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Over limit of grams/sec?

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Old 06-13-2003, 02:27 AM
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Default Over limit of grams/sec?

Is there a way to change the limit of the computers max grams/sec for is air flow. I exceeded over that and my motor went lean. The tech II went to 553 grams then stoped while my rpms proceeded higher.

How are the guys with the turbos etc. getting these numbers with out running into these problems.
Old 06-13-2003, 12:11 PM
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Default Re: Over limit of grams/sec?

The max the pcm will go up to is 512 (actually 511.99). Turbo guys above this either trick the computer with a scalled maf and redo all table or trick it with a maf translator. Another option is just hit the limit and crank the PE tables to compensate (not the best idea, but works)

If thats not acceptable then you switch to an aftermarket pcm.

Gary
Old 06-13-2003, 12:31 PM
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Default Re: Over limit of grams/sec?

my maf scale is 100% stock for tuning and metering accuracy.. it just catches the 430g/s limit(98 car) and i pick up the fueling from there up in the pe table.. i max the 11250hz at just under 4kpm so i logg my a/f ratio and multiply in an increase to the pe table proportionally.
Old 06-13-2003, 04:16 PM
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Default Re: Over limit of grams/sec?

Our trucks gram/sec go higher then the cars for some reason. I looked on my buddies 02 ws6 prog. and it only went to 430 like you said. The trucks go to 553 and then stop. Do you guys know if there is a way to perfectly map the fuel way above the limit.
Old 06-14-2003, 07:30 PM
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Default Re: Over limit of grams/sec?

The trucks go up to 453. The stock computer can only handle numbers up to 512. 512 should be somewhere around 600flywheel horsepower.

If your just a little past that I would just redo the PE table and keep an eye on things when it gets cold out. The PE tables don't compensate for weather changes so if you tune when it's hot and then it gets cold the motor will be leaner.

If you're talking about going WAY over that limit an aftermarket computer would be the way to go like stated earlier.
Old 06-14-2003, 07:49 PM
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Default Re: Over limit of grams/sec?

Sorry, I ment 453 instead of 553. When i had my blower on my 5.3 my truck kept going over 553 at 5500 rpm. One time i even burned off a o2 sensor in a late night race with a camaro. The only reason i didnt keep the blower for this motor was because i knew it was going exceed way over the limit and at the time the guys i was talking to said that i would spend at least 4000 just on a computer setup for it. Do you guys know what type of computer lingenfelter uses on their twin turbo kits that make 700 and something hp? Oh and i believe at 453gram/sec it equals 522 hp. Thats at least what the guy at whipple said when i gave him the numbers to calculate.
Old 06-14-2003, 08:25 PM
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Default Re: Over limit of grams/sec?

Yeah, aftermarket computers are pretty damn exspensive. PSJ(site co-owner) is going to be testing out an aftermarket computer that might be alot easier on the wallet.

I believe Lingenfelter uses the stock computer with some "special" programming. Maybe you could call and see if they could help you out.

The numbers from the guy at whipple sound about right to me for a n/a motor, I know the equation to convert the numbers but, I'm not exactly sure of the conversion constant for a n/a motor. A blown motor would probably be around ~600 flywheel horsepower at that flow.

553g/sec = ALOT of power.

Hopefully in the near future we'll have a relatively inexspensive computer option but, until then you can either rig the stock computer to work or pay big bucks to go with something like a FAST unit.
Old 06-15-2003, 12:07 AM
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Default Re: Over limit of grams/sec?

Until then i just will have to do with nos. The computer cant see that. Oh well i will see what i can do with a different power adder.




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