A non-believer wants boost (and a diode?)

[l88m22vette]

So as much of a purist as I am (or whatever) I have stuck to sorting the car and wanted to wait for a "real" tune, and never liked the idea of the diode mod (its a "hack"), but I realized that $550 extra isn't going to be around for a good while.

I know that dioding and using a MBC works because the ECU compensates for the boost, but is waiting for a "real" tune better, or are there no real drawbacks to the diode mod? Do I just soldier the diode and turn up the boost, or is there more to worry about? I've researched, but I want opinions :confused: In the end this would be a short-step on the way to an actual tune, so its really a question of whether or not I should be patient.

[Murderface]

Honestly, I had a diode+MBC then a chip, and as far as WOT performance they feel pretty much the same to me.

If I had to do it again, I'd do a diode with a bleed style MBC in line with the N75. That way you'd retain stock like part throttle functionality (I'd imagine). My ball+spring MBC wasn't very good in the part throttle department. In theory, N75+extra bleed should.

[myslow1]

im doing the diode.... I have everything i ordered some zenor diodes but misplaced them so whenever i get them again im going to do it to it. For a boost controller as murder said get something with a bleed on it, i have the turbo xs hpbc.

[Skitzafit]

What are you trying to be pure to? The VW guys have been using the diode for some time now. To be honest we all drive a vw. The Audi community can be pretty stingy about admitting it at points. Nothing wrong with getting the most with what you got. If you cant afford to go BT or Expensive tune then do it. No reason to miss out on a little more fun to save face with the community.... just my opinion but I have been known to go full retard and we know you never go full retard....

[Cincy]

My a/f with no tweaks on a nbo2 and 2.0L at 19psi was 12:1 from peak tq to redline. The a/f was better at 19psi then it was at 11psi (more likely due to adaptation since it had a full pulls to get the a/f correct). Most chips run 13:1+ from there on. A compitent person can easily make great power with a diode setup, just look at what i did. You know how much power i made with my setup, and im sure i left a good 10whp and more tq out since i didnt have a vagcom of my own at the time to add in timing. Im now up 3* or so with little to no pull and will add atleast another 1.5* when my ic is on.

[l88m22vette]

See, thats the thing, my BEA has the wbo2 :) Also, Murder, are you talking something like this: http://forums.vwvortex.com/zerothread?id=3965516, or different? I do happen to have an spare N249...

[Cincy]

The all you have to do is run logs after you install and then adjust timing and fuel as needed.

[Murderface]

See, thats the thing, my BEA has the wbo2 :) Also, Murder, are you talking something like this: http://forums.vwvortex.com/zerothread?id=3965516, or different? I do happen to have an spare N249...

I actually designed a setup like that and ran it for a while until I realized...there's no point on a K03s lol. I got everything tweaked (adjusting wastegate, mostly) to the point where my car boosted at WOT off the N75 pretty much the same as it did off a ball+spring MBC. I had mine rigged on a switch. It got to the point where I'd switch back and forth and see no difference. I made sure the solenoid was working...it was.

IMO the stock turbos spool so fast anyway you're not going to see a difference running it off any fancy MBC or EBC if you already have a chip. A bleeder MBC in line with the N75 should do the trick by bleeding some pressure off the N75's signal to the wastegate to acheive a few more PSI.

Here's a diagram of what I did...drawn from memory from stuff I did about a year ago lol:
http://i102.photobucket.com/albums/m96/lmaoxfilip/boostcontrolrig.jpg

Boost signal goes into the solenoid valve, which with the switch off, directs it through the N75. When the switch is flipped, the boost signal goes to the ball and spring MBC.

If you're not chipped, I'd experiment with whatever kind of MBC you want and see what works for you. However something intricate like above is not even worth it on a chipped stock turbo car.

[exTTreme]

there really is no reason for you not to do the diode untill you can afford a tune you might even decide you dont need a tune after you have the diode setup.

[Cincy]

^ true that.

One boost control is plenty for me.

[l88m22vette]

Man, this is exciting, cheap power lol...cincy, did you use stjacket's adjustable MAP? Does he sell them, or would it be easier to make one? I would actually prefer that over the diode, since its "temporary."

[Cincy]

I have one that he sent me that i was going to use on my brother's car, but it has a small map. If you have the larger diam map, ill send you it to use.

BTW, my ATC has a large map

[l88m22vette]

not to sound stupid, but how would I figure that out? I'm going to start my TB in a few hours, so I can look then...

[Cincy]

The part the o-ring sits on the map is either about the size of a nickle or a dime.

http://store.42draftdesigns.com/assets/images/cnc/18tmap.jpg

[225ttroadster]

link to diode mod DIY or more info please... Right now I fiddling with N75 race and MBC setup. The best I can do without getting limited is peak at 21-22 and taper to 16. I am pretty happy with it but I am tired of having to get in and out of the throttle 10 times before it finally lets me have it all.

[Cincy]

Here is the one i did for AF a long time ago, pics are gone since they switched formats. I guess i can redo the pics for the new site here when it warms up

[225ttroadster]

Here is the one i did for AF a long time ago, pics are gone since they switched formats. I guess i can redo the pics for the new site here when it warms up


Where? lol... no link?

[exTTreme]

if you do a search on audiforums.com for diode mod and mbc his thread should pop up i cant insert links from my phone or i would :)

[Cincy]

oh.... copy AND PASTE!!

http://www.audiforums.com/forum/showthread.php?t=57086

[225ttroadster]

oh.... copy AND PASTE!!

http://www.audiforums.com/forum/showthread.php?t=57086

Now when you talk about the actual increase in boost... are you guys talking about HOLDING 18-20 psi on 4bar FPR? or Peaking there? because I already peak at 21-22 and taper back down to 16-17.

[Cincy]

These turbos are tiny, so you will only hold peak till about 5k before it falls off all the way till redline. Also, i can to discover a 3bar is fine. My a/f was 12:1 and holding with a 2.0L and 19psi.

[225ttroadster]

These turbos are tiny, so you will only hold peak till about 5k before it falls off all the way till redline. Also, i can to discover a 3bar is fine. My a/f was 12:1 and holding with a 2.0L and 19psi.

So you are actually talking about "holding" 18-20psi? and yes I understand that it will taper off after 5500ish rpm.

[Cincy]

yes. A spike will be more of a few hundred rpm jump which happens with load. A good bleed style mbc will basically eliminate that. My hpbc doesnt spike, even with an extra 228cc

[225ttroadster]

I have the FORGE MBC which I am pretty sure is a bleed style (considering I can hear it bleed off) and it def. spikes.

[Cincy]

which one? Plus you are using the n75 which isnt the best to prevent spiking

[225ttroadster]

http://www.ecstuning.com/stage/edpd/pagebuild_v2.cgi/?imageID=3420&html=viewimage.html

this one... totally forgot about the stupid n75...

[Cincy]

yes thats a bleed but the n75 is causing the spikes.

[225ttroadster]

i will continue to fiddle with the setup. Order the 4bar and have a go with the diode mod.

[Cincy]

no need for the 4 bar. Plus the 225 doesnt have a 1bar limp mode like the 180. A better mbc or a 4.7v diode should fix your problem. 1 boost controller is always better than 2

[myslow1]

no need for the 4 bar. Plus the 225 doesnt have a 1bar limp mode like the 180. A better mbc or a 4.7v diode should fix your problem. 1 boost controller is always better than 2

hm the ones i have are a 4.7v. that ok for a 225? or should i order some 4.3's

edit: i just looked at ur thread on af looks like i'll be fine

[Cincy]

not thinking you need anything for a 225. He may need one to fix is limp issue

[myslow1]

? huh.

[Cincy]

Plus the 225 doesnt have a 1bar limp mode like the 180.

^^

No limp, no need for a diode.

[myslow1]

^^

No limp, no need for a diode.

oh i thought you were talking to me, i was just making sure i would be ok witha 4.7v instead of a 4.3

[Cincy]

Man, this is exciting, cheap power lol...cincy, did you use stjacket's adjustable MAP? Does he sell them, or would it be easier to make one? I would actually prefer that over the diode, since its "temporary."

Present on its way, should be there tomarrow or thurs ;)

[l88m22vette]

:clap: :clap: thanks!

[Irish*TT*]

Could someone put some pix of all this stuff. The diode and where it goes. Please and thanks!

[Cincy]

If you locate your map on the intercooler (passenger side for 180 cross by the TB and down under the headlight, drivers for 225) there will be a plastic wire loom with 3 wires in it. You strip back the wires and attach the diode like this

http://www.anthonydanna.com/vw/diodemod/noswitchdiodediy.gif

[225ttroadster]

not thinking you need anything for a 225. He may need one to fix is limp issue

ok.. how does the DIODE trick the MAP? Just as a boost controller would? Let the ECU see lower voltages then the map is actually trying give back?

I guess I am lost. Is it worth doing on a 225? As long as someone (cincy, preferably) can tell me that the factory pump and FPR are up to the task and I will not risk going too lean or advanced at those levels without at least some sort of piggy back correction, I would be interested in trying this. I want to see chipped levels of boost (18-20psi) safely without the $500+. That is the object here right? Now I already "spike" at 20-21psi but I taper back down to 16-17 psi. As I stated before. I am aiming for holding or tapering down to the 18-20 psi range (for now/temp.) untill the extra bread for REVO (I think so far) comes along.

PS: I want to MOD this place! and When are we going to get a MIDWEST EURO meet together Vette?

PSS: Vette: we are always doing random shit and/or having parties/ meets/ events etc... mwir.net You should join.. I could use the TT support lol...

[Cincy]

The diode limits the voltage the diode lets past. So a 4.3v will limit the voltage to that passes it to 4.3v which is ~11psi to the ecu (4.7v ~17psi, 5v ~22psi 5v is the limit of the map).

It puts the same tax on the system as a chip, so everything is up to the task no problem. If you are already hitting 20psi, you either are already chipped or raised the psi yourself so you already should know

[225ttroadster]

yea but I am spiking up there... and I use the boost controller to allow it to spike up there. I have heard of chipped guys that spike around 26psi and taper to about 20. I am really not looking to spike that high but hold a solid 18-20psi... untill obviously 5500ish rpm.

[l88m22vette]

This is all great info, I appreciate the input guys; I got a toy off of cincy that may let me do all this w/o having to diode anything (fingers crossed)

[225ttroadster]

This is all great info, I appreciate the input guys; I got a toy off of cincy that may let me do all this w/o having to diode anything (fingers crossed)

details of said "TOY"

[Cincy]

yea but I am spiking up there... and I use the boost controller to allow it to spike up there. I have heard of chipped guys that spike around 26psi and taper to about 20. I am really not looking to spike that high but hold a solid 18-20psi... untill obviously 5500ish rpm.

Just pull the n75 out and you will hold psi as best the turbo will allow. No one should be spiking above 23psi.

details of said "TOY"

Its an adjustable map sensor made by a fellow TTer that sent it to me to try. I didnt want to alter my setup and was going to use it on my brother's car but he has a small map sensor so it was a no go. Basically it rescales the map values so it will still be the only boost controller but still increase the psi. The guy that made it is the only one using it currently. Eric should have it either tomarrow or friday and knowing him, it will be installed this weekend with an update.

[225ttroadster]

Just pull the n75 out and you will hold psi as best the turbo will allow. No one should be spiking above 23psi.



Its an adjustable map sensor made by a fellow TTer that sent it to me to try. I didnt want to alter my setup and was going to use it on my brother's car but he has a small map sensor so it was a no go. Basically it rescales the map values so it will still be the only boost controller but still increase the psi. The guy that made it is the only one using it currently. Eric should have it either tomarrow or friday and knowing him, it will be installed this weekend with an update.


Yea I like how he is quick with the updates...

The map sensor sounds basically like it has a variable resister soldered to it...

Going to rid of the N75 today... well put the Boost controller in its place at least.