Switching fro 12V to 16V

[opeltwinturbo]

When I switched from a 12V to 16V system the car went dead lean. I was not able to start the car on the old 12V program. I had to fatten the enrichment vs coolant temperature by 12% at 63 degrees just to get it to start when stone cold. Once the car is running, the VE table off the old 12V program seem to maintain a decent idle. Correction is 1-2%. After the car warms up, it doesn't want to start.

Has anyone else switched to 16V and had similar experiences. If so, how much did you have to fatten the program, where did you fatten the program - tables or enrichments?

I can't wait to install the 5 BAR MAP sensor. I understand that tuneup is also lots of fun.

 

[NastyGn]

Hey John

You might contact Lawrence Conley. He has some issues when he switch over to the 16V system also. If I remember right he had to get an isolator from the company that made the 16v system to keep the ECM at 12v.

I hope that helps

 

[bruce]

Originally posted by opeltwinturbo
Has anyone else switched to 16V and had similar experiences. If so, how much did you have to fatten the program, where did you fatten the program - tables or enrichments?

Injectors are voltage sensitive. The higher the voltage the faster the opening times. So yes, you'll need to do a fair amount of work redoing the cal.. The opening times are a greater percentage of the PW on time at lower engine speeds, so you'll basically have to redo the whole VE table.
The larger the injector in PPH, and lower the resistance, the more you'll have to do.
Or so I've been told.

Caveat, I'd make real sure the ecm manufacturer OKs the higher operating, and charging voltages. A shorted diode in a 12v can put a 16v ripple in the system, and most oem ecms can handle 17v, for a while. But a shorted diode in a 16v system might break something.

 

[opeltwinturbo]

oem ecms can handle 17v,...

I checked with FAST and MSD and they both liked 16V. The charging voltage is 19V so everything is connected to the load side of the disconnect (kill switch) and isolated when charging.

The only reason I switched to 16V was when running on 12V with a fully charged battery and 140A alternator, the voltage at the end of the pass was 10.9 and duty cycle was 140%. Ouch! Injectors are 160#. A fully discharged 16V battery is 14V.

Neal, I'll give LC a call. Thanks.

 

[S2V6RACER]

I had voltage issues with mine. I went to a Optima yellow battery and a old style GM alternator with a regulator that starts charging as soon as you spin it by hand. Most higher amperage alternators require at least 900 engine RPM's to even begin working, so if you are running under driven pulleys they will not put out CLOSE to enough amperage or maybe not even engagement. You have a charging system problem. I had my alternator built by a local shop and we weighed out all the options out there. Mine puts out 90 amps at idle which is what I needed to sustain voltage and 140 max. These 200 amp and other hot rod alternators in most cases do not come close to their rated amperage per Madison Generator, who I had mine custom built by.

Alternators also lose significant power as they get hot. My alternator is used by GT railways trucks that require about 100 amps at idle and he has never had a complaint by them.

With a fully charged battery and the old alternator without the Optima battery, my fast logs would show 11.8 to 12.1 V and only go up to 12.5V by the end of the run. Now they shoot up to 13.5V as soon as I spin the motor above 1100 RPMS and stay that way for the WHOLE PASS!. I have a race under driven crank pulley.

Alternator cost $120.00 with no core.

 

[bruce]

Originally posted by opeltwinturbo
The only reason I switched to 16V was when running on 12V with a fully charged battery and 140A alternator, the voltage at the end of the pass was 10.9 and duty cycle was 140%. Ouch! Injectors are 160#. A fully discharged 16V battery is 14V.

FWIW, I'd be looking at the charging system, and battery. While changing to 16v may cure the problem, you might be in a way masking other issues.

10.9 might be dropping the reserve ignition capacity down to where your having to run rich, to lower the firing voltage.
Or the fuel pump is nosing over capacity wise and again forcing the need for that much injector DC.

Jus thinking/typing, out loud.

 

[bobc455]

If the injector opens faster, wouldn't you be better off adjusting the injector opening time instead of the VE tables?

I don't think the ECM cares what voltage it gets, I seem to remember hearing Craig say that as long as the car is below 27V, the ECM will be fine.

Is your fuel pressure staying constant through the run?

-Bob Cunningham

 

[HighPSI]

John, give me a call. I switched my car to a 16 volt system right before I went to BG. I run an alternator, so my car is actually running on 18+ volts.
You don't have to redo the entire fuel map. On my car, all it took was some tweaking of the injector opening time. I have not found ANY downside to running the 16 volt system. At BG, my power windows may have been the fastest on the property