[Chad Speier]

Originally Posted by dci

Interesting Chad!!! How accurate do you think that program is? Does your program use it's own flow analysis or do you need to plug the numbers in?


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

It's a program based off 146 cfm/sqin and was written by Mike Leverton and Darin Morgan. Never let me down! You plug your current design data in and it tells you what you need to accomplish your goal. It helps me with MIN CSA airspeed. Which is all dependent on application.

[dci]

Currently the port I described here has a csa at the valve of 3.6" and on my bench flows 497 cfm @ 28". I have not flowed it without a valve yet. So I don't really know how efficient it is.


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[Stan Weiss]

Originally Posted by Chad Speier

Here are a few numbers I come up with from the program I use for everything.

Model Engine
500 CID
1250 HP
8000 peak RPM

4.50in² flowing 655 cfm = 100% efficiency
To achieve goal you will use 3.60in² and 524 cfm of that head

4.50in² flowing 555 cfm = 84% efficiency
To achieve goal you will use 4.25in² and 524 cfm of that head

4.50in² flowing 524 cfm = 76% efficiency
To achieve goal you will use 4.50in² and 524 cfm of that head

Chad,
What CSA area is being used here?

Stan

[BruceWilkie]

Originally Posted by 65nss4spdGTO

The new IA-II iron block is cast at 9.500" with enough deck thickness to get very close to 9.200". This information is based off the two blocks I've had in the shop and sonic tested the decks.

The projected build I have for this project is right around 425ci engine with a 425CFM cylinder head.

Calvin Hill
Hill Performance
708-250-7420

Interesting Calvin... I was simming a 4.25 x 3.75 426 combo awhile back... looked very promising with efficient port very near that flow capacity.

Buildin the real thing is a whole different challenge.

Of interest... One of the better cams I came up with, the net valve seat time was the same seat numbers as the lo-po Pontiac "N" cam... No resemblance beyond that though lol! Not sure if I saved or backed up that particular file as I recall shortening the ex split some with same open point n juggling intake slightly.

[Stan Weiss]

Originally Posted by dci

Currently the port I described here has a csa at the valve of 3.6" and on my bench flows 497 cfm @ 28". I have not flowed it without a valve yet. So I don't really know how efficient it is.


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

Don,
► (497 / 3.6) / 146 = 0.9455859969558599 (94.56% efficiency at that CSA of the port)

Stan

[Chad Speier]

Originally Posted by Stan Weiss

Chad,
What CSA area is being used here?

Stan

Stan it would be 4.50in.

[Chad Speier]

Originally Posted by Stan Weiss

Don,
► (497 / 3.6) / 146 = 0.9455859969558599 (94.56% efficiency at that CSA of the port)

Stan

I have that head 1150hp capable at 500 inches@8000.

What do you come up with?

[Stan Weiss]

Originally Posted by Chad Speier

Stan it would be 4.50in.

Chad,
I worded my question really poorly. Is the CSA used the min, throat, curtain or somewhere else?
Thanks,
stan

[Chad Speier]

Originally Posted by Stan Weiss

Chad,
I worded my question really poorly. Is the CSA used the min, throat, curtain or somewhere else?
Thanks,
stan

Ahh, smart man. That is the key!! I choose the throat but unfortunately it's just MIN area. That is what separates porters, where it's located.

[dci]

Wow!! I did not do the math yet. So it looks like I am headed in the right direction in theory at least LOL.



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[Stan Weiss]

Originally Posted by Chad Speier

I have that head 1150hp capable at 500 inches@8000.

What do you come up with?

Chad,
My software does not do HP simulations.

In a very around about way if the BSFC = 0.453637 then I get 1150 HP.

If MCSA = 3.6 with around 323 fps I get about 128% VE from 500 ci @ 8000 RPM.

That gives me 6781.872 lbs / hr mass air flow @ 13:1 A/F gives me 521.6825 lbs / hr fuel flow.

► 521.6825 / 1150 = 0.4536369565217391

Stan

[johnta1]

Model Engine
500 CID
Using DCI flow of 497 cfm @ 28"
1250 HP
8000 peak RPM

I get around 1240 HP using Mountain Motor radio button:
Estimate HP from Airflow of Head

[dci]

I will be happy with 1150, but if it happens to fall in between 1150 and 1240 it would not disappointment me either LOL.


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[J.C.you]

Don, we did not do any spintron testing. We are at 30 pulls to date.The next session scheduled at the end of the month. The springs were just checked, two exhausts were down alittle, so they were replaced.

[S/st 54]

Originally Posted by dci

I will be happy with 1150, but if it happens to fall in between 1150 and 1240 it would not disappointment me either LOL.


Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

Don, what kind of Rod/Stroke ratio are you looking at or plan on using in the attempt at achieving 2.3hp per cid?

[dci]

JC, That's not bad for 30 passes. What spring are you using?


S\st 54, When I finally do get to build an all out type engine. I think it will be somewhere around 1.57. Right now though I am going to focus on my Popular Hotrodding EMC engine. My plan with it is to come up with a combo that anyone can build and make streetable HP. I cannot tell a lie though. I am going to use a few tricks to try and place well.After all, it is a competition LOL.



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

[Stan Weiss]

Originally Posted by Chad Speier

It's a program based off 146 cfm/sqin and was written by Mike Leverton and Darin Morgan. Never let me down! You plug your current design data in and it tells you what you need to accomplish your goal. It helps me with MIN CSA airspeed. Which is all dependent on application.

Chad,
Since the EMC is a different animal, how well did this program match up HP wise to your Pontiac EMC results?

Stan

[S/st 54]

Originally Posted by dci

JC, That's not bad for 30 passes. What spring are you using?


S\st 54, When I finally do get to build an all out type engine. I think it will be somewhere around 1.57. Right now though I am going to focus on my Popular Hotrodding EMC engine. My plan with it is to come up with a combo that anyone can build and make streetable HP. I cannot tell a lie though. I am going to use a few tricks to try and place well.After all, it is a competition LOL.



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads !!!!!

Sweet! Good luck!

[Chad Speier]

Originally Posted by Stan Weiss

Chad,
Since the EMC is a different animal, how well did this program match up HP wise to your Pontiac EMC results?

Stan

That project baffles me to this day. Here is the issue. Big valve, big flow. Small CSA with big flow equals too fast airspeed.

The EMC head had 2.60in² at the pinch and moved 380 cfm @ .800 which is 146 cfm/sqin of MIN. Out of that it required 2.23in² and 326cfm to make 735@6800 RPM. which is also 146 cfm/sqin..

What I did was set the pinch at 350 fps and let it flow what it did. I was stuck.

[Stan Weiss]

Originally Posted by Chad Speier

That project baffles me to this day. Here is the issue. Big valve, big flow. Small CSA with big flow equals too fast airspeed.

The EMC head had 2.60in² at the pinch and moved 380 cfm @ .800 which is 146 cfm/sqin of MIN. Out of that it required 2.23in² and 326cfm to make 735@6800 RPM. which is also 146 cfm/sqin..

What I did was set the pinch at 350 fps and let it flow what it did. I was stuck.

Chad,
Thanks, since I knew the HP I had used my convoluted method and came up with the needed cfm being around 317.

Stan