Roush Supercharger real world PSI at altitude?

[twist-a-grip]

Just bought a 14 SVT Roush truck for my place in Steamboat (6900ft). Truck is more or less new, has 2800 miles from OKC (700ft). I've never modded a car in my life, so I'm a little unsure how things work. Based on the comments above, my truck will be running a little less PSI vs lower elevation and therefore will be a little down on power. I'm fine with this, as long as it still sounds good - you'll get power loss with all cars due to the higher altitude. However, since I'm new to having a modified truck, wondering if I need to retune it or anything to make it run properly and, most importantly to me, safely? I won't be doing any off-roading or towing, just driving around town and to mtb trailheads and back a forth to WY (4500ft) to see family. Certainly, I'll take as much power as I can get, but not if it jeopardizes reliability.

 

[biturbomg]

What phase Roush is it? If it is the Roush can tune you will be fine but it will be down an easy 2# at elevation. So expect a 40-60hp drop in power which if the truck is new to you may not feel any differnce anyway. Sound should still be good but wont be as loud as it was at sea level. If it has a custom tune I would data log and have them adjust for your elevation and fuel. If you want more power can drop to a lower upper pulley which is the cheapest easy way and if that is not enough add a bigger lower pulley. My 2013 ran the smallest upper pulley and 10% OD lower and made very good power and about 10# at 6000ft.

 

[twist-a-grip]

Stock Roush Phase II off road package - 590/590. Kinda expected 50hp loss, just wasn’t sure if I should retune for altitude for better reliability/safety. I agree that I won’t know what I’m missing since I’ve never seen or driven the truck, but it will still be more fun than the Land Cruiser or 4Runner I was also considering.

 

[Dane]

You're already tuned - it has to be with a supercharger otherwise you'd know it and would have likely blown up by now. If it was a stock tune (that didn't know about the Supercharger) your list of problems would be well beyond obvious.

You're good to go, nothing to worry about.

That being sad, at some point here I'm going to be adding a bunch of mods to my Roush and will then have to re-tune it. I'll be having that done by a race guy in Denver. I can get you that info if you like, but unless you are planning on beefing up the supercharger, and it doesn't sound like you are, you don't need to do anything.

 

[Dane]

Next chapter in the story. I've gone to full Kooks headers with true dual exhaust. I have installed a Melling oil pump. I've gone to a 69mm pulley (from 75).

I'm still seeing the exact same ~6psi. Truck runs fine, but I really expected to see an increase in that number. I have a new JDM tune for the setup (I didn't wind up having the race guy do the tune). It definitely spools up to 6psi quicker, but still caps out there.

I don't know what gives. There are no leaks in the bypass line/valve.

 

[MTF]

When you add headers the PSI will drop 1.5 to 2 PSI
But you went with a smaller SC pulley which will increase boast a PSI maybe a bit more.
So you number shouldn't really change.

But 6 PSI does not sound right, you should be up around 9-10 PSI, like most have stated.
Either the gauge is faulty or you need to double check that your hooking it up correctly.
Wish I could help you further but I don't have a Roush.

Now I just spent about a half hour on the internet there are quite a few guys confused where to hook up a gauge on a Roush.
Basically you need to hook it to the manifold directly not on any hose or bypass hose.
I couldn't find a Raptor Roush combo. Sorry

 

[Dane]

When you add headers the PSI will drop 1.5 to 2 PSI
But you went with a smaller SC pulley which will increase boast a PSI maybe a bit more.
So you number shouldn't really change.

But 6 PSI does not sound right, you should be up around 9-10 PSI, like most have stated.
Either the gauge is faulty or you need to double check that your hooking it up correctly.
Wish I could help you further but I don't have a Roush.

Now I just spent about a half hour on the internet there are quite a few guys confused where to hook up a gauge on a Roush.
Basically you need to hook it to the manifold directly not on any hose or bypass hose.
I couldn't find a Raptor Roush combo. Sorry

9-10 at around 5,700 feet? I’m in Denver.

There’s a port for the gauge hose. It’s hooked up correctly. Though I don’t 100% trust the gauge readings at this point.

 

[MTF]

There is around 2 psi loss in boost from sea to 6000 feet in general, according to the interweb.

 

[Dane]

There is around 2 psi loss in boost from sea to 6000 feet in general, according to the interweb.

Meaning I should be more in the 7-8 range here?

 

[biturbomg]

That does seem about 1# low. What’s the actual DA on days ur seeing the boost before and after. I was a solid 8# at 5500ft on the 69 pulley stock headers, tb etc. When I swapped the lower jumped to 10# but think may have been 11# lots of spin and gauge maxed out if I recall. So before headers and smaller pulley you made 6# and now with smaller pulley and headers your at 6#?


How does it feel? Any faster, more torque etc? Weren’t you going to have a lower out on like a year ago or am I thinking of someone else?