mypoorLS1

iTrader: (4)

Anyone using them? Trying to decide whether I wanna stick the 98 pcm or switch to something like the FAST. Just want to hear pro's and con's

12secSS

iTrader: (30)

Depends on how far you want to go with the tuning. If it is for a street car, the stock 1998 ECM will handle most anything, using one of the two popular tuning suites. If you are going radical and/or a full race car, then the aftermarket/stand alone would be a better choice to extract the most power out of your setup.

Sean Collins

I've made 1000hp with stock PCMs. The PCM is not the issue. If you are building a typical head/cam car with injectors 60pph or less you will have no trouble. the 98 pcm however will hit the air flow/MAF input fq limit before the 99 + unit. this could be a hinderance if you are not familiar with telling the PCM lies to make it do what you want.

12secSS

iTrader: (30)

You missed my point. I know of quite a few people who have made huge power on a stock ECM, that is not the point. My point was if you need to fine tune and customize certain tables to have increased resulotion (as one example). Like making the VE (or MAF table) have 100 rpm increments on the the power range to extract even more (consistent) power, vs the stock 400 increment. The issue with the air flow limit can be overcome with either running an SD setup or using one of the custom 2-BAR setups out there (typically for boosted cars). No need to "lie" to the computer to get the fueling/timing right.

BLWN1

iTrader: (6)

So, are you asking a question, or stating what you want?

Sean Collins

I have tunned every aftermarket system out there, haltech,motec,AEM,BGS3,DFI gen 6&7&7+,Megasuqirt etc etc etc. None of those systems come close to aproaching the complexity of the 1227730 ecm in the 90 camaro outside of injector control and ignition options. you obviously haven't been around the custom calibration game long.

Secondly you can have all the 100rpm increments you want as long as there are only 16 32 in some newer box (read still not enough for fuel control with a typical 3 bar setup)of them. I would rather fix the MAF sizing issue and deal with the granulated airflow reading anyday over fighting with an aftermarket box to idle the engine properly on decel after a big tipin.

mypoorLS1

iTrader: (4)

I was just told that an aftermarket PCM would be easier to tune and get great drivability. It's not all about WOT, I want great throttle response and it has to be very smooth, that's all.

slow

iTrader: (7)

what kind of vehicle combination are you talking about.

I find it VERY hard to any competant tuner to tell you with a straight face, that you will have honest better drivability on a low 12 second combination (in your sig) with an aftermarket pcm, where you need to do ALL of the tuning yourself, vs just using a already proven factory pcm with an altered program for your modifications.

Maybe, due to the nature of my job, I look for factory pcm's for 99.9% of vehicles, but drivability is never something that I have heard improves with a stand alone on a 12 second car.

Ryan

mypoorLS1

iTrader: (4)

Won't be a low 12 second car. New shortblock is ready and am picking out heads now. Have been in lots of ls1's that have been tuned on the street and on the dyno. Most aggressive setups and tunes are not friendly to low rpm operation. Say if you were to have a 230cc intake runner and a cam that makes its power at 6700 rpm. So low rpm will suffer due to low velocity in the runners, can this be tuned out of? Just wanting to know before I put motor back in. I don't want to switch over to an SD tune. So what would I have to do with my maf tables? These are all things I am trying to get sorted out before buying anything else.

dynocar

Amen, and what box gives 100 RPM resolution and why would anything have to be tuned that fine, even if anyone was capable of it?

gametech

iTrader: (1)

The big issue with idle/driveability on a stock pcm is that most people have no understanding of the various additional tables that an aftermarket pcm won't have. If you are just learning to tune, an aftermarket pcm is much easier to control. If you really know what you are doing, all those annoying extra features in a factory pcm are actually quite beneficial. If you only look at WOT power, save the money and get a carburetor. As to the original poster's last question, don't expect a good idle trying to tune a big cam with a maf. The overlap reversion tends to screw up the airflow readings. A 230 duration shouldn't be too bad, but with a really big cam I would go SD and put a restrictor in the map sensor hose to reduce idle fluctuations, or HPtuners has an enhanced 1 bar SD setup that gives an extra table that sort of works like alpha-n for idle. My last English teacher in college would kill me for the previous run-on sentence.

mypoorLS1

iTrader: (4)

At least things are starting to make sense. I have never tuned, but know a guy who has tuned many cars, and one just getting into it trying to get drivability right. Guy that talks about aftermarket PCM's tunes on BMW race cars. It's a whole other ball game I understand but the principles should be the same.

gametech

iTrader: (1)

That is true, it is a whole other ballgame. Race cars don't need to slowly pull away from a stoplight or pass emissions. Your buddy that tunes race cars is probably doing something entirely different than what you need. The simpler aftermarket pcms are actually better for track-only cars, because when the weather conditions change you have a lot less variables to mess with.