VVT Cam .......... or ......... LS3 Conversion

[Huggerorange73]

Originally Posted by SSE 4 2SS

It primarily has to do with LSA and then duration... If the LSA is too small, then the exhaust and intake valves are both open at the same time... This can also be affected by the duration. The exhaust valve can still be open when the intake valve opens, thus, boost swirls through the chamber and out the exhaust valve...reduction in boost...limit the duration, and open the LSA and you retain the boost where you want it, in the cylinder... Basically, you want the exhaust valve closed when the intake valve opens...

This, very much!

Originally Posted by Dangeruss

So is anything else limited at that point? Lope? Power?

Lope is created by LSA....what you're hearing is the valves both being open at the same time. You can retain power with a cam and a blower by using a narrow LSA to limit the amount of time the valves overlap.

I'm on a 113 LSA.....sounds great, but not what you want with a blower.

Originally Posted by Supercharged SS

PQ, have you thought about bigger headers if you do a cam. There might be some gain if you do. I didnt read this entire thread but don't you have 1 3/4's.

Bigger headers hurt boost....same thought process, air is leaving in more volume...that's why you have to swap the pulley out to get back boost lost with headers.

[SSE 4 2SS]

Originally Posted by Dangeruss

So is anything else limited at that point? Lope? Power?

Power is better with the right cam, boost in the cylinders makes more power, and the lope is related to the smaller overlap, which is ok/good for NA motors...like someone else mentioned, with boost, and big cams, be sure to upgrade the springs, valves and pistons kissing is a death sentence...

As an aside to the springs comment, bear in mind these are pretty big valves in these heads, so, think of an umbrella in a hurricane... Big valves and big boost require schwzeneggar springs... I'll be Bach...Is knot a tumah

[Huggerorange73]

Originally Posted by SSE 4 2SS

PQ, I believe the LSA with VVT is where you get into the +... Cams, but don't quote me on that...

The " + " you see following the LSA is advance thats ground into the camshaft already.

[PQ]

Originally Posted by SSE 4 2SS

It primarily has to do with LSA and then duration... If the LSA is too small, then the exhaust and intake valves are both open at the same time... This can also be affected by the duration. The exhaust valve can still be open when the intake valve opens, thus, boost swirls through the chamber and out the exhaust valve...reduction in boost...limit the duration, and open the LSA and you retain the boost where you want it, in the cylinder... Basically, you want the exhaust valve closed when the intake valve opens...

If I do the conversion then I don't have to worry about all that right? Just get a cam that I know works and put it in.

Originally Posted by Supercharged SS

PQ, have you thought about bigger headers if you do a cam. There might be some gain if you do. I didnt read this entire thread but don't you have 1 3/4's.

No way. I'm not gonna spend money on headers when I already have some. I LOVE the sound of these.

Ya, I have 1 3/4 and it may actually be good so as to not lose as much boost when I cam it. It would seem anyway.

Originally Posted by SSE 4 2SS

PQ, I believe the LSA with VVT is where you get into the +... Cams, but don't quote me on that...

Ya, I have to do some more reading. But, again, if I just pull the heads, It becomes much easier.

[Supercharged SS]

You'll need bigger headers for that cam. Yes, you will produce less boost but make more power. Less boost = safer

[Dangeruss]

Originally Posted by SSE 4 2SS

Power is better with the right cam, boost in the cylinders makes more power, and the lope is related to the smaller overlap, which is ok/good for NA motors...like someone else mentioned, with boost, and big cams, be sure to upgrade the springs, valves and pistons kissing is a death sentence...

OK...a vein just popped out of my head. You guys know way more about this than I do.

My Whipple and cam were installed at the same time. The 4" pulley that ships with the Whipple is typically supposed to produce 9lbs of boost. Mine was at 7.3lbs. I had headers, catback exhaust, intake and a cam. Was the drop just a combination of all of the above?

[SSE 4 2SS]

Don't have to worry about all what... The VVT, or the LSA and duration... VVT goes away, then get a suitable cam for boost... My cam is a 121 degree separation, awesome sounding, and works great with boosted motors...

Originally Posted by PQ

If I do the conversion then I don't have to worry about all that right? Just get a cam that I know works and put it in.

No way. I'm not gonna spend money on headers when I already have some. I LOVE the sound of these.

Ya, I have 1 3/4 and it may actually be good so as to not lose as much boost when I cam it. It would seem anyway.

Ya, I have to do some more reading. But, again, if I just pull the heads, It becomes much easier.

[Huggerorange73]

Originally Posted by Dangeruss

OK...a vein just popped out of my head. You guys know way more about this than I do.

My Whipple and cam were installed at the same time. The 4" pulley that ships with the Whipple is typically supposed to produce 9lbs of boost. Mine was at 7.3lbs. I had headers, catback exhaust, intake and a cam. Was the drop just a combination of all of the above?

You got it!

[SSE 4 2SS]

Originally Posted by Dangeruss

OK...a vein just popped out of my head. You guys know way more about this than I do.

My Whipple and cam were installed at the same time. The 4" pulley that ships with the Whipple is typically supposed to produce 9lbs of boost. Mine was at 7.3lbs. I had headers, catback exhaust, intake and a cam. Was the drop just a combination of all of the above?

Without knowing the specs on the cam, it's hard to say...lots of shops will install a rump rump cam for the sound, but, that's not always the best thing... Do you have your specs... And I'm not slamming any shops or peeps... Just throwing info, what little I know out there...

About a year ago, Someone did a good write up, not specifically about this, but this was included...wish I could remember who, might have been Ted...

[Dangeruss]

Hey Randy...it may not have as much lope as mlee's, but I'm pretty happy with my mild VVT cam.

[Supercharged SS]

Originally Posted by Dangeruss

OK...a vein just popped out of my head. You guys know way more about this than I do.

My Whipple and cam were installed at the same time. The 4" pulley that ships with the Whipple is typically supposed to produce 9lbs of boost. Mine was at 7.3lbs. I had headers, catback exhaust, intake and a cam. Was the drop just a combination of all of the above?

What he said. Cam + headers = less boost but more power. Take that out of your equation and blam, there's your 9 lbs.

[Huggerorange73]

Originally Posted by SSE 4 2SS

Without knowing the specs on the cam, it's hard to say...lots of shops will install a rump rump cam for the sound, but, that's not always the best thing... Do you have your specs... And I'm not slamming any shops or peeps... Just throwing info, what little I know out there...

About a year ago, Someone did a good write up, not specifically about this, but this was included...wish I could remember who, might have been Ted...

Headers and the cam are the biggest factors in it....a good tuner/ builder is not going to let you put the wrong cam in it PQ!

[PQ]

Originally Posted by Huggerorange73

Bigger headers hurt boost....same thought process, air is leaving in more volume...that's why you have to swap the pulley out to get back boost lost with headers.

Which is why my 1 3/4 primaried headers may actually work just fine with a cam. Or am I off base on that?

Originally Posted by Supercharged SS

You'll need bigger headers for that cam. Yes, you will produce less boost but make more power. Less boost = safer

But if I keep the boost shouldnt' I be able to make more power and find a happy medium with the whole aspiration process?

Originally Posted by SSE 4 2SS

Don't have to worry about all what... The VVT, or the LSA and duration... VVT goes away, then get a suitable cam for boost... My cam is a 121 degree separation, awesome sounding, and works great with boosted motors...

Worry about LSA. Because it will be constant with a non-VVT cam. With a VVT cam it can change, right?

[Dangeruss]

Originally Posted by Supercharged SS

What he said. Cam + headers = less boost but more power. Take that out of your equation and blam, there's your 9 lbs.

That's what I thought, but I guess I figured the cam made most of the drop.