Crazy Port Velocity

[Grumpy]

obviously the TIME spent in each section of the power bands
would have a large effect or influence on which intake provided the best compromise or better acceleration.
car weight, , converter stall speed, tire diameter and gearing would have an effect on acceleration
assuming a stall speed, and rear gear is selected for racing to maximize acceleration ,
the single plane should have a marginal edge in performance, as this is obviously not a street ,
performance application.

 

[Chad Speier]

The engine runs 6500-8800.. It's amazing to me that they run them that far over peak power, but they do. I would love for it to peak at 7500, just not sure it's possible.

 

[Chad Speier]

I've never really figured the degree of taper. However the opening at the manifold 3.5/3.6in and the runner is 4.850/5.00 long. The head opening is 1.85in and the runner is 5.14 long.

 

[Chad Speier]

Also the reason most run the Victor E is because from carb pad to china rail it's 4" tall. With a 1/2 spacer and the flat hood you have to run, this picture shows the carb/hood clearance.

 

[Indycars]

The engine runs 6500-8800.. It's amazing to me that they run them that far over peak power, but they do.

In light of your comment above, these results from Dynomation's ProIterator may not mean much, but if they interest you I can run them again with different parameters.

Using the computer for what it does best, crunching numbers I setup Dynomation for what's called a dual phase testing. First it test engines by changing the camshaft numbers within limits provided. In this case it's +-8°, in steps of 2°. Then it takes the best and retests by changing the numbers by 4° in steps of 1°. See graphic below.....



Then I tell it to "Optimize Area under Horsepower Curve" from 5000 rpm to 7000 rpm. You will notice that to complete what I have setup it will have to run 19,683 tests.



When the testing was done it gives me the chance to save up to 10 different engines. I saved three.



Below are the three best ProInterator engines compared to Sim02.




It appeared that PI engines #3 and #7 were slightly better than #5. Engine #5 is the yellow line, #3 and #7 are essentially on top of each other.

Below are the new timing numbers for PI engines #3 and #7 and finally the original Sim02 timing numbers (Bullet Camshaft).





.

 

[Chad Speier]

Do you have a power graph with the smaller cam? I will get the exact numbers from Bullet tomorrow, but that is much closer to what I need/want. I was thinking 264/274 on 106 w/.850 lift.

 

[Indycars]

Here you go !

 

[Chad Speier]

I got the new cam nailed down.

55mm
272/280 @.050"
.465"/.465" Lobe Lift
112 LSA
1.90/1.80 rockers

 

[Indycars]

That's a big change for the LSA from 108° to 112°, what prompted you to go in this direction ?

What's the seat-to-seat duration and the Intake Centerline so I can run a sim on this camshaft ?

 

[Chad Speier]

Just trying to move the RPM peak up 3-400 rpm. It's a tool steel cam as well.

The older combos have small headers, 6000 stall, and 106 cams. The newer combos has big headers, 6500+ stall and peak higher. It's out of induction so I'm thinking it's in valve train stability and just moving it up.

Intake is 320º
Exhaust is 328º

 

[Indycars]

Still need the Intake Centerline, that is if you want me to run a sim with the new cam ?

 

[Chad Speier]

Duration@.012": 320/328
Duration@.050": 272/280
Lobe Lift: .465"/.465"
Net Valve Lift: .861"/.815"
LSA:112
Intake Centerline: 108

@.050" Lifter rise:
Intake opens @ 28 btdc
Intake closes @ 64 abdc
Exhaust opens @ 76 bbdc
Exhaust closes @ 24 atdc

 

[Indycars]

Did you want to see it compared to a different Sim ?

 

[Chad Speier]

Did you want to see it compared to a different Sim ?

View attachment 17255

Could you run a complete workup like the Sim.pdf?

 

[Indycars]

I included a glossary that comes at the end of the report, probably not needed for yourself, but an example of a simulation that you might provide to a client. The glossary has a 1 page or 5 page option. Also you will notice your logo is included in the report along with your company information.

Enjoy !

 

[Chad Speier]

THANK YOU!

 

[Indycars]

Your welcome !

 

[Chad Speier]

 

[NewbVetteGuy]

The question, how does a cylinder head that has a 2.04 AVG CSA, and is 172cc, make the power and at 7100??

Port shape perfection? (And cam to take advantage of it?)

Adam

 

[Chad Speier]

Port shape perfection? (And cam to take advantage of it?)

Adam

For sure, all about managing the really fast velocity.