Homemade Turbo Tune !

[bearsbmw]

(WARNING!! Do not try this at home if you don't have much electrical exp or without a volt meter and wireing diagrams)

I talked in a thread awhile back about a crude way to tune your car for almost zero $$$ and well I'm finaly done!!

Thing's you will need

36# injectors
Volt Meter
Boost Activated On/off switch 1psi
Insolated Wires
potentiometer switch
Motor 10:1 Compression
10psi of boost MAX!!
On/ Off switch


First thing will talk about is the boost activated switch...Out of all the mod's you can do this one will be the most important and need's to be done correctly... The worst thing you can do to a non turbo car is spool the turbo while your at half throtle and with the switch we are going to trick the ECU into thinking it's fully open... Wire the switch so that it sends 5volts to the ecu when you get into boost and set the switch for 1psi no less no higher

Second thing is the bigger injectors and for this you will need to set the AFM spring to 48teeth clock wise from stock(for 36# injectors) making the spring tighter...If you use diffrent size injectors note that for every 3 teeth you move on the AFM it's a 2% change in air fuel ratio... I recommend 30# injectors as it will be easyer to get the fuel correct

Third is the use of the potentiometer to control the air intake temp sensor allowing for time retarding and you can wire this up in the cab so you can ajust for outside Winter/Summer seasons... Use a on/off switch to put it back to stock at any time... basicly in the summer you wan't to trick the ECU into thinking it's see the highest temp possible at the AFM and therefor the car retarding the timing fully to allow for those 10psi of boost

this is something you do at your own risk and I don't take any responsibilty for problems you might run into ... If your like me you will find this to be a neat little project and will have fun with it... Excuse my spelling,Grammer, and punctuation

CheerS!

[JoeDellio]

I assume this would only work with a certain turbo? As larger turbos will spit out more cfm's than a smaller turbo would at 10psi. Are you using any kind of wideband to watch A/F ratio?

[bearsbmw]

yes lot's of variables come into play no doubt there but generaly it will work for all turbo's... I was only watching A/F with narrow band back when I did this at 8psi...I'm not looking for a 14:7 burn so rich or lean works for me... If you had ton's of time on your hands you could get close to 14:7 using the narrow band

[kowalski]

interesting idea, this however assumes that the fueling maps will move at the same increments on boost as a stock motor, so getting a perfect tune would be impossible.

however for a budget turbo application this sounds pretty cheap!