NHRA 283cid Stocker Engine

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frnkeore
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Re: NHRA 283cid Stocker Engine

Post by frnkeore »

I have a question, regarding LSA and how Pipe Max predicts it.

This is a build that I'm doing on a 306 CI Ford. I would have thought that the LSA would have been 106 to no more than 108 but, as you can see, PM wants 111 LSA.

Could you explain why PM wants 111?
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Re: NHRA 283cid Stocker Engine

Post by 1972ho »

Would this be for a nhra stocker type engine if not maybe it spec’ed you non stocker type profile camshaft.
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Re: NHRA 283cid Stocker Engine

Post by maxracesoftware »

frnkeore wrote: Tue Sep 29, 2020 3:21 pm I have a question, regarding LSA and how Pipe Max predicts it.

This is a build that I'm doing on a 306 CI Ford. I would have thought that the LSA would have been 106 to no more than 108 but, as you can see, PM wants 111 LSA.

Could you explain why PM wants 111?
using your Pic's info .. i get = 107.971 LSA
... depends on Valvetrain Deflection input values as well .

i really need you to Post an actual ScreenShot of your inputs
... maybe you changed a Choice or Input Value that i cannot see in your Pics , because your Monitor might not refreshed the screen ?? just guessing
so please post screenshot

Also PipeMax did pretty good calculating all rest of Cam Specs

however, you must input actual Dyno Day Weather conditions + both Intake + Exhaust Port FPS and CenterLine Lengths
to get better correlations .
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frnkeore
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Re: NHRA 283cid Stocker Engine

Post by frnkeore »

For level 9, PM recommends a LSA of 111.531. Level 9, closely matches the cam timing (other than LSA) that most closely matches the cam that I want to use.
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Re: NHRA 283cid Stocker Engine

Post by jed »

Larry not to side track this thread but could Pipe Max be used to model a flat head.
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Re: NHRA 283cid Stocker Engine

Post by maxracesoftware »

frnkeore wrote: Wed Sep 30, 2020 1:58 am For level 9, PM recommends a LSA of 111.531. Level 9, closely matches the cam timing (other than LSA) that most closely matches the cam that I want to use.
hi frnkeore ,
the recommended LSA = 111.531
is coming from mostly this Choice :
[ Wedge • Modern Chamber • Hi-Raised Ports ]
Choose : Combustion Chamber Style and Port design

that Choice assumes these Hi-Raised Ports would also have near maximum Valve diameters for the Bore diameter
so the calculated 111.531 LSA is to help stop possible Overscavenging due to Mixture able to go right out the exhaust Port
without never being trapped into the Cylinder !

i need to change this in PipeMax v5.00 to make "very sure" there are really larger valves in that [ Hi-Ports ] choice
your 2.020/1.600 combo .. the 2.020" is a relatively small diameter Intake Valve that would be in a typical Hi-Raised Port design + modern chamber style

If i choose [ Wedge • Small Closed Chamber • Low Ports ]
and input 0.0 value for ValveTrain Deflection
i get LSA = 106.996 Level=10

if i input 0.026" ValveTrain Deflection , i get LSA = 107.971

still PipeMax was very close to your Cam specs !
... you would really need to Dyno test to determine what Cam specs/settings would make highest TQ and HP in your desired RPM Range ?
Last edited by maxracesoftware on Wed Sep 30, 2020 2:45 pm, edited 2 times in total.
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Re: NHRA 283cid Stocker Engine

Post by maxracesoftware »

jed wrote: Wed Sep 30, 2020 11:46 am Larry not to side track this thread but could Pipe Max be used to model a flat head.
jed ,
Choose : Combustion Chamber Style and Port design
[ L-Head or Flat-Head • Briggs-Stratton • Hi-Perf ]
for L-Head simulations ... checkout these 2 PipeMax .PMW included files :

Briggs_and_Stratton_Animal_Engine_Research_12.4103cid_4750RPM_9.34HP_Methanol.PMW
and
Briggs_Stratton_RAPTOR_12.5636CID_4500RPM_6.0HP_3200RPM_7.7TQ.PMW

also look at all the text + data in the NotePad screen inside of PipeMax ... there's a ton of info included
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Re: NHRA 283cid Stocker Engine

Post by frnkeore »

Larry,
Thank you for explaining that for me. I'm looking forward to upgrading to 5.0 and learning more about this 4.5 as I use it more.

Can you tell us how the program generates the cam profiles?
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Re: NHRA 283cid Stocker Engine

Post by Erland Cox »

I am getting acquainted with 4.50 and testing some stuff.
I have a DOHC overhead engine with buckets so i use 1 for rocker ratio.
But the calculated cam specs still come out as roller cam with less lift and duration.

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Re: NHRA 283cid Stocker Engine

Post by maxracesoftware »

Erland Cox wrote: Thu Oct 01, 2020 5:07 pm I am getting acquainted with 4.50 and testing some stuff.
I have a DOHC overhead engine with buckets so i use 1 for rocker ratio.
But the calculated cam specs still come out as roller cam with less lift and duration.

Erland
please Post a screenshot or email a screenshot of the Main input page

if i'm understanding your question correctly ?
what you are seeing is since its a DOHC , this choice is controlling recommended Cam Specs
[ Choose : Number of Intake Valves and Intake Ports per Cylinder ] ... same for Exhaust Number of Valves choice
DOHC :
2 Valves • 2 Ports
or
2 Valves • 1 Siamesed Port

just 1 Cam in Block ...and 1 Intake and 1 Exhaust Valve per Cylinder ... gives you different Cam Specs recommendations
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Re: NHRA 283cid Stocker Engine

Post by Erland Cox »

It is an 8 valve DOHC. 2365cc 6700 rpm.
Needs at least ,575" of intake lift.
What am I doing wrong?

Camshaft = OverHead • Bucket - Direct Action
600 RPM/Sec Dyno Test Level=7 Level=8 Level=9 Level=10 Piston FPM
Peak HorsePower @ 6700 RPM 253,8 257,0 260,2 263,5 3517,50
Peak Torque Lbs-Ft @ 5400 RPM 215,9 220,4 223,2 226,1 2835,00

HorsePower per CID 1,757 1,780 1,802 1,825 Peak HP Fuel
Torque per Cubic Inch 1,495 1,527 1,546 1,565 consumed in
Peak Torque BMEP in psi 225,4 230,2 233,1 236,1 Lbs./ Hour
Throttle Plate CFM @ 1.5 inHg. 336 374 393 412 116,5
--------------------------------- Recommended Camshaft Specs at 0.050” inch Lobe Lift ---------------
Cam Lobe Separation Angle (LSA) 106,736 107,109 107,580 108,008
Intake Minimum Valve Lift 0,39349 0,40972 0,42661 0,44420
Exhaust Minimum Valve Lift 0,39349 0,40972 0,42661 0,44420
Intake Minimum Duration 226,807 228,406 230,062 231,731
Exhaust Minimum Duration 242,722 244,433 246,203 247,985
Overlap Minimum Duration 21,293 22,948 23,914 24,697

Intake Maximum Valve Lift 0,40972 0,42661 0,44420 0,46252
Exhaust Maximum Valve Lift 0,40972 0,42661 0,44420 0,46252
Intake Maximum Duration 228,406 230,062 231,731 233,411
Exhaust Maximum Duration 244,433 246,203 247,985 249,779
Overlap Maximum Duration 22,948 23,914 24,697 25,579

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Re: NHRA 283cid Stocker Engine

Post by Erland Cox »

Seems like I found the fault, I suddenly had 3 intake valves per cylinder.
Thank you!

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Re: NHRA 283cid Stocker Engine

Post by Erland Cox »

Next problem.
Recommended duration is 20 degrees lower than real duration in my engine.
What factors alter the duration?
And the lobe separation is a bit more than I ever have used.

Erland
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Re: NHRA 283cid Stocker Engine

Post by maxracesoftware »

Erland Cox wrote: Thu Oct 01, 2020 6:43 pm Next problem.
Recommended duration is 20 degrees lower than real duration in my engine.
What factors alter the duration?
And the lobe separation is a bit more than I ever have used.

Erland
please email me or PM a screenshot
better yet , Save your simulation file ... then attach it to an email back to me
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Re: NHRA 283cid Stocker Engine

Post by maxracesoftware »

NHRA 283cid Stocker Engine
viewtopic.php?f=1&t=62134&p=877707

Stock Eliminator secrets
viewtopic.php?p=876058#p876058

MotorTrend NHRA 283cid BES Stocker article
https://www.motortrend.com/how-to/1209e ... 283-chevy/


Wade Owens 1966 Chevelle

11.571 ET @ 113 MPH

Peak TQ = 342.0 at 5000 RPM
Peak HP = 373.0 at 6500 RPM

As of this writing, the car has garnered eight class wins and six No. 1
qualifying positions and has run as fast as 11.571 in L/Stock Automatic.

NHRA283cidStocker.jpg
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