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Re: [GMCnet] GMC Coach - New Braunfels, TX [message #78083 is a reply to message #78069] Fri, 26 March 2010 13:37 Go to previous messageGo to previous message
Ken Burton is currently offline  Ken Burton   United States
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma:
Senior Member
emerystora wrote on Fri, 26 March 2010 08:06


On Mar 26, 2010, at 1:16 AM, Ken Burton wrote:

>
>
> roy1 wrote on Thu, 25 March 2010 21:13
>> Ken
>> my hearing isn't all that great so I have an MSD spark control on
>> my HEI and an MSD knock sensor so I can retard the advance curve. I
>> have found 87 to be good most of the time while towing my Toyota
>> but I generally top the tank with a higher octane when I have some
>> serious mountains to climb as the knock sensor will start to do a
>> slow dance on 87 when I start climbing even when I retard the
>> initial to 2 degrees.
>> Roy
>
> I have no problem with knock sensors. Installing one is probably a
> good move for us hard of hearing folks. I have a knock sensor in my
> coach sitting in the right seat. That is how I determined my static
> timing setting. I ran it up until it pinged and then backed it of 2
> degrees. That is where it sits now several years later. Since I
> seldom go in real mountains I never need to change my timing. I did
> climb Trail Ridge Road in Rocky Mountain National Park one time up
> to the top at 11,000 feet and I have been through Eisenhower tunnel
> a couple of times which also is around 11 k. But other than those I
> I'm usually 5,00 or below.


Ken - since I am living at 7200 feet and drive at even higher
elevations a lot, I can tell you that it is very difficult to get an
engine to ping at high elevations. One can actually advance the
static timing to 20 deg advance and still not get pinging but you get
a lot more power on the hills. However, when I did this I would have
to drop the timing back down at lower elevations in order to stop
pinging.

87 octane works fine in the mountains. It is the addition of 10%
ethanol that will drop the mileage and cause vapor lock problems in
hot weather at higher elevations.

Emery Stora
77 Kingsley
Santa Fe, NM



What you say is entirely true. I guess I should have stated it a little differently. It is climbing large grades to get to those altitudes where my concern comes from. Operating at those altitudes actually takes lower octane fuel. That is why the gas companies get by selling lower than 87 octane above 4000 or 5000 feet and still calling it regular fuel.

Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana

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