496ci revamped

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This Crane cam 139791 must not have symmetrical lobes, the timing numbers don't come out with an exact match to the cam card.

Sim03_CamManager_CamSpecs.jpg
Sim03_CamManager_ValveEventTiming.jpg

Cam timing numbers after retarding the cam 4°.

Sim03_CamTimingEvents.JPG

I tried doing all three sims on one graph, but it got very confusing. So what the graph below contains is
Sim02 and Sim03.

Sim03_Crane139791_680_680_AFR315_-4°Retarded.JPG

I invite everyone to review all the numbers, especially Speedlink1973, it's not hard to make a
mistake with so many numbers.

.
 
somethings wrong with the graph,
yeah that 300 cc head should be excellent
index.php


290 heads notice you start at 400 ft lbs and peak near 700 ft lbs and 750 hp,
this graph below looks like a potentially reasonable result
index.php



the above graph should show identical lines on the graph below,for that combo,
plus the new line for the new combo, but the original power curve is vastly different and lower, on that dual curve graph

index.php
 
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Yep something isn't adding up.
I'm thinking one lost a head gasket
:) it's on my cam so I must have forgotten to torque head bolts.

I'm assuming retarding 4 degrees
Helped peak hp but killed the whole range
 
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This helped a bunch,
It's actually where I wanted to be
700 to 750 ish
I had a good Idea N/A 750 was max
Based on heads and cam
Heads will only support 750hp ish
Based on flow numbers 600 lift 360x2 720hp
650 lift 368x 2 736hp max 700 lift 375 x 2 750hp

Torque is where I'm a bit surprised
690 700 I had it at 620 630
 
Indycars said:
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Sim03 w/o Mufflers and Sim04 w/Mufflers

View attachment 10381

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Click to expand...
Hard to see all on my phone.
Appears HP&Torque are down 55-75 numbers though the mufflers.
Typical on large cubic inch engines.
Still plenty.
Using the Crane cam of Grumpy and improved AFR. Heads.

Torque peaks at 5500.
Hp done at 6500.

Make it hard to get a torque converter to work optimal for street and track.
Stick car no issues.

Has to flash fast and not slip any at 6000-6500.
He has a 4L80e.
Race converters for them are insane expensive.
$2,000 to start.
 
Still pulling at 7000.
In the Danger Zone.
Unsafe piston speeds.
Been there done it.
They lived Pontiac 455 with 4.21 inch stroke.
 
Indycars said:
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DynoSim5 tell me that the cam is installed 4° advanced when the intake centerline is 108°.

View attachment 10366

View attachment 10367

What would you like to see next ???

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Click to expand...
Do his layout through the mufflers Rick Dynomotion 5.

Peak torque at 4500.

8 - 9.5 inch -10 inch torque converter diameter typical.
10 inch preferred so he does not drive through the converter with lots of torque.
Over power it...slips destroyed.
 
Maniacmechanic1 said:
Hard to see all on my phone.
Appears HP&Torque are down 55-75 numbers though the mufflers.
Typical on large cubic inch engines.
Still plenty.
Using the Crane cam of Grumpy and improved AFR. Heads.

Torque peaks at 5500.
Hp done at 6500.

Make it hard to get a torque converter to work optimal for street and track.
Stick car no issues.

Has to flash fast and not slip any at 6000-6500.
He has a 4L80e.
Race converters for them are insane expensive.
$2,000 to start.
Click to expand...
Is this advance 4 degrees?
First run looks way better
am I missing something?
 

Attachments

  • Sim01_Howards_635_640_4°A.JPG
    Sim01_Howards_635_640_4°A.JPG
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Maniacmechanic1 said:
Installed at 108 intake centerline.
Makes it 4 degrees advanced Yes.
Click to expand...
Doesn't make sense,
Look at torque curve at 1000rpm
On very first run
400 lbs ft
Now jump forward
To the Grumpy cam and mine
My cam is at 200 lbs ft of torque at 1000rpm's
How did it lose 200 lbs ft of torque ?
I'm assuming retarded 4 degrees
Not advanced
 
What I am seeing is that it is most effective packing more Flow area under the curve in the intake ports.
Exhaust ports to match to maintain Ideal E/I ratio.
And work yet in a safe long life power band.
 
Grumpy said:
everything looks well matched,
in fact ,lookingg over the parts list,
its about the ideal combo for brisk street performance,
and instant responsive performance.

Id have selected different heads ,and added a bit more compression,
and maybe 7-8 degrees more cam duration
but those originally posted components are certainly close to ideal.
(especially for street/strip use)
Id have gone this route on heads
https://www.airflowresearch.com/315cc-bbc-rectangle-port-cylinder-head/
Click to expand...
Hey Grumpy, where at duration wise and lobe separation angle does vacuum become an issue on low end?
My understanding of it is the more overlap the less vacuum on low end.
I don't know for sure.
I'm asking because the 4l80 I have is a manual shift and it has a vacuum actuator in the transgo valve body, I'm not 100% sure how it works, I just know it has to pull vacuum.
 
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Grumpy said:
http://www.wallaceracing.com/calcafhp.php

https://www.powerperformancenews.com/tech/cylinder-head-tech-airflow-vs-power/

https://www.hotrod.com/articles/airflow-research-cylinder-power/

http://garage.grumpysperformance.com/index.php?threads/port-speeds-and-area.333/
Click to expand...
Sounds like cfm does but doesn't matter
I picked that information up off hot rod magazine I believe, off the summit iron head 496 they built, they mentioned the heads would only support 680hp based on cfm
Of 340 on heads.
I'm learning on the fly, I'm really interested in the crane cam you suggested.
 
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