ms4z28

can anyone explain to me why a stock 98 computer will not work over a certain amout of boost and how much boost can you make on it without taking out the maf

CamaroSS19

iTrader: (24)

I want to know too

But my guess is that you cant get operating software to work with a 3 bar map sensor . Just as you cant get real time tunning

I am going ot use a MAF sensor on my build . Also is there any limitation to a maf system on a 98 ?

firefighting1101

iTrader: (48)

im sort of in the same boat...can i use my 98 pcm for a very thorough nitrous tune? although i will be going speed density...

kwiksilverz28

iTrader: (7)

No idea. I made 5.25# and 458hp with P1SC and 98 computer.

9t8z28

iTrader: (19)

I am getting a tune right now. I have a 98 pcm and am pushing 8#

Sideways240sx

iTrader: (22)

98's in the past couldn't work with 3 bar map sensor. So 14.7 psi was the max. Ever. But there are more issues. In the past there was no os for a speed density tune, so all we had was maf tunes. But a maf cant really measure the amount of air for over 500hp give or take...

With a ls1 14.7 psi should get you well over the 500 hp mark which was the issue in the past. Most people will do a 99-02 pcm swap, or a bs3. Either of which you can use a 3 bar map and run more boost.

I have yet to see anyone do it but i talked to hp tuners, and they told me they now have a speed density os for 98's and i think... think i could be wrong that with there new os you can run a 3 bar map.

Again im not a tuner, just know a little bit about it, and i have a turbo 98 so figured id chime in.

The 98's dont have some of the options the newer pcm's have for tuning as well, which makes it a little harder. Lastly i believe the knock sensor's on the 98's are more prone to sensing false knock for some reason and they love to pull timing, so sensitivity almost has to be turned way down for the car to hold any type of timing.

If i wrong on anything sorry, and please correct me.

Chris

needadvice

Is the 99-02 PCM's direct replacements, or is there a bunch of other things that need to be done to make them work?

Sideways240sx

iTrader: (22)

Not an easy swap. I dont know all the details, but i think you also need a cluster out of a 99-02 car and need to repin/wire some stuff. Ive heard it can get pricey with all the little stuff you need.

I have never looked into all what is needed for doing it, but i know it can be done.


Chris

needadvice

So for someone like me who has a 1998 PCM and plans to run a 28psi single turbo set-up, can I just keep the 1998 PCM and buy the BS3 and I'm all set?

SS4Matt

iTrader: (4)

not only do '98 PCM's suck at boost, they suck *** at trying to get to idle with big cams, for whatever reason they are a pain!...my car isn't wired yet, but the BS3 i have will be "piggy backed" to the stock PCM. all my stocker will be in there for is to run the gauges really. i cheaped out on buying a racepack dash so the stock cluster will have to do with a pilar pod :-/

Photochop

iTrader: (74)

After talking to a local tuner, I was in the same boat you're in ms4. I was told the stock MAF will support 13.5-14 lbs of boost (this being the upper threshold of the MAF sensor). The 98 PCM will support a 2 bar tune, not a 3 bar. So you'll have to get a 2 bar map sensor from a cobalt or something similar. I decided to go ahead and go for a speed density tune. It will be better tuned for part throttle, and the boost will come in smoother and the car will likely make more power across the board. I'm having my local tuner tune the car in SD and they'll use HP tuners to do so. With a good kit, 14.7 lbs of boost is a lot. Should be good for at least 650 rwhp (probably 700+). My idea was this now, and eventually once I go th400 and 9" or 12 bolt get a 3 bar sensor, 99+ pcm, (cluster if needed), better heads, and have the car retuned with a lil more boost. But this will be a couple years at least down the line. I'm starting with only 8 lbs and building up to 14 to get used to it, etc

CamaroSS19

iTrader: (24)

How much dose the BS3 cost . I was told by a good tunner that if you get an upgraded maf like the Slp or LPE one that it will incress you power potrential

Frost

iTrader: (45)

yeah right, it's more like 6-7 psi; the MAF is more limited on 98s than the later models...

slow

iTrader: (7)

right limited to 11250 hz, but still the same 512 g/sec limitation.

I have heard of a maf that will support more power, and I am looking to get one for testing. My goal is to put a 98 pcm back in my car, tune it maf, and support more than 500 rwhp with it.

Ryan

Photochop

iTrader: (74)

Don't even bother with it and go speed density

needadvice

If you go SD tune and want to run 28psi, then can the 98 PCM be used, or do you still need the BS3?

Frost

iTrader: (45)

For the money involved at that level, if you have to ask that question...





RYAN - What do you intend to do to get around the internal airflow limit in g? I suppose you could halve the rest of the tables, or scale by some %. If you go that route, and intermediate handler to scale back MAF freq would do what you want and you could likely build it yourself.

stevied916

iTrader: (30)

It's not that hard. All you have to do is repin the pcm harnesses. There are only 4 wires that stay in the same location. You just flash in the fuel segment from a 02 express van from to get the fuel gauge to work and you loose your traction control.

slow

iTrader: (7)

I am going to scale the airflow values by a factor or .6 or so, to get around the 512 g/sec limitation.

I have a lead on a maf that will double the output of the stock 85mm truck maf, that should support power into the 700 hp range.

Ryan

Elcaballoloco

iTrader: (3)

care to share what maf that would be?