Hey guys, as some of you may know, I am in the planning stages of my engine build and I'm using Desktop Dyno 2003 to get a rough idea of HP and TQ numbers. I've added many cams and quite a few heads to my list. I've noticed that the Cam manager has a slider called "Ramp Rate" and I have no idea where to set it for each cam file that I use.

Can any of you guys help me figure out how to determine ramp rate so I can set it properly? I've noticed that when I play with the ramp rate slider that I can gain or lose a ton of HP and TQ...well over 150+ HP/TQ and that's just not accurate enough for me to make some decisions. Can any of the cam specs help me figure it out?

Any help on figuring out how to set that properly is appreciated and if any of you guys need DD 2003, let me know, I can send it to you.

Also, as I've been adding flow numbers to my head files I've come across two different flow numbers for the same heads. (Brodix Race-Rite 200 23° Cylinder Heads - 200cc Intake Ports, 67cc Combustion Chambers)

Jegs flow chart gives me this: Flow chart at the bottom of the page (click More Details): http://www.jegs.com/i/Brodix/158/1011008/10002/-1/755722|10187#

and the Brodix site is here: scroll down for the chart (RR 200 CNC Combustion Chambers) http://www.brodix.com/heads/raceritesb.html

Those are some huge differences and will likely determine which heads I decide to go with. Which numbers do I go with?


Jeff

I hope that when you talk about DD2003 now being able to input ramp rates that you mean both advertised and duration at .050" numbers. Not one or the other!

Correct??

B/c a 290/218 cam will produce less power than a 268/218 cam, imho. Midrange t will be down..

pdq67

Hey Jeff,
I will call the engine builder I know and find out for you today. You may try calling one of the cam company's and ask them? I would think they would be able to answer this one. I'm trying to build a motor as well and I would love to have DD 2003 to play around with.
Thanks!

I hope that when you talk about DD2003 now being able to input ramp rates that you mean both advertised and duration at .050" numbers. Not one or the other!

Correct??

B/c a 290/218 cam will produce less power than a 268/218 cam, imho. Midrange t will be down..

pdq67


Here is a screen shot of it. I circled what I'm talking about in red on the bottom left there. I have to enter it manually because I don't know how to get the seat to seat timing. Any help figuring out seat to seat timing? :)

Hey Jeff,
I will call the engine builder I know and find out for you today. You may try calling one of the cam company's and ask them? I would think they would be able to answer this one. I'm trying to build a motor as well and I would love to have DD 2003 to play around with.
Thanks!

You have a PM.


http://img.photobucket.com/albums/v299/GODZ3R0/Camaro%20Pix/DDscreenshot.jpg

I just called Brodix and the correct flow numbers are on their site, which I assumed in the 1st place, but I had to be 100% sure. The guy from Brodix had no idea where Jegs got those flow numbers.

Now this has me wondering how accurate all of the other flow numbers I've gotten are.


edit: The AFR heads I was looking at have the wrong flow numbers as well on the Jegs site compared to the AFR site. WTF is Jegs trying to do? The AFR numbers at Jegs are below the numbers AFR gives on their site. Do you think Jegs is trying to move certain manufacturers products more by messing with numbers?

Here is are some independant flow numbers, don't know if your heads are listed.


http://racingfeed.com/downloads/chevy_flow_data.pdf#search='cylinder%20head%20flow %20data'


As for cam ramp in the DD program , if you plug in the numbers, the program should tell you what the ramp or agressiveness is. Mine did.

Here is are some independant flow numbers, don't know if your heads are listed.


http://racingfeed.com/downloads/chevy_flow_data.pdf#search='cylinder%20head%20flow %20data (http://racingfeed.com/downloads/chevy_flow_data.pdf#search=%27cylinder%20head%20fl ow%20data)'


As for cam ramp in the DD program , if you plug in the numbers, the program should tell you what the ramp or agressiveness is. Mine did.

Well, I put in the duration at .050 but it won't auto calculate the ramp rate if I don't put in the seat to seat duration which I don't know how to figure out.

If your writing a cam file and you don't have all the numbers DD2003 can't calculate the ramp rate and neither can you.
You can guess but then your just inputing garbage.
The ramp rates are based on seat to .050 and if you don't have the info you can't judge the rate.
Ramp rate has nothing to do with the head's flow rate in the DD2003 program.
What cam are you playing with?

Forgot ,here's the RR200 flow rates -just be sure your set to 28" h20 when you wright the flow file:
http://www.brodix.com/heads/raceritesb.html

I'm playing with 10 or so cams. I have all of the .050 duration numbers but how do I get the seat to seat numbers from that? Is there a formula for it if I have all of the other specs?

I have the flow chart for the Brodix heads, thanks though. :)

That's what I thought. Not a true input both advertised and duration at .050" numbers so it can calculate it!

We are probably still guessing here, imho.

pdq67

PDQ, do you want the program? I can send it to you and you can play with it and maybe help me figure out this seat-to-seat business.

Look, go here and download their free version
http://compcams.com/camquest/default.asp

It's the same as my $200 version except for the Pro stuff. woopee:)

The free version is neater, you can select the level of performance and it offers you a bunch of cams. You get all your CR info etc entered and then use arrow down to go thru the cams. Watch the hp/tq graph as you arrow along.

For info on cam degree inputting,,,,go to the cam mfgr website for advertised and .050 numbers

Look, go here and download their free version
http://compcams.com/camquest/default.asp

It's the same as my $200 version except for the Pro stuff. woopee:)

The free version is neater, you can select the level of performance and it offers you a bunch of cams. You get all your CR info etc entered and then use arrow down to go thru the cams. Watch the hp/tq graph as you arrow along.

For info on cam degree inputting,,,,go to the cam mfgr website for advertised and .050 numbers


So what you're saying is that I input the Advertised duration where it says seat to seat?

Thanks for the comp cams program. It looks pretty cool.

Never mind, I figured it out. Thanks for the help guys.

Jeff ,if your using a pre-written cam file ,the ramp rate will be calculated in DD.
If you go to the cam mfg site ,you can usually get the seat to seat info and plug the info into your cam file.
I may have the files ,list the cam part number's -not the grind numbers.

The AFR heads I was looking at have the wrong flow numbers as well on the Jegs site compared to the AFR site. WTF is Jegs trying to do? The AFR numbers at Jegs are below the numbers AFR gives on their site. Do you think Jegs is trying to move certain manufacturers products more by messing with numbers?

The flow numbers posted for the Brodix heads you linked to are so far out of reality for SBC heads that no one could possibly take them seriously. 420CFM @ 0.600? Also, the valve sizes they indicate are not SBC valves. It looks like a website error.

Jeff ,if your using a pre-written cam file ,the ramp rate will be calculated in DD.
If you go to the cam mfg site ,you can usually get the seat to seat info and plug the info into your cam file.
I may have the files ,list the cam part number's -not the grind numbers.

Hey thanks Mike. In DD I just put in the advertised duration where it asks for the seat to seat and it auto calculates the ramp rate. I downloaded Comp Cams' "CamQuest" and it's exactly like DD03. CamQuest recommends some cams so it has all of the comp cam files pre programmed and it automatically puts the advertised duration numbers where it asks for the seat to seat numbers.

I built a "generic" 350 engine in CamQuest and DD03 with exactly the same specs for everything and Camquest came up with 60HP than what DD came up with so that kind of sucks. TQ was close. I'm going to go with the DD numbers though because they are smaller and more realistic I think. Who knows.


The flow numbers posted for the Brodix heads you linked to are so far out of reality for SBC heads that no one could possibly take them seriously. 420CFM @ 0.600? Also, the valve sizes they indicate are not SBC valves. It looks like a website error.


Ya, I called Brodix and informed them of that the other day. The guy said he had no idea where they got those numbers. I knew the valve size was a mistake and I was very iffy about the flow numbers also, but you never know what some companies will do or what they are capable of so I wanted to make sure and I called Brodix and also check the Brodix site for the flow chart as well as posting here.

edit: wouldn't it be nice to flow 420CFM @ 0.600 though? :D

Another question guys.

I can't figure out how to enter the numbers for the Compression calculator in desktop dyno if I have dished, domed or flat top with valve reliefs. I can do it with flat tops because I know what my Piston Down from TDC is (0.016) but when I check the Valve Relief option I get lost.

Lets say I have these Ross Dome 2 relief pistons (http://store.summitracing.com/partdetail.asp?part=ROS-90761&autoview=sku) I want to use. What numbers would I input for the "Piston Down from TDC in inches" area and what would I put for "Volume Above Piston in CC's" area?

In the "Piston Down from TDC" area it says "Enter Piston Distance Value Within Range: 0.100 to 2.000 inches".

In the "Volume Above Piston" it says "Enter Piston to Block Deck Volume Within Range: 0.10 to 6000.00 CC's"

I'm lost, please help. :yes:

http://img.photobucket.com/albums/v299/GODZ3R0/CS%20Shots/CRCalc.jpg


What would I put in for these Keith Black Flat tops (http://store.summitracing.com/partdetail.asp?part=UEM-9927030-8&autoview=sku) w/4 valve reliefs if I were to use these?

Once you put .025 in for Piston Down From TDC, it should auto-calc Volume Above Piston

Piston Down From TDC is what we call DITH 'down in the ho'. Stock is usually about .025. If you've had the block decked or have special pistons it will vary up to a zero value and some even come out of the ho.

Once you put .025 in for Piston Down From TDC, it should auto-calc Volume Above Piston

Piston Down From TDC is what we call DITH 'down in the ho'. Stock is usually about .025. If you've had the block decked or have special pistons it will vary up to a zero value and some even come out of the ho.

hey Tim, my Piston down from TDC is 0.016 (block was decked) but DD won't let me put anything under .100 unless I have Flat top with no valve relief option checked.

That beats hell outta me. I think I would do a 'save as', close that one and start a new file. You know how sometimes stuff just gets screwed up and you have to start from scratch.:)

Also you can call the sim people, they'll help you out. You paid for it. Your screen shot shows nowhere to input valve relief cc's, so it is a bunch different than my version. Mine doesn't have the toggle for dome vs flat top either.

Try a different calculator
http://members.uia.net/pkelley2/crc.htm