Emxnd

Hey guys, I'm swapping a LQ9 with rectangle port top end into my 1996 Bronco. I'm getting mixed input on if I should run MAF or speed density. The truck will spend a lot of time split between being at sea level and then going through the mountains. Its an adventure vehicle.

How does speed density react to altitude changes compared to a MAF? What should I run known it will semifrequently go up the mountains in the PNW and surraounding national parks?

Woodylyf767

Ask your tuner

Speed density generally does not do well with altitude change if you do not have an additional map sensor going to atmosphere to reference air density

At least this is what my tuner told me

I will not have altitude changes but may still run an additional map this way to not make the correction do the work if I wind up going on a long road trip

low2001gmc

iTrader: (148)

With altitude changes you'll have, stick with MAF definitely.

TrendSetter

many ecus will sample the map sensor at key on and save that as baro to help with altitude changes.

Full Power

.
02 Tahoe, 2 Bar SD tune: No MAF.
Magnuson pushes 11 pounds manifold pressure.
I tuned it in Alaska, at 50 degrees Fahreneit ( summer) at SEA Level.
Drove it through Canada, Montana, Wyoming, Colorado to Texas, Ran great at 105 degrees in Texas.
SanteFe New Mexico, 7000 feet and 80 degrees F: No problem, full boost, smooth idle.
Ran up to south rim of Grand Canyon ( 9200 feet) ran great the whole way, no problems.
We put 11,000 miles on in 3 weeks, 3 canadian provinces and 11 states without issue. Rotated tires once, changed oil once. Other than that, never turned a wrench.
Back in Alaska now. It's been 8 years, that little 4.8 Liter has ZERO oil consumption, and has had NO issues..
.
Short story: Speed Density will run anywhere, at any temperature or elevation, with out issue.
It's ALL about SPEED x Density, with a little help from your IAT

gametech

iTrader: (1)

Altitude affects density, which is calculated based on MAP and temperature. No need to separately take baro readings or any other such nonsense. Tuners that tell you it won't work are either stupid or lazy (or both).
edit-- Millions of factory vehicles were SD only and the manufacturers used the same tune selling them in Denver as the ones sold in Daytona.

NicD

iTrader: (7)

Yeah, there is absolutely no problem running in speed density and going between sea level and up in the mountains.