Altitude/Enviro impact on Speedpro?

[S351 R]

Great board!, and still searching plenty of posts on Speedpro since there is a lot more here than on Corral.

Anyway, have heard that the Speedpro does not react well to changes in altitude, and that as alt. increases it in fact goes lean (opposite of what I would have figured)

Now is this simply a minor effect to the "perfect" tune, or can it become problematic for a daily driver. Are there impacts from weather?

Real close to buying a FAST system, (since my options are very limited with the Saleen voodoo ECM) just want to make sure there won't be unexpected problems on a daily driver.

TIA

 

[Otto J]

i believe with teh wide band 02 option it would not be a problem,you set teh air fuel ratio, and you program your ve table for your vehicle and then factor in how much correction ou would like and that is how it works so if you go higher altitude and it gets leaner the 02 should recognize this and correct to your air fuel ratio
Otto

 

[bobc455]

Tia,

If there is a reason that people say that, it's probaby because of the way it's tuned - for example, I always race at a sea-level track, and the WOT VE values fall right in between two rows of numbers. I put these two rows at identical values.

At a higher elevation, however, I might fall only on the lower row, so in theory I would want a slightly lower set of VE numbers on that row, and a higher set of VE numbers on the high row.

Either way, the WBO2 should take care of it.

And if you have a daily driver, your manifold pressure (kPa) will automatically react - lower atmospheric pressure equals lower manifold pressure (unless you are not in speed-density mode).

-Bob Cunningham
bobc@gnttype.org

 

[S351 R]

Thanks for the input. I just havent heard of much yet that is bad with FAST, so I'll probably order one very soon. Right now, looking into PTE's custom harness - but I need one for a 104pin EEC-V harness; again Saleen's bright idea for an "udate" in '97.

This forum is great and adds a little confidence to inevitable tuning questions I'll have in the future. Tons of archives to still read.

(Also, FWIW I guess my forum jargon got carried away with TIA as Thanks In Advance so Im just plain Kirk... )

 

[Otto J]

kirk where are you located? if your local i can help with the tuning when your ready
Otto

 

[bruce]

Originally posted by S351 R

Anyway, have heard that the Speedpro does not react well to changes in altitude, and that as alt. increases it in fact goes lean (opposite of what I would have figured)

Now is this simply a minor effect to the "perfect" tune, or can it become problematic for a daily driver. Are there impacts from weather?

Most people tend to get Baro and temp corrections backwards.

As BARO increases, you'll need to slightly lean the engine.
As Temp increase, you'll need to add timing.

This is assuming you have the base tune right..........

It takes working under different conditions to see what your engine likes, not all the math modeling predictions are correct.

Also the O2 content actuall changes from location to location, as well as the actual gas brew.

No auto tuning to date can adjust for all the variables, so you still need to know what you're looking for and how to get there.

 

[S351 R]

Otto,
Definitely appreciate the offer, but Im out in San Diego.
And yes, this 91 octane crap sucks. Oh well, probably leave the area in a year or two.
Kirk