No, I'm serious. How does he know? I'd prefer to know exactly how he arrived at this conclusion before I repeat it.


That reflects different ramp rates. There isn't much happening between advertised points and 1mm - 0.50" of lift, which is why effective duration figures exist.

 

Well that info was probably obtained by his cam grinder, when he said "Hey copy this profile onto this blank", and the cam grinder said "wait a minute something here is not the same." I dont see why Mark would exagerate or lie about it, but I understand your hesitance to put faith in it. I would say PM Mark and ask how he is so sure that they are in fact retarded -5*.

Tightening the lobecenter might be the explanation, but without taking you for a ride in my car or anyone else that is running that MIVEC table, I cant really expect you to believe me that it made a tremendous difference. I raced an '88 CBR 1000 this morning and shifted at 8K and the car kept wanting to pull (god's honest truth) except I have my limit set at 8100 since its stock valvesprings and retainers.

So, I apologise for the apparent density but, If I have two cams that are 206 @.050 even though ramp rates might be different and therefore one can make more power than the other, advertised is still theoretically the same right? When I did cam engineering I never bothered to do any measurements that werent in BTDC/ATDC, BBDC/ABDC, LC, and LSA. I used effective duration as a rough guideline, but it wasnt my primary measuring tool.

 

Hi John, I've done further testing today and the results of 0 then 7.8 then 0 advance at 6500 and 7000 RPM are all within 1-2% of each other from intervals in 4th gear from say 6000-7400 or 6250-7250 logging at 30Hz. I can't convincingly replicate the difference you've noted on my present setup and it appears to pull well up top with either setting. I think if I ran less midrange boost (torque) I would want to change later, but as it is it feels good changing at 7000 RPM. Depending on how you cut the intervals and which order you do the testing in the results change in favour of different ones.

 

I'm not insinuating in the least that he is dishonest, however, I certainly know better than to repeat something like this until/unless I know how it was derived. There is not an individual in this business who is infallible, including you, me, and him.


Retarding the intake cam widens the LSA (widens the lobe centerlines).

If those two cams have the same duration at 0.50" but have different ramp rates, they will likely have very different advertised duration. If they have similar ramp rates, they are more likely to have similar advertised duration numbers. FWIW, the terms "advertised" and "effective" are self-explanatory.

 

I think some of this difference that I am feeling might also be a) my other mods, b) other tuning that I have done, and c) atmospheric conditions (temp, humidity) and gas quality.

I have been tuning ignition and fuel with feedback from EVOscan (mainly just for knock count) to get a good daily map before I embark on a pure racegas map. I am running about a 1/3 of a tank of 115 octane to 2/3's 92 (r/m). Temps have been in the low 70's (21*C) and humidity is about 30% or so. I am at sea level as well.

Mods are pretty basic though, full turbo back 3" mandrel, no cat, K&N, and AMS LICP. The bonestock EVO 9 SSL and MR that are also using the exact same map noticed little change above 6500 from the initial map that I had posted. Maybe its the difference in my car's ability to breathe?

 

Which assuming the data I was given is correct, I have advanced the cam from its previously further retarded position thereby tightening the LSA.

As far as the cam timing, its really irrelevant at this point because JC and have both showed that it seems to like advance in the map up top versus being left alone. I am curious if you have PM'd Mark? If not, I will and try to get some "concrete" evidence for the purposes of this discussion. IF nothing else we will know by this winter when I tear my car down for its next incarnation and I can take the cam to a respected cam builder and have it thoroughly examined.

 

Similar mods and conditions here except I tried a cold air intake and removed it as it didn't make any difference to power.

I'm pretty convinced my present map has no more to come safely on our 98 RON.

I then added 10% methanol to the fuel tank and instantly picked up obvious loggable improvements to acceleration across the range, which became more marked when I increased the boost to 28 PSI peak. I could of course now try advancing the intake cam again at the top to see if I can replicate your results. Do you have any numbers for me to digest regarding the improvements you're seeing?

 

I had been using a borrowed G-Tech when I made my posts. I am/was going to use the dragstrip for my benchmark since the only big thing that I have altered is the MIVEC map. Unfortunately at this time I do not have concrete verifiable numbers to give you other than my butt dyno (which we will leave out of the results table for the time being).

With EVOscan I have been logging: Coolant temp, EGR, Knock, RPM, Timing, O2 voltage, and High trim fuel map. I made a hard pull this morning before work but I havent had time to review the logs yet. Later tonight I will post anything relevant.

Would you be willing to email me the .hex that you have? A trade maybe of what I am using and what you have. I will PM email addy.

 

No problem, will email hex file in 10 hours when I'm home from work.

 

Any more new info guys?

 

Currently, with only stock cams, there is not a whole lot more to report. After having talked to several tuners and people with regular access to a dyno, they all report power loss if they change the table above 6500. When I get more time and a little more cash I am going to put an HKS 280 in and see what evil I can brew.

But for whatever reason, my MR seems to like the MIVEC table that I have posted previously. JCSBanks has found some improvement in acceleration which would tend to make me believe there is power to be found.

 

I have read this entire thread and I am slightly confused now. Would you mind posting a link to the current map that you are running and find to work the best.

Thanks

 

https://www.evolutionm.net/forums/sh...9&postcount=24

Confusion stemmed from someone without a IX trying to comment on tuning for a IX. With the exception of him being right about MIVEC working in crank degrees of timing, the rest of what was said is him guessing versus me testing in real life. The only other thing that may have been confusing is my inside information concerning base timing on the intake cam.

Try this map and see what you think. It probably works well for me because of the rest of my ROM, the fact that I live in the NW which is cooler, and the fact that there are so many trees around here we have 20% (exaggeration) more oxygen than most other places in the US. There is also the fact that I have an MR which in the past were different LC than a GSR and if it still holds true this could affect things as well. There are currently 4 other people in my group of friends running my ROM and all of them seem to agree that it works better than stock.

 

Thanks, I will give it a try.

 

Anyone knows why the MIVEC maps for the JDM RS and the JDM GSR/GT are so different?