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Discussion Starter #1
Okay.. I have a really easy and quick question for you guys...

I have a 94 TT auto, anyways, tonight It was pretty cold in Southern Cali and I was WOT on my car... and the higest boost I could hit was .72bar...

The car is completely stock, besides intake, and I recently changed the original OEM plugs to NGK 6097's with like .34 gap...

Also, previous to tonight, I was hitting .80-.82 bar all the time...

So, is there any problem?

P.S. I filled up my tank .. could that have done it.. in the sense of the car beening heavier (maybe a dumb question...)
 
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Discussion Starter #2
I had that same problem with my auto before i when BPU. At WOT, boost normally reaches 0.8 bar but some times goes up to 0.9. I didn't give a shit......... Guess the car has moods......
 

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Don't forget how much external conditions, I.E. humidity & temp effect boost pressure. You'll boost slightly higher when conditions are cooler.:)
 
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Discussion Starter #4
right, thats what I thought... but I only hit like .72bar... shouldnt I have hit at LEAST .80 bar if not more ...
 
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Discussion Starter #7
also could it be one of the hoses above the spark plugs... I cracked one the other day and havent gotten a new one yet...
 
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Once i had a leak at the avc-r hose and boost ran crazy. But at least it should consistently register higher boost with all else being equal.
 
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hmm... so a boost leak before the intake manifold would show higher boost.. how is that possible???

Could a bad intake filter do it... or should I look elsewhere??/
 
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Ya, that was a dumb question. Weight would not affect it. How would it know how much weight you have in the car.
 

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a leak before the throttle body will cause less boost I don't know why a responder said it would make more that is nonsense. Yes a cracked hose near the plugs ( they are from the pcv system will cause a boost leak that is probably your source.) BTW non BPU cars do not need other than stock plugs and it questionable if bpu cars need them if they don't detonate. the 6097 is a non platnum plug and you need to change them more frequently you know. I would be careful modifying the car if you do not have a clear idea of the pros and cons of doing it and what it might cost you if break something.
 

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A leak in a hose that allows boost to escape after the turbos is going to show a lower boost reading, your turbos will also be working extra hard to reach the boost that your wastegate is set at too so leaks like this should be fixed ASAP before you trash a turbo. On th eother hand a leak in the line leading to a boost control device CAN cause boost to go higher. The boost device never sees the level of boost IT'S expecting and so doesn't open the wastegate - boost skyrockets as a result. Depending on where the leak is you can see different effects. Also, weather shouldn't effect the boost level if the level is being electronicly controlled. Bleeder valves and other mechanical devices raise boost via controlled leaks - these kinds of controllers CAN see varying levels of boost due to weather and probably altitude changes - that's their downside. Cost is their upside :)

I'd echo what was said previously about monkeying around under the hood if you're not completely sure about what's going on. The Supra motor is built pretty tough but if you do something to run it lean it will act like any other engine and make expensive noises. Cracked hoses aren't something to be ignored if you can help it - get a replacement ASAP as I'm sure it's cheaper than toasting a piston. On some cars a cracked hose is all it takes to risk making VERY expensive noises (*coughrx7cough*).
 
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