So i'm tuning by friends MR tomorrow and i wanted to see if others have run into this problem or any other problems tuning the MRs. He came down a week ago so i could get rid of some of the DTC codes he kept getting after switching to an FP green and MX1 cams. Got that taken care of and at the same time we did a wot pull for ****s and giggles to get an idea of where he is whp wise. I loaded it into VDR and even VD to compare and these are the results.

The U shaped one is the MR and the other one is my GSR for comparison.





Then today, as i'm looking over his log to see what changes i want to make for tomorrow, i noticed something... interesting. Now this is either just coincidence or something else is going on. As you saw in the plots above, something is happening between 5k and 5750 rpms (ish). Bryan has given me some insight on the matter and the cause is a non linear RPM band in the MRs. So far, i don't think we can "fix" this. but why is the speed of the car staying the same for 500rpms like shown here





and is the psi at the exact same level coincidence as well? what about the fact the these are happening at the same place where the U is taken place? i've heard some people say, "you can tune that U shape out" but i'm not exactly sure how you can "tune" that out. I tried looking for some tables that maybe i didn't have in my xml for the MRs but wasn't able to find anything. What's your guys thoughts on this?

 

To me it looks like transmission issue - like if clutch slipping on the specific amount of torque. It may be either mechanical or electronical in nature. Though I'm not a professional, hence it is only a guess.

 

Fix it with a combo of SST torque tables and Throttle Comp tables

 

perhaps a tip or how to ? the u shape only comes on 4th gear but on 3rd it's normal

 

Well this was a 3rd gear pull. Razor, which ones are the throttle comp tables? I don't recall seeing those in my xml. Do I need to get them from a thread or something?

 

what's your timing doing?

 

timing is fine. nothing abnormal. Well i tuned him today on a mustang dyno (it was a heartbraker one) and he base lined at 275whp with 274wtq and he ended up at 332whp and 324 wtq so not too bad. Everything went smooth though, there was no U shape in the dyno plots on the mustang though.

I'm curious to see what what the logged file will read in VD, i'm going to try to mimic the results on the VD to that of the dyno so i can have more accurate numbers.

 

wow. no offensence, but if your not familar with tuning MR's you just opened a book of pain.

that dip you see is the tps shutting and wgdc's being pulled. it's normal. in first gear the car closes the throttle plate to decrease power during lanches. no fix for this as of yet. this is why my 11.851 pass in my mr was a hard time to achieve and a world's first 11 second pass.

if you have not tuned a SST evo be careful. you need to do your homework before you just go tuning away. you first off need the sst torque tables that are not released to the public.

log tps wgdc's and you will see.

 

I think you are confusing the 1st gear throttle close and this example. That dip is from the non-linear RPM log and how the dyno software data uses data it can cause that dip in the plot. It has nothing to do with the MR throttle close.

I have seen the exact same and I can tell you (at least with my data) without a shadow of a doubt it is *not* closing throttle or pulling WGDC.

Here is an example from me (From my 2010 RA that does not have 1st gear throttle close like an MR), no TPS or WGDC pulled whatsoever during the second run. You can see the boost is the same between the pulls.

Also notice the artificial torque peak on the second plot because of the RPM log causing havoc with the software dyno.



Here is the RPM plot between the two:



You can see what causes the problems in the dyno software. The car actually isn't dropping all that torque. This does not show up on a proper hardware dyno.

The non linear RPM happens from a couple different things, some at the same time, some at seperate times..

 

Mivec

 

Mivec what Aaron?

The two pulls above in my example share the exact same Mivec mapping just FYI.

I'm curious to hear what you mean...

 

bump

 

Ahhh, I saw the same thing and thought it must be a software issue as well. For example my car shows 5 counts each of 1/5/10 mph when starting off; and I can confirm that my car isn't jumping from 1 to 5 to 10, lol!

 

Are you sure you are logging speed at priority 1? If not it will just copy the last sample until the next 1/n interval.

 

it is a software realted issue depending on which software you use. when i tuned it on a real dyno it does not appear. It seems to be related with the linearity of the rpm logging in the systems.