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Are 98 PCMs going to make a difference?

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Old Sep 24, 2005 | 08:06 AM
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Default Are 98 PCMs going to make a difference?

Is it a "bad" thing that the 98 PCM is different and "slower" than those in the 99+? I mean, does it effect the performance or anything at all even after a tune?

I should know this by now, but I've always tried to avoid 98 stuff, especially since I've had an 01 and 00. Now a great deal has come up on a 98 and I don't think I want to pass on it. I'm just afraid that once I start heavily modding it (heads/cam or entire motor) that I might be burdened (slower) mod for mod by the 98 PCM compared to the 99+.
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Old Sep 24, 2005 | 10:15 AM
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the only thing is the support. the tuning is just as good. you use the secondary ve when in sd unlike 01, 02 cars. other than that a good tuner can do the same stuff to a 98 as a 99+. as long as there is no crazy boost and need a 2bar or 3bar setup also.
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Old Sep 24, 2005 | 10:18 AM
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the "name not mentioned in the FI section" did close to 800 rwhp with a turbo 98 formula, so I am not too worried about tuning a 98 pcm.

SD is not the right way to tune imho under boost, as boost is just a measure of ristriction, not of airflow. There is a reason gm put both a maf and a map sensor on our vehicles, they could have saved a lot just installing one

Ryan
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Old Sep 24, 2005 | 10:21 AM
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Originally Posted by slow
the "name not mentioned in the FI section" did close to 800 rwhp with a turbo 98 formula, so I am not too worried about tuning a 98 pcm.

SD is not the right way to tune imho under boost, as boost is just a measure of ristriction, not of airflow. There is a reason gm put both a maf and a map sensor on our vehicles, they could have saved a lot just installing one

Ryan

If boost implies a pressure differential why wouldnt the map sensor be the best sensor to mesure something like that
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Old Sep 24, 2005 | 10:26 AM
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Fueling is based on the amount of air going through the motor

500 grams a second through a stock motor at 9 pounds, or through a heads/cam motor at 4 pounds of boost, both need the same fuel, but the boost level will obviously be lower through a motor with betters heads/cam.

Your right, a map sensor is the best sensor to measure a pressure differential, but a boost number does not give the accurate amount of airflow to determine fueling correctly, imho, for a car that will see varying altitude, air density, temperature, and humidity.

Ryan
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Old Sep 24, 2005 | 10:35 AM
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Well, I never plan on running any sort of forced induction, or even nitrous. I'm going to go cam only for awhile and then heads, and then a stroker in the future. I just want to make sure I can take advantage of everything that 99-02 cars can take advantage of.

FWIW, I'm looking at Rapid or East Side for my tuning.
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Old Sep 24, 2005 | 10:45 AM
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i dont think hptuners has the 2-3 bar set up for the 98's yet

98 maf scale stops at 11,250 as opposed to 12k so it can't calculate the fuel for as much air and you have to lie to it in the PE table.. this works on a dyno (like posted above guy) but not on the street.. and the tune will always be not just right unless you are always driving around at the climate the dyno was in.
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Old Sep 24, 2005 | 10:47 AM
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So optimally, I should just pass on the 98?
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Old Sep 24, 2005 | 10:58 AM
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I'm doing OK with a 98 PCM (~14psi), I wouldnt pass up a nice car because of the 98 PCM.

I still have the 98 PCM, 98 heads, 98 block, 98 rods, 98 rocker arms etc, all the '98 junk' stuff and it still seems to work OK
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Old Sep 24, 2005 | 11:19 AM
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Originally Posted by DMNSPD
So optimally, I should just pass on the 98?
if your ultimate goal with your car is somewhere between 430 and 511.99 grams per second of air then a 99+ would better suit you. past that it doesnt matter so much

the g/s number is roughly equivalent to rwhp
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Old Sep 24, 2005 | 11:23 AM
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get the 98. there are many of us out there. no problems. we have the bigger injectors also. if its a nice car do it. by the time you get all the HP you will have there will most likely be a 1 bar enhanced setup from hptuners out. just get the car.
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Old Sep 24, 2005 | 11:25 AM
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If I buy another Fbody it will be a 99+ just because of the lack of support for the 98 PCMs.

John
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Old Sep 24, 2005 | 09:19 PM
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Spring goals will be 400rwhp. The following year I hope for 450-500rwhp. I have no idea how that relates to "air support", but from the feeling I'm getting, I should just find myself a 99-02. There are plenty of them out there that will be just as nice - by then I might just say **** it and get a Z06
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