What Heads To Go With? Need MORE TQ
03-12-2008, 01:08 PM
#41
I have been thinking, and will prolly do the AFR heads with a 60cc combustion chamber. the AFR heads are 205cc right? Here is a dumb question, my 241 castings what size runners are they and combustion chambers??? Never mind the stock CC is 66.6....
I would not do 5.3 heads, since they are a stock casting and AFR is aftermarket.
Now as far as head gaskets go, i was thinking wither .030 or .040.. I would like my DCR to be around 8.8 or 8.9.. and with 60cc combustion chambers that will work, plus it will raise my SCR....
Jsut did some math with a stock bore 3.9
Right now as i sit with 66.6cc chambers and stock heads my SCR is 10.37 and my DCR is 8.28...
If i get heads with 60cc chambers and i go to .030 head gaskets my SCR will be 11.96 and my DCR will be 9.51
If i get heads with 60cc chambers and i go to .040 head gaskets my SCR will be 11.64 and my DCR will be 9.26
Now will that be too much compression on pump gas.. 93 octane? Also will i need to flycut?
What do you think?
I would not do 5.3 heads, since they are a stock casting and AFR is aftermarket.
Now as far as head gaskets go, i was thinking wither .030 or .040.. I would like my DCR to be around 8.8 or 8.9.. and with 60cc combustion chambers that will work, plus it will raise my SCR....
Jsut did some math with a stock bore 3.9
Right now as i sit with 66.6cc chambers and stock heads my SCR is 10.37 and my DCR is 8.28...
If i get heads with 60cc chambers and i go to .030 head gaskets my SCR will be 11.96 and my DCR will be 9.51
If i get heads with 60cc chambers and i go to .040 head gaskets my SCR will be 11.64 and my DCR will be 9.26
Now will that be too much compression on pump gas.. 93 octane? Also will i need to flycut?
What do you think?
TEXAS SPEED AND PERFORMANCE !!!
03-12-2008, 01:22 PM
#42
he has a 6.0l block and im putting down nearly identical numbers and thats spending well under $1k less on the heads alone (not counting other expenses for getting a 6.0l block, etc) for only a difference of 9rwhp/12rwtq. im still not retuned and running extremely rich...
you have a slightly larger cam than im running so there is no reason why with the right set of heads that 440rwhp/400+ rwtq is easily achievalbe with your setup...
please note, im not slamming that guy's ride by any means, but dont sell yourself short either...
03-12-2008, 07:07 PM
#47
Looks like you are on the right track! Since your cam is advanced, you would be well advised to go a little bigger than 60cc chambers. With a .040" gasket, 64 is all you really need. Personally, my plan is to run that same cam on a 110 or 109 ICL along with a 62cc combustion chamber. Either one gives ~ 8.82 DCR, but you would have a little more torque on the bottom.
As for gaskets, keep in mind that LS series engines have a positive deck clearance. In laymens terms, the piston actually protrudes out of the top of the cylinder .005" - .010". What that means to you is that a .030 thick gasket can put the piston .020" - .025" from the deck of the head - too close for safety at high rpms, and especially in a stick shift where mechanical over-rev (3-2 shift) is possible. In a stock short block, piston rock at TDC can bring it even closer.
The AFR head would be less sensitive to detonation, all things being equal, than a stock casting. The dual quench chamber promotes a more active mixture and better squish than stock. The efficient chamber is one of the key factors to choose it over ported castings. That said, 8.8 is about the max I would go, and certainly not over 9.0 on 93 octane.
It would be interesting to see some data logs of two similar setups. Seems like KR might tell the story at large throttle openings and low engine speeds, if you can keep the tires from spinning
As for gaskets, keep in mind that LS series engines have a positive deck clearance. In laymens terms, the piston actually protrudes out of the top of the cylinder .005" - .010". What that means to you is that a .030 thick gasket can put the piston .020" - .025" from the deck of the head - too close for safety at high rpms, and especially in a stick shift where mechanical over-rev (3-2 shift) is possible. In a stock short block, piston rock at TDC can bring it even closer.
with a ported 5.3 head with 60cc chambers and larger,lazier runners you may be able to get away with no detonation but i would be scared to bump dcr up over 9:0 with a set of afrs since they are quite a bit more efficient and have better cylinder fill in the bottom range so they may come closer to detonation
It would be interesting to see some data logs of two similar setups. Seems like KR might tell the story at large throttle openings and low engine speeds, if you can keep the tires from spinning
03-12-2008, 07:58 PM
#48
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i agree but an afr 205 cc runner almost always has better cylinder fill at lower rpms than a ported stock casting and will be making more power/tq in the lower rev range and even with the dual quench it will be just as likely to spark knock, unless you back down the timing which would be defeating the pourpose of the higher dcr . i'm no expert so my opinion is just that but if i was using an efficient afr head i would keep dcr in the 8.8-8.9 range, using an .040 gasket and mill accordingly.
03-13-2008, 05:09 PM
#52
Looks like you are on the right track! Since your cam is advanced, you would be well advised to go a little bigger than 60cc chambers. With a .040" gasket, 64 is all you really need. Personally, my plan is to run that same cam on a 110 or 109 ICL along with a 62cc combustion chamber. Either one gives ~ 8.82 DCR, but you would have a little more torque on the bottom.
As for gaskets, keep in mind that LS series engines have a positive deck clearance. In laymens terms, the piston actually protrudes out of the top of the cylinder .005" - .010". What that means to you is that a .030 thick gasket can put the piston .020" - .025" from the deck of the head - too close for safety at high rpms, and especially in a stick shift where mechanical over-rev (3-2 shift) is possible. In a stock short block, piston rock at TDC can bring it even closer.
The AFR head would be less sensitive to detonation, all things being equal, than a stock casting. The dual quench chamber promotes a more active mixture and better squish than stock. The efficient chamber is one of the key factors to choose it over ported castings. That said, 8.8 is about the max I would go, and certainly not over 9.0 on 93 octane.
It would be interesting to see some data logs of two similar setups. Seems like KR might tell the story at large throttle openings and low engine speeds, if you can keep the tires from spinning
As for gaskets, keep in mind that LS series engines have a positive deck clearance. In laymens terms, the piston actually protrudes out of the top of the cylinder .005" - .010". What that means to you is that a .030 thick gasket can put the piston .020" - .025" from the deck of the head - too close for safety at high rpms, and especially in a stick shift where mechanical over-rev (3-2 shift) is possible. In a stock short block, piston rock at TDC can bring it even closer.
The AFR head would be less sensitive to detonation, all things being equal, than a stock casting. The dual quench chamber promotes a more active mixture and better squish than stock. The efficient chamber is one of the key factors to choose it over ported castings. That said, 8.8 is about the max I would go, and certainly not over 9.0 on 93 octane.
It would be interesting to see some data logs of two similar setups. Seems like KR might tell the story at large throttle openings and low engine speeds, if you can keep the tires from spinning
Now can someone explain this quench to me?
03-13-2008, 05:14 PM
#53
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I know which way I will build, when the time comes which will be very soon.
03-13-2008, 05:50 PM
#54
Jonas do you think that you might be overlooking the Trickflows?
If you want the power under the curve and raise the torque, wouldn't that make the CNC-ported heads with 13.5 degree valve angles, decreased valve shrouding, increased mid-lift airflow, relocated spark plugs, improved rocker arm-to-valve cover clearance be what your looking for? Just my .02 cents and nothing against the AFR folks!
If you want the power under the curve and raise the torque, wouldn't that make the CNC-ported heads with 13.5 degree valve angles, decreased valve shrouding, increased mid-lift airflow, relocated spark plugs, improved rocker arm-to-valve cover clearance be what your looking for? Just my .02 cents and nothing against the AFR folks!
03-13-2008, 06:15 PM
#55
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the .200" - .400" numbers are pretty important i think acording to the men that know their stuff.
quench is the distance from the top of the piston to the bottom of the deck of the head.something in the low to mid .03x range seems to work great so an .040" gasket with a 63 or 64cc chamber should be a strong, efficient combo.
quench is the distance from the top of the piston to the bottom of the deck of the head.something in the low to mid .03x range seems to work great so an .040" gasket with a 63 or 64cc chamber should be a strong, efficient combo.
Last edited by slow trap; 03-13-2008 at 06:21 PM.
03-13-2008, 06:46 PM
#56
Jonas do you think that you might be overlooking the Trickflows?
If you want the power under the curve and raise the torque, wouldn't that make the CNC-ported heads with 13.5 degree valve angles, decreased valve shrouding, increased mid-lift airflow, relocated spark plugs, improved rocker arm-to-valve cover clearance be what your looking for? Just my .02 cents and nothing against the AFR folks!
If you want the power under the curve and raise the torque, wouldn't that make the CNC-ported heads with 13.5 degree valve angles, decreased valve shrouding, increased mid-lift airflow, relocated spark plugs, improved rocker arm-to-valve cover clearance be what your looking for? Just my .02 cents and nothing against the AFR folks!
03-13-2008, 06:47 PM
#57
the .200" - .400" numbers are pretty important i think acording to the men that know their stuff.
quench is the distance from the top of the piston to the bottom of the deck of the head.something in the low to mid .03x range seems to work great so an .040" gasket with a 63 or 64cc chamber should be a strong, efficient combo.
quench is the distance from the top of the piston to the bottom of the deck of the head.something in the low to mid .03x range seems to work great so an .040" gasket with a 63 or 64cc chamber should be a strong, efficient combo.
03-14-2008, 05:16 AM
#58
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TORCHD 02 TA:
I'll stick my neck out here as the heads I chose lack the general popularity and marketing of many other cylinder heads.
So far, I have had very good results from the PRC Terminator Heads. The heads are 62cc (unmilled), and 200cc runners. It's easy to get a reasonably size cam in there with no milling, and with 200cc runners and with a ~11.0:1 compression, I have had no problem maintaining a HP/TQ curve that comes on early and maintains 400+HP/400+TQ through a significant portion of the power curve.
I.E. 385TQ at 3000rpm's , 415TQ at 4800rpms, and a slowly falling HP/TQ curve that gradually falls to 365TQ at 6300rpm's. And with fairly reasonable track times & traps speeds for being at 6000 feet.
I'm always been somewhat perplexed that Terminator heads lack the aggressive marketing of other head manufactures. Maybe I just lucked out, but I wouldn't necessarily equate their lack of popularity to being an inferior head.
Yes, there have been some prior issues with matching the FAST 90/90 to these heads, but I believe these issues have been resolved.
Theres is no doubt that AFR's and many new cylinder heads have been produced in the last few years that likewise have produced phenomenal results not only in top end HP, but also have very respectable TQ numbers throughout the power curve.
Not wanting to start a "war" on one head being better than another. Just giving you another educated opinion on another option.
I think the bottom line for TQ is to maximize your cylinder pressure to the maximum point possible without detonation raising it's ugly head.
Many ways to go at it, but I thought I would respectfully share my favorable experience with a small runner head with has proven to be a blast to drive both on the street and the track.
Let us know how it goes. And as always, good luck with your project. WeathermanShawn..
I'll stick my neck out here as the heads I chose lack the general popularity and marketing of many other cylinder heads.
So far, I have had very good results from the PRC Terminator Heads. The heads are 62cc (unmilled), and 200cc runners. It's easy to get a reasonably size cam in there with no milling, and with 200cc runners and with a ~11.0:1 compression, I have had no problem maintaining a HP/TQ curve that comes on early and maintains 400+HP/400+TQ through a significant portion of the power curve.
I.E. 385TQ at 3000rpm's , 415TQ at 4800rpms, and a slowly falling HP/TQ curve that gradually falls to 365TQ at 6300rpm's. And with fairly reasonable track times & traps speeds for being at 6000 feet.
I'm always been somewhat perplexed that Terminator heads lack the aggressive marketing of other head manufactures. Maybe I just lucked out, but I wouldn't necessarily equate their lack of popularity to being an inferior head.
Yes, there have been some prior issues with matching the FAST 90/90 to these heads, but I believe these issues have been resolved.
Theres is no doubt that AFR's and many new cylinder heads have been produced in the last few years that likewise have produced phenomenal results not only in top end HP, but also have very respectable TQ numbers throughout the power curve.
Not wanting to start a "war" on one head being better than another. Just giving you another educated opinion on another option.
I think the bottom line for TQ is to maximize your cylinder pressure to the maximum point possible without detonation raising it's ugly head.
Many ways to go at it, but I thought I would respectfully share my favorable experience with a small runner head with has proven to be a blast to drive both on the street and the track.
Let us know how it goes. And as always, good luck with your project. WeathermanShawn..
