples to apples" test? Why not compare a Dart 225 to an ET 225? If Darts make more power out of the box, show us. If somebody really did get these results, there is no reason to hide them. Unless they don't want us to buy Dart heads from them?

I'm not saying that Darts don't have their place. And I really can't imagine Dart releasing a product that is junk. Is it the best, kick *** LSx head right out of the box? NO. Are you getting ripped off? NO. You are getting a set of heads that will make decent power for a decent price. Dollar for horsepower, I wouldn't consider the Darts a bad choice. Personally for me, Dollar for horsepower, the ET's are out of my price range. But if money wasn't an issue - they would be on my car right now.

Rookie

Really? So "any" 12 degree LS-1 head at 215cc will have a smaller mean cross sectional area than a comparable 215cc 15 degree LS-1 head. And therefore if your fuzzy math is correct "any" 11 degree 215cc head will have an even smaller mean cross sectional area than the afore mentioned? Without any regard for port design or shape what so ever? Simply by rolling the valve angle over?

Perhaps you can edumacate me on how an "hour glass shaped" port at 11 degrees and 215cc can have a smaller cross sectional area, than one that is properly designed and shaped at 12 or 15 degrees and 215cc?


I'm just trying to point out with extremes how a blanket statement like that can be incorrect. The reality is we don't really have enough information to say whether or not the cross section is smaller just because of the valve angle.

* Disclaimer: The ET heads I saw at PRI are certainly things of beauty and look to be very well shaped and designed.

BOTTLE ROCKET

iTrader: (4)

Engine and chassis dynos don't win races, but if used to compare several different performance parts like heads, it can give a a good indication of how all the different brands stack up. Not just in peak #s but the entire curve. The vast majority of us spend a lot less time on the track than on the street, and we want low end power instead of just peak #s high in the RPM band.
One thing that is clouding the issue for me, is the apples to oranges compariasons. If the standard, so to speak, for a powerful STREET head has been the 205 AFR head, then how can we compare it to any 215s, and 225s? Does the 225 produce the low end "streetable" torque that most guys want, or are we sacrificing that for "big numbers" on a dyno? (that's not a statement, that's a question)
D331 - If you're saying that the Dart's CC design is what help make the new heads make power, then that should show when we start seeing some hp#s. Don't take any of this as negative, we appricate you sharing the information with us. I'm on your side, If Dart has producted a head that can make the power out of the box for 1/2 the price of the more expensive offering, then they should be commended for doing so. I, like everyone else, don't want to spend any more than "necessary" to get the "best head". That way I can use the rest to be able to buy the overpriced gas and cruise

itchygomey98

iTrader: (2)

I agree. A lot of the parts comparisons I see are not done on a level playing field.

vettenuts

iTrader: (4)

Is it true that Dart is going to another spring setup from the PSI currently being used? (Saw this in another thread and I was going to pull the trigger on a set this weekend).

Malihoochie

The post titled "dart as cast test" should be of interest to those of you asking where/what/whose dyno? Wheel to Wheel has built many very impressive LSx motors and even hold a record or two.

Itchygomey98 - Unfortunately the end user is somewhat stuck, because dry flow #'s (which mean next to nothing) get rammed down everyones throat. These flow #'s that get tossed about often are not equal comparissons (25", 28", inlet pipes, inlet radius plates, radiused clay, w/ exhaust pipe, w/o exhaust pipe, difference in temp., etc.) And no, most people can not afford to test every head, so the masses are trapped trying to make sense of flow #'s that usually don't tell the whole story.
BTW who does have the best, kick *** LSx head right out of the box? And how do you compare them? Dart chose to produce a as cast head to rival the cnc'd offerings by AFR & ET so the average guy could keep some $$$ in his wallet while benifiting from our experience making racing cylinder heads. And from our feedback - so far they are doing just that.

Vettenuts - There is another spring that is being considered, it is capable of more lift, but all the current heads have the PSI #1511's. The current PSI's are a great spring, but I can see why you might be looking to wait for "the next thing" if it is gonna "fit" better with your over .625" lift cam. If the spring change happens - I'm not sure when it would take place.

vettenuts

iTrader: (4)

Thanks for the information. Is Dart considering another beehive design or moving to a dual spring? I have also read some information from PSI and am not sure why they made a statement on the 1500 series, here is what they state:

"15000 Series

This series has all the benefits of the 1200's plus an additional nitriding operation. The nitriding operation, which is also done in house, increases the strength at the surface of the wire and at the same time causes a slight softening of the core material. This trade-off in hardness results in a gain in endurance for the Circle Track and Road Racing Circuit teams who are limited by the onset of fatigue at the wire surface. Since drag racers are not limited by endurance, the loss of core hardness does not make nitriding suitable for their applications."

Based on this description, this sound like a good approach for a street driven car since it sounds like the fatique life is increased. However, since the peak stress is on the outer surface I am somewhat confused unless the fatigue life curve is favorably altered through nitriding. I am confused on the last statement with regards to drag racing.

However, overall they look like really good springs unless the fatigue curve doesn't support the cycles from a street driven vehicle. These looks just like the Isky beehive springs made by PSI, does anyone have any experience with them as far as longevity?