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Discussion Starter #1
How much boost in each gear? I remember reading it before, but can't find it after about 20 minutes of searching.
 

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I believe 1st and 2nd are limited to 5-9lbs and 3rd-5th is 15lbs. Can I ask Why? All gauges are gonna be a little off from the next, so it's pretty hard to get an exact reading, unless you were using a digital boost gauge. If your interested in a gauge PM me. I have a Autometer and and off brand one that I'm not using, they both work just fine.
 

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Discussion Starter #4
WaSaabiPSI said:
I believe 1st and 2nd are limited to 5-9lbs and 3rd-5th is 15lbs. Can I ask Why? All gauges are gonna be a little off from the next, so it's pretty hard to get an exact reading, unless you were using a digital boost gauge. If your interested in a gauge PM me. I have a Autometer and and off brand one that I'm not using, they both work just fine.
No, I heard that boost is limited in each gear until 4th gear. Like 8psi 1st, 10 psi 2nd, etc.
 

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yea boost is limited in all gears. if it wasn't you would be instantly bosting 20lbs like you would if you disconnected the wastegate boost line. I thought you meant limited as below the max boost your car runs on a stock ecu. So why are you wondering?
 

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there are plenty of upgrade packages out there that claim gains to 230-250hp or so and only use a retuned ecu and bolt-ons like exhaust, etc. which normally wouldn't yield such gains, so the majority of the power is from tuning the ecu to allow more boost and/or more aggressive timing.

to answer your question, yes, it is possible to retune for more boost and use the stock apc system. but imo i think it would be more worthwhile to get a mbc and save yourself several hundred $$$.
 

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These numbers will all be higher as altitude increases because the Saab T5 ECU boost to a set manifold ABSOLUTE pressure, and "boost" is a relative overpressure vs. ambient. So someone living in the mountains might see much more PSI than this, but to convert, all you need is an altitude converter, and just ADD the amount of pressure "lost" at altitude to these figures: http://www.2-stroke-porting.com/altiden.htm

EG, at 5,000, add 2.47 psi of boost to these figures.


NG900 stock, manual
:


NG900 stock, automatic:


1999 9-3 SE, T5 only, NOT T7:
 

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i cant get use an MBC on my car as I have T7 managment system, I do run an SMBC though and it does pretty good. I will say though that I currently have all the hardware of a stg 4 Nordic and all I need is the tune. I do have a hard time agreeing with your argument about how opening up the exhaust/ intake doesn't give you much power, doing the bolt ons themself made my car an entirely different creature, with the tune It will be even more of a difference. by the way, the stg. 4 will yield 305 hp, just a heads up.

But thank you for your input anyways.
 

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Adrian - why is the boost on the B204 Auto temperature dependent? Is the ecu programmed to do that, only on the auto transmission??
 

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my boost with an mbc can go to 15 psi in any gear

but, at wot from a stop it will go
15
15
10ish
6-7
6-7

so it will bog down a bit if im trying to push it from a stop, but im guessing with a large intercooler i would be able to hold 15 through out the gears

but if im just driving causaly at highway speed, and floor it it will reach max boost
 

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PMI said:
Adrian - why is the boost on the B204 Auto temperature dependent? Is the ecu programmed to do that, only on the auto transmission??
It's to limit power. When it's cold, the air is very dense and the car will make too much power for the autobox to reliably handle. With T7, they limited boost to air-mass/combustion, so you automatically get less boost when the air is colder.

The autobox on the NG900 is especially weak.
 

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Adrian W said:
It's to limit power. When it's cold, the air is very dense and the car will make too much power for the autobox...
I've seen the graphs before, just never took a close look at the auto trans graph. So if I read this correctly, with the auto transmission, the boost is not just lower, but temperature limited, but with the manual, it is not... (?)
 

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that doesnt make sense how could a HOT 9-3 put out less psi than the ng900 and yet still have more hp the engines are not that dramatically different
 

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the 1999 se still used the same t25 turbo as the ng900 with a different waste gate
does the waste gate change flow?
 

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In 1999 the se HOT model i believe had a t25 with a differnent wastegate

The turbo for the HOT 93s after that year are td04s
 

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lowbudgethero said:
In 1999 the se HOT model i believe had a t25 with a differnent wastegate

The turbo for the HOT 93s after that year are td04s
It might be more than a different wastegate. It could have a whole different exhaust housing, like a higher flow one or something. All I know is the whole turbo is listed different in the EPC ... not JUST the wastegate.

It might be listed differently only because of the wastegate, but I kinda have a hunch that there's more to it than just that. I guess you never know for sure though. :)
 
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