16 PSI of boost Eco mode 850 T-5 Automatic with new MBC

[gotmeaT-5]

Finally got around to fitting my MBC to my 97 850 T-5 today and now have a nice 16 PSI of boost @70mph in Eco mode without adjusting anything compared with 8-10 PSI ish with the stock TCV

Would you all suggest this a good figure to sit at for a chipped T-5 or can I go a little higher if so what would the max safe level be ?

[Jamest5r]

Got to check your fueling before you go any higher mate, but where you are is ok about 1.1 bar.

[t5_monkey]

you NEED to check this ... but i think from memory someone said 17-18 psi....

certainly don't turn it up above 16psi before you know for sure...

[gotmeaT-5]

Thanks for that both.

Why do I need to check fueling for under of over ? Today I will test in Sport mode not sure if I will get a different but I'll keep it around your suggested figures

[BruceT]

Theoretically, you could run x amount of boost (Internals permitting) the problem is the air to fuel mixture.

More boost = more air in the combustion chamber.

So, for example - your car is 'mapped' to have the correct mixture of fuel and air at around 16PSI.

If you have 18psi of boost, your have more air, but the map cant compensation for this added air and injects the same amount of fuel for 16psi.

This means there is more air and not enough fuel, the fuel cools the burn a little (and obviously makes the bang) but with not enough fuel, IF the mixture is goes to far lean (not enough fuel) things start to get far too hot and melt pistons.

That a basic gist of why running more boost than the car is mapped for can result in bad things.

[Rnash2002]

Thanks for that both.

Why do I need to check fueling for under of over ? Today I will test in Sport mode not sure if I will get a different but I'll keep it around your suggested figures

Yes see if its under or over,you want it to be around 12's (AFR's) any good dyno will be able to test these.
Also a good way to see if you are running rich is to boot it but then back off before if changes gear,if you get a pop from the exhaust then signs are theres enough fuel.
But best bet to get the AFR's done on a dyno.