cams
09-03-2007, 02:17 PM
#21
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Originally Posted by Quik
as for tunning, you guys mention what seems to be the hard part about the tuning? i havent encounterd anything to hard yet
09-03-2007, 02:58 PM
#22
Originally Posted by Quik
stock 5.3s flow the same as stock ls1 heads. also the intake valve that is in the 241 are same as the ones in 317s and 243s [minus the ls6 ones]
09-03-2007, 03:31 PM
#23
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Originally Posted by TXsilverado
i thought 243 and ls6 heads were the same....the ls6 having sodium valves...arent the combustion chambers on the 5.3 heads smaller than the ls1's too?
09-03-2007, 04:41 PM
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Originally Posted by TXsilverado
i thought 243 and ls6 heads were the same....the ls6 having sodium valves...arent the combustion chambers on the 5.3 heads smaller than the ls1's too?
09-03-2007, 04:47 PM
#25
Originally Posted by Quik
as for tunning, you guys mention what seems to be the hard part about the tuning? i havent encounterd anything to hard yet
but i wish you could have tried to tune my cam that was in my ls1. that thing was a bitch. one day it would run fine then the next day it wouldn't idle for nothing. i guess that is why lingenfelter stoped making it. it was only a 218/229 560 lift if i remember right and on a 113 lsa but somethng about it made it hard to tune. of course i had it almost dial in right before my truck burnt. 
ok back on topic
09-03-2007, 07:40 PM
#27
Originally Posted by RandomHero
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Now that I think about it you're probably a bad example anyways. that 226/226 (assuming you still have it) is equivalent to about a 220/220 in a 5.3L.
The biggest issues with the trucks is first the heads. They max out even before the intake does. Even if you switch out to 317's you'll see better flow numbers but you'll see a drop in compression, not to mention the valves are too big for that small of a cubed motor.
There's kind of a cool idea floating around about doing a small valve 317 head milled for compression on a 5.3L. I wonder how those would do on a full bolt on/cammed 5.3L with a better intake?
EDIT-I was also a bit perplexed by SportSide not gaining much from the milled 243 heads. That was a bit weird.
Now that I think about it you're probably a bad example anyways. that 226/226 (assuming you still have it) is equivalent to about a 220/220 in a 5.3L.
The biggest issues with the trucks is first the heads. They max out even before the intake does. Even if you switch out to 317's you'll see better flow numbers but you'll see a drop in compression, not to mention the valves are too big for that small of a cubed motor.
There's kind of a cool idea floating around about doing a small valve 317 head milled for compression on a 5.3L. I wonder how those would do on a full bolt on/cammed 5.3L with a better intake?
EDIT-I was also a bit perplexed by SportSide not gaining much from the milled 243 heads. That was a bit weird.
If you move a valve through the highest flowing point of lift for the most amount of time the more air oyu are going to flow. For example most 5.3 heads flow well up to about 550, if you run a 575 lift cam you go through peak flow once going up stay close to it at peak lift then go back through peak flow with the closing of the valve.
Sportside didnt gain much switching to LS6 heads because his compression is about the same as stock and teh LS6 heads dont flow too much better then the 5.3 heads.
09-04-2007, 03:12 AM
#28
Originally Posted by 1slow01Z71
Sportside didnt gain much switching to LS6 heads because his compression is about the same as stock and teh LS6 heads dont flow too much better then the 5.3 heads.
09-04-2007, 05:55 AM
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Of the commom Lsx stock heads, the order of flow according to smokemup.com is:
5.3 < LS1 (barely) < 6.0 < LS6. There is quite a bit of difference between a 5.3 head and a LS6 head especially at higher lifts, ~25 cfm intake @ .500 lift and above. Of course 5.3 heads have the smallest chambers of all, so to use any of the other heads without losing compression they would have to be milled. I don't think you could mill a 6.0 head down from 72cc to 61cc without running into intake fitment problems. Richard from WCCH told me the max they mill is .050. Using the general .006 = 1cc for a LSx, you'd have to mill a 6.0 head .066 to get the chamber down that small.
I agree with Cody, regarding the max lift. I really wish that Comp would publish a graph of lift v. duration for their lobes. It would make explaining cams and valve events alot easier to actually plot out what the intake and exhaust valves are doing during one crank revolution.
5.3 < LS1 (barely) < 6.0 < LS6. There is quite a bit of difference between a 5.3 head and a LS6 head especially at higher lifts, ~25 cfm intake @ .500 lift and above. Of course 5.3 heads have the smallest chambers of all, so to use any of the other heads without losing compression they would have to be milled. I don't think you could mill a 6.0 head down from 72cc to 61cc without running into intake fitment problems. Richard from WCCH told me the max they mill is .050. Using the general .006 = 1cc for a LSx, you'd have to mill a 6.0 head .066 to get the chamber down that small.
I agree with Cody, regarding the max lift. I really wish that Comp would publish a graph of lift v. duration for their lobes. It would make explaining cams and valve events alot easier to actually plot out what the intake and exhaust valves are doing during one crank revolution.
Last edited by tdrumm; 09-04-2007 at 06:01 AM.