Low Numbers?
Low Numbers? Ok my car with a lq4, ls3 heads, ls3 intake and injectors and a cam 224intake and 236 exhaust with a 612 lift it made 428 rwhp and 413 rwhp i think that is kind of low but i don't know???
What size headers? What size exhaust? Was it 1 3/4" headers or 1 7/8" headers? What brand? What size y-pipe?
Lid set-up?
What lsa on the cam and does it have any advance ground in it? Is the cam installed straight up or advanced any?
Torque sounds close, HP sounds a little low, but LSA and ICL can have an effect on that.
I personally am not a fan of the LS3 stuff on anything less than a 4.065" bore. Torque production suffers from not enough air flow at low to mid lifts to satisfy the size runner that those heads have from a big lazy port with not enough velocity. Combined with the huge intake valve and you have a set-up that IMO isn't optimized for a 4.0" bore.
Lid set-up?
What lsa on the cam and does it have any advance ground in it? Is the cam installed straight up or advanced any?
Torque sounds close, HP sounds a little low, but LSA and ICL can have an effect on that.
I personally am not a fan of the LS3 stuff on anything less than a 4.065" bore. Torque production suffers from not enough air flow at low to mid lifts to satisfy the size runner that those heads have from a big lazy port with not enough velocity. Combined with the huge intake valve and you have a set-up that IMO isn't optimized for a 4.0" bore.
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From: REALITY
As others have stated, you need to provide a complete list of your setup from Cam,pushrod length, springs, etc.....
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Verdad Gallardo Without going into great detail....
He is using a 4.0" bore, those heads were designed for a 4.065" bore. I know there will be people that argue that it is minute, but it's a big difference maker in flow at low to mid lifts. Up top in the higher lifts there is more available air mass so you don't see as much of a drop in peak air flow, but torque production suffers. Torque=HP...the more torque you can make and then shift to your advantage where you want it the more hp you will make as a result.
The large intake valve of the LS3 heads along with the large intake runner on a smaller bore with diminished low-mid lift flow numbers will not carry enough port velocity to make efficient torque production. This is why the cathedral port TFS heads make so much overall power and can make huge power up top when the torque curve is taken advantage of and shifted where the power wants to be made, intake manifold design will limit rpm that peak power is made though so the combo as a whole needs to be taken into consideration.
The large runner also does not help and needs the added air flow that a larger bore will offer.
In a nutshell this is the dilemma. Camshaft can only do so much when the short block isn't optimized to the cylinder head. You could try and throw some more intake duration at it to make the IVC event later for more peak hp, keep the ICL tight to not lose a lot of torque it has and then throw 4-6 more degrees on the exhaust duration to try and bump the mid-range and peak numbers some by helping carry the torque out further past peak torque.
Again though there is only so much a camshaft can do.
He is using a 4.0" bore, those heads were designed for a 4.065" bore. I know there will be people that argue that it is minute, but it's a big difference maker in flow at low to mid lifts. Up top in the higher lifts there is more available air mass so you don't see as much of a drop in peak air flow, but torque production suffers. Torque=HP...the more torque you can make and then shift to your advantage where you want it the more hp you will make as a result.
The large intake valve of the LS3 heads along with the large intake runner on a smaller bore with diminished low-mid lift flow numbers will not carry enough port velocity to make efficient torque production. This is why the cathedral port TFS heads make so much overall power and can make huge power up top when the torque curve is taken advantage of and shifted where the power wants to be made, intake manifold design will limit rpm that peak power is made though so the combo as a whole needs to be taken into consideration.
The large runner also does not help and needs the added air flow that a larger bore will offer.
In a nutshell this is the dilemma. Camshaft can only do so much when the short block isn't optimized to the cylinder head. You could try and throw some more intake duration at it to make the IVC event later for more peak hp, keep the ICL tight to not lose a lot of torque it has and then throw 4-6 more degrees on the exhaust duration to try and bump the mid-range and peak numbers some by helping carry the torque out further past peak torque.
Again though there is only so much a camshaft can do.
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Joined: Jan 2010
Posts: 578
Likes: 4
From: REALITY
Without going into great detail....
He is using a 4.0" bore, those heads were designed for a 4.065" bore. I know there will be people that argue that it is minute, but it's a big difference maker in flow at low to mid lifts. Up top in the higher lifts there is more available air mass so you don't see as much of a drop in peak air flow, but torque production suffers. Torque=HP...the more torque you can make and then shift to your advantage where you want it the more hp you will make as a result.
The large intake valve of the LS3 heads along with the large intake runner on a smaller bore with diminished low-mid lift flow numbers will not carry enough port velocity to make efficient torque production. This is why the cathedral port TFS heads make so much overall power and can make huge power up top when the torque curve is taken advantage of and shifted where the power wants to be made, intake manifold design will limit rpm that peak power is made though so the combo as a whole needs to be taken into consideration.
The large runner also does not help and needs the added air flow that a larger bore will offer.
In a nutshell this is the dilemma. Camshaft can only do so much when the short block isn't optimized to the cylinder head. You could try and throw some more intake duration at it to make the IVC event later for more peak hp, keep the ICL tight to not lose a lot of torque it has and then throw 4-6 more degrees on the exhaust duration to try and bump the mid-range and peak numbers some by helping carry the torque out further past peak torque.
Again though there is only so much a camshaft can do.
He is using a 4.0" bore, those heads were designed for a 4.065" bore. I know there will be people that argue that it is minute, but it's a big difference maker in flow at low to mid lifts. Up top in the higher lifts there is more available air mass so you don't see as much of a drop in peak air flow, but torque production suffers. Torque=HP...the more torque you can make and then shift to your advantage where you want it the more hp you will make as a result.
The large intake valve of the LS3 heads along with the large intake runner on a smaller bore with diminished low-mid lift flow numbers will not carry enough port velocity to make efficient torque production. This is why the cathedral port TFS heads make so much overall power and can make huge power up top when the torque curve is taken advantage of and shifted where the power wants to be made, intake manifold design will limit rpm that peak power is made though so the combo as a whole needs to be taken into consideration.
The large runner also does not help and needs the added air flow that a larger bore will offer.
In a nutshell this is the dilemma. Camshaft can only do so much when the short block isn't optimized to the cylinder head. You could try and throw some more intake duration at it to make the IVC event later for more peak hp, keep the ICL tight to not lose a lot of torque it has and then throw 4-6 more degrees on the exhaust duration to try and bump the mid-range and peak numbers some by helping carry the torque out further past peak torque.
Again though there is only so much a camshaft can do.
These heads have no problem making torque even on the 6.0 platform.
At least find out what his total combination is before giving an analysis that the cylinder head selection is the problem. LOL
Last edited by bozzhawg; Sep 16, 2012 at 08:57 AM.
I've seen these things on the dyno first hand day in and day out, have you?
What are your credentials? What does your car run?
I've seen you post a lot of stupid things on this website since you've become a member about how you know everything you state to be true, but I have yet to see a video of your car running at a track or even putting down a reasonably respectable dyno number yourself. Let alone a combination you have put together yourself for someone else and at least attempt to make a number.
Just pointing out that if you live in a glass house don't throw stones.
Last edited by Sales@Tick; Sep 16, 2012 at 01:47 PM.
I am not saying either that the LS3 heads can't make power, I just don't find them optimal for a bore smaller than 4.065" and honestly I believe along with many others that a 4.125" bore really allows them to shine.
Kooljames doesn't need a head swap to make the power he wants, but there are probably several things he can improve upon to boost his numbers.
Kooljames doesn't need a head swap to make the power he wants, but there are probably several things he can improve upon to boost his numbers.
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Remember what the Dyno is for. before and after, not so much the final number by itself. it's a tool to see if you're going in the right direction.
What size headers? What size exhaust? Was it 1 3/4" headers or 1 7/8" headers? What brand? What size y-pipe?
Lid set-up?
What lsa on the cam and does it have any advance ground in it? Is the cam installed straight up or advanced any?
Torque sounds close, HP sounds a little low, but LSA and ICL can have an effect on that.
I personally am not a fan of the LS3 stuff on anything less than a 4.065" bore. Torque production suffers from not enough air flow at low to mid lifts to satisfy the size runner that those heads have from a big lazy port with not enough velocity. Combined with the huge intake valve and you have a set-up that IMO isn't optimized for a 4.0" bore.
Lid set-up?
What lsa on the cam and does it have any advance ground in it? Is the cam installed straight up or advanced any?
Torque sounds close, HP sounds a little low, but LSA and ICL can have an effect on that.
I personally am not a fan of the LS3 stuff on anything less than a 4.065" bore. Torque production suffers from not enough air flow at low to mid lifts to satisfy the size runner that those heads have from a big lazy port with not enough velocity. Combined with the huge intake valve and you have a set-up that IMO isn't optimized for a 4.0" bore.