I have seen 2 different timing maps.....[1st] timing set up to retard timing at set rpm levels all across the psi range [2nd] timing set up to retard timing at set psi levels all across the rpm range ......which do you guys think is the better way to go

 

Ideally it should be a combination of the two. However, I personally would choose based on RPMs since that's upon what the ECU bases timing advance.

--Steve

 

I have seen the same but depending on how you read them you have to remember that it only changes when it reads both values.Meaning -5 degrees timing at 7 pounds of boost at 6500 rpm.If the table says a number at a lower like -5 at 3 pounds of boost at 6500 rpm the car will never see that because by the time the car gets to 6500 it is already up to 6-7 psi.

 

yes..I know that...I was just wondering if either way was better or preferable

 

The advantage of using an RPM-based map is that you can swap out the pulley and not have to change the timing map

--Steve

 

Right on I thought you were asking somthing else.Just trying to return the help that others have offered me.

 

thank you for replying

 

Ditto for SURE.... RPM

 

If you use RPM only, then what happens when you are cruising along at 4000rpm or whatever, but without any boost? In that situation, you wouldnt want an retarding.

The stock ECU makes timing decision based mainly based on RPM vs. MAF voltage (engine load), not just RPM.

 

Good point. However, with the R4 software I don't believe anyone is modifying the timing cells in the unboosted range. In my case, the rows from 1psi to 11psi all have the same timing retard, based on RPMs. I could probably change that to 3 psi since I don't take out any timing below 4000 rpms.

--Steve

 

Zimbo...

Let me get this straight... if I have my R4 set to modify timing only if I'm over 3lbs of boost and I'm using RPM adjustments instead of PSI adjustments to timing, you are saying I can change pulleys without readjusting the map?

Clarify for me... If I'm spinning at the same motor RPM, but the supercharger is spinning faster because of the pulley I swap, I'd be creating more boost sooner. More boost, means more air/fuel in the chamber which means a hotter more volatile detonation in the cylinder. Seems to me you'd have to make adjustments for this

You may be right, but it just doesn't seem logical to me. Can you explain in more detail.

Also, is there an easy way to determine if I'm set up on the RPM based timing adjustments. I'm pretty sure I am, but I'd want to check it.

If you are right on all counts, I'll be getting a pulley ordered this week!

 

mcduck, I'm talking ONLY about the timing map. You would obviously have to increase fuel slightly in the higher cells of the fuel map.

Have you uploaded the map from your ECU? If so, I'd love to see it. You can send it to: s t e v e @ a u d i o e n v y . c o m.

--Steve

 

Mark at split second said it is better to fine tune it in the boost. Both have to be met but if you tune it on the boost its alot more fine tunable because you can adjust every .5 psi instead of every 500 rpm. I started to make a map off of boost, but I haven't finished it.

 

zimbo... still need to get the R4 on my laptop hooked to my SS box to get the readings. I keep meaning to do this, but I have yet to go pick up the proper connectors.

Would you mind PMing my your phone number? I'd love to have a live "walk-thru" when I first hook it up to ensure I only download the settings and not change them.