Topic: turbo diode trick?

[turbojeep95]

Ive been reading some more about turbocharging in a effort to try and finish mine in regards to engine management and I came across this. A 97 tj with a 4.7volt zener diode to trick the map sensor with an fmu. Anyone with any experience with the diode trick care to share their comments?  Heres the article if anyone is interested.   http://www.theturboforums.com/smf/index.php?topic=116982.0

[sharpxmen]

Ive been reading some more about turbocharging in a effort to try and finish mine in regards to engine management and I came across this. A 97 tj with a 4.7volt zener diode to trick the map sensor with an fmu. Anyone with any experience with the diode trick care to share their comments?  Heres the article if anyone is interested.   http://www.theturboforums.com/smf/index.php?topic=116982.0

that zener is just a voltage clamp on the MAP output, the 1 bar MAP will never go over 5v since that is the voltage supply, you would need it if for example you'd use a 2bar map with an adjustable supply to adjust your output for your max boost (so if you have 8 psi boost you want about 4.7v at 8psi and since the 2 bar would give you that value at 14.5 psi in case it has a 5v supply you need more voltage to create the offset, the 4.7 zenner would limit that output voltage so you don't err the computer).

So imo, with the stock map and no MAP adjuster you don't need a voltage clamp (or this zener mod) 

[turbojeep95]

I guess theres goin to be no easy way to do this. Its just the tuning with the split second unit is keeping me from finishing.

[sharpxmen]

I guess theres goin to be no easy way to do this. Its just the tuning with the split second unit is keeping me from finishing.

if you have the split second you should not use this voltage clamp, the Split second takes care of that and beyond. What is your challenge at this time - do you have a wideband AFR monitor that you can log so we can have a look at it? What boost are you running, what injectors do you use, what's your setup?

[turbojeep95]

Its a factory rebuilt turbo from an 86 mustang svo with 48/60 trim. Not sure the size of the wastegate. I have a set of 36lb venom injectors but I think they'll be too high for only 6-8lbs of boost. Just a $50 fuel ratio gauge for now. I also have a bov from an eclipse and a big intercooler from a volvo. Currently runnin 19lb injectors. I just need some pipes welded and an oil drain line into the pan and some engine management. Already tried the adjustable map sensor but the computer seems to figure it out.

[sharpxmen]

Its a factory rebuilt turbo from an 86 mustang svo with 48/60 trim. Not sure the size of the wastegate. I have a set of 36lb venom injectors but I think they'll be too high for only 6-8lbs of boost. Just a $50 fuel ratio gauge for now. I also have a bov from an eclipse and a big intercooler from a volvo. Currently runnin 19lb injectors. I just need some pipes welded and an oil drain line into the pan and some engine management. Already tried the adjustable map sensor but the computer seems to figure it out.

36lb/hr would be too much imo, but you can always calculate the size you need and fine tune it with Split second and if you can the fuel pressure. You should have a wideband at a minimum if not a logging afr device - it's the 14 AFR and below that you need to fine tune, the $50 gauge off the stock narrowband will not give you that information just that you're not above that value. if you're too rich that's not good either (better than too lean but still)