2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

Q about boost

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Old Dec 2, 2004 | 11:35 AM
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Q about boost

I have an 87 t2 and it has a cone filter, magnecor wires and boost gauge installed. other than that the driveline is completely stock oh it has a hole in one of the exhaust pipes from corrosion( have a turbo back exhaust on the way). I just got it a few weeks ago. Anyways after hooking up a boost gauge the car is hitting around 9 psi and it doesnt cut fuel unless I hit 7500 rpms and then the fuel is cut but there is no warning light or buzzer at 7k. It just cuts out at 7500. Is this normal everyone else I hear is not limited(although you should not go above 75oo anyways) and the ones that experience fuel cut seem to say it hits at a certain boost level but Mine just cuts in at the same rpm everytime no matter what gear. Also I have a mbc but it is not hooked up yet. DOes anyone have pics of the lines that should be tapped and which should be t-ed or blocked off if applicable. Thank you
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Old Dec 2, 2004 | 12:22 PM
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9psi? with just an filter... i don't know how your getting that. i'm running intake and cat back and still can't boost more than .4 bar = 5-6psi
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Old Dec 2, 2004 | 12:32 PM
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I don't think you are hitting fuel cut...I think you are leaning out.

-Joe
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Old Dec 2, 2004 | 01:08 PM
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You are in risky territory on the stock fuel system.
Many have been there & cracked an apex seal (including me).
The first cold morning after I gutted the cats - pingety ping in 3rd. I assumed fuel cut, but no such luck.

Turbos love that cold air - just a bit too much..

Last edited by SureShot; Dec 2, 2004 at 01:10 PM.
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Old Dec 2, 2004 | 02:11 PM
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Well then that really sucks because I have a full turbo back exhaust on the way. I just dont understand how its hitting 9 psi. I just boght the gauge and its brand new. Its also been really cold here this week. Ill def lay off the gas pedal. You probably saw in the other thread Im planning on adding a walbro and safc very very soon. Do you think Ill be ok with the stock injectors for a while as long as I dont hook up the boost controller I have laying around??? man things are so much easier on the evo I went from 18 to 24 psi without changing a thing besides intake exhaust and boost controller. I have to be much more careful with this beast. I dont want to rebuild the motor yet
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Old Dec 2, 2004 | 03:47 PM
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With an S-AFC and an FD fuel pump with stock injectors, I have to dial up to +30% at 4K.
That makes the air flow signal to the ECU go nearly to zero at ~5K so you get a brief check light - but it works.
This is with 11PSI boost.

I can't go more without bigger secondary injectors & a FMIC.
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Old Dec 3, 2004 | 09:53 AM
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Ok well Im, installing the exhaust this weekend and I guess Ill watch the gauge and make sure it doesnt go any higher and if it does ill have to drive it nicely till I get an safc and a walbro at least. When upgrading injectors should i go with just bigger secondaries or should all four be upgraded??
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Old Dec 3, 2004 | 01:18 PM
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D/P

Last edited by SureShot; Dec 3, 2004 at 01:21 PM.
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Old Dec 3, 2004 | 01:20 PM
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Originally Posted by bigturbo
When upgrading injectors should i go with just bigger secondaries or should all four be upgraded??
That's a close call.
Most just up the secondarys for max power, however if your turbo spools up at 3K & you go WOT in 3rd at 3500 the primarys may max out before the secondaries come in.
My current turbo is from a J-spec automatic & it spools faster the the origonal turbo which didn't fully light until 4K.

My budget only allows me to dream about a freestanding ECU, which would make the above a non-issue.
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Old Dec 3, 2004 | 04:18 PM
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lol same here man. I wont be able to get a standalone for a while and dont plan on doing it until I upgrade the turbo in a year or so
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Old Dec 6, 2004 | 10:28 AM
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well my wife and I installed a full 3 inch turbo back exhaust this weekend and now the car is hitting 12 psi. I have not given wot or high rpms. I dont plan on it but now i wonder if maybe my boost gauge is off because I dont have an fcd yet(getting one for christmas probably) So at 12 psi wouldnt I hit fuel cut without an fcd?????
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Old Dec 6, 2004 | 11:24 AM
  #12  
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Yah sounds like ur boost gauge is a pos, you should have hit fuel cut like 4psi ago.
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Old Dec 6, 2004 | 12:51 PM
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also since you just installed a 3'' complete exhaust dont you usually get boost creep you should port your wastegate if needed or else you can blow your engine also you should get a new boost gauge id suggest the defi d gauge boost gauge they have great uality gauges that look great and are top of the line made but are expensive but well worth it i have one
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