Jeep Strokers

And im trying to figure out what is / isnt wrong with our calculator.

I think your specific problem is that your using @.050 spec instead of seat to seat. Our calc requires s2s spec.

dwg86 wrote:On the Keith black calculator, it has you enter the IVC at .050 and add 15. When I use this calculator I come up with 8.089 DCR. I know my IVC is [email protected](that is what I degreed my cam at). I'm not trying to be argumentative, I'm just trying to figure out my correct DCR.

adding 15* to the 0.050 event is really a "guess".

The ramp rate is really what determines the IVC. Look at the difference between the stock cams and the aftermarket, most aftermarket have 10* more 0.050 duration than advertised duration compared to a stock cam.....

i'm kinda confused how IVC can be calculated at .050. Because if the valve is raised .050 then its not closed, and IVC means valve CLOSED...... I think there is an error in "terminology" here

If I use This formula..."The intake valve closing point ABDC is calculated in the following manner. First, divide the intake duration by 2, and add that to the lobe seperation. Next, subtract out any ground-in advance. Finally, subtract 180 degrees."
260/2=130, 130+112=242, 242-3=239, 239-180=59. So 59 is my IVC.

You know... I'm going to put the degree wheel back on the engine to see what my IVC is.

dwg 86, i think something is wrong with the IVC spec that you have ..

I think it should be much higher something close to 65.

I would use your adv dur and lsa values.

Your DCR is somewhere between 7.6 and 7.75.

***EDIT***


I took to long to post the above, and it appears your already on the right track.

dwg86 wrote:If I use This formula..."The intake valve closing point ABDC is calculated in the following manner. First, divide the intake duration by 2, and add that to the lobe seperation. Next, subtract out any ground-in advance. Finally, subtract 180 degrees."
260/2=130, 130+112=242, 242-3=239, 239-180=59. So 59 is my IVC.

You know... I'm going to put the degree wheel back on the engine to see what my IVC is.

When I use this formula and enter 59 as the IVC, I come up with the same DCR as using 260 Advertised duration, 112 lobe sep, and 3 degree advance. My DCR is showing 7.75 on the calculator. A little lower than what I wanted. I was hoping for 8.0. After the valve job my head cc's went from 61.4cc to 62.8cc. Oh well, I hope it still runs strong.

dwg86 wrote:"The intake valve closing point ABDC is calculated in the following manner. First, divide the intake duration by 2, and add that to the lobe seperation. Next, subtract out any ground-in advance. Finally, subtract 180 degrees."

Thanks for sharing that.

dwg86 wrote:

dwg86 wrote:If I use This formula..."The intake valve closing point ABDC is calculated in the following manner. First, divide the intake duration by 2, and add that to the lobe seperation. Next, subtract out any ground-in advance. Finally, subtract 180 degrees."
260/2=130, 130+112=242, 242-3=239, 239-180=59. So 59 is my IVC.

You know... I'm going to put the degree wheel back on the engine to see what my IVC is.

When I use this formula and enter 59 as the IVC, I come up with the same DCR as using 260 Advertised duration, 112 lobe sep, and 3 degree advance. My DCR is showing 7.75 on the calculator. A little lower than what I wanted. I was hoping for 8.0. After the valve job my head cc's went from 61.4cc to 62.8cc. Oh well, I hope it still runs strong.

And i think we have the issue solved... good job!

So how do people feel about the calculator only using IVC spec?

The way im thinking about doing it is something like the following:

The user would have two options. Either to put in the IVC spec directly, or to put in the Duration, LSA, and built in advance / retard of the cam and it would automatically fill in the IVC field with the right IVC value and use that for the DCR calculations.

I think that might solve some of these problems.

Also, should their be another field for advance / retard when using IVC spec? This way someone could still calculate what happens when they use an adjustable timing set for example.


What do you guys think?

All input would be greatly appreciated!

I've made some significant changes to the calculator today.

Changes are mainly in appearance for the DCR area. I moved some things around, changed some wording etc. I also made the disabled fields red to make them easier to know that they are disabled. I changed some functions too so that it would automatically disable something if your doing something else. I just basically went through and fixed all the little things i could find that might confuse someone.

Advance / Retard can longer be filled in when using IVC spec. Only when using Duration and LSA. This is to prevent confusion and inaccurate values. I also made it clear that if advance / retard is built in to the cam, then it still needs to be entered into the calculator. I may decide later to have an advance / retard field specifically for IVC spec, but i'm not inclined to do so unless the demand is there for it (which it sounds like it really isn't).

I also added a IVC to the list of results, just like i did for Quench. If you enter duration, lsa and advance / retard it will calculate what the Intake Valve Closing Angle is.

Later today or here in the near future i will add all the cams that SilverXJ gave the specs for. I have a nice idea for this to prevent allot of clutter, i think you guys will like it.

As always, please give me your feedback! Its the only way for me to know if we need some improvements!

I have been trying to figure out the values for the stock 2000 cam. The FSM doesn't give LSA. It does give the IVC, which is 60.9. Using that number and my stroker figures I get a 7.84 DCR. Dyno2003 calculated the LCA @ 107.3. Using that figure and teh states intake duration of 253.3 I come up with a different number. Now, if I use a LSA of 114.3 with 0 advance OR the 107.3 and retarded 7* the DCRs match the IVC number. Might want to put that cam in there just for comparison. I would use the 114.3 LSA, because 107.3 doesn't really make sense.

SilverXJ wrote:I have been trying to figure out the values for the stock 2000 cam. The FSM doesn't give LSA. It does give the IVC, which is 60.9. Using that number and my stroker figures I get a 7.84 DCR. Dyno2003 calculated the LCA @ 107.3. Using that figure and teh states intake duration of 253.3 I come up with a different number. Now, if I use a LSA of 114.3 with 0 advance OR the 107.3 and retarded 7* the DCRs match the IVC number. Might want to put that cam in there just for comparison. I would use the 114.3 LSA, because 107.3 doesn't really make sense.

Ill add it in there thanks. What should i label it though? 99-02??

99-04 I know for sure. Earlier years I don't know.

All cams given to me (Thanks SilverXJ) have been added.

Please tell me what you think!!

I can get the list of cams, but selecting one doesn't import the data to the calculator