Some AFR/CR/Quench Questions!
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Some AFR/CR/Quench Questions! I’m looking to upgrade to AFR 205 heads and a FM11 cam (228"/230" .576"/.595" 114LSA. I would really like your guys input, as I want this done right. I have a built/forged 347” block using Ross pistons (-2cc valve relief’s) that are +.008” BELOW THE DECK. I want to try and achieve optimal Quench along with 11.0:1 CR. To get proper Quench, I would have to use no bigger than a .030” gasket right, maybe even a bit smaller, and don’t really know if this is advisable? How much milling of the heads would need to be done in this case? I am also open to cam options.
Edit: Shortened it down more to the point.
Thanks for your time,
Dan
Edit: Shortened it down more to the point.
Thanks for your time,
Dan
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Thanks JRP! What do think about the H/C combination? Also, do you see any issues mounting the intake manifold to the heads being that they would be milled and the gasket being so thin?
Quench is the area between the top of your piston and your head deck.
Quench is the area between the top of your piston and your head deck.
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Originally Posted by wallstAL
After some thought, I'm not sure about moving to the AFR heads just yet. May just have mine cleaned up with some more massaging of the ports.
I did some of my own calcultions based on both using the formula given in the sticky "LS1 Head CC Volume vs CR" and also using the Ross Piston Calcultor. My current heads are Abssolute Speed. These are supposed to be 62cc heads. With that, I come up with 11.36 CR (sticky formula), and 11.08 on the Ross Calc. using a .025" gasket. That's a pretty big difference, which one is more accurate?
Dan
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i get 11.08 using all formulas; 2 calculators and the one in the sticky forum by hand.
chamber = 62
dech volume = 3.905 x 3.905 x 12.8704 x .008 = 1.5700
gasket volume= 3.905 x 3.905 x 12.8704 x .025 = 4.906
piston dish volume = 2
= 62 + 1.5700 + 4.906 + 2 = 70.496
CR = (710.8575 + 70.496) / 70.496= 11.0865
chamber = 62
dech volume = 3.905 x 3.905 x 12.8704 x .008 = 1.5700
gasket volume= 3.905 x 3.905 x 12.8704 x .025 = 4.906
piston dish volume = 2
= 62 + 1.5700 + 4.906 + 2 = 70.496
CR = (710.8575 + 70.496) / 70.496= 11.0865
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I knew I forgot something on doing my own formula. I forgot to add the 2cc valve reliefs. I was getting 68.50cc on my calcultion because I forgot about that.
Thanks again Jerami!
Dan
Thanks again Jerami!
Dan
Dan
I looked into possibly switching over to afr`s but to be honest I havent seen them making more hp than you or i do and the couple that have were only a few hp more. It was definitly not worth the expense at this point. If you do decided to make the change definitly post the results as I am very interested.
Jeremy
I looked into possibly switching over to afr`s but to be honest I havent seen them making more hp than you or i do and the couple that have were only a few hp more. It was definitly not worth the expense at this point. If you do decided to make the change definitly post the results as I am very interested.
Jeremy
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Will do!
I have a guy local that will massage the ABS heads and port match the FAST 90 intake for me for alot less $$ than I would have to spend on the AFR's, plus I can fix the quench while I'm at it. I may have enough left over for some new wheels even
.
I may still go with the FM11 or FM13 still to tame it down a bit from the Trex, not sure about that either. I know someone posted a real nice graph of the FM11 with ABS heads, very nice TQ. curve, and put down some stout numbers as well, 45x rwhp and 41x rwtq I believe.
Dan
I have a guy local that will massage the ABS heads and port match the FAST 90 intake for me for alot less $$ than I would have to spend on the AFR's, plus I can fix the quench while I'm at it. I may have enough left over for some new wheels even
. I may still go with the FM11 or FM13 still to tame it down a bit from the Trex, not sure about that either. I know someone posted a real nice graph of the FM11 with ABS heads, very nice TQ. curve, and put down some stout numbers as well, 45x rwhp and 41x rwtq I believe.
Dan
Originally Posted by wallstAL
Originally Posted by DanZ28
Will do!
I have a guy local that will massage the ABS heads and port match the FAST 90 intake for me for alot less $$ than I would have to spend on the AFR's, plus I can fix the quench while I'm at it. I may have enough left over for some new wheels even.
I may still go with the FM11 or FM13 still to tame it down a bit from the Trex, not sure about that either. I know someone posted a real nice graph of the FM11 with ABS heads, very nice TQ. curve, and put down some stout numbers as well, 45x rwhp and 41x rwtq I believe.
Dan
I have a guy local that will massage the ABS heads and port match the FAST 90 intake for me for alot less $$ than I would have to spend on the AFR's, plus I can fix the quench while I'm at it. I may have enough left over for some new wheels even
. I may still go with the FM11 or FM13 still to tame it down a bit from the Trex, not sure about that either. I know someone posted a real nice graph of the FM11 with ABS heads, very nice TQ. curve, and put down some stout numbers as well, 45x rwhp and 41x rwtq I believe.
Dan
Look around not many a4 cars in the 430+ range anywhere. I just see one pop up every now and then. Just think man people are still chasing the numbers you have had for a year + already. I think the Fast 90 will show a realy nice gain over the ls6. I doubt you will loose much going to the FM13. I know a few guys running that cam and they are very happy.
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Originally Posted by DrkPhx
Using this calculator (which seems to be more accurate than the Ross one) and putting the specs of: 3.898 bore, 3.622 stroke, .025 head gasket, 62 cc combustion chamber, and 2 cc valve relief it calculates 11.05.
Dan
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Originally Posted by SStrokerAce
There is a minimum size you can make a MLS type gasket. I believe it's .027"
Bret
Bret
Dan
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Originally Posted by offaxis
Dan
Look around not many a4 cars in the 430+ range anywhere. I just see one pop up every now and then. Just think man people are still chasing the numbers you have had for a year + already. I think the Fast 90 will show a realy nice gain over the ls6. I doubt you will loose much going to the FM13. I know a few guys running that cam and they are very happy.
Look around not many a4 cars in the 430+ range anywhere. I just see one pop up every now and then. Just think man people are still chasing the numbers you have had for a year + already. I think the Fast 90 will show a realy nice gain over the ls6. I doubt you will loose much going to the FM13. I know a few guys running that cam and they are very happy.
Only thinking about the cam swap to get some of my low end grunt back, but I'll see how it goes with the new rear/gears and FAST 90/90 setup before I commit to doing something different in the cam deparment. Thanks your feedback..
Dan