I have a question about this modification. What is the reason for the diode install? Since this car is MAF the additional boost and increased air flow will result in the computer changing the injector pulse width to accomodate and add extra fuel, so why is the diode needed? These cars are new to me, but having built a number of nitrous/supercharged mustangs and other vehicles with MAF, I have never had to do this, including cars making well over 500 RWHP. Does the diode lower the voltage feed back to the ECU to keep the MAP voltage within factory range to prevent the computer from "Freaking out" due to the additional boost pressure and sending the computer into safe mode or something? I appreciate the info, thanks guys.
I have a question about this modification. What is the reason for the diode install? Since this car is MAF the additional boost and increased air flow will result in the computer changing the injector pulse width to accomodate and add extra fuel, so why is the diode needed? These cars are new to me, but having built a number of nitrous/supercharged mustangs and other vehicles with MAF, I have never had to do this, including cars making well over 500 RWHP. Does the diode lower the voltage feed back to the ECU to keep the MAP voltage within factory range to prevent the computer from "Freaking out" due to the additional boost pressure and sending the computer into safe mode or something? I appreciate the info, thanks guys.
you just answered your own question there buddy
< Message edited by sean1.8t -- 8/1/2007 7:27:37 PM >
So what effect does the diode have on the rest of the fuel curve if the voltage is lower than the ECU is programmed for? Seems like from 0-9 psi, the factory range, this would lean out the A/F ratio. Have you dyno'd this and recorded A/F ratios at all RPM/Boost ranges? I am not questioning your knowlege or that this works, it seems you have done it to enough cars to prove that it does, I am just wondering if some other tweaking would help increase this modification. I just found a link that showed the AFR and boost levels. Does anyone have a baseline run with the same recorded data? I'm not sure what the factory spec would look like, but considering 14.7 is ideal and many tuners err on the side of caution and run in the 15's on higher boost applications, the modified sheet looks like trouble in the making. You said that you don't know anyone that has ever had a problem after doing this? Is this sheet with a stock FPR? I wonder if that is the culprit? Have you ever pulled the head off a car that ran this for some time? Do you run a colder plug in these cars with the additional boost?
< Message edited by jony51999 -- 8/4/2007 8:53:21 PM >
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the increase in the maf g/s or airflow increases fuel and keeps the a/f in check. The ecu can add/subtract fuel within certain limits, thats why you are limited in boost unlike a chip.
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FACTS > followers 197whp and 292wtq with no chip on stock ic, airbox and catback AEG crank +Scat rods + 83mm Wiseco pistons = CincyTT Version 2.0T For sale - 20mm wrist pin pistons and rods $175 + sh
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You edited the post and added like 15 ?'s. You asked so many ?'s that all of your thoughts are now way to scattered.
Fuel is fine. For a turbo car you want ~12-12.5:1 a/f for the most power and lower for extra safty. Colder plug can be used when raising boost but lower the gap to .028 is deffinatly needed.
Those are about all i get in your random posted thoughts/questions
< Message edited by cincyTT -- 8/4/2007 9:35:02 PM >
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FACTS > followers 197whp and 292wtq with no chip on stock ic, airbox and catback AEG crank +Scat rods + 83mm Wiseco pistons = CincyTT Version 2.0T For sale - 20mm wrist pin pistons and rods $175 + sh
I found the link for the cyno sheets and a lot of questions came up. Sorry about the typo, I meant 13 for the A/F. Regarding the dyno run, is that with the stock FPR? I am wondering because I have seen this on Mustangs with cheap or stock regulators. The FPR will start to flutter under the higher boost pressure which will caused that erratic reading. Once a better aftermarket one is installed, this was fixed. How about the stock fuel pump and lines? What Hp are these good up to? What size are the feed lines?
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Joined: 12/14/2006 From: No longer Ohio Status: offline
The TT is a stock 3bar of fuel pressure with larger injectors and the a4 is a 4bar with smaller injectors. If you are talking about the dyno in the TT thread, he was using a 4bar instead of his stock 3bar which is a factory bosch replacement. Fuel pump is good until you get in the 300whp range and not sure what the stock fuel lines are, but they can handle 500whp range.
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FACTS > followers 197whp and 292wtq with no chip on stock ic, airbox and catback AEG crank +Scat rods + 83mm Wiseco pistons = CincyTT Version 2.0T For sale - 20mm wrist pin pistons and rods $175 + sh
I can make pigs fly Posts: 14882
Joined: 12/14/2006 From: No longer Ohio Status: offline
you can turn the boost to 14psi, but anything over that would set you back into limp. You shouldnt have any spiking issues if your using a ebc
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FACTS > followers 197whp and 292wtq with no chip on stock ic, airbox and catback AEG crank +Scat rods + 83mm Wiseco pistons = CincyTT Version 2.0T For sale - 20mm wrist pin pistons and rods $175 + sh
I can make pigs fly Posts: 14882
Joined: 12/14/2006 From: No longer Ohio Status: offline
nope
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FACTS > followers 197whp and 292wtq with no chip on stock ic, airbox and catback AEG crank +Scat rods + 83mm Wiseco pistons = CincyTT Version 2.0T For sale - 20mm wrist pin pistons and rods $175 + sh
Well im planning on doing this mod once i get a refund check back fro my school. BUT, as always i have a few questions first. It is my understnading that on my B6 i have a 4 bar AFR, with small injectors; meaning the computer can compensate (sp) for the added air and the needed fuel. Is this true???
Second, it is also my understanding that i dont want to run the N75 along with the MBC. I saw a write up where the MBC was directly replaced with the n75, is this a good way to do it, it looked simple enough?
Third, i know that i will need a boost guage and DV along with this mod, so wheres the cheapest place to find either? esp. the guage?
Lastly, i am a little confused as to what the max safe boost level is, i have heard under 14psi, and i have also heard anything under 20psi is fine, whats the real max?? If i had to guess i would say 14-16psi, this is where i plan to run it everyday to stay at a good lower level, or as close as i can.
barrett
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2003 A4 1.8TQ 1997 Chevy K1500 5.7 stroked to 383 fully built R.I.P. 2006 Acura TSX 6MT (Not Really)
I can make pigs fly Posts: 14882
Joined: 12/14/2006 From: No longer Ohio Status: offline
Well im planning on doing this mod once i get a refund check back fro my school. BUT, as always i have a few questions first. It is my understnading that on my B6 i have a 4 bar AFR, with small injectors; meaning the computer can compensate (sp) for the added air and the needed fuel. Is this true???
All a4's have 4bars and smaller injectors and you FPR, not AFR. Yes the ecu will be able to compensate fuel
Second, it is also my understanding that i dont want to run the N75 along with the MBC. I saw a write up where the MBC was directly replaced with the n75, is this a good way to do it, it looked simple enough?
It can be run like that (i prefer it) but it depends on the mbc you choose
Third, i know that i will need a boost guage and DV along with this mod, so wheres the cheapest place to find either? esp. the guage?
You can just get a VDO gauge and 710n from ecstuning.com for about $100 shipped for both.
Lastly, i am a little confused as to what the max safe boost level is, i have heard under 14psi, and i have also heard anything under 20psi is fine, whats the real max?? If i had to guess i would say 14-16psi, this is where i plan to run it everyday to stay at a good lower level, or as close as i can.
without a chip or diode 14psi diode 16-18psi chip 20-22psi (can do more but diminshing returns)
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FACTS > followers 197whp and 292wtq with no chip on stock ic, airbox and catback AEG crank +Scat rods + 83mm Wiseco pistons = CincyTT Version 2.0T For sale - 20mm wrist pin pistons and rods $175 + sh
That was an amazing responce, exaclty what i was looking for. If yuou dont mind me asking, what type of MBC can be used as a direct replacement with the n57? this is how i would like it set up.
barrett
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2003 A4 1.8TQ 1997 Chevy K1500 5.7 stroked to 383 fully built R.I.P. 2006 Acura TSX 6MT (Not Really)
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I use a turboXS hpbc. it has both a bleed and ball&spring on it so i can have fast response (ball and spring) and smooth power delivery (bleed).
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FACTS > followers 197whp and 292wtq with no chip on stock ic, airbox and catback AEG crank +Scat rods + 83mm Wiseco pistons = CincyTT Version 2.0T For sale - 20mm wrist pin pistons and rods $175 + sh
sounds like thats what im going for. are there any different brands of this type MBC that cost less? and before i buy, is a 710?N a solid DV to run? i need no problems with this.
barrett
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2003 A4 1.8TQ 1997 Chevy K1500 5.7 stroked to 383 fully built R.I.P. 2006 Acura TSX 6MT (Not Really)
A 710n is a good dv, but it still is a stock dv and has held good numbers and failed on far less. You will get mixed reviews about this. But it holds a 225's boost just fine and that is about what you will be making with a few more mods
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FACTS > followers 197whp and 292wtq with no chip on stock ic, airbox and catback AEG crank +Scat rods + 83mm Wiseco pistons = CincyTT Version 2.0T For sale - 20mm wrist pin pistons and rods $175 + sh
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Joined: 7/17/2007 From: San Diego, CA Status: offline
Just didn't want to lose this thread. Plan on doing this during the week. Just installed my 710N, freakin' one clamp was so hard to get off...Been following this method through the TT section and the other forums. I just got my car recently, did all the belts and most maintanence. Had them throw on the snub mount during the install ( Feels a little more solid now). Just got done installing my Self Powered Sub and my DV in the same day. Now Im amped to keep working on the 'project'. I <3 my audi, just want it to grow some more balls.
Just wondering if I have to solder the diode on, I haven't seen the diode yet so maybe I'll get it then but...Can I just connect it some other less perminient way?
And was wondering if anyone in San Diego see's this post and has a vagcom if they could help me out while i do this so I can monitor my afr.
00' A4 1.8T Manual 75k mi. Apr Snub Mount 710N DV Inifinity Basslink ontop of crap Symphony II (Sounds sooo much better)
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Joined: 12/14/2006 From: No longer Ohio Status: offline
Soldering isnt perminate, just taking the iron back to the wire will remelt the lead and you can remove it...... takes 2 seconds. You can try wrapping it around the wire, but that worries me personally. Plus if you need to find the link, its in my sig, just click TT or A4 for what version you want to see
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FACTS > followers 197whp and 292wtq with no chip on stock ic, airbox and catback AEG crank +Scat rods + 83mm Wiseco pistons = CincyTT Version 2.0T For sale - 20mm wrist pin pistons and rods $175 + sh
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RE: Cheap power, Diode, MBC, and Boost gauge install - 
