Boost pressure at elevation

[loudelectronics]

Getting sled ready for the season and working on one final issue I have been having with my MCX 190 turbo. Most of the bugs have been worked out with the addition of better clutching and barometric sensor added that was not in instructions on early kits. My final issue is that when I take the sled to the mountains the boost gauge reads lower than what it does at home. At 7000 feet I may pull 3-4 psi max. At 10000 1-2 max psi on boost gauge. I have tried two different gauges (autometer and AEM) with same result. In the prairies I pull 6-7 psi. It is almost like something is setup backwards. Any ideas?

 

[drew562]

Getting sled ready for the season and working on one final issue I have been having with my MCX 190 turbo. Most of the bugs have been worked out with the addition of better clutching and barometric sensor added that was not in instructions on early kits. My final issue is that when I take the sled to the mountains the boost gauge reads lower than what it does at home. At 7000 feet I may pull 3-4 psi max. At 10000 1-2 max psi on boost gauge. I have tried two different gauges (autometer and AEM) with same result. In the prairies I pull 6-7 psi. It is almost like something is setup backwards. Any ideas?

Your boost controller isn't working. As you go up the boost should rise. I've had 3 nytro's and the best set up is a turbo smart boost controller. Manually set by you. Those auto tunes stick and fails. Caused me grief too. The turbo smart mounts on the back by the exhaust. Super simple and fool proof

 

[cstolz]

Might sound stupid but I have a 2010 low boost nytro that the bottom of the plenum broke almost completely off before affecting boost pressure. Had to take it off to find the problem. Had it welded back up and all is good now

 

[loudelectronics]

There has got to be a way to pressurize the controller to see if it is adjusting with boost is there not? I do have a turbosmart controller just have yet to install it as hoping I could get the stock setup working.

 

[174mcx]

I've used my fox float air pump before to test the way your thinking. Get creative and use the pump to mock "boost" and use your boost gauge for reference and see when your waist gate opens.

 

[SNAFU]

If your engine is shut off at elevation what does your boost gauge read?

 

[Merc63]

Boost gauge is reading correctly. You're loosing boost as you climb elevation because the surrounding atmosphere has less pressure, so your turbo will produce less. Do you have a boost controller that compensates for the atmospheric pressure to build equal boost regardless of elevations?

 

[JohnBoyTurbo]

Altitude compensater hooked up backwards. It's only two wires. Seen it before on the bigger mcx kits.

 

[loudelectronics]

With engine turned off the gauge is reading 0 psi. However when at idle it drops to -10. I was wondering if the two wires were reversed on the unit from factory. Will try messing around with that. However I did find that the turbo manifold that bolts from the header to the turbo is leaking due to warpage. Not sure why it is warped but there is some pressure loss I need to fix.

 

[JohnBoyTurbo]

It will show vacuum at idle so the -10lbs is normal. It's easy to check if the wires are backwards. Just cut them and use connectors and put them back together. Go for a ride at elevation and swap the wires and try it. If that's not it just swap back and leave it.