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question on diode mod

969 Views 14 Replies 5 Participants Last post by  EuroTrash88
I have a front mount intercooler, therefore my map sensor isn't plugged into anything, can I still do diode mod? I wired the diodes into the actual sensor plug.. I don't know if that does anything. I can't test it until I get my new coil packs tomorrow. I've been searching quite a bit..
Any help is greatly appreciated.
Thank You


Modified by Anthony1.8 at 7:49 AM 10-20-2008
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Re: question on diode mod (Anthony1.8)

Ok, so your MAP Sensor is not even actually connected?
If that is true, then the diode mod will have no effect as far as I know.
Running the car with no MAP Sensor, im not even sure how the car is able to tell the boost that your running?
Why not attach the MAP Sensor? I have a front mount, and so do many others and it's not a bid deal to attach the MAP Sensor to the piping.
Re: question on diode mod (-02reflexgti-)

Oh ok, do you have any pictures? I'd have to cut into the piping i'm assuming?
Re: question on diode mod (Anthony1.8)

Here is the DIY.
http://forums.vwvortex.com/zerothread?id=3172487
Just run through the thread real quick, and you should be able to find the pictures of J-TEC installing his MAP Sensor.
Don't worry, JB Weld works fine, I have been using that for over a year.
Any questions, just ask.
Re: question on diode mod (Anthony1.8)

Quote, originally posted by Anthony1.8 »
I have a front mount intercooler, therefore my map sensor isn't plugged into anything, can I still do diode mod? I wired the diodes into the actual sensor plug.. I don't know if that does anything. I can't test it until I get my new coil packs tomorrow. I've been searching quite a bit..
Any help is greatly appreciated.
Thank You

Modified by Anthony1.8 at 7:49 AM 10-20-2008

when u say u wired multiple diods to the plug, plz eloborate what u did, cause u cant just run multiple diodes as once. also ur car wont run properly at all without the map connected to the charge pipe. u have to either fabricate or buy the flange for it and have it attached, otherwise the car barely runs from what i've heard, because the fueling is regulated by o2 and map sensor at higer volumes of air when the maf sensor cant read anymore.
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Re: question on diode mod (EuroTrash88)

Yes sir, you are very correct. I actually wanted to also ask him what he meant by "diodes" there should only be a single diode.
Your also right about the car not running well with no MAP Sensor.
To the OP, please install the MAP Sensor and then worry about the diode mod.
Make sure the car runs ok with the MAP hooked up, and then splice the diode.
Re: question on diode mod (-02reflexgti-)

Quote, originally posted by -02reflexgti- »

To the OP, please install the MAP Sensor and then worry about the diode mod.
Make sure the car runs ok with the MAP hooked up, and then splice the diode.

x2
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I appreciate all this help guys,

I am saying diode(s) because I am using a 4.3v zener and a 4.7v zener and a switch, like the tutorial.
Ok, so it sounds like I really got to get the map sensor hooked up, I'll buy that bung and get to work, thanks a lot guys.
Re: (Anthony1.8)

No problem, im glad I could help.
But yeah, your on the right track.
Let me know if you have any more questions.
Re: (-02reflexgti-)

and why not just use a mbc ?..maybe i'mmissing something ...
I got everything hooked up... But how do I test if diode mod works? I'm riding around and I try the switch in all 3 positions, I can't tell the difference. Also, do I have my MBC hooked up right? I just replaced the N75 with the MBC, wga line to mbc, and that other line (coming from the intercooler piping i think?) to the mbc.. and blocked off the intake side where the N75 was connected to..
I'm asking if this is right because, when I turn the MBC all the way down, I have unlimited boost... Like the wastegate won't open.. and when I turn it a couple clicks up, I have 10psi, then a couple more clicks up, i'll have 6 psi, then a couple clicks more i'll have 4psi.. but if I turn it down, it goes up to about 14psi untill i run out of clicks and i'm back to unlimited.. I tried switching the hoses to the MBC thinking they were backwords, same thing happened. Is it cause it's a cheap controller? I have a feeling i'm running these lines wrong..



Modified by Anthony1.8 at 8:41 PM 10-30-2008
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Re: (Anthony1.8)

ok, the diodes are obviously working if your able to boost anything over 15psi, cause thats where hard limp is suppose to kick in, for some ppl the 4.7 doesnt work til they get chipped, for others it works fine like it did for me. as far as the mbc controller goes, post a pic of the mbc and the lines going to it, and i'll tell u if ur right or wrong. gl
kinda same thing here. i dont have the diode on just yet but with the mbc all the way down i spike 15psi untill i go in to limp. but if i turn it up the boost will come down. i have a 2pc mbc. a cheap ebay one. im sure thats my problem
Can any one post a pic of the right Diode for me?
Re: (dixongli)

Quote, originally posted by dixongli »
kinda same thing here. i dont have the diode on just yet but with the mbc all the way down i spike 15psi untill i go in to limp. but if i turn it up the boost will come down. i have a 2pc mbc. a cheap ebay one. im sure thats my problem
Can any one post a pic of the right Diode for me?

You need a 4.3 and 4.7 zener diode, a pic wont help just ebay what i just wrote, they cost a few cents a piece or something. as far as the mbc goes, thats just bs, something u have to realize is, your are no longer using the n75 valve to regulate the turbo constantly. instead the mbc is waiting til boost is achieved to open the wastegate, but the problem is our stock turbos are sooo small that once they spool, they spool extremely fast and peak b4 the mbc has time to open up and allow the wastegate to open, hence you are havin very little control on the amount of boost when you are attempting to control it around the 12-18 psi range. its not that its a cheap mbc, cause all it is, is a bearing in a chamber compressed against the barb with a spring, which is what you control when u turn the knob. hopefully that explained things. if not im me and i'll give further details on how it all works.
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