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max boost with 2.9 pulley?

F

fst

New member
anyone know what the max boost with headers and open exhaust are getting with a 2.9" pulley?
 


it depends on your modifications, every ones car is different. The "rule" is 1 lb of boost per size drop [if i remember correctly]. So we start with ~8Lbs of boost and a 3.8" pulley so technically a 2.9" would be around 17Lbs.

Only way to know for sure is put it on and check.
 
DnaProdigy said:
it depends on your modifications, every ones car is different. The "rule" is 1 lb of boost per size drop [if i remember correctly]. So we start with ~8Lbs of boost and a 3.8" pulley so technically a 2.9" would be around 17Lbs.
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That's a pretty vague rule that doesn't take into account that valve train and exhaust mods will help prevent boost stacking. You'll still make the same power, but at lower boost since the air can't pile up on the intake side.
 
Yea as Sabrewings pointed out the exaust mods, [your headers and 2.5" catback] lower the boost preassure. Now im curious does the ported blower reduce boost also? If i remember correctly that and the ported inlet of the LIM allow for better air flow.
 
will im running a home-ported M90 but stock LIM. i also accidentally set the DTC P0103 for outflowing my MAFF lol. i had to lower the 11 value on my afc a bit since it was saying there was more incoming air when there shouldnt be any. thus far it hasnt came back yet. also up to 90% throttle i get no KR, only a blip of less than a degree and im running ~20-21* of timing at the moment. this is all scanned and tuned though on the freeway, i havent checked on how it runs from a dig/slow roll. however im only seeing no more than 12-12.5# of boost which i kinda think is a tad low, an d i do not believe to have any sort of vac leak.
 


FST: Does that fuel pump rewire give a noticeable change, or did it when you first installed it? Looking into getting one, as I'm hoping to cure the laggy response starts on my GTP. Thanks
 
adidasdude1061 said:
FST: Does that fuel pump rewire give a noticeable change, or did it when you first installed it? Looking into getting one, as I'm hoping to cure the laggy response starts on my GTP. Thanks
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the stock/OEM wires from the fuel pump is like 22-24 gauge wire that looses its power when the pump works overtime when at full throttle, thus fuel isnt keeping up and makes the car run lean. the fuel pump rewire maintains a constant power of 12v from the battery/fuse box directly to the fuel pump when the pump's working hard. it doesnt do so much on starts IIRC.
 
You'd be suprised at how wrong that can be. The stock pump and wiring are capable of keeping up with the fuel demand of the engine. Run a fuel pressure gauge sometime and you'll see that the injectors still get plenty of fuel.
 


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