Race engine vs Street engine with same combo

[CamKing]

Thought some might find this interesting. Maybe a discussion with some dyno results. This might not be a perfect A/B test, but the heads were the same and the components.

Basic engine:
4.165 x 3.48
Both LW Scat cranks
Both Mahle pistons
Both 6.000 rods
Same oil pans

Engine 1:
Whitener 1000hp 4150 VP113 fuel
13.50 compression
Vacuum pump w/11.2"
260/268 Solid Roller
.680 at retainers
106 LSA 102 ICL
677@7300 --- 545@5400

Calculating the efficiency of the output from engine #1, I would say you're right at the limit of that port. It can make more power with a larger cam, and more RPM, but it won't be as efficient.

YES, totally agree. Using my Leverton spreadsheet, it was using all of the cross section and flow to make that power at 7300 rpm based on 146 cfm sq/in.

Yep, when I calculated the 100% VE power for that combo @ 7,300rpm,
I came up with 683hp, and 552ft/lbs.

[SpeierRacingHeads]

Calculating the efficiency of the output from engine #1, I would say you're right at the limit of that port. It can make more power with a larger cam, and more RPM, but it won't be as efficient.

YES, totally agree. Using my Leverton spreadsheet, it was using all of the cross section and flow to make that power at 7300 rpm based on 146 cfm sq/in.

Yep, when I calculated the 100% VE power for that combo @ 7,300rpm,
I came up with 683hp, and 552ft/lbs.

Thanks Mike. Now if I could learn how to read a burette!!!

[Stan Weiss]

The vein is 2" long and .500 at it's peak on the apex. It's around 8cc.

The cc of the wing is irrelevant/you have to have a good amount of area much smaller than 2.3 or its not 205//or 2.3 average/ think about it/ the average of 5,6,and 4 cant be 3./205 starting or milled flange maybe/ in the end dont matter that its much bigger/just observing trends/

If the wing is remove 205 + 8 = 213 cc's. 213 cc's @ 5.4" = 2.407 sq in AVG CSA

Stan

[SpeierRacingHeads]

This shows how big the wing actually is.. This was the master port.

[SpeierRacingHeads]

And as you can see, the port is really low in the casting. Floor to roof is much shorter than most heads. It's much wider than normal.

[gmrocket]

How can the 195cc head have a 2.20 pinch and be 195cc then?

I listed the areas.

Wouldnt even try to speculate/ i would want my own measurements/thats not always cut and dry between people/ but 2.2 mi imus 195 cc from those numvers alone would suggest less major csa variations than your ports stated dimensions/ your port can be whatever you want it to be/being bigger than 205 is not a criticism so dont take it that way/only an observatiom that seem obvious by your specs/ i can be wrong if you prefer that

I know you can't respond but can see this.. so

I don't doubt the cc since its easy to to do and given 5 different people doing it, you should come up with the same

It's the min csa's that are probably off. Just the fact that the wing wasn't in the measurements in the first place tells you the min csa's are are not the minimum, in that area.

Unlike CC'ing, when it comes to measuring and calculating port csa's,, you'll get 5 different answers from 5 different people measuring the same spot..some would be way off.

[6.50camaro]

Corner radius has to coming into play also . You can't fiqure accurate cc's off square corner dimensions . A 1/2" radius on 4 corners will subtract about 3.5 cc per inch off port length. I dont know what Chad uses on that head but they look genrously sized . Dan

[SpeierRacingHeads]

How can the 195cc head have a 2.20 pinch and be 195cc then?

I listed the areas.

Wouldnt even try to speculate/ i would want my own measurements/thats not always cut and dry between people/ but 2.2 mi imus 195 cc from those numvers alone would suggest less major csa variations than your ports stated dimensions/ your port can be whatever you want it to be/being bigger than 205 is not a criticism so dont take it that way/only an observatiom that seem obvious by your specs/ i can be wrong if you prefer that

I know you can't respond but can see this.. so

I don't doubt the cc since its easy to to do and given 5 different people doing it, you should come up with the same

It's the min csa's that are probably off. Just the fact that the wing wasn't in the measurements in the first place tells you the min csa's are are not the minimum, in that area.

Unlike CC'ing, when it comes to measuring and calculating port csa's,, you'll get 5 different answers from 5 different people measuring the same spot..some would be way off.

The wing is nowhere near the pinch MIN CSA. The wing was deducted out of all the cross sections. The cross sections came from the actual digitized port. Maybe the software is wrong?? lol

If I have a sectional of the digitized port from start to finish, it has to be FAR more accurate than anything we do by hand.

[gmrocket]

Wouldnt even try to speculate/ i would want my own measurements/thats not always cut and dry between people/ but 2.2 mi imus 195 cc from those numvers alone would suggest less major csa variations than your ports stated dimensions/ your port can be whatever you want it to be/being bigger than 205 is not a criticism so dont take it that way/only an observatiom that seem obvious by your specs/ i can be wrong if you prefer that

I know you can't respond but can see this.. so

I don't doubt the cc since its easy to to do and given 5 different people doing it, you should come up with the same

It's the min csa's that are probably off. Just the fact that the wing wasn't in the measurements in the first place tells you the min csa's are are not the minimum, in that area.

Unlike CC'ing, when it comes to measuring and calculating port csa's,, you'll get 5 different answers from 5 different people measuring the same spot..some would be way off.

The wing is nowhere near the pinch MIN CSA. The wing was deducted out of all the cross sections. The cross sections came from the actual digitized port. Maybe the software is wrong?? lol

If I have a sectional of the digitized port from start to finish, it has to be FAR more accurate than anything we do by hand.

I meant the csa's

Why would both those engines get the same head in the first place?

[SpeierRacingHeads]

I know you can't respond but can see this.. so

I don't doubt the cc since its easy to to do and given 5 different people doing it, you should come up with the same

It's the min csa's that are probably off. Just the fact that the wing wasn't in the measurements in the first place tells you the min csa's are are not the minimum, in that area.

Unlike CC'ing, when it comes to measuring and calculating port csa's,, you'll get 5 different answers from 5 different people measuring the same spot..some would be way off.

The wing is nowhere near the pinch MIN CSA. The wing was deducted out of all the cross sections. The cross sections came from the actual digitized port. Maybe the software is wrong?? lol

If I have a sectional of the digitized port from start to finish, it has to be FAR more accurate than anything we do by hand.

I meant the csa's

Why would both those engines get the same head in the first place?

I explained that already.

And why not? I wanted one to peak at 7300 and one at 6300. Mission accomplished.

Both made great power. I don't care what anyone says. I know the dyno they were on.

[gmrocket]

Post the dyno sheet for the street engine.

[SpeierRacingHeads]

10.5-1, 231/235 in 108 w/112. .550 lift, 91 Octane from the SuperMarket. 7 pulls, no adjusting except 2º of timing because it's getting a elbow and TB in the car. 3.48 stroke.

Head flowed 293@.600 and 265@.600 through the induction. Carb that was used was a 750 built by Siebert.

That is manifold vacuum.

[SpeierRacingHeads]

Even dyno'd with the accessory belt.

[SpeierRacingHeads]

Here is a video on a Stuska dyno.

[RevTheory]

Sounds really good. Please let us know how it idles when you get it all wired up.