High Altitude Tuning

J

jsevern

Active member
Does anyone know anything about high altitude tuning a 200CID? I live in Colorado and was wondering if I need to tweak anything to optimize the performance of my Mustang. As usual, any info that you can give me is much appreciated. Also, I am looking at some new exhaust headers and have noticed that some of them will not fit on a low mounted starter set up. I'm not really sure what a low mounted starter set up is. Can you all inform me?

Thanks,

Jsevern
 
Howdy Back J:

Ford recommends, in the Service manual, to add an additional 5 degrees of initial advance for elevations above 3,500 ft. That's a good start.

A low mount 200 has the starter located below the oil pan line. Most 200s have a high mount starter with the starter located above the pan line.

Adios, David
 
CZLN6":1gnltbq2 said:
Howdy Back J:

Ford recommends, in the Service manual, to add an additional 5 degrees of initial advance for elevations above 3,500 ft. That's a good start.

A low mount 200 has the starter located below the oil pan line. Most 200s have a high mount starter with the starter located above the pan line.

Adios, David
Click to expand...

Awesome. Thanks David. That is extremely helpful.
 
8) as well as what david said, if you plan on staying above 3500ft all the time, you also need to lean the fuel mixture out a bit due to the less dense air.
 
Without opening up the engine, about all that can be done is advance timing and lean out the mixture. High altitude engines definitely can benefit from increased compression and improved induction.
Joe
 
A low mount 200 has the starter located below the oil pan line. Most 200s have a high mount starter with the starter located above the pan line.

Adios, David[/quote]
generally 1980 and newer 200s have the low mount starter.
 
Howdy Back J:

It would be helpful to know a little more about your location and your car. Auto trans or manual? I'm making the following with the assumption that you have a '65 - '69 200 with a Load-O-Matic distributor.

FoMoCo had an engine specific for some Rocky Mt. and high altitude distribution centers. I would not mess with rejetting without knowing the build destination for your vehicle. Or at least know what jet you now have. There are three external adjustment that can help to tune your carb to make the most of it. 1 is the low speed air screw. It should be tuned for highest idle speed or vacuum if you have a gauge available. 2nd is the accelerator pump pivot point. It has two settings; "hi and lo". the hi setting/pivot hole should be used for temperatures below 50 degrees. The hi for temps above 50 degrees and/or elevations of 5,000 ft and greater. The last is the automatic choke setting. it should be set as lean as possible- only enough choke to have an efficient warm-up. Messing with these three adjustments cannot get you into too much trouble and may help. This engine really needs a summer and a winter tune.

I'd do a good spark plug reading with a new set of Autolite 46 spark plugs for winter use. Based on that information, I'd assess the need to do anything else.

Is this an original engine? Has it ever had the head off? Is it stock,OEM? The reason I ask is that if a valve job as been done and the difference in thickness of OEM head gasket and an aftermarket one has not been compensated for by milling the head you will not have all the compression the engine was designed to have. At higher elevations more CR is better, as per Joe's comment.

Adios, David
 
burnoutstang1":oxmythe7 said:
Where in Colorado? I'm in Boulder.
Click to expand...

I used to live in Boulder. Beautiful place. I am a CU grad. I live in Colorado Springs now. I like it even more than Boulder.
 
CZLN6":rokkhoi4 said:
Howdy Back J:

It would be helpful to know a little more about your location and your car. Auto trans or manual? I'm making the following with the assumption that you have a '65 - '69 200 with a Load-O-Matic distributor.

FoMoCo had an engine specific for some Rocky Mt. and high altitude distribution centers. I would not mess with rejetting without knowing the build destination for your vehicle. Or at least know what jet you now have. There are three external adjustment that can help to tune your carb to make the most of it. 1 is the low speed air screw. It should be tuned for highest idle speed or vacuum if you have a gauge available. 2nd is the accelerator pump pivot point. It has two settings; "hi and lo". the hi setting/pivot hole should be used for temperatures below 50 degrees. The hi for temps above 50 degrees and/or elevations of 5,000 ft and greater. The last is the automatic choke setting. it should be set as lean as possible- only enough choke to have an efficient warm-up. Messing with these three adjustments cannot get you into too much trouble and may help. This engine really needs a summer and a winter tune.

I'd do a good spark plug reading with a new set of Autolite 46 spark plugs for winter use. Based on that information, I'd assess the need to do anything else.

Is this an original engine? Has it ever had the head off? Is it stock,OEM? The reason I ask is that if a valve job as been done and the difference in thickness of OEM head gasket and an aftermarket one has not been compensated for by milling the head you will not have all the compression the engine was designed to have. At higher elevations more CR is better, as per Joe's comment.

Adios, David
Click to expand...

David,

Thanks for all of the great info. I've got a 67, Everything is stock. Load o matic distributor and it is a manual. I'll start to trouble shoot some of the things that you were talkng about next week. Once again, thanks.

Jeff
 
Howdy Back Jeff:

Bill's "Good Luck" may have been refering to the interference of the starter with a header on these vehicles. But know that both Clifford and the newest source for parts CI, our host on this forum, have improved over the years- especially CIs. But you should also know that a header is a very high expense and to really utilize the potential they bring a coordinated engine upgrade is required. There are several other, more cost effective things you can do to "optimize the performance" of your ride.

For example, if you are committed to a fairly stock engine for the time being, and upgrade of you ignition by installing a Petronix Ignitor in place of your contact points. The upgrade will eliminate the need for regular maintainance to re-establish the point gap, will allow you to run a wider spark plug gap for a hotter, more reliable spark. The kit runs about $60 & install will be fairly simple. You should notice a smoother idle, better power and economy.

The other investment is to upgrade you stock exhaust system with 2" diameter pipe and a Turbo type muffler. If you do go to a header at some point in the future this much will already be in place. The best time to do this is when you need some exhaust system repair.

After this you will really need to do some thinking and planning as to what you want, how much you can spend- in other words, have a plan.

Does your '67 have the three speed with full synchros? Do you know where your car was distributed from? I'll be anxious to hear what your spark plugs tell you. How many miles on your engine?

Adios, David
 
David is correct. My headers fit over the starter, but I had to modify it slightly. I tried a bunch of different things, including testing and trying to fit smaller starters to it. Most of the frustration was based on my starter going out, and with them being such a tight fit, it was a tad of a PITA.

At the time, CI wasn't selling headers (2002 ish), and if you wanted performance parts, Clifford was one of your only options.

I also agree about other more worthwhile upgrades prior to installing the headers. I installed mine at the same time I upgraded the dizzy, modified the head, and added the 3x1 offy manifold. I also had twin exhaust with flowmaster installed.

Since then, I've doen the rear disc brake SVO upgrade kit, added an 8 inch rear (3.73's) out of a 66 289 car, and some 16x8 Torque thrusts to the back. I have the v-8 front spindles, but need to get the clutch issues sorted out first.

Anyhoo, back on topic, didn't all 67's and later come with the 3.03, so it should be synchro.. I'm also curious to how many miles, etc.

Bill
 
CZLN6":2jcbv0vc said:
Howdy Back Jeff:

Bill's "Good Luck" may have been refering to the interference of the starter with a header on these vehicles. But know that both Clifford and the newest source for parts CI, our host on this forum, have improved over the years- especially CIs. But you should also know that a header is a very high expense and to really utilize the potential they bring a coordinated engine upgrade is required. There are several other, more cost effective things you can do to "optimize the performance" of your ride.

For example, if you are committed to a fairly stock engine for the time being, and upgrade of you ignition by installing a Petronix Ignitor in place of your contact points. The upgrade will eliminate the need for regular maintainance to re-establish the point gap, will allow you to run a wider spark plug gap for a hotter, more reliable spark. The kit runs about $60 & install will be fairly simple. You should notice a smoother idle, better power and economy.

The other investment is to upgrade you stock exhaust system with 2" diameter pipe and a Turbo type muffler. If you do go to a header at some point in the future this much will already be in place. The best time to do this is when you need some exhaust system repair.

After this you will really need to do some thinking and planning as to what you want, how much you can spend- in other words, have a plan.

Does your '67 have the three speed with full synchros? Do you know where your car was distributed from? I'll be anxious to hear what your spark plugs tell you. How many miles on your engine?

Adios, David
Click to expand...

Hey David,

Not sure about the full syncros thing that you mentioned above. I'm not exactly sure how to tell. My car was distributed from San Jose, CA. I just swapped out the sparks about a month ago so I'll have to do some more digging on that. Also, the engine was rebuilt about 8-10 years ago. I am assuming that it has almost 180,000 total miles on it. Probably only 2000 since the new rebuild.
 
8) if you have the later 9 bolt top cover trans, you have a full synchro trans. that means you can downshift to first gear while the car is still moving. if you have the 4 bolt top cover trans, or the early style 9 bolt top loader, you have a non synchro first gear. the easy way to tell with the 9 bolt cover transmissions is to look at the mounting bolt pattern. if it is tall and narrow, then you have the early trans, and most likely a non synchro first gear. if it a dual pattern or a tall and wide bolt pattern, then you have the later model top loader and it is a full synchro trans.
 
Howdy Jeff:

FYI the 3.03, full synchro three speed was introduce in the '67 model year. Unfortunately, not all '67 vehicles got this latest upgrade. In addition to rbohm's descriptions, a simple test is to down shift into first gear while the car is still moving- as you might, to use engine compression to assist stopping for a stop sign. If you can downshift without double clutching or getting gear grinding you most likely have a 3.03 full synchro three speed trans- which is good. It is a much more user friendly and robust trans than the earlier ones.

Did you get any paper work as to what was done in the engine rebuild? And as far as DSO is concerned, only vehicles from Denver and SLC got the altitude tune. The San Jose/CA engines were the same as all other DSO. That changed drastically in the 1968 model year.

Just for fun, check the casting codes on the engine. On the head is is on top of the log behind the carb. On the block it is under the exhaust manifold. The head may read C7DE- B or C, or both. the block may read C6DE- ?.

What plugs did you put in last? Make and heat range? Have you ever rebuilt the carb?

Adios, David
 
Hey jsevern,

I'm in Longmont Colorado. Maybe ten years back now I purchased a 66 mustang from the original owner. This was a low miles unmolested original car. It had been relocated to Boulder from Lexington KY in the 70's. The car always ran rich so I tracked down a jet for the 1100 carb that was for altitude as per Fords service manual, don't remember the jets number. I installed the jet and found the car would bog down like it was starving for gas at 40-50 mph range. I went back to the original jet and it runs ok. I would stay with your current jetting it's most likely for sea level. Like was posted maybe advance your timing some. I think I'm like advanced 10 degrees from factory timing specs.

Lowell
 
LPlum":b1v3gwn9 said:
Hey jsevern,

I'm in Longmont Colorado. Maybe ten years back now I purchased a 66 mustang from the original owner. This was a low miles unmolested original car. It had been relocated to Boulder from Lexington KY in the 70's. The car always ran rich so I tracked down a jet for the 1100 carb that was for altitude as per Fords service manual, don't remember the jets number. I installed the jet and found the car would bog down like it was starving for gas at 40-50 mph range. I went back to the original jet and it runs ok. I would stay with your current jetting it's most likely for sea level. Like was posted maybe advance your timing some. I think I'm like advanced 10 degrees from factory timing specs.

Lowell
Click to expand...

Thanks Lowell. I really do appreciate the info. Hey, if any of you Colorado guys want to meet up sometime let me know. Maybe this spring. Let me know.

Jeff
 
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