Please say this will work!!!!
Le Mans Master
Joined: Apr 2007
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From: Graceland in a Not Correctly Restored Stingray
Correct that is the same calc I posted and used on advise from other members, I think it was Jackson that originally posted it. Not sure who posted it but below is the link to the debate, the empire net calc, I think is the best because it uses actual closing points as opposed to the KB calc that everyone was using that goes by the @.050 timing + 15*.
You got any thoughts on this particular case?
Drifting
Joined: Apr 2002
Posts: 1,740
Likes: 37
From: Stockton Ca
Try a 6" rod?
This is one of those builds where a 5.7" and 6" rods should be compared. I think that is the longer rods real advantage, it allows more comp or less octane. My TFS heads on .060 350 w/flattops. 218-224 HR, zero ping when starting in 3rd gear. 280 rwhp 315 rwtq w.stk duals.
I also have dual spals and 4 core to keep temps down w/AC on!
Ricisan
I also have dual spals and 4 core to keep temps down w/AC on!
Ricisan
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From: Millington Illinois
St. Jude Donor '08-'09
Correct that is the same calc I posted and used on advise from other members, I think it was Jackson that originally posted it. Not sure who posted it but below is the link to the debate, the empire net calc, I think is the best because it uses actual closing points as opposed to the KB calc that everyone was using that goes by the @.050 timing + 15*.
http://forums.corvetteforum.com/show....php?t=1621965
http://forums.corvetteforum.com/show....php?t=1621965
693HP @ 6500 Rpm @ 656 ft lbs @ 4500, 679 ft lbs @ 3000 rpm. Thanks Rich.
Veteran
Joined: Oct 2005
Posts: 1,284
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From: Nashville, TN
Rich helped me out a lot in fine tuning my design with his calculator. here is the final combo #s . 383 hydraulic roller W/ 150 NOS:I just put the 150 lbs nitrous shot on you figures at 10.2 straight up and here, WOW!:
693HP @ 6500 Rpm @ 656 ft lbs @ 4500, 679 ft lbs @ 3000 rpm. Thanks Rich.
693HP @ 6500 Rpm @ 656 ft lbs @ 4500, 679 ft lbs @ 3000 rpm. Thanks Rich.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
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From: Graceland in a Not Correctly Restored Stingray
Veteran
Joined: Oct 2005
Posts: 1,284
Likes: 81
From: Nashville, TN
I would but he would have to post the exact IVC seat number since he had the cam ground special!
Race Director
Joined: May 2005
Posts: 10,674
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From: Millington Illinois
St. Jude Donor '08-'09
Your welcome glad I could help, it was Jackson and Motorhead that turned me in the right direction with this. I have since found out after tearing my oil pan off and running the piston numbers I never had KB pistons anyway I have 12cc dish Federal Mogul's. For a time last year Eagle was putting the FM 12cc pistons out with their internal balanced 383 kits instead of the KB 18cc pistons. Nice they informed everyone they were switching parts, a$$holes. That puts me @ 10.56:1 SCR and 7.84 DCR with a .042 quench with aluminum RHS 200cc intake runner heads.
Le Mans Master
Joined: Apr 2007
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From: Graceland in a Not Correctly Restored Stingray
(OMG! When blueonblue logs back on, he won't recognize the place, will he?
)
Last edited by TheSkunkWorks; May 11, 2007 at 12:43 AM.
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From: Nashville, TN
Blue on Blue if you want us to figure out your numbers we need the Intake valve closing seat closing point, not the @.050 closing.
Thread Starter
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Joined: Apr 2004
Posts: 74
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From: Iron Station N.C.
Hi Rich I have read so many of your post concerning compression ration and am glad to see you on this post. I would like to have an idle that is somewhat rough, but not the lopping like a NASCAR racer. I seem to just know enough about compression to get me in trouble.
Engine specs:
383 .030 over
5.7 rods
Pistons: speed pro 12.5 dish
1.6:1 Roller Rockers on Intake Valves 1.5:1 Exhaust
Deck clearance: .025
Heads: World S/R Torquers 67cc Pocket ported and Runners cleaned
Cam Specs Intake Exhaust
Gross valve lift: .470 .470
Duration @
.006 Tappet Lift 270 270
Valve Timing Open Close
@ .050 Intake: 6 BTDC 38 ABDC
Exhaust: 38 BBDC 6 ATDC
These specs are for cam installed
@ 106.0 Intake Center Line
Intake Exhaust
Duration @ .050 224 224
Lobe Lift .3130 .3130
Lobe Seperation 106.0
Hope this helps; Skip
Engine specs:
383 .030 over
5.7 rods
Pistons: speed pro 12.5 dish
1.6:1 Roller Rockers on Intake Valves 1.5:1 Exhaust
Deck clearance: .025
Heads: World S/R Torquers 67cc Pocket ported and Runners cleaned
Cam Specs Intake Exhaust
Gross valve lift: .470 .470
Duration @
.006 Tappet Lift 270 270
Valve Timing Open Close
@ .050 Intake: 6 BTDC 38 ABDC
Exhaust: 38 BBDC 6 ATDC
These specs are for cam installed
@ 106.0 Intake Center Line
Intake Exhaust
Duration @ .050 224 224
Lobe Lift .3130 .3130
Lobe Seperation 106.0
Hope this helps; Skip
Veteran
Joined: Oct 2005
Posts: 1,284
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From: Nashville, TN
I need the intake valve closing seat timing off your cam card. It should read on the cam card as valve timing at .006 that is the timing number needed to program into the DCR calc. The standard Magnum 270HR intake closes @ 61, is that the same as what your card reads?
I figured it out with the number you gave with the intake .006 closing at 61 and you are at:
10.5106431866686 static CR
8.6719627742754 Dynamic CR
also your vavle lift on your intake will be at .501 with the 1.6 rockers
I would strongly advise going with aluminum heads or a bigger cam, even if you install your cam at 4* advanced you will still be at 8.42238701318257 DCR. I think you will have problems with pump gas on this set up. Or you can use a thicker bigger bore head gasket like a fel pro but your already at .049 quench so that will put you in the .050's as far quench goes.
Again, I am a novice at this myself, I would check with Motorhead, Jackson or some of the other engine builders on here to see what their opinion is.
Hope this helped.
I figured it out with the number you gave with the intake .006 closing at 61 and you are at:
10.5106431866686 static CR
8.6719627742754 Dynamic CR
also your vavle lift on your intake will be at .501 with the 1.6 rockers
I would strongly advise going with aluminum heads or a bigger cam, even if you install your cam at 4* advanced you will still be at 8.42238701318257 DCR. I think you will have problems with pump gas on this set up. Or you can use a thicker bigger bore head gasket like a fel pro but your already at .049 quench so that will put you in the .050's as far quench goes.
Again, I am a novice at this myself, I would check with Motorhead, Jackson or some of the other engine builders on here to see what their opinion is.
Hope this helped.
Last edited by King Lear; May 11, 2007 at 04:18 PM.
Thread Starter
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From: Iron Station N.C.
Rich, the info I listed was everything that was on my cam card except the grind number and something that listed it as a hydralic adjustment cam. Only thing at .006 was tappet list at 270 for int and exh.
Skip
Skip
Thread Starter
Advanced
Joined: Apr 2004
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From: Iron Station N.C.
Let me tell you what I put in and maybe you can tell me what I am doing wrong.
INPUT:
Advertised Intake Duration: 273 (added 3 for the 1.6:1 rockers)
Advertised Exhaust Duration: 270
Lobe Seperation: 106
Intake Lobe Centerline: 102
RESULTS:
Seat Timing:
......................Open.............. ................Close
Intake..............34.5 BTDC.......................58.5 ABDC
Exhaust............65 BBDC.......................25 ATDC
Overlap:.....59.5....................... .Total Advance: 4*
I figured 68cc for the head volume since I will remove at least 1cc with polishing, and I intend to check them. With .020 gasket thickness, 4.100 gasket bore, .025 piston to deck clearance, and 12.5 dish pistons; I get:
Static Comp: 8.15722
Dynamic Comp: 9.70433
Quench: .045
Now I am likely to have put something in wrong and maybe you could show me my mistake, but if these figures are correct would it run OK on 93 octane in your opinion?
Thanks again for your input.
INPUT:
Advertised Intake Duration: 273 (added 3 for the 1.6:1 rockers)
Advertised Exhaust Duration: 270
Lobe Seperation: 106
Intake Lobe Centerline: 102
RESULTS:
Seat Timing:
......................Open.............. ................Close
Intake..............34.5 BTDC.......................58.5 ABDC
Exhaust............65 BBDC.......................25 ATDC
Overlap:.....59.5....................... .Total Advance: 4*
I figured 68cc for the head volume since I will remove at least 1cc with polishing, and I intend to check them. With .020 gasket thickness, 4.100 gasket bore, .025 piston to deck clearance, and 12.5 dish pistons; I get:
Static Comp: 8.15722
Dynamic Comp: 9.70433
Quench: .045
Now I am likely to have put something in wrong and maybe you could show me my mistake, but if these figures are correct would it run OK on 93 octane in your opinion?
Thanks again for your input.
Veteran
Joined: Oct 2005
Posts: 1,284
Likes: 81
From: Nashville, TN
Let me tell you what I put in and maybe you can tell me what I am doing wrong.
INPUT:
Advertised Intake Duration: 273 (added 3 for the 1.6:1 rockers)
Advertised Exhaust Duration: 270
Lobe Seperation: 106
Intake Lobe Centerline: 102
RESULTS:
Seat Timing:
......................Open.............. ................Close
Intake..............34.5 BTDC.......................58.5 ABDC
Exhaust............65 BBDC.......................25 ATDC
Overlap:.....59.5....................... .Total Advance: 4*
I figured 68cc for the head volume since I will remove at least 1cc with polishing, and I intend to check them. With .020 gasket thickness, 4.100 gasket bore, .025 piston to deck clearance, and 12.5 dish pistons; I get:
Static Comp: 8.15722
Dynamic Comp: 9.70433
Quench: .045
Now I am likely to have put something in wrong and maybe you could show me my mistake, but if these figures are correct would it run OK on 93 octane in your opinion?
Thanks again for your input.
INPUT:
Advertised Intake Duration: 273 (added 3 for the 1.6:1 rockers)
Advertised Exhaust Duration: 270
Lobe Seperation: 106
Intake Lobe Centerline: 102
RESULTS:
Seat Timing:
......................Open.............. ................Close
Intake..............34.5 BTDC.......................58.5 ABDC
Exhaust............65 BBDC.......................25 ATDC
Overlap:.....59.5....................... .Total Advance: 4*
I figured 68cc for the head volume since I will remove at least 1cc with polishing, and I intend to check them. With .020 gasket thickness, 4.100 gasket bore, .025 piston to deck clearance, and 12.5 dish pistons; I get:
Static Comp: 8.15722
Dynamic Comp: 9.70433
Quench: .045
Now I am likely to have put something in wrong and maybe you could show me my mistake, but if these figures are correct would it run OK on 93 octane in your opinion?
Thanks again for your input.
Ok so with the:
Advertised Intake Duration: 273 (added 3 for the 1.6:1 rockers)
Advertised Exhaust Duration: 270
Lobe Seperation: 106
Intake Lobe Centerline: 102
I came up with the same seat timing, next we go to the
dynamic stroke length which is 3.08347312177741
piston BDC is 0.6665
bore 4.030
stroke 3.75
head 68cc
.020 gasket thickness
gasket bore 4.100
deck clearance .025
piston 12.5 dish
you get:
SCR 9.70433822187498
DCR 8.15722478666967
now with the same numbers with a intake centerline of 106 they are:
SCR 9.70433822187498
DCR 7.93749991637485
the first numbers I gave you were with the .024 thickness and 5cc flat tops
You might be alright if the numbers you gave me were exact but if it were me I wouldn't try it.
now if you retarded the timing 4* with this set up you would get a ICL of 110*
SCR 9.70433822187498
DCR 7.70395103914939
This I think you would be alright with 93 octane and iron heads given all the above numbers were correct.
Veteran
Joined: Oct 2005
Posts: 1,284
Likes: 81
From: Nashville, TN
My DCR is at 7.77208820273557 and I very pleased with the street performance. Also my heads are aluminum so I could have went for more but decided to play it safe. Again this is just my opinion, your best bet would be to call all the manufacturers of your heads, camshaft and pistons and give them all your numbers and see what they come up with. They will know the tolerances of their products combined better then I do, I am just going by the empire net calculator.
Rich
Last edited by King Lear; May 12, 2007 at 01:20 AM.
Race Director
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
King Lear, your numbers look pretty good to me
I ran the 270H cam with iron heads and ~10:1cr with no problems on pump gas, I did not run a vaccum advance though
I ran the 270H cam with iron heads and ~10:1cr with no problems on pump gas, I did not run a vaccum advance though
Drifting
Joined: Apr 2002
Posts: 1,740
Likes: 37
From: Stockton Ca
I have seen the 5.7 vs. 6" debate. I think the real advantage of better rod/stroke ratio is the few extra deg spent at tdc. The extra burn time doesn't show on dyno, but does it decrease detonation?
Ricisan
Ricisan
Le Mans Master
Joined: Apr 2007
Posts: 7,353
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From: Graceland in a Not Correctly Restored Stingray
I believe any slight reduction in DCR due to improving rod length in this particular case would likely be offset by the increaded dwell time the piston would spend near TDC, which could even necessitate that timing be further retarded. So, for an engine already over the edge, it's likely a wash-out, at best, with reduced friction as the sole benefit...