Tuning for Altitude? (LSx/OLSD)

[35R]

Anyone have experience tuning in LSx/OLSD for altitude compensation?

I noticed my tune was somewhat "off" at Wakefield (someone told me Wakefield is about 800m up?) Anyway doing a little research here and there it seems with altitude (thinner air) we might expect to run a little richer right?

The other issue is temps, on the way to Goulburn there were 2* temps!

Anyone have any tips/tricks/advice on stuff they have done to dynamically adjust for altitude (if at all possible?)

thanks

:)

[Delft Maloo]

i have found that in my car and some of the ones iv tuned that it simply doesnt register the kpa level that you see else at the lower sea levels, i have not seen anything in any of my tables in 1 or 2bar systems that would be of any use. the only bandiad i see is making sure that your ve cell transitions are as accurate as possible.

[SSUte01]

Dunc,

It may run richer or it may run leaner it will depend on your airflow model (VE) at slightly less pressure as with speed density pressure dictates flow.

I have had some experience given that I live at sea level. My car along with any others I've done since I 've lived in Newcastle have been tuned at sea level and I have raced mine at Heathcote (with WB) and logged at my parents house (about 1500ft altitude) and one other car competed at Summernats (Canberra) and the AFRs were all within 0.2 - 1% of those at sea level. They are the only two I have hard evidence where tuned at one altitude then measured the AFRs at a vastly different altitude.

My only advice for accounting for density variation is to make sure your 90 - 95 - 100 - 105kPa fueling are all tuned during the initial tuning process, sorry if that sounds patronising, its not how it is intended. Generally on most days at see level the pressure will be ~100kPa is what you will see at WOT maybe some 95kPa depending on the atmospherics. What I personally do (OMFG imagine actually giving advice for tuning on the internet ;) ) is use the WOT row from the VE model (be it 95, 100 or whatever) and copy/paste to one row above (more pressure) and one row below (less pressure) and scale them by 3% so for example if WOT in Sydney is 100kPa (close enough to 1 atmosphere/Bar) then I use that for 95kPa but mult by 0.97 and use it for 105kPa and mult by 1.03. Try to get a WOT run where you are as close as possible to one of the increments probably 100kPa rather than in the middle, say 97-98kPa.

I know this is not perfect but it has been within tolerences for me.

Ideally, you need to restrict the intake at Sydney to even more accurately model the airflow at less pressure or move to higher altitude - one method of achieving this is to only allow say ~80% (or whatever it takes) TPS to restrict your intake by about 5kPa then 10kPa and that should be plenty. Alternatively, do some 3rd or 4th gear starts on the straights of Wakefield and use that data and it will be near perfect for Goulbourn.

As for temp correction I change the IAT/ECT bias and have found that works within 1-2% between the peaks and troughs of summer and winter.

I hope that I made sense there and that it is of some help :)

[Delft Maloo]

as for the temps you are able to adjust this in your iat and olfa tables. Even during summer in the early mornings 5-7am travelling to sydney i was seeing iat's of 7-13* after the intercooler which was only a couple of * off ambient for that time of year.
I did have trouble with my open loop table with the coolant temps, as with the lower iat temps i was getting i was also registering bettween 65-75*c coolant temps thus bringing it into some of the areas on the table that would start adding fuel as you it does in a cold start situation.
I had to remove the adder portions of the table in the lower coolant temp/ higher ve area to stable out the afr's while on the hwy.
hope any of this makes sense:lmao: .

[35R]

thanks guys, a couple of things to try there. I think Wakefield is 800m? (2400ft) - i've noticed once i get to Pheasants nest, the car will start chugging in high gear / lower rpm. But when i get back to sydney, all good again. I'll logg it all the way down next time.

[BOMI]

Dunc, did a search for you and found that its 702m above sea level.

See this PDF, http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0011/87275/graziers-guide-pastures-section2.pdf


Troy :)

[35R]

Dunc, did a search for you and found that its 702m above sea level.

See this PDF, http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0011/87275/graziers-guide-pastures-section2.pdf


Troy :)

thanks Troy

[rice racing]

thanks guys, a couple of things to try there. I think Wakefield is 800m? (2400ft) - i've noticed once i get to Pheasants nest, the car will start chugging in high gear / lower rpm. But when i get back to sydney, all good again. I'll logg it all the way down next time.

You will know the exact altitude (+- a few meters) with your Race Logic VBOX (or performance box) ;)