I live at around 4800' and was wondering if there would be any difference in boost psi and egt's at sea level

Thanks

 

I would think yes, there would be a difference if only because the air's thinner up there. Seems you'd have to spool the turbo a bit higher to achieve the same charge air density.

Check this out ~ http://www.engineeringtoolbox.com/ai...ume-d_195.html

 

For some reason I thought I could get a little more boost and have lower egt's. I know you have more hp at sea level. My thinking is probably twisted in some way.

 

I checked out the site, I guess I'll have to do some studying

Thanks

 

A 12 cm turbine housing would be an excellent upgrade for your truck. You need to spin the turbo faster to get the same air density into the engine as it would get at lower elevations.

You will run into EGT problems sooner because of the thinner air.

 

For all practical purposes a change in altitude will not impact the boost or power of a Cummins turbodiesel. That assumes you are running it within the design and power parameters for which it was intended, and have not blocked the wastegate.

The turbo will automatically compensate for the change in altitude, and will create the same manifold pressure (density of air charge and available oxygen) at 9,000 feet as it will at sea level, and then the wastegate opens and spills excess exhaust to keep the manifold pressure within design limits.

The only problems that occur are starting issues that can get a bit sticky once you are above 10,000 feet, but once you learn to overfuel the starting cycle even that is easily overcome.

If you have enriched the fuel such that you have blocked the wastegate to keep a Cummins from just making black smoke, then you could have a power loss at altitudes above 10,000 feet. Normally, it would only be something that would appear at full load and throttle, and you would see a major increase in black smoke from unburned fuel.

 

Right now I have a w/gated (disconnected) 14cm housing from banks. So far I top out with 20 psi boost but that will change later when I switch injectors. I was just curious.

 

Thanks everyone.

 

I live at 6200 feet and routinely get above 9k elevation. My truck has only been to sea level once on a trip I took to the northwest. It has been to Kansas City many times which has an elevation of about 800ft. You will definitely notice a difference. Not that the truck runs poorly or is a dog up high at all but I notice it runs better (maybe not better but peppier)at sea level and when it is in KC. The turbo does help it overcome the lack of o2 but doesnt negate it. 20psi at 5k elev is less dense with 02 than it is at sea level. The pressure is compared to ambient or whatever the technical term is not what it is at sea level(unless you are at sea level). So while you get plenty of pressure at elevation it is still not the same amount of O2 as it would be at sea level(so now you have 20psi of less o2 dense air). You will notice turbo lag to be a bit less at sea level/lower elevation compared to elevation. Egt's are also a bit better at lower elevation. To add to it a bit more since the density is less at elevation you have less drag so the truck works a bit less. Small as it may be it is still a factor. Also on my truck lower elevation also means less smoke particularily at takeoff. The turbo air charge is denser so the engine gets a bit more o2 with less psi thereby allowing the fuel to burn more completely with less pressure as compared to elevation allowing boost to build faster. And while my 12cm housing spools fine with the minimal mods I have at elevation it is not as fast spooling as the hy 9cm I had before. I swapped out my hy9 for the hx with the 12 not so much because of egts but because of surge and bark the egt reduction was just gravy for me.

So to really answer your question I dont think you will see anymore boost because pressure is pressure and when compared to ambient you will see no difference in boost pressure just the amount of o2 in the charge. You will notice the pressure come up a bit quicker. Your egts would be a bit less at sea level(at least that is what I have seen in my truck).

 

TURBO CHARGING, THE BEST ELEVATION COMPONSATION TOOL!!!!!! TRY AND GO FROM SEA LEVEL TO 9000 FEET W/OUT ONE

 

Frequently towing my 5th wheel over the passes here in Colorado (10,000 and 11,000 feet), this is what I've noticed. Yes, the turbo is slower to spool. You can make a tremendous black cloud if you tromp on the go pedal at 10,000 feet towing 10,000 pounds! The boost is down just a hair from at sea level. I can get a max boost of around 26# at sea level. My max boost at 10,000 feet seems to be around 24#. The EGTs do rocket up quicker. This is partly because you effectively lower the high boost effeciency of the compressor. Normally, the H1C compressor is only good to somewhere around the mid 20s psi (approaching 30 psi) without super-heating the charge air. Due to the less dense air at altitude, this number is lower. I believe you start super-heating the charge air in the low 20s psi. Also, because the air is less dense, the intercooler is less effective. So it all snowballs at some point. All that said, I can still maintain 20-22 psi boost and have EGTs in the 1100* range for quite a while...at least long enough to get up to the Eisenhower tunnel and over Vail pass. Now my radiator?...that's a whole other story!

 

This applies to wastegated turbos, which no 1st gen came with. Durn 2nd genners.

 

Same goes for this guy.

 

Another good reason for me to change to a WH1C.