mikecronis

I want usability for sea-level altitudes. The Edelbrock installer indicated he can win a few ponies as long as I don't go below 2000 feet altitude if he adjusts the canned-tune.

I'd rather be able to drive at all altitudes, of course.

If I used the canned-tune but primarily stay at-altitude (Colorado Springs, CO) will I be running too rich that my plugs will foul, etc.? Any experience on that?

Unreal

Car won't run rich, and any good tuner should be able to get more power, and be safe at all levels. The canned tune is pretty bad.

mikecronis

Yeah, forum searches indicate a guy here in Colorado says it's based on hot weather in San Diego (or similar) near sea-level as the basis for the canned-tune. I know the e-Force is not the absolute best setup, but I liked some of the mild benefits and stock hood option.

You're saying the canned won't run the engine rich with a bone-stock setup at 7000 feet?

Unreal

No, as the car measures airflow and is tuned for lower airflow. Up at 7k it just sees less airflow, so injects less fuel.

old motorhead

Won't boost pressure (and WOT cylinder pressure) go up as he climbs down out of the clouds. Does timing advance need to be adjusted to account for this?

Unreal

No, it has tables for different loads, and will just move to the different part of the table. At high elevation he may see 8000hz airflow on the maf, and at sea level 9000hz. So car sees more air, adds fuel, and adjust timing. These are not carb cars. They measure the air going in, so as long as that is done properly, you can drive it from -1000 to 10000ft without issues.

Yes boost goes up, but so does the air reading.

Eforce doesn't change anything in this aspect. A stock GM corvette is made to run in both Denver and California. You don't see special dealer tunes just for high elevation. The car has a barometer, maf, map, iat, etc to adjust for conditions.

mikecronis

Got the e-Force and sure enough, sooty tailpipes. Running rich (or burning oil). Manifold pressure stops at 15.74 PSI and not more. Mathing-it-out it's about 7.5 PSI boost-pressure at 6700ft. altitude. Not sure if it stops due to a mechanical thing or not.

Idle sometimes bogs between 1.5 and 2k rpm in between the point where the blow-off-valve opens.

mikecronis

So I checked my MAP sensor with Engine OFF and switch in the ON position and it reads 11.74 PSI.

At full boost it tops-out at 15.74 PSI. I think this means I get exactly 6 PSI.
Idle is negative (vacuum) at 4.74 or minus 7 PSI.
Deceleration is 2.1 or about minus 9.64 PSI.

I'm a little disappointed I'm only getting 6 PSI boost instead of 8. I am at 5700 feet, however, so I've read you won't get as much pressure?

CI GS

There’s no blow-off valve, it’s a bypass valve that simply reroutes boost internally into the chamber in front of the rotors, in order to reduce manifold pressure once the throttle closes and the engine sees vacuum. So, the bog can’t be caused from that opening on accelerating, as it actually closes on acceleration. More than likely, it’s bogging when it goes into power enrichment mode, and you just need the car properly tuned at your altitude.
The sooty tailpipes are most likely from it being tuned rich (the Edelbrock and Magnuson “canned” tunes are rich).
If you’re seeing only 15.74psi at that altitude, then that basically equates to 1 psi of boost at sea level, in terms of the power that your car will make. I can only imagine that the thinner air at that altitude also compresses less, so it probably normal for an “8 psi pulley” to only make 6psi at that altitude. I would definitely pulley down a couple of pulley sizes to pick up some boost and get it properly tuned.