vic_s197

I just installed my mac o/r downpipe And stainless works s tube muffler, I'm running a livernois 91 v10 tune, I drove it all day with zero issues but today I decided to hit the mountains up in Breckenridge, co and on the way there when I'd give it a little throttle to get me up the hill the turbos would bark and sound like ****, kinda like a surging sound only when I have it throttle, then it would stop for a couple miles then start doing it again, I changed the tune to my 87 tow tune but I haven't been on the hw yet so I can't test it yet till tomorrow, could it be the high elevation? I'm a little worried it might be the turbos. The truck is a 2012 fx4 with 14,000 miles.

Snowflake

I would dare say you have a leak up where your down pipe hooks to the turbo. It doesn't take much to change the sound. Retighten your pipes and you should be fine.

vic_s197

Il give that a shot when I get back tomorrow, but if i did wouldn't it do it all the time?

Snowflake

That would depend on heat cycles. I know a lot of time when installing headers you have to retighten after a few cycles.

vic_s197

I honestly forgot about that, Il do that tomorrow, I figured the high elevation might have something to do with it I'm up at 12,000 ft right now

jcain

You need to realize one thing about turbos, as well. Turbos are going to make X amount of boost, via the wastegate's commanded operation. Say your tune says make no more than 19psi, the wastegate will start opening to bleed off excess psi at 19psi. The difference you at 12,000' vs the California guy at sea level, is your turbos are working WAY harder to create the same 19psi. So when you release the throttle and close the blade, open the bpv, your turbos are spinning much faster initially and may be stalling or spinning backwards with such an instant stop in air flow. While you may have a leak, I'm doubtful, I'd chalk it up to exactly what you think it is. I'd be more aware of 100% loading of the engine and abrupt throttle releases.

vic_s197

I had that issue a while back with my old v2 tune they would bark when I would get off the throttle l, I updated to the v10 and hasn't done that till yesterday but your right about them spinning pretty hard to make the same amount of boost. I will be leaving here in a couple hours I will see how it runs and report back

eco-charged

I also live in CO. And I also run the LMS 91v10 tune. I completely lose my turbos when I drive in the mountains. Contact Anthony at LMS they will modify your tune for high altitude

vic_s197

Well it doesn't do it when I'm around town but this is my first time coming up this high, Il call them and let them know thanks man.

eco-charged

It doesnt do it around town for me either. Only on i70 up to breck or something. It shows me a p0299 DTC. Let me know if this is the sane one u have