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Discussion Starter #1
Ok I've had my turbo setup for around a year now all was running well... Well about a month ago my car started having a problem. The cars runs really good out of boost and even in boost up to 10 psi.. I have the wastegate set to 18psi.. Engine boosts hard in 1st and 2nd but then 3rd, 4th, and 5th hit a brick wall after 10psi... It like backfires really bad and loses power...

I'm sure 1st and 2nd run good cause it doesn't boost higher than 10psi (holset hx35).. I thought maybe it was spark blow out so I got new plugs and gapped them .25 to be sure.. Runs better now but still has the issue. No CEL.. I did get a new auto zone distributor recently.. I've already exchanged it twice cause I'm thinking it might be the cheap distributor??

I'm stumped I don't wanna start pouring money into it if its something simple..
 

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Discussion Starter #3
Stock map sensor. But I have it tuned to run rich in the last columns. Like I said it used to run perfect but recently started this.

I might need to see if its over boosting.. When I changed the old plugs it looked like it was running lean.
 

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the artist formerly known as drexelstudent11
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Stock map sensor. But I have it tuned to run rich in the last columns. Like I said it used to run perfect but recently started this.

I might need to see if its over boosting.. When I changed the old plugs it looked like it was running lean.
stock map sensor can read around 11psi.


get a 2.5 or 3 bar map
 

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\/Your Mom Was Here\/
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Stock map sensor. But I have it tuned to run rich in the last columns. Like I said it used to run perfect but recently started this.

I might need to see if its over boosting.. When I changed the old plugs it looked like it was running lean.
Maybe you have a boost leak now? Check the connections out and see, it's free!
 

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Maybe you have a boost leak now? Check the connections out and see, it's free!
Boost leak wont give you a backfire. Anyway, I've been pushing 12-14 Psi on my z6 setup for a year with the stock map and no issues. Only time i ever hit a 'brick wall/backfire' was with spark blow out. That was my first guess. but then again you said you changed plugs. When i changed to NGK 4644 it stopped my issue
 

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it depends on what your atmosphere pressure is. if you are high altitude then your gauge will read higher than normal while still being at the same absolute value on the map sensor.

ie you gauge pressure can be over the stock psi limit of the map

also the sensor will just go up to 5 volts at roughly 11psi and stop increasing voltage. so your computer think you are running lower boost than you actually are.

so it is completely possible for you to run over the stock psi of the map sensor. this is highly not recommended because you can not set an electronic boost cut if you get a boost spike. also it will not run as well because you have to give the same amount of fuel at 11 vs 14 ( roughly)

just get a darn better map sensor they are stupid cheap. i believe high profile sells them in you PM him ( I believe he is a site sponsor correct me if im wrong ) and he is just a great guy that does great things
 

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Discussion Starter #10
Boost leak wont give you a backfire. Anyway, I've been pushing 12-14 Psi on my z6 setup for a year with the stock map and no issues. Only time i ever hit a 'brick wall/backfire' was with spark blow out. That was my first guess. but then again you said you changed plugs. When i changed to NGK 4644 it stopped my issue
Thank you. Ive had a boost leak b4 so I know its not that..

You can run more boost than what the stock map can read. Ive been running this tune for almost 2 years no problem until now. I originally had a 2.5bsr sensor but I couldn't get the car to run with it (tuned on TurboEDIT)

Im running NGK bkr7e plugs.. Might try those plugs..

Seems like a timing issue with the way it backfires..
 

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Omni 2.5BAR plug and play, IF you ABSOLUTELY need the offset values I have them.
 

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Discussion Starter #18
I am having same problem at about 4 lbs I tried maps distributors just got new plugs oem Ngks 7 and gaped to .026 and still have it
Well let's figure this out I'm ready to go fast again lol..

My next thing I was gonna get a OEM distributor but if you've tried it I prob won't get one.

Idk I'm gonna do a lil more research. Keep me updated if you figure it out.
 

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I changed my coil and sensor in the distributor also new wires 10.2mm and while I changed my rims I noticed a boost leak I fixed it but still same problem but defiantly noticeably better. Now when I start the car it's at -24 -25ish vacuum when idling and if I don't beat on it. But when I build boost or beat on it spittle bit it starts to idle funny and the idle vacuum goes up to -20 and sounds louder idk what the fuck
 

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Above 10psi I recommend ngk 7173. Above 22, 4554.

Hiting a pressure brick wall can sometimes be caused by plug heat and gap... but usually around 12psi on a 57 trim t04e.

Start at .030 plug gap, and keep trying in -.002 incriments down to .020 to see if the problem goes away.

Having the map not sense all of your boost is a bad idea. Too much room for problems, and no ignition control past 10psi.
 
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