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Discussion Starter · #1 ·
Just wondering how many psi roughly should I be pushing with the mods I have done. Mods in Sig.
 

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i've got 10 psi with 3.4, S&S headers, full 2.5" exhaust, and fenderwell. my guess for yours would be 10-12.
 

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MilzyZ34 said:
i've got 10 psi with 3.4, S&S headers, full 2.5" exhaust, and fenderwell. my guess for yours would be 10-12.

when I just had the 3.4, d/p, ubend and a fwi, I saw about 11lbs of boost. On really cold days id see about 12.


stock is around 8lbs of boost, or at least thats what ive read in most places
 

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Discussion Starter · #5 ·
Wow, then I wonder what i was actually pushing stock. I have hit 14.5 psi. Any thoughts???
 

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14.5 is really high for your mods, time to invest in some rockers or a cam and get rid of that boost stacking. Optimal effciency is around 11-12 psi with our blowers, at 14.5psi your blower is spitting out very hot air. An easy fix to that would be rockers, 1 step hotter plugs, and PEMs. You may be able to pull an extra 2-3 tenths out of the car too.
 

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Discussion Starter · #7 ·

Yeah, The next thing I will be doing is the rockers, but Im under a little setback right now. I think the timing chain tensioner either backed off or broke on me putting slack in the timing chain, now when i start it, the timing chain smacks the cover. My car is still under warranty for about 5k miles. I just have to take the Mps off. Waiting on the arrival of the backing plate. I am still fairly new to my car. I bought it about a year ago in july. so I dont exactly know what some stuff means..(Im Retarded) Like PEM'S??
 

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Well, you didn't mention that...That's why your boost is so high. Generally, slack in the chain will retard the cam, enhancing upper rpm performance. Since lower RPM's aren't opening the valves when they should be, you're boost stacking like crazy. I'd be willing to bet that just replacing your timing chain will bring your boost down a couple of PSI.
 

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Discussion Starter · #9 ·
I havent ran the car down the road since I heard the noise. I hit that PSI over a month ago. I dont know. I guess we will see after it is fixed.. Am I glad it is still under warranty!!! :D
 

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my GTP pushes 10-11 psi

I have a 97 GTP. My mods are Borla exhaust, SLP headers, 8.5 MSD wires, Intense PCM, 3.4" pulley, Bosch Plugs, and finderwell cold air w/ K&N. I have just recently put the boost guage in and it is about 10-11 psi, but if i put it in neutral and rev it up it goes up to about 15 psi. That's prolly not good for it.
 

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Ron Vogel said:
14.5 is really high for your mods, time to invest in some rockers or a cam and get rid of that boost stacking. Optimal effciency is around 11-12 psi with our blowers, at 14.5psi your blower is spitting out very hot air. An easy fix to that would be rockers, 1 step hotter plugs, and PEMs. You may be able to pull an extra 2-3 tenths out of the car too.
you mean one step colder????
 

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Normal for me is in the 11's but I have seen it as high as 13.6 on a cold day. From what I have read, anything more that 12'ish is a waste for the M90 SC, as they were designed to run at peak effieciency there.
 

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Discussion Starter · #15 ·
Ron Vogel said:
14.5 is really high for your mods, time to invest in some rockers or a cam and get rid of that boost stacking. Optimal effciency is around 11-12 psi with our blowers, at 14.5psi your blower is spitting out very hot air. An easy fix to that would be rockers, 1 step hotter plugs, and PEMs. You may be able to pull an extra 2-3 tenths out of the car too.


Ok. It was a spun rod bearing. not the timing chain. i still dont know why the boost was so high. anyways.. the part im retarded about is .. i dont know what PEM is. it was used a few responses ago but i dont know what it is.. Could someone tell me please.
 

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JimboGTP99 said:
Ok. It was a spun rod bearing. not the timing chain. i still dont know why the boost was so high. anyways.. the part im retarded about is .. i dont know what PEM is. it was used a few responses ago but i dont know what it is.. Could someone tell me please.
PEM's Ported Exhaust Manifolds
IMO... if You feel the need to open up the exhaust manifolds you might as well look into headers.
 

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Opening up the exhaust and intake makes a BIG difference... for reference, I have Headers, no cat, no resonator, and a VS camshaft.. 9 lbs of boost on a 3.25 :)

Many have told me to up the boost to 12 with a 3.0 or 3.1 but I like running 22 degrees of timing with no knock on 9lbs.. makes tuning easier too hehe.

Good luck :)
 

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Timing chain tensioner break fairly often sometimes with no ill effect somtimes with. I would drop a cam in it while you have the cover off.

BTW your font sucks and is terribly hard to read.
 

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Discussion Starter · #19 ·
spd98 said:
Timing chain tensioner break fairly often sometimes with no ill effect somtimes with. I would drop a cam in it while you have the cover off.

BTW your font sucks and is terribly hard to read.


It was actually a spun rod bearing. Its in the shop and still under warranty.. or yes i would def have a cam put in. But i dont think the people who I have my warranty through would allow that... know what I mean vern!
 
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