View Single Post
Dr J Dr J is offline
Registered User
Dr J's Avatar
Join Date: Apr 2008
Location: Miami
Posts: 662
It's been a while since I updated so here goes. So far I am very happy with the way the car works and responds. It essentially has a street tune and will eventually get dynoed when I reinstall the supercharger. here are a few things I learned.

On the VE table:
1) It's a shame that the infinity does not have an auto tune function like the Megasquirt. They already give you what the VE should be but does not automate the update.
2) the AEMdata software is great, but, again, I had to spend hours looking at my data logs to estimate VEs.
3) then came this awesome tool from a fellow Pelicanite
Tuning the AEM Infinity, check out this helpful tool...
Much more automated but I had to preprocess the data to remove points where there are transients, wallWetting, etc. A lot of work up front. Then I figured that it would be better to use the median rather than the mean so...
4) I developed my own Excel to give me the mean values rather than averages. Although not as neat as #3, it gave me the data I wanted. Then had it finally look at number of hits on each table entry and remove those with few hits and finally...
5) I found MegaLogViewer. OMG. This thing lets you create your own filters, load the data as a csv from AEM data and produces the corrected VE table, along with many other visualization tools. Finally, what I was looking for! Also, the thing is blazing fast even on my old computer.
Get this. It is what you need.

1) I decided I wanted to use the three pin IACV used on the 3.2. It takes 12v in the center pin and I use two lowside outputs to PWM the remaining pins. When one is 75% voltage, the other is at 25%. Fully open one way is 0% to 100%, etc.
2) had a bit of problem getting the valve to reliably respond in the idle position table. A little search showed that these things can be very nonlinear. After reading this, Bosch rotary idle valve info - FrankenCIS - FrankenCIS Community
I did an experiment. Without starting the car, look inside the IACV, and change the position value from 0 to 100% in steps of 10%. Well it seems that below 25% and above 75% the values are nonlinear so I changed my lowside tables so that 0 is 25% and 100 is 75%. Now its much better. I am much happier with the idle response. Using the idle screw, I adjusted the idle to where the response of the IACV is reasonable.
3) once his is set up right and the VE at idle is close, there are less hassles, particularly with feedback. On the IACV PID, I am exploring different values but it works fine with P=D=0. I was set at 0.02. For the spark feedback I'm at 0.002 for P, 0.001 for D and 0 for I.
4) At the advice of others on the board, I set idle AFR to 13.5. I dont have an ITB setup so I explored leaner mixtures. Lo and behold, it works just fine at 14.0 and even leaner. The EFI makes for a smooth engine. I left it at 14. Why not save gas?
5) above about position 60 or so, the IACV is sufficiently open that you can hear an annoying sucking sound- need to avoid having it open it so much.

Well, I will keep posting as I continue to learn and improve the tuning!
1979 SC, Slant nose wide-body cab conversion. AEM Infinity EFI. Whipple Supercharged!
Old 11-06-2017, 01:46 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #27 (permalink)