desktop dyno

[shawnxj]

ok so i bought the $100 version of desktop dyno but i don't know what kinda head setup to input. i have an 0630 head and don't know anything except the intake and exhaust valve sizes. how do i find out if it's a wedge open design or wedge closed design or whatever and the flow numbers?

[yuppiexj]

It's here somewhere.

Here's a set of numbers I have used before.
http://www.jeep4.0performance.4mg.com/tech_specs.html

There are several threads regarding porting dos and don'ts

[5-90]

ok so i bought the $100 version of desktop dyno but i don't know what kinda head setup to input. i have an 0630 head and don't know anything except the intake and exhaust valve sizes. how do i find out if it's a wedge open design or wedge closed design or whatever and the flow numbers?

I believe the site quited below is Dino Savva's - consider his numbers authoritative.

I'll have to dig up my copy of Jeep Engines to see what they consider the chambers to be.

NB: I've found (through rather long use...) that the dyno sim programmes can be rather, er, "optomistic" in their assessments. I don't consider this the fault of the computer - merely that it's not a "real world" sim, and doesn't take parasitic drag into account as much as it should. However, if you generate all of your data on the same sim programme, it's still useful for an "apples to apples" comparision. Just bear in mind that your /actual/ power output is likely to be 5-10% /lower/ than what the sim tells you it is. (I don't think it considers bolt-ons, either...)

[Plechtan]

For the Bonneville engine I started with Desktop dyno, and found problems with the modeling of the intake system. 1bolt put the same information , plus a whole lot more into EA Pro and his info was spot on. I havent seen him post in a while. His idea was to model the jeep engine with different options and see what works the best.

If you ave specific goals you should probably just post them. People on the board have built everything from mild to wild. They can probably recoment the parts that are bes for your application.

I think DD is a great tool to show you want happens when you change engine components. Playing with it i learned alot. but if you want real numbers you really need somting like EA pro.

[shawnxj]

i mainly got dd to see the difference cams made because i know absolutely nothing about cams so i wanted to make a more educated decision and this board was no help at all in helping me pick a cam for what i wanted to do. actually the link to dino's site for his numbers has been the most help i've gotten here

[SilverXJ]

I don't think DD is great for absolute numbers, but it is good to compare items like cams and air flow, as Plechtan said. I don't think the version I have of DD (IIRC 2005?) has the option for chamber style. However, I do have several cam files and head flow files that may work with the newer version. If interested I could zip them up and put them on my FTP.

[Cheromaniac]

ok so i bought the $100 version of desktop dyno but i don't know what kinda head setup to input. i have an 0630 head and don't know anything except the intake and exhaust valve sizes. how do i find out if it's a wedge open design or wedge closed design or whatever and the flow numbers?

The 4.0 head has an open chamber wedge design.

[shawnxj]

that would be cool silver i'd appreciate the info. and thanks for the clarifaction dino

[SilverXJ]

Here are all the files I have pertaining to the 4.0L engine. I can't guarantee 100% accuracy on all the files, so use at your own risk and all. http://www.jeep.blackonyx.net/forum/Dyno2003files.zip

-Chris

[shawnxj]

thanks silver

[MoFo]

I have a friend with a licensed copy of Desktop Dyno 2003 who is letting me use it to see if it is what I need for cam selection. My goal is to build high torque at low RPM.

I have emailed questions to the creator but have had no response after 5 days, so I thouht I would ask those of you that use this program.

In the compression ratio section,
How do I input a piston-to-deck height greater than .1"? I am trying to check the program against the stock 4.0L specifications.
How do you input piston dish volume?

The program seems to output a HP and Torque graph in the range of 2000 to 10000 RPM. I really need data below 2000. I am interested in the range of 800 to 4000 RPM. Is there some way to change and limit the scale within these bounds?