16 Volt Setup

[Alky V6]

Thank you for coming to the rescue ijames. The last two posts by ijames and Bent6 are factually correct. Very well put by both. I was becoming afraid I was the only one that understood electricity.

Understand the risk involved when switching to 16V.

 

[BlownV6]

Donnie, Stick with transmissions!! Electric still isnt your thing!! MIke

 

[Alky V6]

Donnie, Stick with transmissions!! Electric still isnt your thing!! MIke

Yeah, I have to admit I didn't explain it as well as ijames, but I hope you now 'see the light' after ijames' explanation. The key to understanding is resistance, resistance, resistance. Read his post again.

The loads (resistance values) in an automotive 12V system are constant. The resistance values don't change, but very little because of heat buildup or with temperature sending units, potentiometers (TPS), etc. Pick a solenoid and measure the resistance value (ohms). Even simpler, take a long length of 16 gauge wire and measure the resistance with a simple volt/ohm meter. Now take the equations I posted earlier and plug in your resistance and voltage values. You will see the amperage value increase with more voltage. Mike, please just do it. Transmissions have electrical switches, solenoids and force motors. There are probably more electrical problems than mechanical with transmissions these days. I have to deal with electrical issues with cars on a daily basis. I don't teach the subject, but I do understand it. And anyone considering changing the voltage rating of their auto should too.

Another thing to ponder. If the fuel map has been tuned with 12V and you switch to 16V and the electronic injectors see this 16V, you may have to play with the voltage compensation value of your ECM to get your fueling back on track or adjust your fuel map. Fuel injectors will deliver slightly different volumes at different voltages (quicker turn on times). If your ECM is built in such a manner that it will supply a flat 12V to your injectors no matter what the main circuit voltage, then you don't have to worry about that. I haven't heard of a system that does that though.

 

[Bent6]

If you switch from a 12v system to a 16v system you WILL have to adjust your VE tables and sometimes the spark map as well. The 16v system will increase the fuel pump speed, increase injector response and give a hotter spark. Some folks increase plug gap to compensate for the spark. Again, IMO the 16v setup is THE way to go with a race only car.

 

[Alky V6]

Thanks for confirming that Bent6. Be careful about increasing plug gap. In a high boost, high cylinder pressure, along with a hotter secondary current situation, the larger spark plug gap would raise your ignition secondary circuit kv level to a point that 1) wears on the secondary circuit components (mainly wires), 2) causes voltage leaking and crossfiring (again, the wires). 40kv is a good upper limit in most cases.

 

[turbopaul]

I guess nobody read my post I repeat, you do not get anything more out of the stock ignition except for being able to rev higher before the ignition starts to fall off. The stock ignition is current limited to 6.5 amps. No amount of higher voltage is gonna change that 6.5 amps. The output transistor is in a current feedback loop which is why you can't get more than 6.5 amps. The higher voltage allows for quicker charge, hence the higher rpm before ignition dropoff.

 

[Alky V6]

I guess nobody read my post I repeat, you do not get anything more out of the stock ignition except for being able to rev higher before the ignition starts to fall off. The stock ignition is current limited to 6.5 amps. No amount of higher voltage is gonna change that 6.5 amps. The output transistor is in a current feedback loop which is why you can't get more than 6.5 amps. The higher voltage allows for quicker charge, hence the higher rpm before ignition dropoff.

Is that true for aftermarket ignition systems too?

 

[turbopaul]

Most aftermarket ignitions are cd ignitions. I only have experience with an MSD 7 and that was many many years ago, and I don't remember if it has output regulation. If you go by the specs provided by MSD, it implies output regulation.
I'm sure most people are still running the stock ignition system, and whether you run a volt booster or change to a 16 volt system, the stock system will not give you more output with higher voltage....only more heat and higher rpm capability.

Without going over each and every response again, the main point about higher voltage has been missed. When you raise voltage in a DC circuit, current increases, but the good news, or bad news, is the power. Power = E squared/ r. It's that squared term that can be a killer to the load. It's the power, not the current that makes magic smoke. I've only touched on this subject a little bit, so maybe we should have a discussion about every system on the car and exactly what happens?? The other power killer is Power = I squared R.
This has to do with AC power transmission lines and why really high voltage is better than low voltage and why you have less current with higher voltage. And please don't mix AC circuits with DC circuits. There are some similarities between the two and also some dissimilarities.

HTH

 

[Alky V6]

Dang AC. Forgot about that. Good thing I don't work on houses.

I was wondering about the MSD units. We've all witnessed the reliability issues with MSD boxes. I personally don't use one, but I see other racers at the track dealing with them. Does going to 16V with an MSD box make it more of a problem?

 

[turbopaul]

You have to ask MSD or look at the spec. I wouldn't think that 16 volts would be a problem, but you never know.

 

[Bent6]

No problems with MSDs and 16v. I just made the switch to an MSD 7AL2 and distributor from the stock DIS system. I do know the 7AL2 makes a stronger spark with 16v.

 

[John Wilde]

No problems with MSDs and 16v. I just made the switch to an MSD 7AL2 and distributor from the stock DIS system. I do know the 7AL2 makes a stronger spark with 16v.

Will, that is great news.
Good luck this week!

 

[Bent6]

Will, that is great news.
Good luck this week!

Thanks John. Hoping the switch to the 7AL2 with distributor will solve many of my past gremlins along with a little extra HP to boot. New heads + XFI + good ignition should = FAST car......at least that's what I hope. PLUS it has a 16v electrical system!:biggrin: :biggrin:

 

[Alky V6]

I'm seeing this more and more. Why are people having to switch to a distributor? Are most of the same people using the XFI system?

 

[turbodragster]

im running an msd 8 , xfi , and a distributor

 

[steveX]

I don`t know if 12 volt is an issue, most of you might what to up-grade to a higher amp output on your system. i`m running a 12volt 200amp alternator, and the battery is a 1000 ccc (cold cranking amp) 80`s caddy fleetwood brougham . Never had and issue with voltage. also remember this TR is a 20+ yrs old car. so it will be a good idea to make sure all metal panel are grounded (rust will cause low voltage/signal on any circuit).

 

[Alky V6]

So some people are finding that they have to go to a XFI plus a MSD box plus convert to 16v to get an adequate spark?

 

[John Wilde]

I'm seeing this more and more. Why are people having to switch to a distributor? Are most of the same people using the XFI system?

Kenny does this with MoTeCs as well.
He also does COP set ups, not sure he is a big
fan of the stock ignition on a HP application.

 

[Chevota]

So some people are finding that they have to go to a XFI plus a MSD box plus convert to 16v to get an adequate spark?

Not here! 16v, XFI, and stock ignition with NO spark problems....and you know the rest of my combo.

Scott Wile

 

[Jeff Rand]

Not here! 16v, XFI, and stock ignition with NO spark problems....and you know the rest of my combo.

Scott Wile

And you never have to use the high position on the windsheild wipers.
Jeff