6.0 LS Build

[KnightmareZ]

It's all about valve events and how long you keep that valve open to let as much air in and how much you are able to get out on the exhaust side
Actually the cam you speak of would have more overlap 54.5* vs 51*
Should lope a very little bit more, nothing noticeable
As far as low rpm torque the XER Lobes would close at 64.5* ABDC vs summits at 65* ABDC the lower the closing angle the higher the DCR and cylinder pressure.
But as far as numbers are concerned, trivial and almost dead equal until we start talking about the area between where that valve opens, the ramp rate, the lift and then where the valve closes.
Now when you envision the summit lobe coming off the seat at 274 at .004 and 222 at .050 with a .545 lift vs 273 at .004 and 224 @ .050 with .581 lift its pretty obvious which one took in the most air and will have the most cylinder pressure down low. More air entering the chamber will generate higher cylinder pressures given they are closing at the same time. Or in this case the XER even sooner. This means more torque down low. You spell it out like the only gains would be 5500 to 6500 with loss of torque down low. LOL The XER lobe in this example would drag this soft summit lobe throughout the powerband.

[68Formula]

Actually the cam you speak of would have more overlap 54.5* vs 51*
Should lope a very little bit more, nothing noticeable
As far as low rpm torque the XER Lobes would close at 64.5* ABDC vs summits at 65* ABDC the lower the closing angle the higher the DCR and cylinder pressure.

Which is pretty much what I said:

They have virtually the same overlap, so idle will be same.

But as far as numbers are concerned, trivial and almost dead equal

Which is why I wasn't worried about a couple degrees overlap difference.

Now when you envision the summit lobe coming off the seat at 274 at .004 and 222 at .050 with a .545 lift vs 273 at .004 and 224 @ .050 with .581 lift its pretty obvious which one took in the most air and will have the most cylinder pressure down low. More air entering the chamber will generate higher cylinder pressures given they are closing at the same time. Or in this case the XER even sooner. This means more torque down low.

Between the earlier intake centerline (107 versus 108) and the 2 degrees shorter duration @ 0.50" lift on the Summit, I expected a slight increase in torque down low. With the stock head flow and the fact that you're almost at peak flow by .550" lift, the tiny bit lift difference @ low speeds isn't significant enough to impact cylinder filling. Which is why I wrote:

The XER will probably put a few more HP on the very top of the RPM range (like 5500-6500) with a little less torque below that. Won't make much difference unless you change over to CNC ported L92 heads or aftermarket.

You seem to think I was being hard on the XER cam, when really I considered them virtually equal (only minor differences depending where you were in the rpm band).

However, since you came back with a very strong statement of:

The XER lobe in this example would drag this soft summit lobe throughout the powerband.

I decided to toss it into DynoSim and see that that said. I already had the LQ4 modeled previously anyway, and it's been validated against published real world dyno data with various camshafts, so it's reasonable accurate.

Using both the 0.50" and advertised duration, stock heads, factory intake, compression, and long tube headers, they were within 1-2 ft-lbs torque difference below 4000rpm. So basically the same. No slight edge to the Summit, but the XER doesn't "drag it" either. The curves are basically on top of each other.

Now above 4000rpm, you can see the power curves begin to separate with the XER on top, but still talking single digit horsepower with only 6hp difference at the peak. So the XER isn't dragging it on the top end either (even above 6k). I attribute that to the added exhaust duration of the Summit. The 317s aren't as efficient on the exhaust side, and on naturally aspirated engine it it helps quite a bit.

Again, CNC ported heads would make a bigger gap between the two (starting from about peak torque rpm up to peak hp rpm). Or maybe if you were using L92 heads with their more efficient exhaust ports, you might see a little more separation.

[pro86tourn]

Which is pretty much what I said:



Which is why I wasn't worried about a couple degrees overlap difference.




Between the earlier intake centerline (107 versus 108) and the 2 degrees shorter duration @ 0.50" lift on the Summit, I expected a slight increase in torque down low. With the stock head flow and the fact that you're almost at peak flow by .550" lift, the tiny bit lift difference @ low speeds isn't significant enough to impact cylinder filling. Which is why I wrote:



You seem to think I was being hard on the XER cam, when really I considered them virtually equal (only minor differences depending where you were in the rpm band).

However, since you came back with a very strong statement of:

I decided to toss it into DynoSim and see that that said. I already had the LQ4 modeled previously anyway, and it's been validated against published real world dyno data with various camshafts, so it's reasonable accurate.

Using both the 0.50" and advertised duration, stock heads, factory intake, compression, and long tube headers, they were within 1-2 ft-lbs torque difference below 4000rpm. So basically the same. No slight edge to the Summit, but the XER doesn't "drag it" either. The curves are basically on top of each other.

Now above 4000rpm, you can see the power curves begin to separate with the XER on top, but still talking single digit horsepower with only 6hp difference at the peak. So the XER isn't dragging it on the top end either (even above 6k). I attribute that to the added exhaust duration of the Summit. The 317s aren't as efficient on the exhaust side, and on naturally aspirated engine it it helps quite a bit.

Again, CNC ported heads would make a bigger gap between the two (starting from about peak torque rpm up to peak hp rpm). Or maybe if you were using L92 heads with their more efficient exhaust ports, you might see a little more separation.

Which dyno sim do you use? the software seems interesting... maybe I could use such tech to see how certain parts would impact the build.

[pro86tourn]

Finally got the engine out and on the stand.. now time to clean it up ... any of you guys have tips on the easiest way to degrease this thing !!

[79 Camaro]

Since you are going to disassemble to check everything just unbolt parts and send to the machine shop hot tank. Stuff like coils and other more delicate parts clean by hand with degreaser.

[KnightmareZ]

Which is pretty much what I said:



Which is why I wasn't worried about a couple degrees overlap difference.




Between the earlier intake centerline (107 versus 108) and the 2 degrees shorter duration @ 0.50" lift on the Summit, I expected a slight increase in torque down low. With the stock head flow and the fact that you're almost at peak flow by .550" lift, the tiny bit lift difference @ low speeds isn't significant enough to impact cylinder filling. Which is why I wrote:



You seem to think I was being hard on the XER cam, when really I considered them virtually equal (only minor differences depending where you were in the rpm band).

However, since you came back with a very strong statement of:

I decided to toss it into DynoSim and see that that said. I already had the LQ4 modeled previously anyway, and it's been validated against published real world dyno data with various camshafts, so it's reasonable accurate.

Using both the 0.50" and advertised duration, stock heads, factory intake, compression, and long tube headers, they were within 1-2 ft-lbs torque difference below 4000rpm. So basically the same. No slight edge to the Summit, but the XER doesn't "drag it" either. The curves are basically on top of each other.

Now above 4000rpm, you can see the power curves begin to separate with the XER on top, but still talking single digit horsepower with only 6hp difference at the peak. So the XER isn't dragging it on the top end either (even above 6k). I attribute that to the added exhaust duration of the Summit. The 317s aren't as efficient on the exhaust side, and on naturally aspirated engine it it helps quite a bit.

Again, CNC ported heads would make a bigger gap between the two (starting from about peak torque rpm up to peak hp rpm). Or maybe if you were using L92 heads with their more efficient exhaust ports, you might see a little more separation.

On overlap, I was agreeing with you. Maybe I came off wrong LOL.
On the other, I am speaking about the area under the curve. Or how much area there is seat to seat. There's a point when even a numerically smaller lobe at .050 will take in as much or even more charge as larger lobe profiles with less under the curve. This charge, is what it is, once the IV closes. The one with the most will build the most cylinder pressure with the same IVC angle. As far as ICLs, those should be a byproduct of a well thought out set of VEs. But generally speaking, yes. the sooner the ICL the better it performs lower in the RPMs given the same lobes/ same setup. Again you have to keep the VE's in mind as well as the lobe profiles when cutting a cam.

[btmatt]

Tape it up real good and use some purple power and power washer. Awesome stuff

[pro86tourn]

Tape it up real good and use some purple power and power washer. Awesome stuff

I will try that!

Where do you lad's get your engine dress up stuff? Valve covers, cam overs, lifter covers? Summit? Jegs?

[68Formula]

Which dyno sim do you use? the software seems interesting... maybe I could use such tech to see how certain parts would impact the build.

DynoSim5. It's not the most sophisticated out there, but it's ok for the price. Best to start with similar build combinations, to get the models close to real world results, and then you can change aspects as a comparison.

[pro86tourn]

DynoSim5. It's not the most sophisticated out there, but it's ok for the price. Best to start with similar build combinations, to get the models close to real world results, and then you can change aspects as a comparison.

Awesome ! I will check it out!

Next on list is... oil pan, mounts, timing chain, headers.. would you guys reuse water pump/harmonic balancer? Recommendations?

[pro86tourn]

So I decided on using the 243 heads (ported) just waiting for them to return next week from the machine shop.

Next I need the parts to assemble... can anyone offer any advice on what to get ..

Timing chain
ARP?
Gaskets?
Etc etc etc ‘’

So many options out there makes it quite interesting!!!