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Dart 180 cc alloy head as cast

General engine tech -- Drag Racing to Circle Track

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digger
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Re: Dart 180 cc alloy head as cast

Post by digger » Fri Nov 29, 2019 5:34 am

i think when you compare two ports/runners of differening size but similar efficiency what happens is essentially better cylinder fill on the 2nd half of inlet period and less reversion in the due to higher amplitude inlet wave of the smaller runner diameter. moreso than whats happening while piston is moving down.

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Re: Dart 180 cc alloy head as cast

Post by zums » Fri Nov 29, 2019 7:41 am

digger wrote:
Fri Nov 29, 2019 5:34 am
i think when you compare two ports/runners of differening size but similar efficiency what happens is essentially better cylinder fill on the 2nd half of inlet period and less reversion in the due to higher amplitude inlet wave of the smaller runner diameter. moreso than whats happening while piston is moving down.
I agree with most of what you said, i think the R&D part is finding the right timing of the pressure drop and balancing against IVC which is where manipulating valve seat geometry and tdc csa can be used along with port size.
Tom

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Re: Dart 180 cc alloy head as cast

Post by CGT » Fri Nov 29, 2019 8:45 am

zums wrote:
Fri Nov 29, 2019 7:41 am
manipulating valve seat geometry and tdc csa
I assume your talking about window csa?
"Never let your hobby ride you. Work while you work and play while you play"

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Re: Dart 180 cc alloy head as cast

Post by RevTheory » Fri Nov 29, 2019 10:01 am

When you guys are talking about port velocity, both average and local, are you more concerned with it at running engine valve lift or retainer-to-guide contact?

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Re: Dart 180 cc alloy head as cast

Post by SpeierRacingHeads » Fri Nov 29, 2019 10:55 am

Elroy wrote:
Thu Nov 28, 2019 10:58 pm
Well this is all new to me but.//information is good///its free information on the internet from what im seeing at my age but be careful what you absorb and attempt to transfer to your project//use to be word of mouth///its your job to decipher and take from the results given to you////examples given of "205" heads despite math suggesting otherwise///makes it hard for comparisons////confusing to me why lie being old school.///good info on the net but be careful of marketing /nothing has changed still deliberate disinformation////up to you if you wanna use previous examples to wade through the politics..
Im old and a retired analyst so to speak//. In my career pointing out falsehoods and disinformation was a daily duty//. its come to me quickly that the internet hasn't just given voice to good examples with facts///but also bad. same shit different venue//. People are people/ follow the money, doesnt even have to be alot of it.
Are you still whining about my cylinder head?

I told you I'd send you one, I'm not really hiding something. I can read..

better yet, come see me... MO isn't that far.
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Re: Dart 180 cc alloy head as cast

Post by steve316 » Fri Nov 29, 2019 11:35 am

Chad I though you were in Kansas?

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Re: Dart 180 cc alloy head as cast

Post by SpeierRacingHeads » Fri Nov 29, 2019 11:46 am

steve316 wrote:
Fri Nov 29, 2019 11:35 am
Chad I though you were in Kansas?
I am, but most of my fan base is in MO. Just assumed...
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Re: Dart 180 cc alloy head as cast

Post by CGT » Fri Nov 29, 2019 12:13 pm

Hey Steve316. How's the SB2?
"Never let your hobby ride you. Work while you work and play while you play"

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Re: Dart 180 cc alloy head as cast

Post by steve316 » Fri Nov 29, 2019 12:39 pm

I need to up compression & I added rocker; tire speed low, need to add gear. Thanks for asking

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Re: Dart 180 cc alloy head as cast

Post by steve316 » Fri Nov 29, 2019 12:45 pm

Steve sorry about hijacking; I believe you are going to exceed your expectations on this build

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Re: Dart 180 cc alloy head as cast

Post by zums » Fri Nov 29, 2019 1:02 pm

CGT wrote:
Fri Nov 29, 2019 8:45 am
zums wrote:
Fri Nov 29, 2019 7:41 am
manipulating valve seat geometry and tdc csa
I assume your talking about window csa?
Yes window csa. If your induction is too big for the cube and rpm because it just" has to be no more than 350fps at the st , and keep flowing .300 past your peak lift" and can keep up with piston demand on the first half of the stroke, my opinion is you just destroyed any ability to gain 100 + VE ABC
Steve, good luck wading through this
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Re: Dart 180 cc alloy head as cast

Post by CGT » Fri Nov 29, 2019 2:13 pm

zums wrote:
Fri Nov 29, 2019 1:02 pm
and can keep up with piston demand on the first half of the stroke, my opinion is you just destroyed any ability to gain 100 + VE ABC
So this scenario would create less depression on the second half of the stroke at and around BDC? Am I interpreting that right?
"Never let your hobby ride you. Work while you work and play while you play"

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Re: Dart 180 cc alloy head as cast

Post by Stan Weiss » Fri Nov 29, 2019 2:55 pm

How about some numbers. What is 1st half of stroke / second half of stroke?

Lets look at a 6" rod 383 ci engine.
Peak Piston Flow Demand around 74 ATDC
Piston 1/2 way down the hole around 81 ATDC
Peak Valve Lift around 106-112 ATDC

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Do you use engine simulation software that uses cylinder head flow files?
We have a package of more than 3025 DFW or FLW Files

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Re: Dart 180 cc alloy head as cast

Post by zums » Fri Nov 29, 2019 3:22 pm

CGT wrote:
Fri Nov 29, 2019 2:13 pm
zums wrote:
Fri Nov 29, 2019 1:02 pm
and can keep up with piston demand on the first half of the stroke, my opinion is you just destroyed any ability to gain 100 + VE ABC
So this scenario would create less depression on the second half of the stroke at and around BDC? Am I interpreting that right?
In general terms yes, nothing is etched in stone, rpm is a big factor, the piston is already slowing down 20 -30* before the cams max IC, if you blow your wad so to speak in the first half, your basically empty at bdc
Tom

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Re: Dart 180 cc alloy head as cast

Post by Stan Weiss » Fri Nov 29, 2019 5:08 pm

Green line is the Head flow (Out of box Dart 180 Iron Eagle numbers from Larry Meaux) map against a cam I selected. 6" rod 383 ci engine. Blue line piston flow demand @ 7500 RPM Red line piston flow demand @ 5000 RPM.

Stan

Code: Select all

_______I__N__T__A__K__E
Rocker_Arm_Ratio_=_1.650_________Valve_Lash_=_0.02100
VALVE_____Lift______Opens___Closes__Duration
_________________Deg_BTDC__Deg_ABDC_____________Area
_________0.00000____47.69_|__84.37_|_312.05_|__61.01
_________0.00600____44.55_|__80.80_|_305.35_|__60.99
_________0.01000____42.73_|__78.67_|_301.39_|__60.98
_________0.02000____38.71_|__73.99_|_292.70_|__60.91
_________0.04000____32.32_|__66.84_|_279.16_|__60.69
_________0.05000____29.68_|__63.94_|_273.61_|__60.56
_________0.10000____18.96_|__52.59_|_251.56_|__59.70
_________0.15000____10.52_|__43.84_|_234.35_|__58.68
_________0.20000_____3.06_|__36.19_|_219.26_|__57.27
_________0.25000____-3.97_|__29.07_|_205.10_|__55.41
_________0.30000___-10.85_|__22.20_|_191.36_|__53.71
_________0.35000___-17.79_|__15.20_|_177.41_|__51.04
_________0.40000___-24.96_|___7.98_|_163.03_|__48.74
_________0.45000___-32.52_|___0.38_|_147.86_|__45.30
_________0.50000___-40.80_|__-7.88_|_131.31_|__41.46
_________0.55000___-50.19_|_-17.26_|_112.55_|__36.16
_________0.60000___-61.45_|_-28.50_|__90.05_|__29.76
_________0.65000___-76.72_|_-43.55_|__59.73_|__20.32
CAM
_________0.00600____56.01_|__92.95_|_328.96_|__39.04
_________0.01000____50.50_|__87.43_|_317.93_|__39.00
_________0.02000____41.86_|__77.65_|_299.51_|__38.83
_________0.04000____30.98_|__65.35_|_276.33_|__38.48
_________0.05000____26.89_|__60.95_|_267.84_|__38.29
_________0.10000____11.47_|__44.82_|_236.29_|__37.07
_________0.15000____-0.70_|__32.36_|_211.67_|__35.53
_________0.20000___-12.08_|__20.95_|_188.87_|__33.37
_________0.25000___-23.72_|___9.23_|_165.51_|__30.83
_________0.30000___-36.39_|__-3.48_|_140.13_|__27.21
_________0.35000___-51.53_|_-18.59_|_109.88_|__22.27
_________0.40000___-72.76_|_-39.65_|__67.59_|__14.31
ab-cam-cfm-pfd-383.gif
ab-cfm-dart-180.gif
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Stan Weiss / World Wide Enterprises
Offering Performance Software Since 1987
Do you use engine simulation software that uses cylinder head flow files?
We have a package of more than 3025 DFW or FLW Files

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