5.0 LS cam for 7500.

[Tom68]

I think their challenge is to make peak HP at 7500 with good flowing heads on a 5.0 LS and compare it to a coyote.

The question is does it need a Coyote sized cam, sub 223 degrees ??? If that's what Coyotes use for 7500, or does it need Greg's 247 degree cam choice.

Hopefully we get to find out in the future.


https://youtu.be/suOCWgT8iiU

[Bigchief632]

I don't know why this seems like such a feat. What heads? How's he coming up with a 5 litre LS? Big bore short stroke? Big bored 4.8? I've done 408+ LS engines that spin 8000+ with hydraulic roller cams in the 250 ish range.

[Tom68]

I don't know why this seems like such a feat. What heads? How's he coming up with a 5 litre LS? Big bore short stroke? Big bored 4.8? I've done 408+ LS engines that spin 8000+ with hydraulic roller cams in the 250 ish range.

No big feat, just that Ben and Greg in the video come up with pretty different intake duration for the same goal. Sub 223 v 247.

Ported 799s, 3.858 bore.

6 month old video, maybe the results are in ?

[In-Tech]

I'm slowly putting together a 5L for a "crackerbox" boat. 2.94 stroke, solid roller .903 lifters, 9000rpm. We'll see how that goes in a few months.

[hoffman900]

I think their challenge is to make peak HP at 7500 with good flowing heads on a 5.0 LS and compare it to a coyote.

The question is does it need a Coyote sized cam, sub 223 degrees ??? If that's what Coyotes use for 7500, or does it need Greg's 247 degree cam choice.

Hopefully we get to find out in the future.


https://youtu.be/suOCWgT8iiU

Not really following along here?

Are you saying a 2 valve LS will need the same duration as a 4 valve Coyote?

Kind of all meaningless without looking at valve area. For the same peak, my observation a properly built 4 valve will make more torque due to valve area advantage resulting in less duration needed. It’s hard getting around the valve area vs time loss advantage of a pentroof 4 valve.


7500 (8000rpm redline) 302ci road race engines (or 4 cylinders with similar bore / stroke) that I’ve seen are around 250-255* at .050” and around 0.700” valve lift (if you can get it), depending on the heads obviously.

You could probably be more aggressive for a hero dyno motor shootout and / or a drag race engine.

[Tom68]

Are you saying a 2 valve LS will need the same duration as a 4 valve Coyote?

Kind of all meaningless without looking at valve area. For the same peak, my observation a properly built 4 valve will make more torque due to valve area advantage resulting in less duration needed. It’s hard getting around the valve area vs time loss advantage of a pentroof 4 valve.


7500 (8000rpm redline) 302ci road race engines (or 4 cylinders with similar bore / stroke) that I’ve seen are around 250-255* at .050” and around 0.700” valve lift (if you can get it), depending on the heads obviously.

You could probably be more aggressive for a hero dyno motor shootout and / or a drag race engine.

Nah, I think the LS will need the bigger cam and of course not be comparable to the Coyote through the rest of the rev range.

I'm assuming they arecomparing to a Coyote with a smaller cam that nonetheless peaks at 7500.

I'm curious to see what they come up with and the test results. The project dates back to early 2021 so I guess I better not hold my breath.

https://www.enginelabs.com/engine-tech/ ... the-ls5-0/

[hoffman900]

Are you saying a 2 valve LS will need the same duration as a 4 valve Coyote?

Kind of all meaningless without looking at valve area. For the same peak, my observation a properly built 4 valve will make more torque due to valve area advantage resulting in less duration needed. It’s hard getting around the valve area vs time loss advantage of a pentroof 4 valve.


7500 (8000rpm redline) 302ci road race engines (or 4 cylinders with similar bore / stroke) that I’ve seen are around 250-255* at .050” and around 0.700” valve lift (if you can get it), depending on the heads obviously.

You could probably be more aggressive for a hero dyno motor shootout and / or a drag race engine.

Nah, I think the LS will need the bigger cam and of course not be comparable to the Coyote through the rest of the rev range.

I'm curious to see what they come up with and the test results. The project dates back to early 2021 so I guess I better not hold my breath.

https://www.enginelabs.com/engine-tech/ ... the-ls5-0/

You can look at the 2013 EMC Challenge results to see (they really ruined it after that year once they realized the 4 valve heads were going to dominate and probably effect sponsor sales ) . Stock casting mod motors vs aftermarket LS and and vintage architecture headed engines and their camshaft durations vs power curves. The Coyote head should be even better than those ones.

I like how that EngineLabs article tries to be scientific and then they write this:

Initially, we’ve found people fall into two camps. Camp one says, “if displacement is the same, they will probably perform the same.” Camp two is of the mind that because one is a pushrod engine and the other is an overhead cam engine, the two engines will perform wildly differently. If we take into account the power-per-cubic-inch numbers from the previous tests, we certainly have our work cut out for us to get the LS5.0 to match the Coyote’s results.

What camp thinks it’s the oushrods that make a difference? Lol. It’s 4 valves vs 2 valves. That’s the difference, that’s what the engine “sees”.

[Tom68]

You can look at the 2013 EMC Challenge results to see (they really ruined it after that year once they realized the 4 valve heads were going to dominate and probably effect sponsor sales ) . Stock casting mod motors vs aftermarket LS and and vintage architecture headed engines and their camshaft durations vs power curves. The Coyote head should be even better than those ones.

I like how that EngineLabs article tries to be scientific and then they write this:

Initially, we’ve found people fall into two camps. Camp one says, “if displacement is the same, they will probably perform the same.” Camp two is of the mind that because one is a pushrod engine and the other is an overhead cam engine, the two engines will perform wildly differently. If we take into account the power-per-cubic-inch numbers from the previous tests, we certainly have our work cut out for us to get the LS5.0 to match the Coyote’s results.

What camp thinks it’s the oushrods that make a difference? Lol. It’s 4 valves vs 2 valves. That’s the difference, that’s what the engine “sees”.

Yer that 2013 Challenge covers it.

https://www.motortrend.com/news/2013-am ... allenge-2/

[Tom68]

Bens smaller cam formula.

https://www.enginelabs.com/engine-tech/ ... -of-efi-u/

[In-Tech]

I'm slowly putting together a 5L for a "crackerbox" boat. 2.94 stroke, solid roller .903 lifters, 9000rpm. We'll see how that goes in a few months.

Hiya Folks,
I found out a bit more info on our project. It is very budget limited and that sucks but is what it is. It is limited to a 650 carb. I absolutely love anything limited carb. I'll keep everyone posted as we progress. It's going to be a fun project for me.

[hoffman900]

Bens smaller cam formula.

https://www.enginelabs.com/engine-tech/ ... -of-efi-u/

Those numbers read like it has to last a single dyno pull and will fall on its fave immediately after. 230* at .050 and over .600 valve lift?

He did qualify it that it could want 275* at .050” and you need to dyno test. So he gets that it isn’t that simple.

[CamKing]

This is what I would recommend for making peak HP at 7,500rpm, for a 5.0L with a 3.26" stroke, and enough port to supply the engine at 7,500rpm.

Intake: 244@.050", .637" Valve Lift
Exhaust: 248-254@.050", .610"-630" Valve Lift(depending on exhaust port size)
110 to 114 LSA, depending on compression ratio.

With a cam below 230@.050", the power would start dropping off at 6,900rpm.

If you measure the curtain area at every .050" of valve lift, you will see why a 2-Valve engine needs much more duration then a 4-valve.

[Stan Weiss]

Can someone else do the calculations using Ben's method?

Using Ben's method I get 197.25 degrees @ 0.050" Now to fair this method uses a fixed VE% of 100%.

Stan

[CamKing]

Can someone else do the calculations using Ben's method?
Using Ben's method I get 197.25 degrees @ 0.050" Now to fair this method uses a fixed VE% of 100%.

It takes a special calculator to do YouTube math.

[GARY C]

Can someone else do the calculations using Ben's method?
Using Ben's method I get 197.25 degrees @ 0.050" Now to fair this method uses a fixed VE% of 100%.

It takes a special calculator to do YouTube math.