ANOTHER POWER COMANDER QUESTION

[kawbuc]

How can i convince my son inlaw that he does not need the power comader . He has not changed the intake at all. Just changed pipes. Someone at the stealership is telling him that if he changes pipes to Vance and Hines , he will run too lean if he dont have the power comander and will damage his engine. Is there something out there i can go to , print it out and explain to him that if he dont change his intake , he should be ok ?
Am i correct ?

[cactusjack]

You are correct. If someone is only changing exhaust, a fuel processor isn't necessary. Aftermarket exhaust, by itself, will not cause an engine to run lean. The entire system has to be balanced. If you open the intake and allow more air into the engine, you then need to add a less restrictive exhaust to allow that increased volume of air to exit. At this point you would install a fuel processor to adjust the fuel mixture to obtain an optimum air:fuel ratio.

What you do to one side (exhaust) you must also do to the other (intake).

[macmac]

I don't consider this exactly true.. A great deal of varriance in specs on these bikes happens.

Some of these bikes are so overly lean they ping all stock at 70 degrees, running hi test. Others do not. I am speaking in terms of total stock bikes, that haven't had a thing altered.

On the other hand there is no need to go with the most expensive fuel modual there is either.

There are 2 lesser moduals for far less money and both work well. The Cobra which I am not familar with, but CJ is, and the TFI which I am, and run on my bike.

If this bike ever pinged as it is and any changed occurs it might be a good idea to consoder one of the lesser costly moduals.

If the V&H pipes are run and still there is no sign of ping, AND no more changes are made then 'maybe' you don't need any modual.

In my experience with a 01 Nomad and then a 06 Nomad both of them pinged stock running 91 octane fuels. So perhaps both of my bikes were a bit overly lean to start with.

Neither of these bikes were Cali models.

[taranis]

cactusjack nailed it.

Think of it as three pieces to a smooth running engine:

1. Air intake
2. Fuel intake
3. Exhaust

Air and Fuel intake must be in balance for a smooth and efficient running engine. Opening up the exhaust does absolutely nothing to this equation. By adding a more open exhaust, he'll allow the exhaust gasses to escape easier, but that will not change the air/fuel ratio at all.

As stated above, if he adds a more open intake, then this air/fuel ratio will be upset - more air in = more air out; the caveat is the amount of fuel going into the cylinders for combustion would also need to be raised, hence the need for the fuel processor.

If he's not upgrading the intake, the mechanic is blowing smoke. Take the bike elsewhere.

Edit: As Mac said above, these bikes are lean out of the crate anyway, so a Fuel Processor certainly won't hurt, and will likely allow him to run a lower octane fuel and reduce heat-related wear on the motor. Unless he's already pinging on 91+ octane, or begins to after the exhaust install, it's not absolutely necessary.

I have an '06 with the V&H Baggers, stock intake and no other mods, and I run 91-93 octane with no pinging whatsoever.

Good advice is to go with the V&H first, ride it awhile, then decide yes/no on the Fuel Processor.

[phenrichs]

Your soninlaw ever been on the site? Perhaps he should stop by. There is a huge number of members that have done the mods and done the tests to know about this. If you can't convince him maybe they can.

[macmac]

Taranis, Not quite... Almost but not quite. V&H will change the back pressure, and if the bike is at the border line of ping, but isn't the V&H set up could created that slight difference.

V&H pipes do not share any back pressure as the stock set up does, and so the pulse does not extract gasses in the same way. There is a changed when anything is done..

Most of the time just an exhaust change leaves mix and breathing as it was, so far a the human ear and eye can tell, but not 'always'.

[dkdixie]

My V&H pipes were installed soon after I purchased an 08 Nomad. A few months later I added a TFI unit. The bike was extremely lean before and after pipes were installed.
The TFI made a huge difference. I'm confident it would have made a difference if I had installed it when the the stock pipes were on.

[taranis]

Originally Posted by macmac

Taranis, Not quite... Almost but not quite. V&H will change the back pressure, and if the bike is at the border line of ping, but isn't the V&H set up could created that slight difference.

V&H pipes do not share any back pressure as the stock set up does, and so the pulse does not extract gasses in the same way. There is a changed when anything is done..

Most of the time just an exhaust change leaves mix and breathing as it was, so far a the human ear and eye can tell, but not 'always'.

You know, I thought about that, even typed it, but edited it out at the last second because I wasn't sure with these bikes.

Learn something new every day. Thanks, Mac.

[macmac]

Taranis, There is a real word for this, and for my life I can't command the alledged brain to come out with it. I did last night while sleeping, and since then I forgot it again.

I am sure dkdixie is correct, that is a all stock bike would be better off with a TFI. With that said any fuel modual, just that I have had 2 TFI's, and liked both of them.

[redjay]

Hi Macmac, are you thinking the word is scavenging ?